Search

In Simon-type interference tasks, participants are asked to perform a 2-choice reaction on a stimulus dimension while ignoring the stimulus position. Commonly, robust congruency effects are found; that is, reactions are faster when the relevant stimulus attribute and the assigned response match the location of the stimulus. Simon congruency effects are regularly attributed to a fast, nonverbal processing route. In 3 experiments, we tested the importance of verbal representations in the Simon effect by manipulating the format of representations (verbal vs. nonverbal) with stimulus material (i.e., words vs. gratings) and stimulus arrangement (i.e., horizontally vs. vertically). Results of the first experiment point to a modulation of the Simon effects by both factors when they were manipulated between subjects, up to an inversion of the Simon effect for words presented in vertical arrangement. We replicated the inverse congruency effect for verbal material in vertical arrangement when a within-participant design was used (Experiment 2) and when the impact of reading processes was ruled out (Experiment 3). One cause for this inversion might be the construction of language-based representations that counteract automatic processing given the stimulus arrangement. To investigate this, we assessed individual differences in the use of inner speech for self-instruction. Using hierarchical linear modeling analysis, we found that self-rated evaluative and motivational inner speech processes accounted for a significant portion of the Simon effect. This supports claims that individual differences predict performance even in simple cognitive tasks such as the Simon task and highlights the flexibility of basic cognitive processes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

In the last two decades, individual-differences research has put forward 3 cognitive psychometric constructs: executive control (i.e., the ability to monitor and control ongoing thoughts and actions), working memory capacity (WMC, i.e., the ability to retain access to a limited amount of information in the service of complex tasks), and fluid intelligence (gF, i.e., the ability to reason with novel information). These constructs have been proposed to be closely related, but previous research failed to substantiate a strong correlation between executive control and the other two constructs. This might arise from the difficulty in establishing executive control as a latent variable and from differences in the way the 3 constructs are measured (i.e., executive control is typically measured through reaction times, whereas WMC and gF are measured through accuracy). The purpose of the present study was to overcome these difficulties by measuring executive control through accuracy. Despite good reliabilities of all measures, structural equation modeling identified no coherent factor of executive control. Furthermore, WMC and gF-modeled as distinct but correlated factors-were unrelated to the individual measures of executive control. Hence, measuring executive control through accuracy did not overcome the difficulties of establishing executive control as a latent variable. These findings call into question the existence of executive control as a psychometric construct and the assumption that WMC and gF are closely related to the ability to control ongoing thoughts and actions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The purpose of the present study was to determine whether responding to multiple concurrent conflicts results in a simultaneous or sequential conflict resolution. To this end, we measured event-related potentials (ERPs) in a paradigm combining a Stroop and a flanker task. In this paradigm, participants were asked to respond to the color of the central letter while ignoring the meaning of the word (Stroop task) and the color of the flanking letters (flanker task). Trials were either incongruent (i.e., inducing a conflict between two response alternatives) or congruent (i.e., inducing no response conflict) in both tasks, or incongruent in one task and congruent in the other task. The behavioral results showed a smaller Stroop congruency effect (i.e., a smaller difference between Stroop incongruent and congruent trials) for flanker incongruent than for flanker congruent trials, replicating previous findings. The ERP results showed that an early ERP component (i.e., P2) was associated with the resolution of the flanker conflict, whereas a later component (i.e., N450) was associated with the resolution of the Stroop conflict. Together, these findings emphasize a sequential organization of conflict resolution processes in the brain which is adaptive when facing multiple concurrent conflicts., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Aging has been assumed to go along with deficient inhibitory processes in cognitive performance. According to this inhibition deficit hypothesis, older adults are less able to suppress or ignore irrelevant thoughts and actions than young adults are. This hypothesis has been investigated in a large number of studies. We conducted a meta-analysis to determine whether there is an inhibition deficit in older age and whether this deficit is general or task-specific. We selected 176 studies in which young and older adults were tested on tasks commonly assumed to measure inhibition (i.e., the color Stroop, flanker, Simon, stop-signal, go/no-go, global-local, positive and negative compatibility tasks, as well as the paradigm assessing n-2 repetition costs in task switching). For most tasks (i.e., the color Stroop, flanker, and local tasks, as well as the n-2 repetition costs), the results speak against an inhibition deficit in older age. Only in a few tasks (i.e., the go/no-go and stop-signal tasks), older adults showed impaired inhibition. Moreover, for four tasks (i.e., the Simon, global, positive and negative compatibility tasks), the results suggest that more studies are necessary to draw a firm conclusion. Together, the present findings call into question the hypothesis of a general inhibition deficit in older age.

Inhibition is often conceptualized as a unitary construct reflecting the ability to ignore and suppress irrelevant information. At the same time, it has been subdivided into inhibition of prepotent responses (i.e., the ability to stop dominant responses) and resistance to distracter interference (i.e., the ability to ignore distracting information). The present study investigated the unity and diversity of inhibition as a psychometric construct, and tested the hypothesis of an inhibition deficit in older age. We measured inhibition in young and old adults with 11 established laboratory tasks: antisaccade, stop-signal, color Stroop, number Stroop, arrow flanker, letter flanker, Simon, global-local, positive and negative compatibility tasks, and n-2 repetition costs in task switching. In both age groups, the inhibition measures from individual tasks had good reliabilities, but correlated only weakly among each other. Structural equation modeling identified a 2-factor model with factors for inhibition of prepotent responses and resistance to distracter interference. Older adults scored worse in the inhibition of prepotent response, but better in the resistance to distracter interference. However, the model had low explanatory power. Together, these findings call into question inhibition as a psychometric construct and the hypothesis of an inhibition deficit in older age. (PsycINFO Database Record, ((c) 2018 APA, all rights reserved).)

In a prospective memory task, verbal instructions are used to define an appropriate target event as retrieval cue. This target event is typically part of an ongoing activity and is thus bivalent as it involves features relevant for both the prospective memory task and the ongoing task. Task switching research has demonstrated that responding to bivalent stimuli is costly and can slow down even subsequent performance. Thus, responding to prospective memory targets may also result in after-effects, expressed as slowed subsequent ongoing task performance. So far, ongoing task slowing has been mainly considered as a measure of strategic monitoring for the prospective memory cues. The purpose of this study was to investigate whether after-effects of responding to prospective memory targets contribute to this slowing. In four experiments, a prospective memory task was embedded in a task-switching paradigm and we manipulated the degree of task-set overlap between the prospective memory task and the ongoing task. The results showed consistent after-effects of responding to prospective memory targets in each experiment. Increasing task-set overlap increased the amount and longevity of the after-effects. Surprisingly, prospective memory retrieval was not accompanied by strategic monitoring. Thus, this study demonstrates that ongoing task slowing can occur in the absence of monitoring costs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

It is assumed that we recruit cognitive control (i.e., attentional adjustment and/or inhibition) to resolve 2 conflicts at a time, such as driving toward a red traffic light and taking care of a near-by ambulance car. A few studies have addressed this issue by combining a Simon task (that required responding with left or right key-press to a stimulus presented on the left or right side of the screen) with either a Stroop task (that required identifying the color of color words) or a Flanker task (that required identifying the target character among flankers). In most studies, the results revealed no interaction between the conflict tasks. However, these studies include a small stimulus set, and participants might have learned the stimulus-response mappings for each stimulus. Thus, it is possible that participants have more relied on episodic memory than on cognitive control to perform the task. In 5 experiments, we combined the 3 tasks pairwise, and we increased the stimulus set size to circumvent episodic memory contributions. The results revealed an interaction between the conflict tasks: Irrespective of task combination, the congruency effect of 1 task was smaller when the stimulus was incongruent for the other task. This suggests that when 2 conflicts are presented concurrently, the control processes induced by 1 conflict source can affect the control processes induced by the other conflict source. (PsycINFO Database Record, ((c) 2016 APA, all rights reserved).)

Encountering a conflict triggers an adjustment of cognitive control. This adjustment of cognitive control can even affect subsequent performance. The purpose of the present study was to determine whether more conflict triggers more adjustment of cognitive control for subsequent performance. To this end, we focussed on the bivalency effect, that is, the adjustment of cognitive control following the conflict induced by bivalent stimuli (i.e., stimuli with relevant features for two tasks). In two experiments, we tested whether the amount of conflict triggered by bivalent stimuli affected the bivalency effect. Bivalent stimuli were either compatible (i.e., affording one response) or incompatible (i.e., affording two different responses). Thus, compatible bivalent stimuli involved a task conflict, whereas incompatible bivalent stimuli involved a task and a response conflict. The results showed that the bivalency effect was not affected by this manipulation. This indicates that more conflict does not trigger more adjustment of cognitive control for subsequent performance. Therefore, only the occurrence of conflict--not its amount--is determinant for cognitive control., (Copyright © 2013 Elsevier B.V. All rights reserved.)

When bivalent stimuli (i.e., stimuli with features for two different tasks) appear occasionally, performance is slower on subsequent univalent stimuli. This "bivalency effect" reflects an adjustment of cognitive control arising from the more demanding context created by bivalent stimuli. So far, it has been investigated only on task switch trials, but not on task repetition trials. Here, we used a paradigm with predictable switches and repetitions on three tasks, with bivalent stimuli occasionally occurring on one task. In three experiments, we found a substantial bivalency effect for all trials with at least one source of conflict. However, this effect was reduced for the repetition trials sharing no features with bivalent stimuli, that is, for those without conflict. This confirms that the bivalency effect reflects an adjustment of cognitive control. The news is that this adjustment of cognitive control is sensitive to the presence of conflict, but neither to its amount nor to its source.