Dissociable effects of fear and disgust in proactive and reactive inhibition

Numerous studies have demonstrated that negative emotional distracters impair inhibitory control. Nevertheless, two issues have emerged in prior studies. First, fear and disgust were inappropriately treated as a single category, which is particularly concerning given that they have been recently demonstrated to exert different impacts on inhibitory control. Second, inhibitory control might not be a unitary construct, as it can be further divided into proactive and reactive inhibition. Therefore, the present study aimed to investigate whether fearful and disgusting distracters have differential effects on proactive and reactive inhibition. Twenty-four female participants were instructed to perform a modified stop-signal task superimposed on a fearful, disgusting, or neutral image cue. Results showed that fearful distracters improved reactive inhibition when compared to disgusting and neutral distracters, while disgusting distracters enhanced proactive inhibition when compared to fearful distracters. Further, reactive and proactive inhibition was positively correlated under fearful, disgusting, and neutral contexts. This study is the first to provide evidence that fear and disgust may affect proactive and reactive inhibition differently. These results add to a growing literature linking emotion and inhibitory control, and they expand our understanding of the relationship between emotion and inhibition.     

Action-centred negative priming: Evidence for reactive inhibition

Experiments are described in which the spatial relationship between a stimulus and respondent is held constant in terms of visual and body-centred coordinates, while the complexity of the response is manipulated. It is demonstrated that the degree of complexity of an action directed to the same spatial location determines the level of negative priming observed. This result supports the notions that (1) inhibitory selection mechanisms act on action-centred representations, and (2) the level of inhibition is reactive to the relative potency of the evoked action. The results are also discussed in terms of alternative explanations of negative priming. It is concluded that the results are inconsistent with theories that do not involve inhibitory selection mechanisms.     

The physical properties of bar-pressing behaviour and the problem of reactive inhibition

Many of the terms used in the literature on reactive inhibition are vague, subjective or incorrect. The weighted bar is not a suitable device in the study of this problem, since it records irrelevant aspects of behaviour. An experiment using apparatus which gives a continuous record of the force which a rat applies to a knob produces the following results. After much practice, pressing becomes sharp and brief and the amount of activity per reward is reduced. Under conditions of no (intentional) secondary reward the amount of activity during extinction is at first positively correlated with the average activity per reward during training, but the correlation diminishes as extinction proceeds. With auditory secondary reward there is no correlation.     

Reward prospect rapidly speeds up response inhibition via reactive control

Response inhibition is an important cognitive-control function that allows for already-initiated or habitual behavioral responses to be promptly withheld when needed. A typical paradigm to study this function is the stop-signal task. From this task, the stop-signal response time (SSRT) can be derived, which indexes how rapidly an already-initiated response can be canceled. Typically, SSRTs range around 200 ms, identifying response inhibition as a particularly rapid cognitive-control process. Even so, it has recently been shown that SSRTs can be further accelerated if successful response inhibition is rewarded. Since this earlier study effectively ruled out differential preparatory (proactive) control adjustments, the reward benefits likely relied on boosted reactive control. Yet, given how rapidly such control processes would need to be enhanced, alternative explanations circumventing reactive control are important to consider. We addressed this question with an fMRI study by gauging the overlap of the brain networks associated with reward-related and response-inhibition-related processes in a reward-modulated stop-signal task. In line with the view that reactive control can indeed be boosted swiftly by reward availability, we found that the activity in key brain areas related to response inhibition was enhanced for reward-related stop trials. Furthermore, we observed that this beneficial reward effect was triggered by enhanced connectivity between task-unspecific (reward-related) and task-specific (inhibition-related) areas in the medial prefrontal cortex (mPFC). The present data hence suggest that reward information can be translated very rapidly into behavioral benefits (here, within ~200 ms) through enhanced reactive control, underscoring the immediate responsiveness of such control processes to reward availability in general.     

Training and transfer effects of response inhibition training in children and adults

Response inhibition is crucial for mental and physical health but studies assessing the trainability of this type of inhibition are rare. Thirty‐nine children aged 10‐12 years and 46 adults aged 18‐24 years were assigned to an adaptive go/no‐go inhibition training condition or an active control condition. Transfer of training effects to performance on tasks assessing response inhibition, interference control, working memory updating, task‐switching, and non‐verbal fluid intelligence were assessed during 3‐ and 6‐month follow‐up sessions and/or an immediate post‐training session. Significant training improvements and positive transfer effects to a similar response inhibition task with other stimuli were observed for both children and adults. Reliable albeit short‐lived transfer effects were only found for the children, specifically to working memory updating and task switching. These results suggest some potential for response‐inhibition training programs to enhance aspects of cognitive functioning in children but not adults.     

Proactive versus reactive task-set inhibition: Evidence from flanker compatibility effects

Two converging tests were used to determine whether people proactively inhibit recently performed tasks when switching to new tasks. A task-cuing paradigm was used. In each trial, the relevant stimulus was accompanied by flankers belonging either to the task performed on the immediately preceding trial (lag 1) or a more distant trial (lag 21). If the just-performed task is inhibited when switching to another task, and this inhibition declines across trials, then flanker interference should be smaller with lag 1 flankers than with lag 21 flankers. Experiment 1, following the methods of Hübner, Dreisbach, Haider, and Kluwe (2003), failed to confirm this prediction. The prediction was confirmed in Experiment 2, however, using a design modified to provide greater incentives for task-set inhibition. The results provide evidence that inhibition can be applied proactively, to reduce the ability of an abandoned task to interfere with the performance of other tasks.     

Plasticity of inhibition in older adults: Retest practice and transfer effects

This study assessed plasticity of inhibition in older adults through examining retest practice effects in a six-session training paradigm using the Stroop task and the training-induced transfer effects to a range of cognitive measures. Fifty-six older adults (aged 60-84 years, mean = 71.05, standard deviation = 6.17) participated in this study. They were evenly assigned to one of four groups: summary feedback, individualized and adaptive feedback, no-feedback, or a no-contact control group. The results suggest that older adults are able to improve inhibition across retest sessions but unable to transfer the retest practice effects to other tasks. In addition, the improvement is not item specific and feedback does not appear to moderate the magnitude of the training benefits; however, feedback does appear to reduce interference variance across retest practice sessions. (PsycINFO Database Record (c) 2012 APA, all rights reserved).