# Perceptual resolution of ambiguity: A divisive normalization account for both interocular color grouping and difference enhancement

## TL;DR

This paper explains how the brain resolves visual ambiguity using a model that can enhance either similarities or differences in color stimuli.

## Contribution

The study introduces a divisive normalization framework that unifies explanations for both similarity-based and difference-enhanced perceptual outcomes.

## Key findings

- Divisive normalization can account for similarity enhancement in perceptual grouping.
- The model also explains difference enhancement during binocular rivalry.
- Empirical and simulated results support the framework's ability to explain opposite perceptual outcomes.

## Abstract

Our visual system usually provides a unique and functional representation of the external world. At times, however, there is more than one compelling interpretation of the same retinal stimulus; in this case, neural populations compete for perceptual dominance to resolve ambiguity. Spatial and temporal context can guide this perceptual experience. Recent evidence shows that ambiguous retinal stimuli are sometimes resolved by enhancing either similarities or differences among multiple ambiguous stimuli. Although rivalry has traditionally been attributed to differences in stimulus strength, color vision introduces nonlinearities that are difficult to reconcile with luminance-based models. Here, it is shown that a tuned, divisive normalization framework can explain how perceptual selection can flexibly yield either similarity-based “grouped” percepts or difference-enhanced percepts during binocular rivalry. Empirical and simulated results show that divisive normalization can account for perceptual representations of either similarity enhancement (so-called grouping) or difference enhancement, offering a unified framework for opposite perceptual outcomes.