Levels of processing model: Difference between revisions

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The '''levels-of-processing effect''', identified by [[Fergus I. M. Craik]] and Robert S. Lockhart in 1972, describes [[memory]] [[recollection|recall]] of [[Stimulus (physiology)|stimuli]] as a function of the depth of mental processing. A stimulus’s mental processing depth is determined by connections with preexisting memory, time spent processing the stimulus, cognitive effort, and sensory input mode. Depth of processing falls on a shallow to deep continuum. Shallow processing (e.g., processing based on [[phonemic]] and [[Orthography|orthographic]] components) leads to a fragile memory trace that is susceptible to rapid decay. Conversely, deep processing (e.g., [[Semantics|semantic]] processing) results in a more durable memory trace. This theory contradicts the multi-store [[Atkinson-Shiffrin memory model]] in its representation of memory strength as continuously variable.

The '''levels-of-processing effect''' was first identified by [[Fergus I. M. Craik]] and Robert S. Lockhart in [[1972]].

==Modifiers==

The fundamental concept of the levels-of-processing effect is that different methods of encoding information into [[memory]] result in different types of memory codes. Memory codes differ in their strength. The strength of the memory code, in turn, determines speed of decay of the memory trace and success of ([[recollection|recall]]) from memory over time.

[[Familiarity heuristic|Familiarity]], transfer-appropriate processing, the self-reference effect, and the explicit nature of a stimulus modify the levels-of-processing effect by manipulating mental processing depth factors.

===Familiarity===

A stimulus will have a higher [[Recollection|recall]] value if it is highly compatible with preexisting semantic structures (Craik, 1972). According to [[semantic network]] theories, this is because such a stimulus will have many connections to other encoded memories, which are activated based on closeness in semantic network structure (Rhodes, 2000). This activation increases cognitive analysis, increasing the strength of the memory representation. The familiarity modifier has been tested in [[implicit memory]] experiments, where subjects report false memories when presented with related stimuli (Toth, 1996).

===Specificity of processing===

This structure of memory suggests that memory doesn’t have separate levels of storage. This is contrary to views such as the three-store model of memory. Levels-of-Processing considers that there is an infinite number of processing levels of memory being encoded. The levels are indistinct and boundaries between the levels are nonexistent. Under this model, storage is said to be determined by processing.

Specificity of processing describes the increased recall value of a stimulus when presented in the method with which it was input. For example, auditory stimuli (spoken words and sounds) have the highest recall value when spoken, and visual stimuli have the highest recall value when a subject is presented with images (Vaidya et al., 2002). In lexical (word-based) writing tasks, words are recalled most effectively with semantic cues (asking for words with a particular meaning) if they are encoded semantically (self-generated by the subject as being related to a particular meaning). Words are recalled most effectively with data-driven cues (word completion) if they are read, rather than generated by a subject (Blaxton, 1989).

===Self-reference effect===

Craik & Lockhart (1972) used an incidental learning task to examine the hypothesis that the manner of encoding affects the strength of the resulting memory trace. Research participants in the incidental learning task viewed a series of words on a computer screen and answered simple yes/no questions about those words (e.g., "Is the word printed in capital letters?").

The self-reference effect describes the greater recall capacity for a particular stimulus if it is related semantically to the subject. This can be thought of as a corollary of the familiarity modifier, because stimuli specifically related to an event in a person’s life will have widespread activation in that person’s semantic network (Symons & Johnson, 1997). For example, the recall value of a personality trait adjective is higher when subjects are asked whether the trait adjective applies to them than when asked whether trait adjective has a meaning similar to another trait (Kelley et al., 2002).

The types of questions the participants were asked to answer were designed to affect the manner in which the words were encoded into memory. Certain questions had participants encode the '''physical''' aspects of the stimuli (e.g., "Is the word printed in capital letters?"). Other questions had participants encode the '''acoustic''' properties of the stimuli (e.g., "Does this word rhyme with "DOG"?"). Other questions had participants encode the '''semantic''' aspects of the stimuli (e.g., "Does the word fit in the following sentence - "The ________ walked into the house"). Following the incidental learning task, participants were given a surprise memory test.

===Implicit memory and levels-of-processing===

Craik & Lockhart predicted that attending to the physical features of the stimuli would result in shallow encoding and a weak memory trace. Attending to the acoustic properties of the stimuli would result in a moderate level of processing and a moderately strong memory trace. Attending to the semantic properties of the stimulus would result in the deepest level of processing and the strongest memory trace. The results of the experiment confirmed the hypothesis. The deeper the level of processing, the more likely it was that the word would be remembered. Also, there was higher recall when the words were connected by logic (fish and ocean)<!-- this would indicate an association in semantic memory -->, as opposed to concretely connected words (fish and hand). Effects such as these are termed the self-reference effect.<!-- This is just wrong. The self-reference effect is when memory is improved because the person encodes the new information by tying the information in with his or her own life and experiences-->

Implicit memory tests, in contrast with explicit memory tests, measure the recall value of a particular stimulus based on later performance on stimulus-related tasks. During these tasks, the subject does not explicitly recall the stimulus, but the previous stimulus still effects performance (Roediger, 1990). For example, in a word-completion implicit memory task, if a subject reads a list containing the word “dog,” the subject provides this word more readily when asked for three-letter words beginning in “d.” The levels-of-processing effect is only found for explicit memory tests. One study found that word completion tasks were unaffected by levels of semantic encodings achieved using three words with various levels of meaning in common (Schacter & McGlynn, 1989). Another found that typical level-of-processing effects are reversed in word completion tasks; subjects recalled pictures pairs more completely if they were shown a word representing a picture rather than asked to rate a picture for pleasantness (semantic encoding) (Roediger, Stadler, Weldon, & Riegler, 1992). Typical level-of-processing theory would predict that picture encodings would create deeper processing than lexical encoding (see discussion of visual sensory modes below).

==Sensory Modes ==

Physical- Visual feature of the word (lowercase, uppercase); shallow code; weak memory trace; fast decay

Different sensory modes, by their nature, involve different depths of processing, generally producing higher recall value in certain senses than others. However, there is significant room for the modifiers mentioned earlier to affect levels-of-processing to be activated within each sensory mode.

Acoustic- Sound the word makes (rhyming); moderate code; moderate strength memory trace; moderate decay

Semantic- deeper meaning or function of the word (pleasantness of word, ability of word to fit in a sentence); deep code; strong memory trace; slow decay

===Vision===

The test used to illustrate their [[hypothesis]] showed, roughly speaking, that:

[[Visual perception|Visual input]] creates the strongest recall value of all senses, and also allows the widest spectrum of levels-of-processing modifiers. It is also one of the most widely studied. Within visual studies, pictures have been shown to have a greater recall value than words. However, semantic associations have the reverse effect in picture memories appear to be reversed to those in other memories. When logical details are stressed, rather than physical details, an image’s recall value becomes lower (Intraub & Nicklos, 1985). Visual word memorization is subject to the standard modifiers mentioned earlier of semantic connection, and was used for Craik & Lockhart’s original work. Craik & Lockhart’s participants in the learning task viewed a series of words on a computer screen and answered simple yes/no questions about those words (e.g., "Is the word printed in capital letters?"). The types of questions the participants were asked to answer were designed to affect the manner in which the words were encoded into memory. Certain questions had participants encode the [[Orthography|orthographic]] aspects of the stimuli (e.g., "Is the word printed in capital letters?"). Other questions had participants encode the [[phonological]] properties of the stimuli (e.g., "Does this word rhyme with "DOG"?"). Other questions had participants encode the [[semantic]] aspects of the stimuli (e.g., "Does the word fit in the following sentence - "The ________ walked into the house"). In a subsequent memory test, Craik & Lockhart found that participants attending to the physical features of the words had the weakest memory trace, participants attending to the acoustic properties of the words had a moderately strong memory trace, and participants attending to semantic properties of the words had the strongest trace.

===Hearing===

# Those that hear a passage of text can recall parts of it (audible [[input]])

Auditory stimuli follow conventional levels-of-processing rules, although are somewhat weaker in general [[Recollection|recall]] value when compared with vision. Some studies suggest that auditory weakness is only present for [[explicit memory]] (direct recall), rather than [[implicit memory]] (Habib & Nyberg, 1997). When test subjects are presented with auditory versus visual word cues, they only perform worse on directed recall of a spoken word versus a seen word, and perform about equally on implicit free-association tests. Within auditory stimuli, semantic analysis produces the highest levels of recall ability for stimuli. Experiments suggest that levels-of-processing on the auditory level is directly correlated with neural activation (see “Neural Evidence” below) (Fletcher, Shallice, & Dolan, 1998).

# Those that read a passage of text can recall most of it (visual input)

# Those that write down the text can recall most if not all of it, even with the written form taken away (audible or visual input plus physical output)

# Those that understand the meaning behind the text will have the strongest ability to recall the passage (conceptual input)

===Touch===

The sliding-scale of increased ability to encode/recall is the focus of the study. Greater processing will lead to greater amounts of information available for recall. Craik and Lockhart postulate depth of processing to fall on a shallow to deep continuum. Shallow processing (e.g., processing words based on their phonemic and orthographic components) leads to a fragile memory trace that is susceptible to rapid decay. Conversely, deep processing (e.g., semantic or meaning based processing) results in a more durable memory trace.

[[Tactile]] memory representations are similar in nature to visual representations, although there is not enough data to reliably compare the strength of the two kinds of stimuli. One study suggests that there is a difference in mental processing level due to innate differences between visual and tactile stimuli representations (Kavitha Srinivas, Greene, & Easton, 1997). In this study, subjects were presented with an object in both visual and tactile form (a subject is shown a sphere but cannot touch it, and later is given a similar sphere to only hold and not view). Subjects had more trouble identifying size difference in visual fields than using tactile feedback. A suggestion for the lower level of size processing in visual fields is that it results from the high variance in viewed object size due to perspective and distance.

===Smell===

Whether the information is being encoded more effectively or being recalled more effectively is unclear. A typical paradigm employed to investigate the Levels of Processing theory is the incidental learning paradigm. Results reveal superior recall for items processed deeply compared to those items processed at the more shallow level (Eysenck, 1974: Hyde & Jenkins, 1969)<!-- Craik and Lockhart used an incidental learning paradigm. All that an incidental learning paradigm is, is a task in which people don't know that their memory for the stimuli presented in the task will be tested later. Consequently, they don't purposefully engage in any tricks to improve their memory for the stimuli. Any learning is incidental - hence the name -->.

[[Odor]] memory is weaker than visual memory, achieving a successful identification rate of only 70-80% of visual memory (Schab, 1991). Levels-of-processing effects have been found within odor memory if subjects are asked to “visualize” smells and associate them with a particular picture. Subjects who perform this task have a different recall value on explicit memory tests than subjects who memorize smells using self-chosen methods. The difference in recall value, however, depends on the subject, and the subject’s ability to form images from odors. Attributing verbal attributes to odors has similar effects. Semantic processing of odors (e.g. attributing the “mud” odor to “smell like a puddle”) has found to have the most positive effects on recall.

==Neural External linksEvidence ==

Several brain imaging studies using [[positron emission tomography]] and [[functional magnetic resonance imaging]] techniques have shown that higher levels of processing [[correlate]] with more brain activity and activity in different parts of the brain than lower levels. For example, in a lexical analysis task, subjects showed activity in the [[prefrontal cortex|left inferior prefrontal cortex]] only when identifying whether the word represented a living or nonliving object, and not when identifying whether or not the word contained an “a” (Kapur et al., 1994). Similarly, an auditory analysis task showed increased activation in the left inferior prefrontal cortex when subjects performed increasingly [[semantic]] word manipulations (Fletcher et al., 1998). Synaptic aspects of word recognition have been correlated with the [[Operculum (brain)|left frontal operculum]] and the cortex lining the junction of the inferior frontal and inferior precentral sulcus (Friederici, Opitz, & von Cramon, 2000). The self-reference effect also has neural correlates with a region of the medial [[prefrontal cortex]], which was activated in an experiment where subjects analyzed the relevance of data to themselves (W. M. Kelley et al., 2006). Specificity of processing is explained on a neurological basis by studies that show brain activity in the same ___location when a visual memory is encoded and retrieved, and lexical memory in a different ___location (Vaidya, Zhao, Desmond, & Gabrieli, 2002). Visual memory areas were mostly located within the bilateral [[Extrastriate cortex|extrastriate visual cortex]].

* [http://www.scienceaid.co.uk/psychology/cognition/levelsltm.html Science aid: Levels of Processing] Psychology resource for teens

* [http://picard.montclair.edu/psychology/adams/craik-and-lockhart-1972.htm Paper on the Craik and Lockhart work]

* [http://coglab.wadsworth.com/experiments/Levels/ Experiments related to the cognitive effect]

==Mental References Disorders==

Levels-of-processing effects interact in various ways with [[mental disorders]]. In particular, levels-of-processing effects appear to be strengthened in patients with [[Memory and aging|age-related memory degradation]], selectively strengthened in [[panic disorder]] patients, unaffected in [[Alzheimer's disease]] patients, and reversed in [[autistic]] patients.

* Craik, F.I.M., & Lockhart, R.S. (1972). Levels of processing: A framework for memory research. ''Journal of Verbal Learning and Verbal Behavior'',''11'', 671-684

* Eysenck, M.W. (1974). Age differences in incidental learning. Developmental Psychology, 10, 936-941.

* Hyde, T.S., & Jenkins, J.J. (1969). Differential effects of incidental tasks on the organization of recall of a list of highly associated words. Journal of Experimental Psychology, 82, 472-481.

* Sternberg, R.J. (2006). Cognitive Psychology fourth Edition. Memory, 5, 167-169.

===Age-Related Memory Degradation===

{{psych-stub|Levels-of-processing effect}}

Memory encoding strength derived from higher levels-of-processing appears to be conserved despite other losses in memory function with age. Several studies show that, in older individuals, the ability to process semantically in contrast with non-semantically is improved by this disparity (Grady & F. I. Craik, 2000). Neural imagining studies show decreased [[Prefrontal cortex|left-prefrontal cortex]] activity when words and images are presented to older subjects than with younger subjects, but roughly equal activity when assessing [[semantic]] connections (Grady & F. I. Craik, 2000).

===Panic Disorders===

[[Category:Educational psychology]]

Panic disorders appear to modify levels-of-processing by increasing ability to [Recollection|recall]] words with [[Threat|threatening]] meanings over positive and neutral words. In one study, both implicit (free recall) and explicit (memory of emotional aspects) memorization of word lists were enhanced by threatening meanings in such patients (Cloitre & Liebowitz, 1991). One possible interpretation of this is that subjects with panic disorders process threatening information more completely and immediately.

[[Category:Psychological theories]]

===Alzheimer’s Disease===

Modern studies show an increased effect of levels-of-processing in Alzheimer patients. Specifically, there is a significantly higher recall value for semantically encoded stimuli over physically encoded stimuli. In one such experiment, subjects maintained a higher recall value in words chosen by meaning over words selected by numerical order (Scott, Wright, Rai, Exton-Smith, & Gardiner, 1991).

===Autism===

In autistic patients, levels-of-processing effects are reversed in that semantically presented stimuli have a lower recall value than physically presented stimuli. In one study, [[phonological]] and [[orthographic]] processing created higher recall value in word list-recall tests (Toichi & Kamio, 2002). Other studies have explicitly found non-semantically processed stimuli to be more accurately processed by autistic patients than in healthy patients (Bertone, Mottron, Jelenic, & Faubert, 2005). No clear conclusions have been drawn as to the cause of this oddity.

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