IPSY - Kolloquium mit Dr. Aleshin
"Development of perceptual dynamics and behaviour with age and gender, as revealed by binocular rivalry dynamics"
Perceptual function is known to change over the course of development and maturation and also to depend on gender and mental health. Here we show that the dynamics of binocular rivalry (BR), if established with sufficient precision, is a sensitive index for perceptual differences between different populations.
We established the statistical distribution of 'dominance periods' during BR i.e., mean, variance, and skewness -- in neuro-typical cohorts at different stages of development and maturation (females and males, aged 12 to over 60) as well as in non-typical cohorts diagnosed with autism spectrum disorder and borderline personality disorder. To attain sufficient precision in comparatively short measurement periods, we relied on an improved non-report paradigm which uses optokinetic nystagmus (OKN) to determine BR reversals with 100 ms precision.
Our empirical results confirm clearly distinct developmental trajectories for neuro-typical females (peaking at age 19) and males (peaking at age 24). Non-typical groups fall clearly outside both trajectories. To go beyond these descriptive results, we reproduced the observed statistics with a stochastic dynamical model for multistable perception, combining inhibition (between alternative representations), adaptation (of dominant representations), and intrinsic noise (in each representation). By fitting this model to the observations from each cohort, we could encapsulate key aspects of the perceptual dynamics and predict perceptual performance under more general conditions.
In particular, we used in silico experiments to predict reversals of BR in response to randomly fluctuating inputs. These experiments predict the relative influence on perception of external stimulation (input bias) and internal state (adaptation bias). We further predict perceptual performance in terms of 'sensitivity', 'stability', and 'exploration'.
We conclude that a quantitative and model-based analysis of BR dynamics reveals simple and interpretable group differences, corroborating and extending prior developmental and psychopathological findings. Our results reveal clear differences between males and females in both the time course and direction of development of the dynamical regime of perception. Finally, our approach opens up new territories in computational psychiatry by showing the profound power of theoretical models on predicting complex behaviour and departures from the norm.
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