Abstract
The Go/No-go task is used to study voluntary control in humans. But, only a few studies have been done along with the numerosity. In this study, we explore and understand the interaction of different numerosity with voluntary control. We have designed two experiments by modifying the Go/No-go task. First with relative numerosity comparison judgment and second with subitizing/estimation judgment. In Experiment 1, initially, participants adapted to reference numerosity of N=13. In the test phase, participants compare the displayed numerosity with reference and respond accordingly. The trials can be divided into two conditions: a) where lesser numerosities are go stimulus and greater numerosities are no-go stimulus, and b) vice-versa (named as Smallgo and Largego, respectively). We have computed d-prime (d’) for two conditions separately. Results for Experiment 1 do not show any difference between Smallgo and Largego conditions across the blocks. In Experiment 2, we have eliminated the adaptation block. We have chosen two numerosity sets; one set in the subitizing range, small numerosity (<=5), and another set in large numerosity >11. Here the two conditions are a) small numerosity as go stimulus and large numerosity as a no-go, and b) vice-versa (Smallgo and Largego respectively). We have maintained the values of other variables like number of trials, ISI, number of blocks, and the ratio of go/no-go trials, from Experiment1. A two-way ANOVA yielded a main effect for two conditions (Smallgo and Largego) in Experiment 2, F(1,350)=9.94,p<0.01, such that the d’ value is significantly higher for the Smallgo than the Largego. This suggests that participants can employ voluntary control more confidently and accurately in Smallgo conditions compared to Largego conditions. The mechanistic details of such an effect need to be investigated further.