The article explores the phenomenon of perceptual rivalry, particularly binocular rivalry (BR) and ambiguous figure rivalry (AFR), in humans and flies. It highlights the clinical significance of BR rate differences in bipolar disorder (BD), suggesting that slow BR rate could serve as a biological marker for the disorder. The authors discuss the genetic and molecular underpinnings of individual variation in BR rate, emphasizing the heritability and reliability of this trait. They also review the relationship between attention and rivalry, noting that attentional selection and suppression mechanisms play crucial roles in both human and fly models of rivalry. The article describes how Drosophila melanogaster, a model organism, can be used to study attentional switching and perceptual rivalry, with recent electrophysiological evidence showing alternating unilateral local field potential (LFP) activity during visual rivalry. This model is proposed as a valuable tool for understanding the genetic and molecular basis of individual variation in BR rate and its potential clinical applications.The article explores the phenomenon of perceptual rivalry, particularly binocular rivalry (BR) and ambiguous figure rivalry (AFR), in humans and flies. It highlights the clinical significance of BR rate differences in bipolar disorder (BD), suggesting that slow BR rate could serve as a biological marker for the disorder. The authors discuss the genetic and molecular underpinnings of individual variation in BR rate, emphasizing the heritability and reliability of this trait. They also review the relationship between attention and rivalry, noting that attentional selection and suppression mechanisms play crucial roles in both human and fly models of rivalry. The article describes how Drosophila melanogaster, a model organism, can be used to study attentional switching and perceptual rivalry, with recent electrophysiological evidence showing alternating unilateral local field potential (LFP) activity during visual rivalry. This model is proposed as a valuable tool for understanding the genetic and molecular basis of individual variation in BR rate and its potential clinical applications.