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==Experiments==
<!-- Deleted image removed: [[File:fourshapesexp.png|thumb|alt=An example of four colored shapes and two black letters.|An example of the stimuli found in Treisman et al. (1982).]] -->In order to test the statement that features are independent in the early preattentive stage, Treisman and Schmidt (1982) designed an experiment in which participants are shown a picture involving four shapes and two black numbers for one-fifth of a second. After the display, a random-dot masking field appeared on screen to eliminate “any residual perception that might remain after the stimuli were turned off” <ref>Cognitive Psychology, E. Bruce Goldstein, P 105</ref>. The task of participants was to report the black numbers first, followed by what colored shapes they saw at four locations.The results of this experiment verified Treisman and Schmidt's hypothesis. In 18% of trials, participants reported seeing shapes “made up of a combination of features from two different stimuli” <ref>Cognitive Psychology, E. Bruce Goldstein, P 105 </ref>, even when the stimuli had great differences. This is an [[illusory conjunction]], an often occurring illusion people experience during visual search. While people can typically remember the presence of an object, they often forget its ___location or color. They occur in various situations; for example, you may identify a passing person wearing a red shirt and yellow hat and very quickly transform him or her into one wearing a yellow shirt and red hat. Feature integration theory can explain illusory conjunctions – in Treisman’s words, features are “free floating” so they may be incorrectly combined <ref>Treisman, A. Cognitive Psychology 12, 97-136 (1980)</ref>.
Research participant R.M., a [[Bálint's syndrome]] sufferer who is unable to focus attention on individual objects, experiences illusory conjunctions when presented with simple stimuli such as a "blue O" or a "red T." For 23% of trials, even when able to view the stimulus for as long as 10 seconds, R.M. reported seeing a "red O" or a "blue T" <ref> Friedman-Hill et al., 1995; Robertson et al., 1997. </ref>. This finding is in accordance with feature integration theory's prediction of how one with a lack of focused attention would erroneously combine features.
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