Male Smokers' and Non-Smokers' Response Inhibition in Go/No-Go Tasks: Effect of Three Task Parameters

Abstract

Impaired response inhibition plays a major role in many addictive behaviors. However, in studies using go/no-go tasks, findings regarding the presence of response inhibition deficits in nicotine-dependent individuals are mixed. This might be due to differences between studies on a number of task parameters. Here we aimed to identify task conditions under which go/no-go task performance deficits can be observed in smokers and to characterize the nature of such deficits. Sixty-one male students (30 smokers, 31 non-smokers) performed a go/no-go task while independently manipulating three task parameters: (1) percentage no-go trials (50% or 25%), (2) stimulus presentation time (600 ms or 200 ms), and (3) nature of no-go stimuli (cigarette related or cigarette unrelated). Three measures, reaction time on go trials and percentage correct responses on go and no-go trials, served as performance indicators. Under 200-ms but not 600-ms stimulus presentation conditions, the smokers responded faster on go trials and made more errors on both go and no-go trials than the non-smokers did. These differences occurred irrespective of the percentage of no-go trials and nature of no-go stimuli. The accuracy differences disappeared after controlling for the response time differences, suggesting a strong speed-accuracy trade-off. This study contributes to unraveling the conditions under which smokers display impaired inhibition performance and helps to characterize the nature of this impairment. Under task conditions prompting fast responding, smokers are more prone to increase response speed and to make more errors than non-smokers.

Fig 1. Example of a trial with a cigarette-related and cigarette-unrelated picture in the go/no-go task.

Fig 2

Left: Mean reaction time (+ SEM) of smokers and non-smokers on go trials of the 600-ms stimulus presentation time blocks. Values are presented separately for each no-go stimulus percentage and stimulus type condition. The only significant effect was faster overall responding on the 25% no-go trials condition than the 50% condition (p < 0.001). Right: Mean (+ SEM) proportion of trials of the 600-ms stimulus presentation time blocks on which smokers and non-smokers correctly omitted responding to the no-go stimulus, separately for each no-go stimulus percentage and stimulus type condition. The only significant effect was a higher accuracy rate for the 50% no-go trials condition than the 25% condition (p < 0.001).

Fig 3

Left: Mean reaction time (+ SEM) of smokers and non-smokers on go trials of the 200-ms stimulus presentation time blocks. Values are presented separately for each no-go stimulus percentage and stimulus type condition. Overall, smokers responded faster than non-smokers (p < 0.001), and the 25% no-go trial condition elicited faster responding than the 50% condition (p = 0.01), especially for smokers (p < 0.001). Middle: Mean (+ SD) proportion of trials of the 200-ms stimulus presentation time blocks on which smokers and non-smokers correctly omitted responding to the no-go stimulus. Overall, non-smokers were more accurate than smokers (p = 0.001) and response accuracy was larger in the 50% no-go trial condition than the 25% condition (p < 0.001). Right: Mean (+ SD) proportion of trials of the 200-ms stimulus presentation time blocks on which smokers and non-smokers responded to the go stimulus. Overall, non-smokers were more accurate than smokers (p = 0.001) and response accuracy was larger in the 50% no-go trial condition than the 25% condition (p < 0.001), especially for the smokers (p < 0.001).