Academic journal article Attention, Perception and Psychophysics

The Effect of Memory and Context Changes on Color Matches to Real Objects

Academic journal article Attention, Perception and Psychophysics

The Effect of Memory and Context Changes on Color Matches to Real Objects

Article excerpt

Published online: 31 March 2015

© The Psychonomic Society, Inc. 2015

Abstract Real-world color identification tasks often require matching the color of objects between contexts and after a temporal delay, thus placing demands on both perceptual and memory processes. Although the mechanisms of matching colors between different contexts have been widely studied under the rubric of color constancy, little research has investigated the role of long-term memory in such tasks or how memory interacts with color constancy. To investigate this relationship, observers made color matches to real study objects that spanned color space, and we independently manipulated the illumination impinging on the objects, the surfaces in which objects were embedded, and the delay between seeing the study object and selecting its color match. Adding a 10-min delay increased both the bias and variability of color matches compared to a baseline condition. These memory errors were well accounted for by modeling memory as a noisy but unbiased version of perception constrained by the matching methods. Surprisingly, we did not observe significant increases in errors when illumination and surround changes were added to the 10-minute delay, although the context changes alone did elicit significant errors.

Keywords Color constancy . Memory . Color memory

Introduction

Recognizing and identifying objects in the real world requires both perception and memory. Consider shopping for an item, such as a scarf, to match an item already at home, such as a pair of shoes (Fig. 1). Performing this task requires the cooperation of several systems: the shoes must be held in long-term memory, and then each potential scarf must be perceived and held in working memory while a judgment ismade as to the best match. Upon reaching home, we may discover that the selected scarf and shoes do not match (Fig. 1, bottom right). Errors in such tasks are often attributed to memory, but the perceptual and memory processes involved in real-world tasks have rarely been studied jointly.

To understand why perceptual processes might introduce errors to real-world color memory tasks, consider again Fig. 1. Items at the store are viewed under different illumination and surrounded by different surfaces than they are at home. Thus, the light that reaches the eye from the scarf in the two locations is also different (two circles in Fig. 1). Maintaining stability of color appearance across such changes in the illumination and surrounding surfaces, an ability known as color constancy, poses a challenge for the perceptual system. Although failures of color constancy are rarely salient features of visual experience, a large body of empirical research demonstrates that color constancy is imperfect (see Brainard and Radonjic (2014), Foster (2011), Shevell and Kingdom (2008), and Smithson (2005), for review). The pattern of errors made by observers is well understood: observers typically fail to compensate entirely for the physical change in chromaticity of the light reflected by an object that is caused by a change in the illuminant.

Here we sought to address two questions: (1) How does long-term memory affect the representation (both bias and variability) of color? (2) How does changing the context between encoding and retrieval-that is, adding the perceptual demands associated with color constancy -affect that long-term memory representation? To address these questions, we asked observers to identify the paint color of real, three-dimensional study objects as we independently manipulated the delay between seeing the study object and identifying its paint color, the illumination under which the matching paint color was identified and the color of the surface surrounding the study object.

Predictions for long-term memory

Consistent with intuition, there is consensus that memory introduces errors in color tasks, although there is considerable disagreement about the type and magnitude of errors introduced by memory for color. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.