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Jody C. Culham, Jacqueline C. Snow, Antonio Rangel; Bringing the real world into the fMRI scanner: Real objects amplify the neural correlates of valuation compared to photos. Journal of Vision 2013;13(9):499. doi: 10.1167/13.9.499.
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© ARVO (1962-2015); The Authors (2016-present)
Our understanding of the cognitive and neural basis of object perception is largely based upon studies that have examined responses to drawings or photos of objects rather than actual objects themselves. Recent fMRI evidence from our laboratory (Snow et al., 2011, Scientific Reports) suggested that the neural mechanisms involved in processing or representing real objects differ from those of photos. Our fMRI results are supported by recent behavioral data on the influence of real objects on consumer behaviour. Bushong et al., (2010, American Economic Review) found that the form in which objects were displayed had a sizeable influence on participants value ratings. Specifically, students were willing to pay over 60% more for common snack foods when they were presented as real items versus color photos. Such goal-directed decisions can be identified in the form of a ’value signal’ encoded in the ventro-medial prefrontal cortex (vmPFC) (Hare et al., 2009, Science). Here we used fMRI to monitor brain activity during trials in which hungry observers made behavioral decisions about their desire to consume common snack foods. Critically, we contrasted neural responses for real items vs. color photos of those items matched for features like size and viewpoint. We found that fMRI responses in vmPFC correlated significantly with observers’ trial-by-trial value judgments about the foods, consistent with the earlier results. Strikingly, however, we found that the use of real items amplified value-based fMRI responses in vmPFC. Real items elicited FMRI responses in vmPFC that were more negative for aversive foods, and more positive for desirable foods, than those elicited by the corresponding photos. Our results reveal a neural correlate in vmPFC for the value-based differences associated with real-world objects over photos. Moreover, they provide further evidence that images are an imperfect proxy for real objects.
Meeting abstract presented at VSS 2013
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