Development of inhibitory control across the life span.

The stop-signal procedure was used to examine the development of inhibitory control. A group of 275 participants, 6 to 81 years of age, performed a visual choice reaction time (go) task and attempted to inhibit their responses to the go task when they heard a stop signal. Reaction times to the stop and go signals were used to assess performance in inhibition and response execution, respectively. Results indicated the speed of stopping becomes faster with increasing age throughout childhood, with limited evidence of slowing across adulthood. By contrast, strong evidence was obtained for age-related speeding of go-signal reaction time throughout childhood, followed by marked slowing throughout adulthood. Hierarchical regression confirmed that the age-related change in inhibitory control could not be explained by general speeding or slowing of responses. Findings are discussed in regard to the contrast between the development of inhibition and response execution and the utility of the stop-signal procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automaticity of cognitive control: Goal priming in response-inhibition paradigms.

Response inhibition is a hallmark of cognitive control. An executive system inhibits responses by activating a stop goal when a stop signal is presented. The authors asked whether the stop goal could be primed by task-irrelevant information in stop-signal and go/no-go paradigms. In Experiment 1, the task-irrelevant primes GO, ###, or STOP were presented in the go stimulus. Go performance was slower for STOP than for ### or GO. This suggests that the stop goal was primed by task-irrelevant information. In Experiment 2, STOP primed the stop goal only in conditions in which the goal was relevant to the task context. In Experiment 3, GO, ###, or STOP were presented as stop signals. Stop performance was slower for GO than for ### or STOP. These findings suggest that task goals can be primed and that response inhibition and executive control can be influenced by automatic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proactive adjustments of response strategies in the stop-signal paradigm.

In the stop-signal paradigm, fast responses are harder to inhibit than slow responses, so subjects must balance speed in the go task with successful stopping in the stop task. In theory, subjects achieve this balance by adjusting response thresholds for the go task, making proactive adjustments in response to instructions that indicate that relevant stop signals are likely to occur. The 5 experiments reported here tested this theoretical claim, presenting cues that indicated whether or not stop signals were relevant for the next few trials. Subjects made proactive response-strategy adjustments in each experiment: Diffusion-model fits showed that response threshold increased when participants expected stop signals to occur, slowing go responses and increasing accuracy. Furthermore, the results show that subjects can make proactive response-strategy adjustments on a trial-by-trial basis, suggesting a flexible cognitive system that can proactively adjust itself in changing environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the ability to inhibit thought and action: A theory of an act of control.

Presents a theory of the inhibition of thought and action to account for people's performance in situations that require them to stop or change their current thoughts and actions. The theory proposes that a control signal, such as an external stop signal or an error during performance, starts a stopping process that races against the processes underlying ongoing thought and action. If the stopping process wins, thought and action are inhibited; if the ongoing process wins, thought and action run on to completion. The theory is formally developed to account for many aspects of performance in situations with explicit stop signals, and it is applied to data obtained from 3 adult observers in a series of RT tasks. The relation between response inhibition and other acts of control in motor performance and in cognition is discussed, and the implications of the theory are considered in terms of current thinking about attentional control and automaticity. (69 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blindness to response-compatible stimuli.

This contribution is devoted to the question of whether action-control processes may be demonstrated to influence perception. This influence is predicted from a framework in which stimulus processing and action control are assumed to share common codes, thus possibly interfering with each other. In 5 experiments, a paradigm was used that required a motor action during the presentation of a stimulus. The participants were presented with masked right- or left-pointing arrows shortly before executing an already prepared left or right keypress response. We found that the identification probability of the arrow was reduced when the to-be-executed reaction was compatible with the presented arrow. For example, the perception of a right-pointing arrow was impaired when presented during the execution of a right response as compared with that of a left response. The theoretical implications of this finding as well as its relation to other, seemingly similar phenomena (repetition blindness, inhibition of return, psychological refractory period) are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The psychological refractory period of stopping.

The author examined whether the act of control of stopping is subject to the psychological refractory period (PRP) and whether stopping causes a PRP for the processing of subsequent stimuli. The task was to execute or to stop a rapid finger tapping. PRP interference was predicted for double-stimulation trials, in which 2 signals to tap or stop were presented in rapid succession. The experiments showed that stopping ongoing action is subject to and produces PRP interference similar to starting. Responses to signals to continue an ongoing action do not produce PRP interference. The results suggest that selection or initiation of new responses, but not mere response choice, constituted the processing bottleneck that caused the PRP in the present task. Further results indicate that the inhibition of not-yet-executed actions, in contrast to action termination, does not suffer PRP interference and that response inhibitions and terminations should be distinguished. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear detection and visual awareness in perceiving bodily expressions.

Many research reports have concluded that emotional information can be processed without observers being aware of it. The case for perception without awareness has almost always been made with the use of facial expressions. In view of the similarities between facial and bodily expressions for rapid perception and communication of emotional signals, we conjectured that perception of bodily expressions may also not necessarily require visual awareness. Our study investigates the role of visual awareness in the perception of bodily expressions using a backward masking technique in combination with confidence ratings on a trial-by-trial basis. Participants had to detect in three separate experiments masked fearful, angry and happy bodily expressions among masked neutral bodily actions as distractors and subsequently the participants had to indicate their confidence. The onset between target and mask (Stimulus Onset Asynchrony, SOA) varied from ?50 to +133 ms. Sensitivity measurements (d-prime) as well as the confidence of the participants showed that the bodies could be detected reliably in all SOA conditions. In an important finding, a lack of covariance was observed between the objective and subjective measurements when the participants had to detect fearful bodily expressions, yet this was not the case when participants had to detect happy or angry bodily expressions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effects of d-Amphetamine and ethanol on a measure of behavioral inhibition in humans.

Little is known about the acute effects of psychoactive drugs on impulsivity and decision making in humans. This study examined the effects of d-amphetamine (AMP; 10 and 20 mg; N?=?20) and ethanol (EtOH; 0.2, 0.4, and 0.8 g/kg; N?=?17) on the stop task, a putative measure of behavioral inhibition and impulsivity in healthy human volunteers. The stop task provides a measure of the reaction time (RT) needed to inhibit a response (Stop RT [SRT]), relative to the time taken to execute a simple response (Go RT [GRT]). Healthy volunteers performed the stop task before and after receiving one of the drugs. AMP decreased SRT–that is, improved inhibition–only in participants with slow baseline SRTs. EtOH increased SRTs–that is, impaired inhibition–at doses that did not affect GRTs. These results suggest that AMP and EtOH have specific and distinctive effects on the ability to inhibit responses. Impairment in the ability to inhibit responses is thought to reflect a certain form of impulsivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active masks and active inhibition: A comment on Lleras and Enns (2004) and on Verleger, Ja?kowski, Aydemir, van der Lubbe, and Groen (2004).

Verleger, Ja?kowski, Aydemir, van der Lubbe, and Groen (see record 2004-21166-002) and Lleras and Enns (see record 2004-21166-001) have argued that negative compatibility effects (NCEs) obtained with masked primes do not reflect self-inhibition processes in motor control. Instead, NCEs are assumed to reflect activation of the response opposite to the prime, triggered by the presence of prime/targetlike features in the mask. Thus, no NCEs should be elicited when masks do not contain such task-relevant features. In Experiments 1 and 3, the authors demonstrate that NCEs can be obtained when masks contain only irrelevant features. Experiment 2 demonstrates that positive compatibility effects (PCEs) will occur with such masks when masked primes are presented peripherally. These results are inconsistent with the mask-induced activation accounts but are in line with the self-inhibition hypothesis of the NCE. Although perceptual interactions and mask-induced motor activations may contribute to NCEs under certain conditions, they cannot provide a full explanation for these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Amodio et al. (2008).

Reports an error in "Individual differences in the regulation of intergroup bias: The role of conflict monitoring and neural signals for control" by David M. Amodio, Patricia G. Devine and Eddie Harmon-Jones (Journal of Personality and Social Psychology, 2008[Jan], Vol 94[1], 60-74). In this article, there was an error in Figure 4. The corrected figure is provided in this erratum. (The following abstract of the original article appeared in record 2007-19165-005.) Low-prejudice people vary considerably in their ability to regulate intergroup responses. The authors hypothesized that this variability arises from a neural mechanism for monitoring conflict between automatic race-biased tendencies and egalitarian intentions. In Study 1, they found that low-prejudice participants whose nonprejudiced responses are motivated by internal (but not external) factors exhibited better control on a stereotype-inhibition task than did participants motivated by a combination of internal and external factors. This difference was associated with greater conflict-monitoring activity, measured by event-related potentials, when responses required stereotype inhibition. Study 2 demonstrated that group differences were specific to response control in the domain of prejudice. Results indicate that conflict monitoring, a preconscious component of response control, accounts for variability in intergroup bias among low-prejudice participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How does bilingualism improve executive control? A comparison of active and reactive inhibition mechanisms.

It has been claimed that bilingualism enhances inhibitory control, but the available evidence is equivocal. The authors evaluated several possible versions of the inhibition hypothesis by comparing monolinguals and bilinguals with regard to stop signal performance, inhibition of return, and the attentional blink. These three phenomena, it can be argued, tap into different aspects of inhibition. Monolinguals and bilinguals did not differ in stop signal reaction time and thus were comparable in terms of active-inhibitory efficiency. However, bilinguals showed no facilitation from spatial cues, showed a strong inhibition of return effect, and exhibited a more pronounced attentional blink. These results suggest that bilinguals do not differ from monolinguals in terms of active inhibition but have acquired a better ability to maintain action goals and to use them to bias goal-related information. Under some circumstances, this ability may indirectly lead to more pronounced reactive inhibition of irrelevant information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Smiles make it easier and so do frowns: Masked affective stimuli influence mental effort.

Two experiments tested the hypothesis that exposure to masked emotional expressions during the performance of cognitive tasks influences effort mobilization. In support of the predictions, participants who processed masked sad faces during task performance under “do your best” instructions showed stronger sympathetic nervous system discharge to the heart (shorter pre-ejection period, higher systolic blood pressure) than participants who were exposed to masked smiling faces or angry faces. Assessed task appraisals suggest that these effects on effort-related cardiovascular reactivity occurred because the masked emotional stimuli influenced the level of experienced task difficulty. The findings are compatible with the effects of consciously experienced affect on effort-related cardiovascular response. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Inhibitory Control in Rats Performing a Stop-Signal Reaction-Time Task: Effects of Lesions of the Medial Striatum and d-Amphetamine.

The stop-signal task measures the ability to inhibit a response that has already been initiated, that is, the ability to stop. Imaging studies have implicated frontostriatal circuitry in the mediation of this form of response control. The authors report inhibition functions of normal rats and those with medial striatal damage performing the stop-signal task. Excitotoxic lesions of the medial striatum produced significant deficits on task performance, including increased omissions on the go task and flattened inhibition function, possibly as a result of increased reaction-time mean and variability. Medial striatal lesions also significantly slowed stop-signal reaction time. Subsequent treatment with d-amphetamine removed (0.3 mg/kg) or exacerbated (1.0 mg/kg) this deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulating the masked congruence priming effect with the hands and the mouth.

The authors report a series of experiments in which they use the masked congruence priming paradigm to investigate the processing of masked primes in the manual and verbal response modalities. In the manual response modality, they found that masked incongruent primes produced interference relative to both congruent and neutral primes. This finding, which replicates the standard finding in the masked congruence priming literature, is presumed to reflect the conflict that arises between two incompatible responses and, thus, to index the extent of processing of the masked prime. Somewhat surprisingly, when participants were asked to respond verbally in the same task, masked incongruent primes no longer produced interference, but masked congruent primes produced facilitation. These findings are surprising because they suggest that the processing of nonconsciously perceived primes extends to the response level in the manual, but not verbal, response modality. The authors propose that the modulation of the masked congruence priming effect by response modality is due to verbal, but not manual, responses being mediated by the lexical-phonological production system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Indirect regulation of translational termination efficiency at highly expressed genes and recoding sites by the factor recycling function of Escherichia coli release factor RF3

Prokaryotic release factor RF3 is a stimulatory protein that increases the rate of translational termination by the decoding release factors RF1 and RF2. The favoured model for RF3 function is the recycling of RF1 and RF2 after polypeptide release by displacing the factors from the ribosome. In this study, we have demonstrated that RF3 also plays an indirect role in the decoding of stop signals of highly expressed genes and recoding sites by accentuating the influence of the base following the stop codon (+4 base) on termination signal strength. The efficiency of decoding strong stop signals (e.g. UAAU and UAAG) in vivo is markedly improved with increased RF3 activity, while weak signals (UGAC and UAGC) are only modestly affected. However, RF3 is not responsible for the +4 base influence on termination signal strength, since prfC- strains lacking the protein still exhibit the same qualitative effect. The differential effect of RF3 at stop signals can be mimicked by modest overexpression of decoding RF. These findings can be interpreted according to current views of RF3 as a recycling factor, which functions to maintain the concentration of free decoding RF at stop signals, some of which are highly responsive to changes in RF levels.     

Evaluation of genetic variability in the dopamine receptor D2 in relation to behavioral inhibition and impulsivity/sensation seeking: An exploratory study with d-amphetamine in healthy participants.

The dopamine D2 receptor (DRD2) appears to be involved in impulsive behaviors, and particularly in behavioral inhibition. We sought to determine whether inhibition and impulsivity were related to genetic polymorphisms in the DRD2 gene (DRD2) in healthy volunteers (N = 93). Participants received placebo or d-amphetamine in random order. They performed the stop task, measuring behavioral inhibition, and rated their mood states on each session. They also completed the Zuckerman–Kuhlman Personality Questionnaire, including an Impulsivity subscale. We investigated the association between 12 single nucleotide polymorphisms (SNPs) and haplotypes in DRD2 and stop task performance in the nondrug (i.e., placebo) session and on the personality measure of impulsivity. We secondarily evaluated the DRD2 SNPs in relation to response to d-amphetamine on stop task performance and mood ratings. Mood was not related to genotypes in either the drug free condition or in response to drug. However, 2 SNPs, rs4648317 and rs12364283, and a haplotype block consisting of those SNPs, were associated with better performance on the stop task in the drug free condition and lower scores on the Impulsivity subscale. We also found that rs12364283 was associated with effects of d-amphetamine on stop task performance: d-amphetamine decreased stop reaction time (RT) in the A/A group but increased stop RT in the combined A/G + G/G genotype. Of the SNPs we evaluated, rs12364283, which has been associated with DRD2 expression, was the most significantly associated with inhibition and impulsivity. The significant relationship between DRD2 genotype and both behavioral inhibition and impulsivity suggests a possible common genetic influence on behavioral and self-report measures of impulsivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Balancing cognitive demands: Control adjustments in the stop-signal paradigm.

Cognitive control enables flexible interaction with a dynamic environment. In 2 experiments, the authors investigated control adjustments in the stop-signal paradigm, a procedure that requires balancing speed (going) and caution (stopping) in a dual-task environment. Focusing on the slowing of go reaction times after stop signals, the authors tested 5 competing hypotheses for post-stop-signal adjustments: goal priority, error detection, conflict monitoring, surprise, and memory. Reaction times increased after both successful and failed inhibition, consistent with the goal priority hypothesis and inconsistent with the error detection and conflict hypotheses. Post-stop-signal slowing was greater if the go task stimulus repeated on consecutive trials, suggesting a contribution of memory. We also found evidence for slowing based on more than the immediately preceding stop signal. Post-stop-signal slowing was greater when stop signals occurred more frequently (Experiment 1), inconsistent with the surprise hypothesis, and when inhibition failed more frequently (Experiment 2). This suggests that more global manipulations encompassing many trials affect post-stop-signal adjustments. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Unconscious priming of association judgments.

Participants judged whether pairs of target words were associated or not-associated in meaning (association judgment task). Target pairs were preceded by a brief (200 ms) related or unrelated (prime) word presented to the nondominant eye. Each participant performed 2 blocks of association judgment task trials: 1 with primes that were legible, and 1 with primes that were masked by a pattern simultaneously presented to the dominant eye. Across 2 experiments, significantly larger masked priming effects were observed for participants who could not detect priming words (low-d′ participants) than for participants who could partially see priming words (high-d′ participants). This result suggests that undetectable masked primes can activate word meaning and that conscious attempts to process masked primes may inhibit unconscious activation. Additionally, evidence is presented that supports claims that spreading activation is the crucial mechanism responsible for unconscious priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the control of single-prime negative priming: The effects of practice and time course.

Single-prime negative priming refers to the phenomenon wherein repetition of a prime as the probe target results in delayed response. Sometimes this effect has been found to be contingent on participants’ unawareness of the primes, and sometimes it has not. Further, sometimes this effect has been found to be eliminated when the prime could predict the following probe target, and sometimes it has not. An integrative account is postulated to account for these findings. Three experiments supported this account by demonstrating that (a) regardless of the proportion of prime repetition, negative priming was the default effect; (b) the control mechanism was triggered to activate the prime after there was enough practice for the detection of the contingency between the prime and probe; and (c) it took time for the control mechanism to overcome the negative-priming effect and produce a positive-priming effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bottom-up influences on voluntary task switching: The elusive homunculus escapes.

Voluntary action can be studied by giving participants free choice over which task to perform in response to each presented stimulus. In such experiments, performance costs are observed when participants choose to switch tasks from the previous trial. It has been proposed that these costs primarily index the time-consuming operation of top-down control processes that support voluntary action. The present experiments showed, contrary to this view, that greater costs were associated with voluntary switching to the easier task of a pair. These increased switch costs for the easier task were accompanied by a reliable preference of the participants for performing the other, more difficult task. Interference between tasks during response selection was identified as the critical factor driving these effects of task difficulty. Together, the findings suggest that participants’ voluntary choices, and the time taken to execute those choices, may not directly index the operation of cognitive control but instead may reflect complex interactions between top-down and bottom-up influences on behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)