Serial dependence in numerosity perception.
Michele Fornaciai1, Joonkoo Park1,2; 1University of Massachusetts, Amherst, MA, USA., 2Commonwealth Honors College, Amherst, MA, USA.
Attractive serial dependence represents an adaptive change in the representation of sensory information, whereby current stimuli appear more similar to previous ones. Here, we characterize the behavioral and neural signatures of serial dependence in numerosity perception, demonstrating that the perceived numerosity of dot-array stimuli in different numerical ranges is biased by a preceding irrelevant stimulus (“inducer”) in an attractive way. First, we show that this effect has a weak spatial specificity and a relatively broad tuning for numerosity, and that it has a clear cortical origin (rather than subcortical). Second, we show that the attractive effect is stronger when a discrimination task involves a sequential presentation of the stimuli, rather than a simultaneous presentation, suggesting that the biases are potentially amplified at a decisional stage. Nevertheless, using electroencephalogram and a passive-viewing paradigm, we show that a neural signature of attractive serial dependence emerges even in the absence of an explicit task early in the visual stream, suggesting that serial dependence has a clear perceptual origin independently from a decision process. Our results collectively suggest that serial dependence results from a cortical neural computation starting from an early level of perceptual processing potentially subserving perceptual stability and influencing downstream cognitive stages.
Topic Area: PERCEPTION & ACTION: Vision