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Journal of cognition 4(1), 55 (2021). doi:10.5334/joc.186, Published by Ubiquity Press, London

Cues help in retrieving and implementing task-sets, that are actual representations of the to-be performed task in working memory. However, whereas previous studies revealed that the effectiveness of selecting and implementing task-sets based on cues depends on the type of cue (i.e., transparent words vs. arbitrary shapes), it is still unclear which characteristics of cues are responsible for these differences and whether the impact of the cue is bound to task-set retrieval only or also impacts task-set representations. For instance, the amount of interference during actual task performance has been reported to alter dependent on cue type as do preparation gains such as the reduction of switch cost. To investigate the effectiveness of cue characteristics (i.e., cue transparency and cue format), we manipulated those within- and between-participants in three experiments. Main dependent measures were switch costs in reaction times and error rates that occur when participants have to switch task-sets, and thus update working memory content. Our results consistently show beneficial effects of transparent cues for the reduction of switch cost. The influence of cue format was manifest in within-participants manipulation only and was mainly found in error rates. Overall, our data suggest that the amount of interference experienced in actual task performance can be significantly modulated dependent on cue type, suggesting flexible adaptation of the cognitive system to contextual information.

The present study investigated mechanisms of adaptive cognitive control in working memory (WM). WM is conceived as a system for short-term maintenance, updating and manipulation of representations required for goal-directed action. Adaptive control refers to the finding of flexible adjustments of control processes based on conflict. For instance, a higher frequency of incongruent stimuli, that is, stimuli evoking conflicting response tendencies, leads to a higher level of cognitive control as reflected by smaller congruency effects (i.e., the difference between congruent and incongruent items). Likewise, conflict on the previous trial leads to a higher level of cognitive control on the current trial. To investigate adaptive control in WM, we used a modified Sternberg paradigm. Participants memorized two differently colored lists of four digits (i.e., 2 5 7 1), in which corresponding positions in both lists contained the same digits (congruent items) or different digits (incongruent items). Participants were required to make a match/mismatch judgement (Experiment 1 and 2) or to recollect the correct digit at a probed position in one of the two lists (Experiment 3). In all experiments, we could replicate both hallmark effects of adaptive control, the proportion congruency effect, and the congruency sequence effect. Our results strongly support the assumption that WM representations can be dynamically adapted based on the amount of conflict, and that adaptive control of WM follows the same principles that have previously been shown for selective attention.

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

Working memory (WM) holds and manipulates representations for ongoing cognition. Oberauer (Psychology of Learning and Motivation, 51, 45–100, 2009) distinguishes between two analogous WM sub-systems: a declarative WM which handles the objects of thought, and a procedural WM which handles the representations of (cognitive) actions. Here, we assessed whether analogous effects are observed when participants switch between memory sets (declarative representations) and when they switch between task sets (procedural representations). One mechanism assumed to facilitate switching in procedural WM is the inhibition of previously used, but currently irrelevant task sets, as indexed by n-2 task-repetition costs (Mayr & Keele, Journal of Experimental Psychology: General, 129(1), 4–26, 2000). In this study we tested for an analogous effect in declarative WM. We assessed the evidence for n-2 list-repetition costs across eight experiments in which participants switched between memory lists to perform speeded classifications, mental arithmetic, or a local recognition test. N-2 list-repetition costs were obtained consistently in conditions assumed to increase interference between memory lists, and when lists formed chunks in long-term memory. Further analyses across experiments revealed a substantial contribution of episodic memory to n-2 list-repetition costs, thereby questioning the interpretation of n-2 repetition costs as reflecting inhibition. We reanalyzed the data of eight task-switching experiments, and observed that episodic memory also contributes to n-2 task-repetition costs. Taken together, these results show analogous processing principles in declarative and procedural WM, and question the relevance of inhibitory processes for efficient switching between mental sets.

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).

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

Many researchers have employed secondary tasks, which have to be performed in parallel with a primary task requirement, to examine how successful task selection is accomplished in the context of task switching. The influence of such a secondary task on the observed switch cost (i.e., the cost arising when the currently relevant task differs from the task performed most recently) is seen as indicative that cognitive processes such as self-instruction are involved. Most secondary tasks chosen so far have required the repeated utterance of a word or syllable or a rhythmic movement of the foot. In the present study, we manipulated the dynamics of the to-be-performed secondary task (i.e., a repeated utterance or movement, or a static task that involved similar muscles-holding a spattle in the mouth or pressing keys). Additionally, we tested for modality-specific influences by asking participants to perform a dynamic or nondynamic (i.e., static) secondary task with two effector systems, namely oral and manual. Overall, our secondary tasks led to a reduced (rather than an increased) switch cost, as compared to a control condition without any secondary task. This reduction in switch cost was dependent on the secondary-task dynamics but independent of the effectors involved, showing larger switch-cost reductions for dynamic secondary tasks. To explain this finding, we suggest that performing secondary tasks interferes with the formation of episodic-memory traces that would lead to retrieval benefits in the case of a task repetition, so that our reduced task-switch costs actually represent reduced repetition benefits.

In three task-switching experiments, we investigated the relationship of n-1 switch cost and n-2 repetition cost. N-1 switch cost is observed when participants are asked to switch from one classification task to another, e.g., from judging a digit as odd or even to judging a digit as smaller or larger than five. N-2 repetition cost is observed when participants are asked to switch among three tasks (thereafter called A, B, and C). This cost is observed when the task on trial n-2 is repeated in trial n (i.e., in task sequences like ABA) compared to when it is switched (i.e., in task sequences like CBA). So far, the n-1 switch cost is assumed to be caused either by reconfiguration processes or by episodic-memory inertia from the previously activated task-set. N-2 repetition cost is thought to reflect lingering inhibitory processes for resolving conflict among tasks. Whereas both views are integrated in some models, it is up to date unclear whether n-2 repetition cost is related to n-1 switch cost. To examine this relationship, we decomposed the processes underlying n-1 switch cost and n-2 repetition cost using a diffusion model analysis as well as a linear ballistic accumulator model. The results showed that n-1 switch cost reflects interference caused by the residual activation of the previous task set as indicated by slower evidence accumulation processes. In contrast, there were no consistent parameter modulations underlying n-2 repetition cost. These findings emphasize that different cognitive processes are involved in n-1 switch cost and n-2 repetition cost.

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.

Cognitive flexibility can be studied using the task-switching paradigm. This paradigm requires subjects to adapt behaviour to changing contexts as indicated by a cue. In our study, we addressed the question of how cue-based implementation of mental “task sets” occurs. We assumed that cues build up associations to the tasks that they indicate. These associations lead to retrieval of the associated task set once the cue shows up again. In three experiments, we tested this assumption using a negative transfer paradigm. First participants were exposed to one cue–task mapping. After a training phase, the cue–task mapping changed in either of two ways. Whereas one group of participants got new cues, the other experienced a reversal of the learnt cue–task mapping. Our results show that participants build up cue–task associations and that these formerly learnt associations can hamper the implementation of new cue–task mappings (particular with mapping reversal). Prolonged preparation time decreased the cost of changing the cue–task mapping but did not change the overall pattern of results.

Inhibition of abandoned tasks in task switching can be inferred when a worse performance is found with n - 2 task repetitions (ABA sequences) than with nonrepetitions (CBA sequences). Recent evidence has shown that this inhibition effect decreases with long intertrial intervals (i.e., response-cue intervals, RCIs). Two alternatives have been proposed to account for this decrease. One alternative attributes the observed decrease to the decay of inhibition itself. The other alternative proposes that decay of the activation of competing tasks reduces the interference and leads to less inhibition. To decide between these alternatives, we manipulated RCI trialwise. The results favor the decay-of-activation account as an explanation for the decreased inhibition effect. This links the amount of inhibition to the activation level of the competing tasks, whereas evidence for the decay of inhibition remains weak.

The article investigates the mechanisms of selecting and updating representations in declarative and procedural working memory (WM). Declarative WM holds the objects of thought available, whereas procedural WM holds representations of what to do with these objects. Both systems consist of three embedded components: activated long-term memory, a central capacity-limited component for building structures through temporary bindings, and a single-element focus of attention. Five experiments test the hypothesis of analogous mechanisms in declarative and procedural WM, investigating repetition effects across trials for individual representations (objects and responses) and for sets (memory sets and task sets), as well as set-congruency effects. Evidence for analogous processes was obtained from three phenomena: (1) Costs of task switching and of list switching are reduced with longer preparation interval. (2) The effects of task congruency and of list congruency are undiminished with longer preparation interval. (3) Response repetition interacts with task repetition in procedural WM; here we show an analogous interaction of list repetition with item repetition in declarative WM. All three patterns were reproduced by a connectionist model implementing the assumed selection and updating mechanisms. The model consists of two modules, an item-selection module selecting individual items from a memory set, or responses from a task set, and a set-selection module for selecting memory sets or task sets. The model codes the matrix of binding weights in the item-selection module as a pattern of activation in the set-selection module, thereby providing a mechanism for building chunks in LTM, and for unpacking them as structures into working memory.

We investigate interference between declarative and procedural representations in working memory (WM). Declarative representations are objects of thought, whereas procedural representations provide the (cognitive) actions to work upon these objects. In eight dual-task experiments we varied the number of representations to be maintained in WM (memory load). In Experiments 1–4, we varied declarative and procedural load separately in the two tasks used. In Experiments 5–8, only declarative or procedural load was manipulated in both tasks employed. We measured how much performance in the currently relevant task was impaired by increasing the load in the currently irrelevant task. These cross-task load effects were larger for Experiment 5–8 compared to Experiment 1–4. Yet, in task-switch trials we also obtained cross-task load effects in Experiment 1–4. Our findings support the distinction of declarative and procedural WM as largely independent sub-systems or distinct representational spaces.

The question whether being bilingual yields cognitive benefits is highly controversial with prior studies providing inconsistent results. Failures to replicate the bilingual advantage have been attributed to methodological factors such as comparing dichotomous groups and measuring cognitive abilities separately with single tasks. Therefore, the authors evaluated the 4 most prominent hypotheses of bilingual advantages for inhibitory control, conflict monitoring, shifting, and general cognitive performance by assessing bilingualism on 3 continuous dimensions (age of acquisition, proficiency, and usage) in a sample of 118 young adults and relating it to 9 cognitive abilities each measured by multiple tasks. Linear mixed-effects models accounting for multiple sources of variance simultaneously and controlling for parents' education as an index of socioeconomic status revealed no evidence for any of the 4 hypotheses. Hence, the authors' results suggest that bilingual benefits are not as broad and as robust as has been previously claimed. Instead, earlier effects were possibly due to task-specific effects in selective and often small samples.

The article investigates the relation between declarative and procedural working memory (WM; Oberauer 2009). Two experiments test the assumption that representations in the two subsystems are selected for processing in analogous ways. Participants carried out a series of decisions on memorized lists of digits. For each decision they had to select declarative and procedural representations. Regarding declarative representations participants selected a memory set and a digit within this set as the input to each decision. With respect to the procedural representations they selected a task set to be applied to the selected digit and a response within that task set. We independently manipulated the number of lists and the number of tasks to be switched among (one two or three; Experiment 1) and preparation time for a list switch (Experiment 2). For three effects commonly observed in taskswitch studies analogues in declarative WM were found: list switch costs mixing costs and residual switch costs. List and task switch costs were underadditive suggesting that declarative and procedural representations are selected separately and in parallel. The findings support the hypothesis of two analogous WM subsystems. Keywords: Working memory; Task switching.

The concept of inhibition plays a major role in cognitive psychology. In the present article, we review the evidence for the inhibition of task sets. In the first part, we critically discuss empirical findings of task inhibition from studies that applied variants of the task-switching methodology and argue that most of these findings— such as switch cost asymmetries—are ambiguous. In the second part, we focus on n-22 task-repetition costs, which currently constitute the most convincing evidence for inhibition of task sets. n-22 repetition costs refer to the performance impairment in sequences of the ABA type relative to CBA, which can be interpreted in terms of persisting inhibition of previously abandoned tasks. The available evidence suggests that inhibition is primarily triggered by conflict at selection of stimulus attributes and at the response level. Author Note

The aim of the present study was to examine the contribution of overlapping response sets to the occurrence of task inhibition, measured as n-2 task repetition cost. We had subjects switch among four tasks. Three tasks overlapped on both stimulus set and response set. A fourth, neutral, univalent task never overlapped on the stimulus set but, across three experiments, varied in terms of the degree of overlap in the response set. We found that overlap in response set affects task inhibition. We suggest that response set overlap increases the competition among tasks and, thus, triggers task inhibition to resolve this competition.

We used language-defined response sets (digit names from 1 to 9 in different languages) to explore inhibitory processes in language switching. Subjects were required to switch between two (Experiment 1) or among three (Experiment 2) languages. In Experiment 1, we obtained a shift cost when subjects switched between their first and second language, between their first and third language, or between their second and third language. For each language pairing, the shift cost was larger for the relatively dominant language than for the nondominant language (i.e., asymmetric shift cost). In Experiment 2, we assessed inhibition of response sets as reflected in n-2 repetition cost (i.e., the difference between ABA and CBA language sequences). We discuss both effects with respect to inhibitory processes in language switching. The results suggest different functional characteristics of the processes underlying asymmetric shift cost and n-2 repetition cost.

The present study investigates the influence of preparation on inhibitory effects in cued task switching. In three experiments, we assessed n − 2 repetition costs as marker of inhibition of the just executed and now irrelevant task by comparing performance in task sequences such as ABA (i.e., n − 2 repetitions, with A, B and C standing for different tasks) to task sequences such as CBA (i.e., n − 2 switches). Specifically, we varied the cue–target interval (CTI) to examine cue-based preparation effects. In addition, we manipulated cue type (i.e., abstract, verbal, and direct cues) across the three experiments. We obtained significant reductions of n − 2 repetition costs with prolonged CTI when using abstract cues (i.e., coloured frames) and task names (i.e., digit), but not when using the task-specific stimulus–response mapping as cue for the upcoming task. These data suggest that cue-based preparation is not a uniform process but depends on the information provided by the cue.

Abstract. Task inhibition was explored in two experiments that employed a paradigm in which participants switched among three tasks. Two tasks required manual choice responses based on numerical judgment (parity or magnitude), whereas a third task required an unconditional double-press of both response keys. Both experiments showed that switching to a just-abandoned task (n-2 task repetition) generally leads to a performance cost relative to switching to another task. Specifically, this task inhibition effect also occurred for the double-press task, suggesting inhibition of response mode. Prolonging the task-cuing interval showed that advance task preparation reduced only inhibition of the double-press task but not of the choice tasks (Experiment 1). Prolonging the response-cue interval led to a decrease of the inhibition effect in all tasks (Experiment 2), suggesting a time-based release of task inhibition. Together, the experiments support the notion of a response-related component of task inhibition.

Performance of task sequences is assumed to rely on activation and inhibition of tasks. An empirical marker of task inhibition is the so-called n - 2 repetition cost, which is assessed by comparing performance in trial n - 2 task repetitions (i.e., ABA) with that in n - 2 task switches (i.e., CBA). Current theoretical accounts assume that inhibition acts on the level of task representations (i.e., task sets). However, another potential target of task inhibition could be the representation of the task cue. To decide between these two alternatives, the authors used a 2:1 cue-to-task mapping design. They found significant n - 2 task repetition costs both with n - 2 cue repetitions and n - 2 cue switches. These costs were about equal (Experiment 1), and this data pattern was found for both short and long cuing intervals (Experiment 2). Together, the data suggest that task inhibition acts on task sets and not on cue representations. Keywords: cognitive control, task sequence performance, inhibition, cue-based processes The performance of task sequences relies on the activation of the currently relevant task (or "task set"; e.g., Rogers & Monsell, 1995) and on the inhibition of competing, but currently irrelevant tasks (e.g., Mayr & Keele, 2000; Schuch & Koch, 2003). Experimental paradigms designed to assess task-sequence performance usually also make use of valid cues that unambiguously indicate which task to perform next. Thereby it is assumed that participants create a task set that consists of multiple components (e.g., Meiran, 2000), such as a "stimulus set" that refers to relevant stimuli or stimulus dimensions and a "response set" that refers to response-related processes (Meiran, 2000; Schuch & Koch, 2003). Whereas stimulus set and response set are assumed to be the core of task sets, the cue is commonly thought to act as a memory retrieval aid to select the correct task set in long-term memory (see, e.g., Mayr & Kliegl, 2000, 2003; Rubinstein, Meyer, & Evans, 2001; Schneider & Logan, 2005, for discussion). Current theories assume that inhibitory processes in the performance of task sequences exert their influence on the last abandoned task set (Mayr & Keele, 2000) or task-specific action rules (e.g., Schuch & Koch, 2003). An empirical marker of the inhibitory processes in the control of task sequences are the so-called n - 2 repetition costs. These costs are observed when comparing performance of an n - 2 repetition of task (i.e., ABA) with that of an n - 2 switch (i.e., CBA). These n - 2 repetition costs are thought to reflect persistence of inhibition that was exerted toward Task A when implementing Task B in Trial n - 1. Thus, when participants are required to switch from Task A to Task B, residual activation of the recently performed Task A impairs the successful implementation of Task B (Gade & Koch, 2005). To overcome this impairment, inhibition suppresses Task A (see also Mayr & Keele, 2000). When participants are then required to return to Task A, this task is still inhibited and its implementation and/or execution takes longer. Recently, however, Logan and Bundesen (2003; see also Schneider & Logan, 2005) pointed out that a change in task is usually associated with a change in cue, as experimenters usually use one cue per task. Thus, models claiming that the cue acts as a memory-retrieval aid for the currently relevant task set need to show that it is not cue processing itself but rather the task set that is activated or inhibited (see, e.g., Forstmann, Brass & Koch, 2007; Gade & Koch, 2007a; Mayr & Kliegl, 2003; Schneider & Logan, 2005, for discussion). The aim of the present study was to examine whether cues (or cue-related processes) are the target of inhibitory processes in task switching. In the present study, we used a 2:1 cue-to-task mapping, so that each task was indicated by two different cues. With regard to inhibitory processes in task switching, only one study has used a 2:1 cue-to-task mapping (Mayr & Kliegl, 2003, Experiment 3). …