Slow and Steady: Training Induced Improvements to Response Time Consistency Are Due to Overall Slowing and Minimized Extremely Slow Responses

摘要

Previous studies on response time intraindividual variability (RT IIV) have focused on differences between groups, ignoring the potential for modification. The current study provides a detailed analysis of RT IIV training effects across three age groups. Healthy adults (40 young [aged 18-30], 40 young-old [aged 65-74], and 41 old-old [aged 75-85]) were assigned to feedback or no feedback (standard) conditions during a touch-screen feature integration task. In the feedback condition, participants were shown their performance on the previous block of trials and encouraged to improve going forward. Transfer was assessed by comparing pre- and posttraining performance on a 4-choice RT task. Data were analyzed with respect to RT IIV, ex-Gaussian distribution fitting, and the diffusion model of RT decision making. Significant feedback-related reductions were observed in Target RT IIV and the ex-Gaussian parameter tau, accompanied by an increase in mu. There was no significant change in sigma, and no evidence of transfer to the 4-choice RT task. The diffusion model analysis indicated that feedback training promoted a reduction in response threshold for the young and young-old groups, as well as a modulation of drift rate throughout training in the young group. The findings indicate that training to improve consistency induces overall slowing, but also reduces the frequency of extremely slow responses that have been linked to brief attention lapses. The results provide evidence that RT consistency is malleable, but improvements are not necessarily transferable.