DOI: 10.5061/dryad.280gb5mz4
title: Feature selective adaptation of numerosity perception

description: Perceptual adaptation has been widely used to infer the existence of
 numerosity detectors, enabling animals to quickly estimate the number of
 objects in a scene. Here we investigated, in humans, whether numerosity
 adaptation is influenced by stimuli features changes as previous research
 suggested that adaptation is more pronounced when adapting and test
 stimuli share the same color. We tested whether such adaptation reduction
 is due to a novelty effect (due to changing stimulus features) or changes
 of stimuli identity. Numerosity adaptation was measured for stimuli
 matched or unmatched for low-level (color, luminance, shape, motion) or
 high-level (letters' identity, face emotions) features. Robust
 numerosity adaptation occurred in all conditions but it was reduced when
 adapting and test stimuli differed for color, luminance, and shape.
 However, no reduction was observed between moving and still stimuli, a
 readable change that did not affect item’s identity. Similarly, changes in
 letters' spatial rotations or face features did not affect adaptation
 magnitude. Image dissimilarity, quantified by Gabor filters modeling V1
 predicted numerosity adaptation strength. These findings suggest that
 low-level feature changes, rather than novelty per sè, affect adaptation
 strength with numerosity mechanisms operating on categorized items in
 addition to the total quantity of the set.
description: # Feature selective adaptation of numerosity perception
 [https://doi.org/10.5061/dryad.280gb5mz4](https://doi.org/10.5061/dryad.280gb5mz4) We investigated, in humans, whether numerosity adaptation is influenced by stimuli features changes as previous research suggested that adaptation is more pronounced when adapting and test stimuli share the same color. Numerosity adaptation was measured for stimuli matched or unmatched for low-level (Experiment 1: color, Experiment 2: luminance, Experiment 3: shape, Experiment 4: motion) or high-level (Experiment 5: letters' identity, Experiment 6:face emotions) features. Across all experiments, a total of 56 participants took part in the study (mean age: 25.2, standard deviation: 3.9, 37 females). Each participant performed one or more of six different experiments which differed in the type of feature characterizing the arrays of visual stimuli. Each experiment aimed at investigating whether and to what extent the congruency between the adapting and adapted stimuli for a given feature modulated the magnitude of the adaptation aftereffects. To this end, each session comprised trials in which adaptor and test were identical (congruent condition) and trials in which they differed for a given feature (incongruent condition) with the two conditions presented interleaved. ## Description of the data and file structure The .xlsx file contains the points of subjective equality (PSEs) separately measured for each of the 6 experiments (see first row for the name of the experiment) and participant . For each experiment, columns show: 1) the participant id (not necessarily consistent across experiments), 2) the PSEs measured in the baseline condition (PSE baseline), 3) the PSE measured in the adaptation condition in which adaptor and test stimuli were congruent (PSE congruent), and 4-6) the PSE values measured in the adaptation conditions in which adaptor and test stimuli were incongruent (PSE incongruent).