August 2023
Volume 23, Issue 9
Open Access
Vision Sciences Society Annual Meeting Abstract  |   August 2023
The size of a novel object is learned rapidly, and unlearned slowly, for purposes of computing apparent distance.
Author Affiliations
  • Albert Yonas
    Arizona State University
  • Sahana Lawrence
    Arizona State University
  • Emily Martin
    Arizona State University
  • Carl Granrud
    University of Northern Colorado
  • Ben Backus
    Vivid Vision, Inc.
  • Sherryse Corrrow
    Bethel College
  • Joshua Weekes
    Arizona State University
Journal of Vision August 2023, Vol.23, 5480. doi:
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      Albert Yonas, Sahana Lawrence, Emily Martin, Carl Granrud, Ben Backus, Sherryse Corrrow, Joshua Weekes; The size of a novel object is learned rapidly, and unlearned slowly, for purposes of computing apparent distance.. Journal of Vision 2023;23(9):5480.

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      © ARVO (1962-2015); The Authors (2016-present)

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Familiar size is a distance cue. An object's known physical size and its visual angle are sufficient to determine its distance from a viewer. Although there is controversy, new evidence strongly supports the conclusion that humans utilize this cue. But how quickly can an object's size become familiar, for purposes of distance perception? 31 college freshmen were asked to study the size, shape, and color of two unfamiliar objects, one 14 cm tall and another 7 cm tall, for 30 seconds. Then, while viewing with one eye, to eliminate binocular information, they were asked to estimate the distance to two objects: one of the original object and the second an object doubled in size but identical in color and shape. The objects were placed 350 cm from the observer, and apparent distance was measured by having observers stop a moving pointer when they perceived it to be at the same distance as each object. Fourteen observers judged the double-sized object to be approximately 50 centimeters closer, on average, than the control object. These observers consistently expressed surprise about the actual size and distance of the double-sized object upon viewing it with two eyes. The other 17 participants perceived the double-sized object as larger than the object they had seen during familiarization, and their distance estimates were less affected by familiar size. In about half of the participants, 30 seconds were sufficient to learn the size of an object for purposes of distance perception. Remarkably, viewing the double-sized object binocularly at 50 cm did not extinguish the illusion for many participants. Thus, disillusion for them was a slower process. In the real world, many objects have a single size, so rapidly utilizing the learned size of an object for distance perception has ecological validity as a perceptual strategy.


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