Time estimation relative to response inhibition in the differential reinforcement of low-rate responding in young adults

Abstract With recent proposal suggests the multifaceted nature of impulsivity, researchers have been intrigued by the question of whether the impulsive behaviour measured in the traditionally psychological paradigms is unitary. One such paradigm, the differential reinforcement of low-rate responding (DRL), has been used to assess response inhibition, but its’ underlying mechanism has still been debated. In the present research, we examined and differentiated the effects of both response inhibition and time estimation on a multisession DRL-10 seconds (DRL-10s) in a large sample of normal young adults, as well as with three other measures including the stop-signal reaction task (SSRT), time production task-10 seconds (TPT-10s), and the Barrett impulsivity scale-11 (BIS-11). The results showed that individual differences existed in DRL. High efficiency adults produced more reinforced responses, peak rate, and longer peak time, with fewer numbers of total, non-reinforced, and burst responses than low efficiency adults. Most importantly, principal component analysis yielded significant loadings for both efficiency ratio and peak time in the last DRL session with the accuracy of TPT-10s, but none of the DRL indices had loadings with SSRT. In sum, the differential degrees of involvement of the timing process, relative to response inhibition, were observed in DRL.