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[[File:Washoe chimpanzee.jpg|thumb|right|300px|'''[[Washoe (chimpanzee)|Washoe]]''', a female [[common chimpanzee]] who was the first non-human to learn to communicate using [[American Sign Language]], as part of a [[animal research|research experiment]] on [[animal language acquisition]].]]

'''Animal cognition''' is the study of the mental capacities of [[animal]]s. It has developed out of [[comparative psychology]], including the study of animal conditioning and learning, but has also been strongly influenced by research in [[ethology]], [[behavioral ecology]], and [[evolutionary psychology]]. The alternative name [[cognitive ethology]] is therefore sometimes used; much of what used to be considered under the title of ''animal intelligence'' is now thought of under this heading.<ref name ="Shettleworth">{{cite book|author=Shettleworth, S.J.|year=2010|title=Cognition, Evolution and Behavior|edition=2|publisher=Oxford Press, New York}}</ref>

Research has examined animal cognition in [[mammals]] (especially [[primate intelligence|primates]], [[Cetacean intelligence|cetaceans]], [[elephant intelligence|elephants]], [[Dog intelligence|dogs]], [[Cat intelligence|cats]], [[horse]]s,<ref name=Krueger_heinze_2008>{{cite journal|author=Krueger, K. and Heinze, J.|year=2008|title=Horse sense: social status of horses (Equus caballus) affects their likelihood of copying other horses` behavior|journal=Animal Cognition|volume=11|issue=3|pages=431–439|DOI=10.1007/s10071-007-0133-0|url=http://epub.uni-regensburg.de/19384/3/Krueger_Heinze_2007_Horse_sense.pdf}}</ref><ref name=Krueger_farmer_heinze_2008>{{cite journal|author=Krueger, K., Farmer, K. and Heinze, J.|year=2013|title=The effects of age, rank and neophobia on social learning in horses|journal=Animal Cognition|volume=|pages=|url=http://epub.uni-regensburg.de/29424/1/Krueger_2013.pdf}}</ref> [[raccoons]] and [[rodents]]), [[bird intelligence|birds]] (including [[Parrots#Intelligence and learning|parrots]], [[Corvidae#Intelligence|corvids]] and [[Pigeon intelligence|pigeons]]), [[reptiles]] ([[Monitor lizard#Intelligence|lizards]] and [[snakes]]), [[fish]] and [[invertebrates]] (including [[cephalopod intelligence|cephalopods]], [[Pain in invertebrates#Cognitive abilities|spiders]] and [[Pain in invertebrates#Cognitive abilities|insects]]).<ref name ="Shettleworth" />

== Historical background ==

{{ethology}}

=== Animal cognition from anecdote to laboratory ===

The behavior of non-human animals has captivated human imagination from antiquity, and over the centuries many writers have speculated about the animal mind, or its absence, as [[Descartes]] would have it.<ref>Descartes, R. (1649), ''Passions of the Soul''</ref> Speculation about animal intelligence gradually yielded to scientific study after [[Charles Darwin|Darwin]] placed humans and animals on a continuum, although Darwin’s largely anecdotal approach to the topic would not pass scientific muster later on.<ref>Darwin, C. 1871, ''The descent of man, and selection in relation to sex''</ref> Unsatisfied with the anecdotal method of Darwin and his protégé J. G. Romanes,<ref>Romanes, J. G. 1883, ''Animal Intelligence''</ref> [[E. L. Thorndike]] brought animal behavior into the laboratory for objective scrutiny. Thorndike’s careful observations of the escape of cats, dogs, and chicks from puzzle boxes led him to conclude that intelligent behavior may be compounded of simple associations and that inference to animal reason, insight, or consciousness is unnecessary and misleading.<ref>Thorndike, E. L. 1911, ''Animal intelligence''.</ref> At about the same time, [[I. P. Pavlov]] began his seminal studies of conditioned reflexes in dogs. Pavlov quickly abandoned attempts to infer canine mental processes; such attempts, he said, led only to disagreement and confusion. He was, however, willing to propose unseen physiological processes that might explain his observations.<ref>Pavlov, I.P. 1928, ''Lectures on conditioned reflexes''</ref>

=== The behavioristic half-century ===

The work of Thorndike, Pavlov and a little later of the outspoken behaviorist [[John B. Watson]]<ref>Watson, J. B. (1913). Psychology as the Behaviorist Views it. ''Psychological Review, 20'', 158-177</ref> set the direction of much research on animal behavior for more than half a century. During this time there was considerable progress in understanding simple associations; notably, around 1930 the differences between Thorndike's [[Operant conditioning|instrumental (or operant) conditioning]] and Pavlov's [[Classical conditioning|classical (or Pavlovian) conditioning]] were clarified, first by Miller and Kanorski, and then by [[B. F. Skinner]].<ref>Miller, S. & Konorski, J. (1928) Sur une forme particulière des reflexes conditionels. ''Comptes Rendus des Seances de la Societe de Biologie et de ses Filiales'', 99, 1155-1157</ref><ref>Skinner, B. F. (1932) ''The Behavior of Organisms''</ref> Many experiments on conditioning followed; they generated some complex theories,<ref>Hull, C. L. (1943) ''The Principles of Behavior''</ref> but they made little or no reference to intervening mental processes. Probably the most explicit dismissal of the idea that mental processes control behavior was the [[radical behaviorism]] of Skinner. This view seeks to explain behavior, including "private events" like mental images, solely by reference to the environmental contingencies impinging on the human or animal.<ref>Skinner, B. F. ''About Behaviorism'' 1976</ref>

Despite the predominantly behaviorist orientation of research before 1960, the rejection of mental processes in animals was not universal during those years. Influential exceptions included, for example, [[Wolfgang Köhler]] and his insightful chimpanzees<ref>Köhler, W. (1917) ''The Mentality of Apes''</ref> and [[Edward Tolman]] whose proposed [[cognitive map]] was a significant contribution to subsequent cognitive research in both humans and animals.<ref>Tolman, E. C. (1948) ''Cognitive maps in rats and men'' Psychological Review, 55, 189-208</ref>

=== The cognitive revolution ===

Beginning around 1960, a "[[Cognitive psychology|cognitive revolution]]" in research on humans<ref>Niesser, U. (1967) ‘’Cognitive Psychology’’</ref> gradually spurred a similar transformation of research with animals. Inference to processes not directly observable became acceptable and then commonplace. An important proponent of this shift in thinking was [[Donald O. Hebb]], who argued that "mind" is simply a name for processes in the head that control complex behavior, and that it is both necessary and possible to infer those processes from behavior.<ref>p. 3, Hebb, D. O. 1958 ‘’ A Textbook of Psychology’’</ref> Animals came to be seen as "goal seeking agents that acquire, store, retrieve, and internally process information at many levels of cognitive complexity.".<ref name="Menzel">p. 2 , Menzel, R. & Fischer, J. (2010) ‘’Animal Thinking: Contemporary Issues in Comparative Cognition’’</ref> However, it is interesting to note that many cognitive experiments with animals made, and still make, ingenious use of conditioning methods pioneered by Thorndike and Pavlov.<ref name="Wass">Wasserman & Zentall (eds) (2006) ‘’Comparative Cognition’’</ref>

The scientific status of "consciousness" in animals continues to be hotly debated. Serious consideration of conscious thought in animals has been advocated by some (e.g., [[Donald Griffin]]),<ref>Griffin, D.(1985) ‘’Animal Thinking’’</ref> but the larger research community has been notably cool to such suggestions.<ref>p.8 ff, Wasserman & Zentall (eds) (2006) ‘’Comparative Cognition’’</ref>

== Methods ==

The acceleration of research on animal cognition in the last 50 years has led to a rapid expansion in the variety of species studied and methods employed. The remarkable behavior of large-brained animals such as [[primates]] and [[cetacea]] has claimed special attention, but all sorts of mammals large and small, birds, fish, ants, bees, and others have been brought into the laboratory or observed in carefully controlled field studies. In the laboratory, animals push levers, pull strings, dig for food, swim in water mazes, or respond to images on computer screens in discrimination, [[attention]], [[memory]], and [[categorization]] experiments.<ref name="Wass"/> Careful field studies explore memory for food caches, navigation by stars,{{citation needed|date=July 2012}} communication, tool use, identification of [[Conspecificity|conspecifics]], and many other matters. Studies often focus on the behavior of animals in their natural environments and discuss the putative function of the behavior for the propagation and survival of the species. These developments reflect an increased cross-fertilization from related fields such as [[ethology]] and behavioral biology. Also, contributions from [[behavioral neuroscience]] are beginning to clarify the physiological substrate of some inferred mental process.

Several long term research projects have captured a good deal of attention. These include ape-language experiments such as the [[Washoe (chimpanzee)|Washoe]] project and [[Nim Chimpsky|project Nim]]. Other animal projects include [[Irene Pepperberg]]'s extended series of studies with the [[African Gray Parrot]] [[Alex (parrot)|Alex]], [[Louis Herman|Louis Herman's]] work with [[bottlenosed dolphin]]s, and studies of long-term memory in pigeons in which birds were shown to remember pictures for periods of several years.

Some researchers have made effective use of a [[Jean Piaget|Piagetian]] methodology, taking tasks which human children are known to master at different stages of development, and investigating which of them can be performed by particular species. Others have been inspired by concerns for [[animal welfare]] and the management of domestic species: for example [[Temple Grandin]] has harnessed her unique expertise in animal welfare and the ethical treatment of farm livestock to highlight underlying similarities between humans and other animals.<ref>Grandin, Temple (2009) ''Animals Make Us Human: Creating the Best life for Animals'' (with Catherine Johnson)</ref> From a methodological point of view, one of the main risks in this sort of work is [[anthropomorphism]], the tendency to interpret an animal's behavior in terms of human [[feeling]]s, thoughts, and motivations.<ref name="Shettleworth"/>

== Research questions ==

[[Image:Chimpanzee and stick.jpg|250px|thumb|right|The common chimpanzee can use tools. This individual is using a stick to get food.]]

Human and animal cognition have much in common, and this is reflected in the research summarized below; most of the headings found here might also appear in an article on human cognition. Of course, research in the two also differs in important respects. Notably, much research with humans either studies or involves language, and much research with animals is related directly or indirectly to behaviors important to survival in natural settings. Following are summaries of some of the major areas of research in animal cognition.

=== Perception ===

Like humans, non-human animals process information from eyes, ears, and other sensory organs to perceive the environment. Perceptual processes have been studied in many species, with results that are often similar to those in humans. Equally interesting are those perceptual processes that differ from, or go beyond those found in humans, such as [[Animal echolocation|echolocation]] in bats and dolphins, motion detection by [[Lateral line|skin receptors]] in fish, and extraordinary visual acuity, motion sensitivity and ability to see ultraviolet light in some [[Bird vision|birds]].<ref>Stebbins, W. C. & M. A. Berkley (1990) ''Comparative Perception,Vol. I, Basic Mechanisms; Vol. II, Complex Signals'' New York: Wiley.</ref>

=== Attention ===

Much of what is happening in the world at any moment is irrelevant to current behavior. [[Attention]] refers to mental processes that select relevant information, inhibit irrelevant information, and switch among these as the situation demands.<ref>Smith, E. E., and Kosslyn, S. M. (2007) "Cognitive Psychology: Mind and Brain" Pearson Prentice Hall.</ref> Often the selective process is tuned before relevant information appears; such expectation makes for rapid selection of key stimuli when they become available. A large body of research has explored the way attention and expectation affect the behavior of non-human animals, and much of this work suggests that attention operates in birds, mammals and reptiles in much the same way that it does in humans.<ref>Blough, D. S. (2006) Reaction-time explorations of visual attention, perception, and decision in pigeons. In E. A. Wasserman & T. R. Zentall (Eds) ''Comparative Cognition: Experimental Explorations of Animal Intelligence’’ pp. 89-105. New York: Oxford.</ref>

The following paragraphs contain brief accounts of several experiments. These are intended to give the reader a bit of the flavor of research on attention, but they barely scratch the surface, and readers should consult the references for descriptions of many other experiments. Also, one must interpret putative "attentional" effects with caution, because they can often be accounted for in several different ways. For example, lack of response to a current stimulus might reflect inattention, but it might also reflect lack of motivation, or result from past learning that suppresses response to that stimulus or promotes an alternative response. Most experiments include control conditions intended to exclude as many alternative interpretations as possible.

==== Selective learning ====

Animals trained to discriminate between two stimuli, say black versus white, can be said to attend to the "brightness dimension," but this says little about whether this dimension is selected in preference to others. More enlightenment comes from experiments that allow the animal to choose from several alternatives. For example, several studies have shown that performance is better on, for example, a color discrimination (e.g. blue vs green) after the animal has learned another color discrimination (e.g. red vs orange) than it is after training on a different dimension such as an X shape versus and O shape. The reverse effect happens after training on forms. Thus, the earlier learning appears to affect which dimension, color or form, the animal will attend to.<ref>N. J. Mackintosh (1983) ''Conditioning and Associative Learning’’ New York: Oxford</ref>

Other experiments have shown that after animals have learned to respond to one aspect of the environment responsiveness to other aspects is suppressed. In "blocking", for example, an animal is conditioned to respond to one stimulus ("A") by pairing that stimulus with reward or punishment. After the animal responds consistently to A, a second stimulus ("B") accompanies A on additional training trials. Later tests with the B stimulus alone elicit little response, suggesting that learning about B has been blocked by prior learning about A .<ref>Kamin, L. J. (1969) Predictability, surprise, attention, and conditioning. In Campbell and Church (eds.) ‘’Punishment and aversive behavior’’, New York: Appleton-Century-Crofts pp. 279-296</ref> This result supports the hypothesis that stimuli are neglected if they fail to provide new information. Thus, in the experiment just cited, the animal failed to attend to B because B added no information to that supplied by A. If true, this interpretation is an important insight into attentional processing, but this conclusion remains uncertain because blocking and several related phenomena can be explained by models of conditioning that do not invoke attention.<ref>Mackintosh, N. J. (1994) ‘’Animal Learning and Cognition’’ San Diego: Academic Press</ref>

==== Divided attention ====

Casual observation suggests that attention is a limited resource and is not all-or-none: the more attention is devoted to one aspect or dimension of the environment, the less is available for others.<ref>Zentall, T. R. (2004) Selective and divided attention in animals. ‘’Behavioural Processes’’ 69, 1-16</ref> In preparing a meal you may divide your attention among a number of things, but a sudden spill may distract you from a falling souffle. A number of experiments have studied this sort of thing in animals. For example, in one experiment, a tone and a light came on simultaneously. The pigeon subjects gained reward only by choosing the correct combination of the two dimensions (a high pitch together with a yellow light). The birds did fairly well at this task, presumably by dividing attention between the two dimensions. When only one of the stimulus dimensions varied, while the other was held at its rewarded value, discrimination improved on the variable stimulus, and later tests showed that discrimination had also gotten worse on the alternative stimulus dimension.<ref>Blough, D. S. (1969) Attention shifts in a maintained discrimination. ‘’[[Science (journal)|Science]]’’,166, 125-126</ref> These outcomes are consistent with the idea that attention is a limited resource that can be more or less focused among incoming stimuli.

==== Visual search and attentional priming ====

As noted above, attention functions to select information that is of special use to the animal. Visual search typically calls for this sort of selection, and search tasks have been used extensively in both humans and animals to determine the characteristics of attentional selection and the factors that control it.

Experimental research on visual search in animals was initially prompted by field observations published by Luc Tinbergen (1960).<ref>Tinbergen, L. (1960) The natural control of insects in pine woods: I. Factors influencing the intensity of predation by songbirds. ‘’Archives Néerlandasises de Zoologie’’ 13, 265-343.</ref> Tinbergen observed that birds are selective when foraging for insects. For example, he found that birds tended to catch the same type of insect repeatedly even though several types were available. Tinbergen suggested that this prey selection was caused by an attentional bias that improved detection of one type of insect while suppressing detection of others. This "attentional priming" is commonly said to result from a pretrial activation of a mental representation of the attended object, which Tinbergen called a "searching image."

Tinbergen’s field observations on priming have been supported by a number of experiments. For example, Pietrewicz and Kamil (1977, 1979)<ref>Pietrewicz, A. T. & Kamil, A. C. (1977) Visual detection of crypic prey by blue jays ‘’(Cyanocitta cristata). Science,’’ 195,580-582.</ref><ref>Pietrewicz, A. T. Kamil, A. C. (1979) Search image formation in the blue jay ‘’(Cyanocitta cristata). Science,’’ 204, 1332-1333)</ref> presented blue jays with pictures of tree trunks upon which rested either a moth of species A, a moth of species B, or no moth at all. The birds were rewarded for pecks at a picture showing a moth. Crucially, the probability with which a particular species of moth was detected was higher after repeated trials with that species (e.g. A, A, A,...) than it was after a mixture of trials (e.g. A, B, B, A, B, A, A...). These results suggest again that sequential encounters with an object can establish an attentional predisposition to see the object.

Another way to produce attentional priming in search is to provide an advance signal that is associated with the target. For example, if you hear a song sparrow you may be predisposed to detect a song sparrow in a shrub, or among other birds. A number of experiments have reproduced this effect in animal subjects.<ref>Blough, P. M. (1989). Attentional priming and visual search in pigeons. ‘’Journal of Experimental Psychology: Animal Behavior Processes,’’ 17, 292-298.</ref><ref>Kamil, A.C. & Bond, A. B. (2006) Selective attention, priming, and foraging behavior. In E. A. Wasserman and T. R. Zentall(eds) ‘’Comparative Cognition: Experimental Exploration of Animal Intelligence’’ New York: Oxford</ref>

Still other experiments have explored nature of stimulus factors that affect the speed and accuracy of visual search. For example, the time taken to find a single target increases as the number of items in the visual field increases. This rise in RT is steep if the distracters are similar to the target, less steep if they are dissimilar, and may not occur if the distracters are very different in from the target in form or color.<ref>Blough, D. S. & Blough, P. M. (1990) Reaction-time assessments of visual processes in pigeons. In M. Berkley & W. Stebbins (Eds.) ‘’Comparative perception (pp. 245-276). New York:Wiley.</ref>

=== Concepts and categories ===

Fundamental but difficult to define, the [[concept]] of "concept" was discussed for hundreds of years by philosophers before it became a focus of psychological study. Concepts enable humans and animals to organize the world into functional groups; the groups may be composed of perceptually similar objects or events, diverse things that have a common function, relationships such as same versus different, or relations among relations such as analogies.<ref name =Cats>E. E. Smith & D. L. Medin (1981) ‘’Categories and Concepts’’ Harvard Univ. Press</ref> Extensive discussions on these matters together with many references may be found in Shettleworth (2010)<ref name ="Shettleworth" /> Wasserman and Zentall (2006)<ref name="Wass"/> and in Zentall ''et al.'' (2008). The latter is freely available online<ref name = Zentall>Zentall, T. R., Wasserman, E. A., Lazareva, O. F., Thompson, R. R. K., Ratterman, M. J. (2008). Concept Learning in Animals. ‘’Comparative Cognition & Behavior Reviews’’, 3 , 13-45. Retrieved from http://psyc.queensu.ca/ccbr/index.html {{doi|10.3819/ccbr.2008.30002}}</ref>

==== Methods ====

Most work on animal concepts has been done with visual stimuli, which can easily be constructed and presented in great variety, but auditory and other stimuli have been used as well.<ref>Dooling, R. J., & Okanoya, K. (1995). Psychophysical methods for assessing perceptual categories. In G. M.Klump, R. J.Dooling, R. R.Fay, & W. C.Stebbins (Eds.),’’ Methods in Comparative Psychoacoustics’’ (pp. 307–318). Basel, Switzerland: Birkhäuser Verlag.</ref> Pigeons have been widely used, for they have excellent vision and are readily conditioned to respond to visual targets; other birds and a number of other animals have been studied as well.<ref name="Shettleworth" />

In a typical experiment, a bird or other animal confronts a computer monitor on which a large number of pictures appear one by one, and the subject gets a reward for pecking or touching a picture of a category item and no reward for non-category items. Alternatively, a subject may be offered a choice between two or more pictures. Many experiments end with the presentation of items never seen before; successful sorting of these items shows that the animal has not simply learned many specific stimulus-response associations. A related method, sometimes used to study relational concepts, is matching-to-sample. In this task an animal sees one stimulus and then chooses between two or more alternatives, one of which is the same as the first; the animal is then rewarded for choosing the matching stimulus.<ref name = "Shettleworth"/><ref name=Wass/><ref name =Zentall/>

==== Perceptual categories ====

Perceptual categorization is said to occur when a person or animal responds in a similar way to a range of stimuli that share common features. For example, a squirrel climbs a tree when it sees Rex, Shep, or Trixie, which suggests that it categorizes all three as something to avoid. This sorting of instances into groups is crucial to survival. Among other things, an animal must categorize if it is to apply learning about one object (e.g. Rex bit me) to new instances of that category (dogs may bite).<ref name = "Shettleworth"/><ref name=Wass/><ref name = Zentall/>

===== Natural categories =====

Many animals readily classify objects by perceived differences in form or color. For example, bees or pigeons quickly learn to choose any red object and reject any green object if red leads to reward and green does not. Seemingly much more difficult is an animal’s ability to categorize natural objects that vary a great deal in color and form even while belonging to the same group. In a classic study, [[Richard J. Herrnstein]] trained pigeons to respond to the presence or absence of human beings in photographs.<ref>R. J. Herrnstein (1964) ‘’Complex Visual Concept in the Pigeon’’ Science, 146, 549-551</ref> The birds readily learned to peck photos that contained partial or full views of humans and to avoid pecking photos with no human, despite great differences in the form, size, and color of both the humans displayed and in the non-human pictures. In follow-up studies, pigeons categorized other natural objects (e.g. trees) and after training they were able without reward to sort photos they had not seen before .<ref>R. J. Herrnstein (1979) ‘’Acquisition, Generalization, and Discrimination Reversal of a Natural Concept’’ J. of Experimental Psychology: Animal Behavior Processes, 5, 116-129</ref><ref>R. S. Bhatt, E. A. Wasserman, W.F.J. Reynolds, & K. S.. Knauss (1988) ‘’Conceptual behavior in pigeons: Categorization of both familiar and novel examples from four classes of natural and articifial stimuli.’’ J. of Experimental Psychology: Animal Behavior Processes, 14, 219-234</ref> Similar work has been done with natural auditory categories, for example, bird songs <ref>H-W Tu, E. Smith & R. J. Dooling, (2011). Acoustic and perceptual categories of vocal elements in the warble song of budgerigars (Melopsittacus undulates) ‘’J. of Comparative Psychology, 125, 420-430)’’</ref>

==== Functional or associative categories ====

Perceptually unrelated stimuli may come to be responded to as members of a class if they have a common use or lead to common consequences. An oft-cited study by Vaughan (1988) provides an example.<ref>W. Vaughan, Jr. (1988) Formation of equivalence sets in pigeons. ‘’Journal of Experimental Psychology: Animal Behavior Process 14, 36-42</ref> Vaughan divided a large set of unrelated pictures into two arbitrary sets, A and B. Pigeons got food for pecking at pictures in set A but not for pecks at pictures in set B. After they had learned this task fairly well, the outcome was reversed: items in set B led to food and items in set A did not. Then the outcome was reversed again, and then again, and so on. Vaughan found that after 20 or more reversals, associating reward with a few pictures in one set caused the birds to respond to the other pictures in that set without further reward, as if they were thinking "if these pictures in set A bring food, the others in set A must also bring food." That is, the birds now categorized the pictures in each set as functionally equivalent. Several other procedures have yielded similar results.<ref name = "Shettleworth"/><ref name = Zentall/>

==== Relational or abstract categories ====

When tested in a simple stimulus matching-to-sample task (described above) many animals readily learn specific item combinations, such as "touch red if the sample is red, touch green if the sample is green." But this does not demonstrate that they distinguish between "same" and "different" as general concepts. Better evidence is provided if, after training, an animal successfully makes a choice that matches a novel sample that it has never seen before. Monkeys and chimpanzees do learn to do this, as do pigeons if they are given a great deal of practice with many different stimuli. However, because the sample is presented first, successful matching might mean that the animal is simply choosing the most recently seen "familiar" item rather than the conceptually "same" item. A number of studies have attempted to distinguish these possibilities, with mixed results.<ref name = "Shettleworth"/><ref name=Zentall/>

==== Rule learning ====

The use of rules has sometimes been considered an ability restricted to humans, but a number of experiments have shown evidence of simple rule learning in primates<ref>See, e.g., D’Amato, M., & M. Columbo (1988). Representation of serial order in monkeys (‘’Cebus apella’’). ‘’Journal of Experimental Psychology: Animal Behavior Processes,’’ 14, 11-139</ref> and also in other animals. Much of the evidence has come from studies of sequence learning in which the "rule" consists of the order in which a series of events occurs. Rule use is shown if the animal learns to discriminate different orders of events and transfers this discrimination to new events arranged in the same order. For example, Murphy ''et al.'' (2008)<ref>Murphy, R. A., E. Mondragon & V. A. Murphy (2008) Rule learning by rats. ‘’Science’’, 319, 1849-1851.[http://www.cal-r.org/mondragon/home/Papers/MurphyMondragonMurphy-08.pdf]</ref> trained rats to discriminate between visual sequences. For one group ABA and BAB were rewarded, where A="bright light" and B="dim light." Other stimulus triplets were not rewarded. The rats learned the visual sequence, although both bright and dim lights were equally associated with reward. More importantly, in a second experiment with auditory stimuli, rats responded correctly to sequences of novel stimuli that were arranged in the same order as those previously learned. Similar sequence learning has been demonstrated in birds and other animals as well.<ref>Kundrey, S. M. A., B Strandell, H. Mathis & J. D. Rowan (2010) Learning of monotonic and nonmonotonic sequences in domesticated horses (‘’Equus callabus’’) and chickens (‘’Gallus domesticus’’). ‘’Learning and Motivation,’’ 14, 213-223.</ref>

=== Memory ===

The categories that have been developed to analyze [[memory|human memory]] ([[short term memory]], [[long term memory]], [[working memory]]) have been applied to the study of animal memory, and some of the phenomena characteristic of human short term memory (e.g. the [[serial position effect]]) have been detected in animals, particularly [[monkey]]s.<ref>{{cite journal |last1 = Wright |last2 = Santiago |last3 = Sands |last4 = Kendrick |last5 = Cook |year = 1985 |title = Memory processing of serial lists by pigeons, monkeys, and people |journal = Science |volume = 229 |pages = 287–289 |bibcode = 1985Sci...229..287W |first2 = Hector C. |first3 = Stephen F. |first4 = Donald F. |first5 = Robert G. |doi = 10.1126/science.9304205 |pmid = 9304205 |first1 = AA |issue = 4710 }}</ref> However most progress has been made in the analysis of [[spatial memory]]; some of this work has sought to clarify the physiological basis of spatial memory and the role of the [[hippocampus]]; other work has explored the spatial memory of [[scatter-hoarder]] animals such as [[Clark's Nutcracker]], certain [[jay]]s, [[tit (bird)|tits]] and certain [[squirrel]]s, whose ecological niches require them to remember the locations of thousands of caches,<ref name = "Shettleworth"/><ref>{{cite journal |last1 = Balda |first1 = R. |last2 = Kamil |first2 = A. C. |year = 1992 |title = Long-term spatial memory in Clark's nutcracker, ''Nucifraga columbiana'' |journal = Animal Behaviour |volume = 44 |pages = 761–769 |doi = 10.1016/S0003-3472(05)80302-1 |issue = 4 }}</ref> often following radical changes in the environment.

Memory has been widely investigated in foraging honeybees, ''Apis mellifera'', which use both transient short-term working memory that is non-feeder specific and a feeder specific

long-term reference memory.<ref name="Greggers and Menzel, (1993)">{{cite journal |last1 = Greggers |first1 = U. |last2 = Menzel |first2 = R. |year = 1993 |title = Memory dynamics and foraging strategies of honeybees |journal = [[Behavioral Ecology and Sociobiology]] |volume = 32 |pages = 17–29 |doi = 10.1007/BF00172219 }}</ref><ref name="Menzel, (1993)">{{cite journal |last1 = Menzel |first1 = R. |year = 1993 |title = Associative learning in honey-bees |journal = Apidologie |volume = 24 |pages = 157–168 |doi = 10.1051/apido:19930301 |issue = 3 }}</ref><ref name="Wustenberg et al., (1998)">Wustenberg, D., Gerber, B. and Menzel, R. (1998). Long- but not medium-term retention of olfactory memory in honeybees is impaired by actinomycin D and anisomycin. ''European Journal of Neuroscience'', '''10'''': 2742-2745</ref> Memory induced in a free-flying honeybee by a single learning trial lasts for days and, by three learning trials, for a lifetime.<ref name="Hammer and Menzel, (1995)">{{cite journal |last1 = Hammer |first1 = M. |last2 = Menzel |first2 = R. |year = 1995 |title = Learning and memory in the honeybee |journal = Journal of Neuroscience |volume = 15 |pages = 1617–1630 |pmid = 7891123 |issue = 3 Pt 1 }}</ref> Slugs, ''Limax flavus'', have a short-term memory of approximately 1 min and long-term memory of 1 month.<ref name="Yamada et al., (1992)">{{cite journal |last1 = Yamada |first1 = A. |last2 = Sekiguchi |first2 = T. |last3 = Suzuki |first3 = H. |last4 = Mizukami |first4 = A. et al. |year = 1992 |title = Behavioral analysis of internal memory states using cooling-induced retrograde anmesia in Limax flavus |journal = The Journal of Neuroscience |volume = 12 |pages = 729–735 |pmid = 1545237 |issue = 3 }}</ref>

====Methods====

As in humans, research with animals distinguishes between “working” or “short-term” memory from “reference” or long-term memory. Tests of working memory evaluate memory for events that happened in the recent past, usually within the last few seconds or minutes. Tests of reference memory evaluate memory for regularities such as “pressing a lever brings food” or “children give me peanuts.”

=====Habituation=====

{{main|Habituation}}

This is one of the simplest tests for memory spanning a short time interval. The test compares an animal’s response to a stimulus or event on one occasion to its response on a previous occasion. If the second response differs consistently from the first, the animal must have remembered something about the first, unless some other factor such as motivation, sensory sensitivity, or the test stimulus has changed.

=====Delayed response=====

Delayed response tasks are among the most useful methods used to study short-term memory in animals. Dating from research by Hunter (1913), the animal was shown a stimulus, such as a picture or a colored light, and a few seconds or minutes later the animal had to choose among alternative stimuli. In Hunter's studies, for example, a light appeared briefly in one of three goal boxes and then later the animal was allowed to choose among the boxes, finding food behind the one that had been lighted.<ref>Hunter, W. S. (1913) "The delayed reaction in animals and children" Behavior Monographs, 2</ref> Most research has been done with some variation of the "delayed matching-to-sample" task. For example, in the initial study with this task, a pigeon was presented with a flickering or steady light. Then, a few seconds later, two pecking keys were illuminated, one with a steady light and one with a flickering light. The bird got food if it pecked the key that matched the original stimulus.<ref>Blough, D. S. (1958) "Delayed matching in the pigeon", Journal of the Experimental Analysis of Behavior, 2, 151-160.</ref>

A commonly-used variation of the matching-to-sample task requires the animal to use the initial stimulus to control a later choice between different stimuli. For example, if the initial stimulus is a black circle, the animal learns to choose "red" after the delay; if it is a black square, the correct choice is "green". Ingenious variations of this method have been used to explore many aspects of memory, including forgetting due to interference and memory for multiple items.<ref name="Shettleworth"/>

=====Radial arm maze=====

{{main|Radial arm maze}}

The [[radial arm maze]] is used to test memory for spatial ___location and to determine the mental processes by which ___location is determined. In a radial maze test, an animal is placed on a small platform from which paths lead in various directions to goal boxes; the animal finds food in one or more goal boxes. Having found food in a box, the animal must return to the central platform. The maze may be used to test both reference and working memory. Suppose, for example, that over a number of sessions the same 4 arms of an 8-arm maze always lead to food. If in a later test session the animal goes to a box that has never been baited, this indicates a failure of reference memory. On the other hand, if the animal goes to a box that it has already emptied during the same test session, this indicates a failure of working memory. Various confounding factors, such as odor cues, are carefully controlled in such experiments.<ref>Shettleworth, S. J. (2010) "Cognition, Evolution, and Behavior" New York: Oxford</ref>

=====Water maze=====

{{main|Morris water navigation task}}

The [[water maze]] is used to test an animal's memory for spatial ___location and to discover how an animal is able to determine locations. Typically the maze is circular tank filled with water that has been made milky so that it is opaque. Located somewhere in the maze is small platform placed just below the surface of the water. When placed in the tank, the animal swims around until it finds and climbs up on the platform. With practice the animal finds the platform more and more quickly. Reference memory is assessed by removing the platform and observing the relative amount of time the animal spends swimming in the area where the platform had been located. Visual and other cues in and around the tank may be varied to assess the animal's reliance on landmarks and the geometric relations among them.<ref>Vorhees, C. V. & Williams, M. T. (2006) "Morris water maze: procedures for assessing spatial and related forms of learning and memory", Nature Protocols 1, - 848 - 858 Published online: 27 July 2006 {{DOI|10.1038/nprot.2006.116}}</ref>

=== Spatial cognition ===

Whether an animal ranges over a territory of measured in square kilometers or square meters, its survival typically depends on its ability to do such things as find a food source and then return to its nest. Sometimes such a task can be performed rather simply, for example by following a chemical trail. Typically, however, the animal must somehow acquire and use information about locations, directions, and distances. Following paragraphs outline some of the ways that animals do this.<ref name="Shettleworth"/><ref name="pigeon.psy.tufts.edu">[http://pigeon.psy.tufts.edu/asc/toc.htm Animal Spatial Cognition:Comparative, Neural & Computational Approaches]</ref>

*'''Beacons''' Animals often learn what their nest or other goal looks like, and if it is within sight they may simply move toward it; it is said to serve as a "beacon".

*'''Landmarks''' When an animal is unable to see its goal, it may learn the appearance of nearby objects and use these landmarks as guides. Researchers working with birds and bees have demonstrated this by moving prominent objects in the vicinity of nest sites, causing returning foragers to hunt for their nest in a new ___location.<ref name="Shettleworth"/>

*'''Dead reckoning''' [[Dead reckoning]], also known as "path integration," is the process of computing one's position by starting from a known ___location and keeping track of the distances and directions subsequently traveled. Classic experiments have shown that the desert ant keeps track of its position in this way as it wanders for many meters searching for food. Though it travels in a randomly twisted path, it heads straight home when it finds food. However, if the ant is picked up and released some meters to the east, for example, it heads for a ___location displaced by the same amount to the east of its home nest.

*'''Cognitive maps''' Some animals appear to construct a [[cognitive map]] of their surroundings, meaning that they acquire and use information that enables them to compute how far and in what direction to go to get from one ___location to another. Such a map-like representation is thought to be used, for example, when an animal goes directly from one food source to another even though its previous experience has involved only travel between each source and home.<ref name="Shettleworth"/><ref>{{cite book |author = Lund, Nick |title = Animal cognition |publisher = Psychology Press |year = 2002 |isbn = 978-0-415-25298-0 |page = 4 |url = http://books.google.com/books?id=Ti4cgStf6q8C&pg=PA4 }}</ref> Research in this area <ref name="pigeon.psy.tufts.edu"/> has also explored such topics as the use of geometric properties of the environment by rats and pigeons, and the ability of [[rat]]s to represent a spatial pattern in either [[radial arm maze]]s or [[Morris water navigation task|water mazes]]. Spatial cognition is sometimes explored in [[visual search]] experiments in which a human or animal searches the environment for a particular object.{{Citation needed|date=January 2012}}

====Long-distance navigation; homing====

{{main|Animal navigation}}

Many animals travel hundreds or thousands of miles in seasonal migrations or returns to breeding grounds. They may be guided by the sun, the stars, the polarization of light, magnetic cues, olfactory cues, winds, or a combination of these.

It has been hypothesized that animals such as apes and wolves are good at spatial cognition because this skill is necessary for survival. This ability may have eroded somewhat in dogs because humans have provided necessities such as food and shelter during some 15,000 years of domestication.<ref>{{cite journal|last=Savolainen|first=Peter|coauthors=Ya-ping Zhang, Jing Luo, Joakim Lundeberg, Thomas Leitner|title=Genetic Evidence for an East Asian Origin of Domestic Dogs|date=22 November 2002|volume=298|pages=1060–1062|url=http://www.sciencemag.org/content/298/5598/1610.full.pdf|bibcode=2002Sci...298.1610S|last2=Zhang|last3=Luo|last4=Lundeberg|last5=Leitner|journal=Science|doi=10.1126/science.1073906|issue=5598|pmid=12446907}}</ref><ref>{{cite journal|last=Fiset|first=Sylvain|author2=Vickie Plourde|title=Object Permanence in Domestic Dogs (Canis lupus familiaris) and Gray Wolves (Canis lupus)|journal=Journal of Comparative Psychology|date=29 October 2012|pages=2|doi=10.1037/a0030595}}</ref><ref>{{cite journal|last=Brauer|first=Juliane|coauthors=Juliane Kaminski, Julia Riedel, Josep Call, Michael Tomasello|title=Making Inferences About the Location of Hidden Food: Social Dog, Causal Ape|journal=Journal of Comparative Psychology|year=2006|volume=120|issue=1|pages=38–47|doi=10.1037/0735-7036.120.1.38|pmid=16551163}}</ref>

=== Timing ===

{{further|Time perception}}

==== Time of day: Circadian rhythms ====

{{main|Circadian rhythms}}

The behavior of most animals is synchronized with the earth's daily light-dark cycle. Thus, many animals are active during the day, others are active at night, still others near dawn and dusk. Though one might think that these "circadian rhythms" are controlled simply by the presence or absence of light, nearly every animal that has been studied has been shown to have a "biological clock" that yields cycles of activity even when the animal is in constant illumination or darkness.<ref name = "Shettleworth" /> Circadian rhythms are so automatic and fundamental to living things&nbsp;— they occur even in plants<ref>{{cite journal |last1 = Webb |first1 = Alex A.R. |year = 2003 |title = The physiology of circadian rhythms in plants |journal = New Phytologist |volume = 160 |pages = 281–303 |doi = 10.1046/j.1469-8137.2003.00895.x |issue = 2 }}</ref> - that they are usually discussed separately from cognitive processes, and the reader is referred to the main article ([[Circadian rhythms]]) for further information.

==== Interval timing ====

Survival often depends on an animal's ability to time intervals. For example, rufous hummingbirds feed on the nectar of flowers, and they often return to the same flower, but only after the flower had had enough time to replenish its supply of nectar. In one experiment hummingbirds fed on artificial flowers that quickly emptied of nectar but were refilled at some fixed time (e.g. twenty minutes) later. The birds learned to come back to the flowers at about the right time, learning the refill rates of up to eight separate flowers and remembering how long ago they had visited each one.<ref>{{cite journal |last1 = Henderson |first1 = et al. |year = 2006 |title = Timing in free-living rufous hummingbirds, ''Selasphorus rufus'' |journal = Current Biology |volume = 16 |pages = 512–515 |doi = 10.1016/j.cub.2006.01.054 |pmid = 16527747 |last2 = Hurly |first2 = TA |last3 = Bateson |first3 = M |last4 = Healy |first4 = SD |issue = 5 }}</ref>

The details of interval timing have been studied in a number of species. One of the most common methods is the "peak procedure". In a typical experiment, a rat in an [[operant chamber]] presses a lever for food. A light comes on, a lever-press brings a food pellet at a fixed later time, say 10 seconds, and then the light goes off. Timing is measured during occasional test trials on which no food is presented and the light stays on. On these test trials the rat presses the lever more and more until about 10 sec and then, when no food comes, gradually stops pressing. The time at which the rat presses most on these test trials is taken to be its estimate of the payoff time.

Experiments using the peak procedure and other methods have shown that animals can time short intervals quite exactly, can time more than one event at once, and can integrate time with spatial and other cues. Such tests have also been used for quantitative tests of theories of animal timing, though no one theory has yet gained unanimous agreement.<ref name="Shettleworth"/>

=== Tool and weapon use ===

{{Main|Tool use by animals}}

Because tool use is traditionally assumed to be a uniquely human trait, discussion of the cognitive underpinnings of animal tool use very often includes consideration of insight and comparisons of the overall intelligence and brain size. There is also considerable debate about what constitutes a "tool". A wide range of animals is considered to use tools including mammals, birds, fish, cephalopods and insects.

====Mammals====

Tool use has been reported many times in both wild and captive [[primate]]s, particularly the great apes. The use of tools by primates is varied and includes hunting (mammals, invertebrates, fish), collecting honey, processing food (nuts, fruits, vegetables and seeds), collecting water, weapons and shelter. Research in 2007 shows that chimpanzees in the [[Fongoli]] [[savannah]] sharpen sticks to use as [[spear]]s when hunting, considered the first evidence of systematic use of weapons in a species other than humans.<ref>[http://news.nationalgeographic.com/news/2007/02/070222-chimps-spears.html Chimps Use "Spears" to Hunt Mammals, Study Says] John Roach for National Geographic News (February 22, 2007) (accessed on June 12, 2010)</ref> Other mammals that spontaneously use tools in the wild and captive include [[elephant]]s, [[bear]]s, [[cetacean]]s, [[sea otter]]s and [[mongoose]]s.

====Birds====

Several species of birds have been recorded as using tools in the wild including Warblers, Parrots, Egyptian Vultures, Brown-headed Nuthatches, Gulls and Owls. One species examined extensively under laboratory conditions is the New Caledonian crow. One individual called “Betty”, spontaneously made a wire tool to solve a novel problem in the laboratory and attracted considerable attention. She was being tested to see whether she would select a wire hook rather than a straight wire to pull a little bucket of meat out of a well. Betty tried poking the straight wire at the meat. After a series of failures with this direct approach, she withdrew the wire and began directing it at the bottom of the well, which was secured to its base with duct tape. The wire soon became stuck, whereupon Betty pulled it sideways, bending it and unsticking it. She then inserted the hook into the well and extracted the meat. In all but one of 10 subsequent trials with only straight wire provided, she also made and used a hook in the same manner, but not before trying the straight wire first.<ref>{{cite journal|last=Hunt|first=G.R|title=Manufacture and use of hook-tools by New Caledonian crows|journal=Nature|volume=379|pages=249–251|doi=10.1038/379249a0|year=1996|issue=6562|bibcode = 1996Natur.379..249H }}</ref><ref name="psycnet">{{cite journal|last=Shettleworth|first=Sara J.|title=Do Animals Have Insight, and What Is Insight Anyway?|journal=Canadian Journal of Experimental Psychology|year=2012|volume=66|issue=4|pages=217–226|doi=10.1037/a0030674|url=http://psycnet.apa.org/journals/cep/66/4/217.pdf}}</ref> Some other species of birds, such as the [[Woodpecker Finch]] of the [[Galapagos Islands]], use particular tools as an essential part of their [[foraging]] behavior. However, these behaviors are often quite inflexible and cannot be applied effectively in new situations.

Several species of [[corvid]]s have also been trained to use tools in controlled experiments, or use bread crumbs for bait-fishing.<ref>[http://www.orenhasson.com/EN/bait-fishing.htm]{{Verify credibility|date=January 2012}}</ref>{{Verify credibility|date=January 2012}}

====Fish====

Several species of [[wrasses]] have been observed using rocks as anvils to crack [[bivalve]] (scallops, urchins and clams) shells. It was first filmed [http://scienceblog.com/48078/video-show-tool-use-by-a-fish/] in an orange-dotted tuskfish (''Choerodon anchorago'') in 2009 by Giacomo Bernardi. The fish fans sand to unearth the bivalve, takes it into its mouth, swims several metres to a rock which it uses as an anvil by smashing the mollusc apart with sideward thrashes of the head. This behaviour has been recorded in a [[blackspot tuskfish]] (''Choerodon schoenleinii'') on Australia's Great Barrier Reef, yellowhead wrasse (''[[Halichoeres garnoti]]'') in Florida and a six-bar wrasse (''[[Thalassoma hardwicke]]'') in an aquarium setting. These species are at opposite ends of the phylogenetic tree in this [[Family (biology)|family]], so this behaviour may be a deep-seated trait in all wrasses.<ref>{{cite web|url=http://bio.research.ucsc.edu/people/bernardi/Bernardi/Publications/2011Tools.pdf|title=The use of tools by wrasses (Labridae). DOI=10.1007/s00338-011-0823-6|author=Bernardi, G.|year=2011|accessdate=July 7, 2013}}</ref>

====Invertebrates====

Some [[cephalopod]]s are known to use [[coconut]] shells for protection or [[camouflage]].<ref>{{Cite journal |last = Finn |first = J. K. |author2=Tregenza, T.|author3=Tregenza, N. |title = Defensive tool use in a coconut-carrying octopus |journal = Current Biology |volume = 19 |issue = 23 |pages = R1069–R1070 |year = 2009 |doi = 10.1016/j.cub.2009.10.052 |pmid = 20064403 }}</ref>

Ants of the species ''[[Conomyrma bicolor]]'' pick up stones and other small objects with their mandibles and drop them down the vertical entrances of rival colonies, allowing workers to forage for food without competition.<ref>{{cite journal |author=Michael H.J. Möglich & Gary D. Alpert |year=1979 |title=Stone dropping by Conomyrma bicolor (Hymenoptera: Formicidae): A new technique of interference competition |journal=[[Behavioral Ecology and Sociobiology]] |volume=2 |issue=6 |pages=105–113 |jstor=4599265}}</ref>

=== Reasoning and problem solving ===

Closely related to tool use is the study of reasoning and problem solving. It has been observed that the manner in which chimpanzees solve problems, such as that of retrieving bananas positioned out of reach, is not through [[trial-and-error]]. Instead, they were observed to proceed in a manner that was "unwaveringly purposeful."<ref>Wolfgang Köhler ''The Mentality of Apes'' (1917)</ref>

It is clear that animals of quite a range of species are capable of solving a range of problems that are argued to involve abstract reasoning;<ref>For Chimpanzees, see for example [[David Premack]] (1983) ''[[The Mind of an Ape#Other concepts|The Mind of an Ape]]''</ref> modern research has tended to show that the performances of [[Wolfgang Köhler]]'s chimpanzees, who could achieve spontaneous solutions to problems without training, were by no means unique to that species, and that apparently similar behavior can be found in animals usually thought of as much less intelligent, if appropriate training is given.<ref>Pepperberg, I. M. (1999). The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots. Cambridge MA: Harvard University Press.</ref> [[Causal Reasoning (Psychology)|Causal reasoning]] has also been observed in rooks and New Caledonian crows.<ref>{{cite journal |pmid = 17171360 |doi = 10.1007/s10071-006-0061-4 |volume = 10 |issue = 2 |title = Non-tool-using rooks, Corvus frugilegus, solve the trap-tube problem |date=April 2007 |journal = Anim Cogn |pages = 225–31 |last1 = Tebbich |first1 = Sabine |last2 = Seed |first2 = Amanda M. |last3 = Emery |first3 = Nathan J. |last4 = Clayton |first4 = Nicola S. }}</ref><ref>{{cite journal |doi = 10.1098/rspb.2008.1107 |volume = 276 |issue = 1655 |title = Do New Caledonian crows solve physical problems through causal reasoning? |date=January 2009 |journal = Proc. R. Soc. B |pages = 247–254 |last1 = Taylor |first1 = A.H |last2 = Hunt |first2 = G.R |last3 = Medina |first3 = F.S |last4 = Gray |first4 = R.D |pmid = 18796393 |pmc = 2674354 }}</ref>

=== Language ===

{{main|Animal language}}

{{further|Talking animal}}

The modeling of human language in animals is known as [[animal language]] research. In addition to the ape-language experiments mentioned above, there have also been more or less successful attempts to teach language or language-like behavior to some non-primate species, including [[parrots]] and [[Great Spotted Woodpecker]]s. Arguing from his own results with the animal [[Nim Chimpsky]] and his analysis of others results, Herbert Terrace criticized the idea that chimps can produce new sentences.<ref>Terrace, H., L.A. Petitto, R.J. Sanders, T.G. Bever(1979)Science 206 (4421): 891–902</ref> Shortly thereafter [[Louis Herman]] published research on artificial language comprehension in the bottlenosed dolphin. (Herman, Richards, & Wolz, 1984). Though this sort of research has been controversial, especially among [[cognitive linguistics|cognitive linguists]], many researchers agree that many animals can understand the meaning of individual words, and some may understand simple sentences and syntactic variations, but there is little evidence that any animal can produce new strings of symbols that correspond to new sentences.<ref name = "Shettleworth"/>

=== Consciousness ===

[[File:Mirror test with a Baboon.JPG|thumb|Mirror test with a baboon]]

The sense in which animals can be said to have [[consciousness]] or a [[self-concept]] has been hotly debated; it is often referred to as the debate over animal minds. The best known research technique in this area is the [[mirror test]] devised by [[Gordon G. Gallup]], in which an animal's skin is marked in some way while it is asleep or sedated, and it is then allowed to see its reflection in a mirror; if the animal spontaneously directs grooming behavior towards the mark, that is taken as an indication that it is aware of itself. Self-awareness, by this criterion, has been reported for chimpanzees and also for other great apes, the [[European Magpie]],<ref>{{cite journal |first = Helmut, Ariane, and Onur |last = Prior, Schwarz, and Güntürkün |title = Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition |journal = PLoS Biology |publisher = Public Library of Science |year = 2008 |doi = 10.1371/journal.pbio.0060202 |accessdate = 2008-08-21 |url = http://biology.plosjournals.org/archive/1545-7885/6/8/pdf/10.1371_journal.pbio.0060202-L.pdf |volume = 6 |pages = e202 |pmid = 18715117 |last2 = Schwarz |first2 = A |last3 = Güntürkün |first3 = O |issue = 8 |pmc = 2517622 |last4 = De Waal |first4 = Frans | editor1-last=De Waal | editor1-first=Frans }}</ref> some [[cetaceans]] and a solitary [[elephant]], but not for monkeys. The mirror test has attracted controversy among some researchers because it is entirely focused on vision, the primary sense in humans, while other species rely more heavily on other senses such as the [[olfactory]] sense in dogs.{{Citation needed|date=April 2008}}

It has been suggested that [[metacognition]] in some animals provides some evidence for cognitive self-awareness.<ref>{{Cite journal |doi = 10.1037/a0020129 |last = Couchman |first = Justin J. |author2=Coutinho, M. V. C.|author3=Beran, M. J.|author4=Smith, J. D. |title = Beyond Stimulus Cues and Reinforcement Signals: A New Approach to Animal Metacognition |journal = Journal of Comparative Psychology |volume = 124 |issue = 4 |pages = , 356&nbsp;–368 |year = 2010 |url = http://www.apa.org/pubs/journals/features/com-124-4-356.pdf |pmid = 20836592 |pmc = 2991470 }}</ref> The great apes, dolphins, and [[rhesus monkeys]] have demonstrated the ability to monitor their own mental states and use an "I don't know" response to avoid answering difficult questions. These species might also be aware of the strength of their memories. Unlike the mirror test, which relies primarily on body images and bodily self-awareness, uncertainty monitoring paradigms are focused on the kinds of mental states that might be linked to mental self-awareness.{{Citation needed|date=January 2012}}

A different approach to determine whether a non-human animal is conscious derives from passive speech research with a macaw (see [[Talking Birds#Arielle|Arielle]]). Some researchers propose that by passively listening to an animal's voluntary speech, it is possible to learn about the thoughts of another creature and to determine that the speaker is conscious. This type of research was originally used to investigate a child's [[crib talk|crib speech]] by Weir (1962) and in investigations of early speech in children by Greenfield and others (1976). With speech-capable birds, the methods of passive-speech research open a new avenue for investigation.{{Citation needed|date=January 2012}}

In July, 2012 during the "Consciousness in Human and Nonhuman Animals" conference in Cambridge a group of scientists announced and signed a declaration with the following conclusions:

{{quotation|Convergent evidence indicates that non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.<ref name=cdeclaration>{{cite web|title=The Cambridge Declaration on Consciousness|url=http://fcmconference.org/img/CambridgeDeclarationOnConsciousness.pdf|accessdate=12 August 2012}}</ref>}}

=== Animal insight ===

{{See also|Reason}}

Along with consciousness comes insight. Do animals have that “outside-the-box” or the “Aha! experience", sometimes called the [[Eureka effect]]? That thinking process that helps them solve everyday problems and help them to adapt in the outside world. Some may argue that this is called instinct, but insight is different. [[Wolfgang Köhler]] is usually credited with introducing the concept of insight into the psychological world.<ref name="psycnet" /> Köhler worked with apes that became masters of solving puzzles he gave them. Köhler followed [[Edward Thorndike]]’s theory that animals solve problems gradually, first finding success through a process of trial and error and slowly becoming more skillful. Köhler came to disagree with this theory saying, “Thorndike’s animals could only escape by chance at first because their structure did not permit other kinds of situations.”<ref name="psycnet" /> More recently, it has been shown that Asian elephants (''Elephas maximus'') may exhibit insightful problem solving. A male was observed moving a box to a position where it could be stood upon to reach food that had been deliberately hung out of reach.<ref>{{cite doi|10.1371/journal.pone.0023251}}</ref>

Contemporary studies of human insight address the cognitive and neural mechanisms underlying problem-solving behavior that fit this definition. In the case of animals, this usually means associative learning. Because we cannot simply ask animals about their “aha” experiences we should define insightful behavior in terms of processes such as mental trial and error or casual understanding.<ref name="psycnet" />

=== Numeracy ===

Some animals are capable of distinguishing between different amounts and rudimentary counting. Elephants have been known to perform simple arithmetic, and rhesus monkeys and pigeons, in some sense, can count.<ref>[http://www.timesonline.co.uk/tol/news/world/asia/article4660924.ece Elephants show flair for arithmetic]</ref><ref>[http://www.columbia.edu/cu/psychology/primatecognitionlab/References/BrannonTerrace2000.pdf Representation of the Numerosities 1-9 by Rhesus Macaques (Macaca) mulatto]</ref><ref>[https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxkYW1pYW5zY2FyZnBoZHxneDoyODc0NzAwNTQzMThiNjg2 Pigeons on Par with Primates in Numerical Competence]</ref> Ants are able to use quantitative values and transmit this information.<ref>Zhanna Reznikova, Boris Ryabko, "A Study of Ants' Numerical Competence". ''[[Electronic Transactions on Artificial Intelligence]]'', Issue: Vol. 5(2001): Section B: pp. 111-126</ref><ref>Reznikova, Zh. I. (2007). ''Animal Intelligence: From Individual to Social Cognition''. Cambridge University Press</ref> For instance, ants of several species are able to estimate quite precisely numbers of encounters with members of other colonies on their feeding territories.<ref>Reznikova, Zh. I. (1999). Ethological mechanisms of population dynamic in species ant communities. Russian Journal of Ecology, 30, 3, 187–197</ref><ref>{{cite journal |last1 = Brown |first1 = M. J. F. |last2 = Gordon |first2 = D. M. |year = 2000 |title = How resources and encounters affect the distribution of foraging activity in a seed-harvesting ants |journal = Behavioral Ecology and Sociobiology |volume = 47 |pages = 195–203 |doi = 10.1007/s002650050011 |issue = 3 }}</ref> Numeracy has been described in the yellow mealworm beetle, ''[[Tenebrio molitor]]'',<ref name="Carazo et al., 2009">{{cite journal |last1 = Carazo |first1 = P. |last2 = Font |first2 = E. |last3 = Forteza-Behrendt |first3 = E. |last4 = Desfilis |first4 = E. et al. | author-separator =, | author-name-separator= |year = 2009 |title = Quantity discrimination in Tenebrio molitor: evidence of numerosity discrimination in an invertebrate? |journal = Animal Cognition |volume = 12 |pages = 463–470 |doi = 10.1007/s10071-008-0207-7 |issue = 3 |pmid = 19118405 }}</ref> and the honeybee.<ref name="Dacke and Srinivasan, 2008">{{cite journal |last1 = Dacke |first1 = M. |last2 = Srinivasan |first2 = M.V. |year = 2008 |title = Evidence for counting in insects |journal = Animal Cognition |volume = 11 |pages = 683–689 |doi = 10.1007/s10071-008-0159-y |pmid = 18504627 |issue = 4 }}</ref>

[[Western lowland gorilla]]s given the choice between two food trays demonstrated the ability to choose the tray with more food items at a rate higher than chance after training.<ref>Anderson, U.S., Stoinski, T.S., Bloomsmith, M.A., Marr, M.J., Smith, A.D., & Maple, T.L. (2005). Relative numerousness judgment and summation in young and old western lowland gorillas" ''Journal of Comparative Psychology'' 119, 285–295.</ref> In a similar task, [[chimpanzee]]s chose the option with larger amount of food.<ref>Boysen S.T., Berntson G.G., Mukobi K.L. (2001) Size matters: impact of item size and quantity on array choice by chimpanzees (Pan troglodytes) J. Comp. Psychol, 115, 106–110.</ref> [[Salamander]]s given a choice between two displays with differing amounts of fruit flies, used as a food reward, reliably choose the display with more flies, as shown in a particular experiment.<ref>Uller C., Jaeger R., Guidry G., Martin C. (2003) Salamanders (Plethodon cinereus) go for more: rudiments of number in an amphibian. Anim Cogn, 6, 105-112.</ref>

Other experiments have been conducted that show animals’ abilities to differentiate between non-food quantities. [[American black bear]]s demonstrated quantity differentiation abilities in a task with a computer screen. The bears were trained to touch a computer monitor with a paw or nose to choose a quantity of dots in one of two boxes on the screen. Each bear was trained with [[reinforcement]] to pick a larger or smaller amount. During training, the bears were rewarded with food for a correct response. All bears performed better than what random error predicted on the trials with static, non-moving dots, indicating that they could differentiate between the two quantities. The bears choosing correctly in congruent (number of dots coincided with area of the dots) and incongruent (number of dots did not coincide with area of the dots) trials suggests that they were indeed choosing between quantities that appeared on the screen, not just a larger or smaller [[retina|retinal image]], which would indicate they are only judging size.<ref>Vonk J., Beran M.J. (2012) Bears ‘count’ too: quantity estimation and comparison in black bears, Ursus americanus, Animal Behaviour, 84, 1, 231-238.</ref>

[[Bottlenose dolphin]]s have shown the ability to choose an array with fewer dots compared to one with more dots. Experimenters set up two boards showing various numbers of dots in a poolside setup. The dolphins were initially trained to choose the board with the fewer number of dots. This was done by rewarding the dolphin when it chose the board with the fewer number of dots. In the experimental trials, two boards were set up, and the dolphin would emerge from the water and point to one board. The dolphins chose the arrays with fewer dots at a rate much larger than chance, indicating they can differentiate between quantities.<ref>Jaakkola K., Fellner W., Erb L., Rodriguez M., Guarino E. (2005) Understanding of the concept of numerically "less" by bottlenose dolphins (Tursiops truncatus) Journal of Comparative Psychology, 119, 286–303.</ref>

A particular [[African Grey Parrot|grey parrot]], after training, has shown the ability to differentiate between the numbers zero through six using [[Talking bird|vocalizations]]. After number and vocalization training, this was done by asking the parrot how many objects there were in a display. The parrot was able to identify the correct amount at a rate higher than chance.<ref>Pepperberg I. (2006) Grey parrot numerical competence: a review. Anim Cogn, 9, 377–391.</ref>

[[Pterophyllum|Angelfish]], when put in an unfamiliar environment will group together with conspecifics, an action named [[Shoaling and schooling|shoaling]]. Given the choice between two groups of differing size, the angelfish will choose the larger of the two groups. This can be seen with a discrimination ratio of 2:1 or greater, such that, as long as one group has at least twice the fish as another group, it will join the larger one.<ref>Gómez-Laplaza, L.M. & Gerlai, R. (2010). Can angelfish (Pterophyllum scalare) count? Discrimination between different shoal sizes follows Weber’s law. Anim. Cogn, 14, 1-9.</ref>

[[Monitor lizard]]s have been shown to be capable of numeracy, and some species can distinguish among numbers up to six.<ref>King, Dennis & Green, Brian. 1999. ''Goannas: The Biology of Varanid Lizards''. University of New South Wales Press. ISBN 0-86840-456-X, p. 43.</ref>

==Biological constraints==

[[File:AB003 Hedgehog from Rajasthan.jpg|right|200px|thumb|Hedgehogs instinctively roll into a ball when threatened, making them unsuitable for studies on aversion avoidance]]

Instinctive tendencies should be considered during interpretation of results from experiments on animal cognition. For example, dogs and rats easily learn to avoid an electric shock from the floor by moving to another part of the experimental chamber when they hear a tone preceding the shock. However, [[hedgehog]]s fail to learn this avoidance behavior. Whilst this might seem to show an inability to learn, the hedgehog's instinctive reaction to a threat is to curl up into a ball, a response that interferes with possible escape behavior in this situation.

[[Instinctive drift]] is another biological constraint that can influence interpretation of animal cognition studies. Instinctive drift is the tendency of an animal to revert to [[instinctive behavior]]s that can interfere with learned responses. The concept originated with [[Keller Breland|Keller]] and [[Marian Breland|Marian]] Breland when they taught a [[raccoon]] to put coins into a box. The raccoon drifted to its instinctive behavior of rubbing the coins with its paws, as it would do when forging for food.<ref name="Breland and Breland, (1961)">Breland, K. and Breland, M. (1961). The misbehavior of organisms" ''American Psychologist'' 16: 681-684</ref>

== Cognitive faculty by species ==

A common image is the ''[[Great chain of being|scala naturae]]'', the ladder of nature on which animals of different species occupy successively higher rungs, with humans typically at the top.<ref name=campbell1991snr>Campbell, C.B.G., & Hodos, W. (1991). The Scala Naturae revisited: Evolutionary scales and anagenesis in comparative psychology. J. Comp. Psychol. 105:211-221</ref>

A more fruitful approach has been to recognize that different animals may have different kinds of cognitive processes, which are better understood in terms of the ways in which they are cognitively adapted to their different ecological niches, than by positing any kind of hierarchy. (See [[Sara Shettleworth|Shettleworth]] (1998), Reznikova (2007).)

One question that can be asked coherently is how far different species are intelligent in the same ways as humans are, i.e., are their cognitive processes similar to ours. Not surprisingly, our closest biological relatives, the [[great ape]]s, tend to do best on such an assessment. Among the birds, [[corvid]]s and parrots have typically been found to perform well. [[Octopod]]es have also been shown to exhibit a number of higher-level skills such as tool use,<ref>{{cite journal |doi = 10.1016/j.cub.2009.10.052 |title = Defensive tool use in a coconut-carrying octopus |year = 2009 |last1 = Finn |first1 = Julian K. |last2 = Tregenza |first2 = Tom |last3 = Norman |first3 = Mark D. |journal = Current Biology |volume = 19 |issue = 23 |pages = R1069–70 |pmid = 20064403 }}</ref> but the amount of research on [[cephalopod intelligence]] is still limited.{{Citation needed|date=January 2012}}

[[Baboon]]s have been shown to be capable of recognizing words.<ref>[http://www.nature.com/news/baboons-can-learn-to-recognize-words-1.10432 Baboons can learn to recognize words; Monkeys' ability suggests that reading taps into general systems of pattern recognition] 12 April 2012 [[Nature (journal)|Nature]]</ref><ref>[http://www.latimes.com/news/science/la-sci-word-recognition-20120413,0,5510844.story Baboons can recognize written words, study finds; The monkeys don't assign meaning to them, but learn what letter combinations are common to real words, the study authors say] April 12, 2012 [[Los Angeles Times]]</ref><ref>[http://www.sciencenews.org/view/generic/id/339869/title/Baboons_show_their_word_skills Baboons show their word skills; Reading may stem from a visual aptitude shared by all primates] May 5, 2012</ref>

== See also ==

{{Portal|Thinking|Animals|Animal rights}}

* [[Anthropomorphism]]

* [[Cetacean intelligence]]

* [[Deception in animals]]

* [[Dog intelligence]]

* [[Pain in invertebrates#Cognitive abilities|Cognitive abilities]]

{{-}}

==References==

{{reflist|35em}}

== Further reading ==

* Brown, M.F., & Cook, R.G. (Eds.). (2006). Animal Spatial Cognition: Comparative, Neural, and Computational Approaches. [On-line]. Available: www.pigeon.psy.tufts.edu/asc/

* Goodall, J. (1991). ''Through a window''. London: Penguin.

* Griffin, D. R. (1992). ''Animal minds''. Chicago: University of Chicago Press.

* Hilgard, E. R. (1958). ''Theories of learning'', 2nd edn. London: Methuen.

* Neisser, U. (1967). ''Cognitive psychology''. New York, Appleton-Century-Crofts.

* Romanes, G. J. (1886). ''Animal intelligence'', 4th edn. London: Kegan Paul, Trench.

* Shettleworth, S. J. (1998) (2010,2nd ed). ''Cognition, evolution and behavior''. New York: Oxford University Press.

* Skinner, B. F. (1969). ''Contingencies of reinforcement: a theoretical analysis''. New York: Appleton-Century-Crofts.

* Narby, Jeremy. (2005) ''Intelligence In Nature''. New York: Penguin.

* Lurz, Robert W. (2009) [http://www.themontrealreview.com/2009/Mindreading-animals.php ''Mindreading Animals: The Debate over What Animals Know about Other Minds'']. The MIT Press.

== External links ==

* [http://www.scientificamerican.com/article.cfm?id=the-limits-of-intelligence The limits of intelligence] Douglas Fox, ''[[Scientific American]]'', 14 June 2011.

* {{Sep entry|cognition-animal|Animal Cognition|Kristin Andrews}}

* {{Sep entry|consciousness-animal|Animal Consciousness|Colin Allen}}

* [http://www.animalcognition.net/home.html Animal Cognition Network]

* {{IEP|ani-mind|Animal Minds}}

* [http://digitalcommons.unl.edu/biosciaviancog/ Center for Avian Cognition] University of Nebraska ([[Alan Kamil]], Alan Bond)

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{{Animal communication}}

{{Great ape language}}

{{DEFAULTSORT:Animal Cognition}}

[[Category:Zoology]]

[[Category:Animal intelligence]]

[[Category:Animal rights]]