Working Memory Load Effects on the Tilt Aftereffect.

Gaoxing Mei,Mofen Cen,Xu Luo,Yun Pan,Shiming Qiu

doi:10.3389/fpsyg.2021.618712

Abstract

Prolonged exposure to an oriented stimulus causes a subsequent test stimulus to be perceived as tilted in the opposite direction, a phenomenon referred to as the tilt aftereffect (TAE). Previous studies have demonstrated that high-level cognitive functions such as attention can modulate the TAE, which is generally well-known as a low-level perceptual process. However, it is unclear whether working memory load, another high-level cognitive function, could modulate the TAE. To address this issue, here we developed a new paradigm by combining a working memory load task with a TAE task. Participants firstly remembered a stream of digits (Experiment 1) or four color-shape conjunctions (Experiment 2) under high/low load conditions, and then recognized the probe stimuli (digits or a color-shape conjunction), which were presented at the center of an adapting grating. After the recognition task (i.e., the adaptation stage), participants performed an orientation judgment task to measure their TAEs. The result of Experiment 1, where the load stimuli were digits, showed that the magnitude of the TAEs were reduced under the condition of the high working memory load compared to that of the low working memory load. However, we failed to replicate the finding in Experiment 2, where the load stimuli were color-shape conjunctions. Together, our two experiments provided mixed evidence regarding the working memory load effects on the TAE and further replications are needed in future work.

Highlights

Maintaining high sensitivity to an ever-changing visual environment is a fundamental characteristic of human visual system
These results indicated that the tilt aftereffect (TAE) still appeared despite being away from attentional focus for the grating adaptors
The results demonstrated a stronger magnitude of TAEs under the low relative to high working load condition (4.26◦ vs. 3.17◦, p = 0.010), indicating that high relative to low working memory load attenuated the magnitude of the TAE

Summary

Introduction

Maintaining high sensitivity to an ever-changing visual environment is a fundamental characteristic of human visual system. A typical example is the tilt aftereffect (TAE), in which prolonged exposure to an oriented stimulus (e.g., a grating tilted at 15◦ clockwise from vertical) causes a subsequent vertical stimulus (e.g., a vertical grating) to appear to be tilted in the opposite direction (e.g., slightly counterclockwise tilt from vertical) (Gibson and Radner, 1937) It is well-known that the TAE is a low-level perceptual process in the primary visual cortex (e.g., Blakemore et al, 1970), several psychophysical results have shown that attention, as a high-level cognitive function, can increase the magnitude of the TAE (Spivey and Spirn, 2000; Festman and Ahissar, 2004; Montaser-Kouhsari and Rajimehr, 2004; Jung and Chong, 2014; Pavan et al, 2016). These psychophysical and neuroimaging results indicate that attention modulates the low-level TAE originated from the primary visual cortex

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