methods-for-presenting-real-world-objects-under-controlled-laboratory

Methods for Presenting Real-world Objects Under Controlled Laboratory Conditions

Our knowledge of human object vision is based almost exclusively on studies in which the stimuli are presented in the form of computerized two-dimensional ...

University of Nevada, Reno

The visual and haptic perceptual systems are understood to share a common neural representation of object shape. A region thought to be critical for recognizing visual and haptic shape information is the lateral occipital complex (LOC). We investigated whether LOC is essential for haptic shape recognition in humans by studying behavioral responses and brain activation for haptically explored objects in a patient (M.C.) with bilateral lesions of the occipitotemporal cortex, including LOC. Despite severe deficits in recognizing objects using vision, M.C. was able to accurately recognize objects via touch. M.C.'s psychophysical response profile to haptically explored shapes was also indistinguishable from controls. Using fMRI, M.C. showed no object-selective visual or haptic responses in LOC, but her pattern of haptic activation in other brain regions was remarkably similar to healthy controls. Although LOC is routinely active during visual and haptic shape recognition tasks, it is not essential for haptic recognition of object shape.

Preserved Haptic Shape Processing after Bilateral LOC Lesions.

Laboratory studies of human dietary choice have relied on computerized two-dimensional (2D) images as stimuli, whereas in everyday life, consumers make decisions in the context of real foods that have actual caloric content and afford grasping and consumption. Surprisingly, few studies have compared whether real foods are valued more than 2D images of foods, and in the studies that have, differences in the stimuli and testing conditions could have resulted in inflated bids for the real foods. Moreover, although the caloric content of food images has been shown to influence valuation, no studies to date have investigated whether 'real food exposure effects' on valuation reflect greater sensitivity to the caloric content of real foods versus images. Here, we compared willingness-to-pay (WTP) for, and expectations about satiety after consuming, everyday snack foods that were displayed as real foods versus 2D images. Critically, our 2D images were matched closely to the real foods for size, background, illumination, and apparent distance, and trial presentation and stimulus timing were identical across conditions. We used linear mixed effects modeling to determine whether effects of display format were modulated by food preference and the caloric content of the foods. Compared to food images, observers were willing to pay 6.62% more for (Experiment 1) and believed that they would feel more satiated after consuming (Experiment 2), foods displayed as real objects. Moreover, these effects appeared to be consistent across food preference, caloric content, as well as observers' estimates of the caloric content of the foods. Together, our results confirm that consumers' perception and valuation of everyday foods is influenced by the format in which they are displayed. Our findings raise important new insights into the factors that shape dietary choice in real-world contexts and highlight potential avenues for improving public health approaches to diet and obesity.

The real deal: Willingness-to-pay and satiety expectations are greater for real foods versus their images.

Patients with visual agnosia show severe deficits in recognizing two-dimensional (2-D) images of objects, despite the fact that early visual processes such as figure-ground segmentation, and stereopsis, are largely intact. Strikingly, however, these patients can nevertheless show a preservation in their ability to recognize real-world objects -a phenomenon known as the 'real-object advantage' (ROA) in agnosia. To uncover the mechanisms that support the ROA, patients were asked to identify objects whose size was congruent or incongruent with typical real-world size, presented in different display formats (real objects, 2-D and 3-D images). While recognition of images was extremely poor, real object recognition was surprisingly preserved, but only when physical size matched real-world size. Analogous display format and size manipulations did not influence the recognition of common geometric shapes that lacked real-world size associations. These neuropsychological data provide evidence for a surprising preservation of size-coding of real-world-sized tangible objects in patients for whom ventral contributions to image processing are severely disrupted. We propose that object size information is largely mediated by dorsal visual cortex and that this information, together with detailed representation of object shape which is also subserved by dorsal cortex, serve as the basis of the ROA.

Article	Year
Preserved Haptic Shape Processing after Bilateral LOC Lesions. The Journal of neuroscience : the official journal of the Society for Neuroscience\| PubMed ID: 26446226	2015
The real deal: Willingness-to-pay and satiety expectations are greater for real foods versus their images. Cortex; a journal devoted to the study of the nervous system and behavior\| PubMed ID: 29233524	2018
Real-world size coding of solid objects, but not 2-D or 3-D images, in visual agnosia patients with bilateral ventral lesions. Cortex; a journal devoted to the study of the nervous system and behavior\| PubMed ID: 30987739	2019

Jacqueline C. Snow

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