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The prospect of enhancing cognition through behavioural training interventions, for example, the repetitive practice of cognitive tasks or metacognitive strategy instruction, has seen a surge in popularity over the past 20 years. Although overwhelming evidence demonstrates that such training interventions increase performance in the trained tasks, controversy remains over whether these benefits transfer to other tasks and abilities beyond the trained context. In this Review, we provide an overview of the effectiveness of cognitive training to induce transfer to untrained tasks, with a particular focus on the theoretical mechanisms that have been proposed to underlie training and transfer effects. We highlight that there is relatively little evidence that training enhances cognitive capacity, that is, the overall cognitive resources available to an individual. By contrast, substantial evidence supports training-induced improvements in cognitive efficiency, that is, optimized performance within existing cognitive capacity limits. We conclude that shifting research towards identifying the cognitive mechanisms underlying gains in cognitive efficiency offers a fruitful avenue for developing effective cognitive training interventions. However, to advance our understanding of human cognition and cognitive plasticity we must strive to develop and refine theories that generate testable hypotheses.

Switching between two or more tasks is a key component in our modern world. Task switching, however, requires time-consuming executive control processes and thus produces performance costs when compared to task repetitions. While executive control during task switching has been associated with activation in the lateral prefrontal cortex (lPFC), only few studies so far have investigated the causal relation between lPFC activation and task-switching performance by modulating lPFC activation. In these studies, the results of lPFC modulation were not conclusive or limited to the left lPFC. In the present study, we aimed to investigate the effect of non-invasive transcranial direct current stimulation [tDCS; anodal tDCS (1 mA, 20 min) vs. cathodal tDCS (1 mA, 20 min) vs. sham tDCS (1 mA, 30 s)] over the right inferior frontal junction on task-switching performance in a well-established task-switching paradigm. In response times, we found a significant effect of tDCS Condition (atDCS, ctDCS vs. sham) on task-switching costs, indicating the modulation of task-switching performance by tDCS. In addition, we found a task-unspecific tDCS Condition effect in the first experimental session, in which participants were least familiar with the task, indicating a general enhancement of task performance in both task repetitions and task-switching trials. Taken together, our study provides evidence that the right lPFC is involved in task switching as well as in general task processing. Further studies are needed to investigate whether these findings can be translated into clinically relevant improvement in older subjects or populations with executive function impairment.

Background Executive functions (EFs) are important determinants of health behaviors. In the present study, a meta-analysis was conducted to investigate the relationship between EFs and physical activity (PA) behavior. Methods Systematic searches were carried out in PsycInfo, MEDLINE, and SPORTDiscus databases throughout April 2021. Prospective empirical studies conducted with general healthy populations across the lifespan, which reported the relationship between baseline EFs and later PA behavior were selected. Results Eight studies were found eligible. Results of the multilevel meta-analysis revealed a small but significant total effect size for EFs on PA behavior of z = 0.12. High heterogeneity was observed among studies. When potential moderators were tested, residual heterogeneity remained significant and the effects of the moderators were not significant. The effect size dropped when accounted for publication bias. Conclusions Despite limitations, the study provided evidence for EFs’ determinant role on PA behavior. More research is however encouraged to inform PA promotion programs that are well-prepared for individual differences in EFs.

Inspecting new visual information in a face can affect the perception of subsequently seen faces. In experimental settings for example, previously seen manipulated versions of a face can lead to a clear bias of the participant’s perception of subsequent images: Original images are then perceived as manipulated in the opposite direction of the adaptor while images that are more similar to the adaptor are perceived as normal or natural. These so-called face adaptation effects can be a useful tool to provide information about which facial information is processed and stored in facial memory. Most experiments so far used variants of the second-order relationship configural information (e.g., spatial relations between facial features) when investigating these effects. However, non-configural face information (e.g., color) was mainly neglected when focusing on face adaptation, although this type of information plays an important role in face processing. Therefore, we investigated adaptation effects of non-configural face information by employing brightness alterations. Our results provide clear evidence for brightness adaptation effects (Experiment 1). These effects are face-specific to some extent (Experiments 2 and 3) and robust over time (Experiments 4 and 5). They support the assumption that non-configural face information is not only relevant in face perception but also in face retention. Brightness information seems to be stored in memory and thus is even involved in face recognition.

Aim: The present study was designed to investigate how behavioral (dual-action) demands in dual tasks are mentally represented in older adults and how these representations might contribute to the ...

Background Planning and executive functions (EFs; inhibition, updating, shifting) are self-regulatory variables that help people to become and stay physically active. The aim of this study was to examine how and for whom a planning intervention affects physical activity (PA) behavior in the short term. Therefore, the mediating role of planning and the moderating role of intentions and EFs for the planning–behavior link were examined. Method In a randomized control trial with two treatment groups (planning group vs. control group) and two points of measurement (t1 and t2, 1 week apart), n = 200 students participated in both measurements. At t1, participants filled in standardized questionnaires assessing PA behavior, intention, and planning. Computer-based tests assessed the following EFs: inhibition, updating, and shifting. At t2, planning and PA behavior were measured again. Moderated mediation analyses were conducted. Results A significant increase in PA between t1 and t2 was found for the planning group compared with the control group. Furthermore, planning cognitions significantly mediated the effect of the planning group on behavior and intention, as well as the EF updating moderated the association between planning and behavior. Forming plans was particularly beneficial for participants with high intentions and lower updating performance. Conclusion Planning enhances PA behavior, particularly when PA intention is high. Poor performance in updating can be compensated by planning since encouraging people to generate plans might facilitate automatic enactment of the behavior.

Dual-tasks (DT) require the employment of task-order representations that schedule the processing of 2 tasks. Evidence for this assumption stems from the observation that in DTs with variable order, performance is improved in trials with repeated processing order relative to the preceding trial in comparison to trials with reversed processing order. So far, it is an open question whether these order representations only contain order information or whether they also integrate component task information. To tackle this question, we applied a DT with variable task-order consisting of an auditory and a visual task. In Experiment 1, in addition to task-order, the visual task varied randomly from trial to trial while the auditory task kept constant. In Experiment 2, the auditory task varied. In Experiment 3, both component tasks varied. In all experiments, performance benefits occurred in trials with a repeated relative to trials with a reversed processing order, irrespective of a repeated or a changed component task. This indicates that order representations in DTs only contain order information. The findings are in line with the view that multitasking situations are represented as an agglomeration of distinct components that can be individually adjusted to changing task demands. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

In this study, we examined the interaction of automatic (i.e., automatic affective evaluations) and reflective [i.e., reflective intention and executive functions (EFs)] processes on physical activity (PA) behavior based on dual-process theories. We expected main effects as well as significant interaction effects between automatic associations, intention, and EFs on behavior. In particular, a well-controlled implicit-association-test (IAT) was applied to assess automatic affective evaluation. A prospective study with two points of measurement (N=212 students) was conducted. At t1, age, sex, PA behavior (control variables), automatic associations, EFs (shifting, updating, inhibition), and PA intention (predictors and moderators) were assessed with standardized questionnaires and tests. At t2 (4weeks later), PA behavior (dependent variable) was measured with a standardized questionnaire. A hierarchical multiple linear regression analysis including two- and three-way interactions between IAT results, intention, and EFs on PA behavior was conducted. Results showed that the interactions Intention x Shifting and IAT x Intention x Inhibition were significant. Moderation analyses revealed that participants with higher intentions and lower inhibition values (improved inhibition abilities) showed a negative association between IAT and PA, while those with lower intentions and lower inhibition values showed a positive association between IAT and PA, which was documented in a significant slope difference test between these two groups. Thus, both automatic and reflective processes contribute and interact in predicting PA. As well as fostering more positive affective evaluations towards PA, interventions to strengthen PA intentions and to improve EFs could help to increase PA behavior.

Dual-task performance typically leads to performance impairments in comparison to single tasks (i.e., dual-task costs). The literature discusses the contribution to these dual-task costs due to (1) bottleneck limitations in the dual-component tasks and (2) executive control processes regulating access to this bottleneck. Previous studies investigated the characteristics of executive control processes primarily triggered by external stimulus information. In the present study, however, we investigated the existence as well as the characteristics of internally triggered and driven endogenous control processes to regulate bottleneck access. In detail, we presented dual-task blocks with varying task orders and informed participants in advance about repetitions of the same task order as well as switches between different task orders (i.e., task-order repetitions and switches were predictable). Experiment 1 demonstrated that task-order information and an increased preparation time generally increase the efficiency for endogenous task-order control and improves preparation for task-order switches. This finding is basically consistent with the assumption of the existence of endogenous control processes. Experiment 2, however, did not provide evidence that this endogenous control is related with working-memory maintenance mechanisms. Experiment 3 showed that endogenous control does not only fully complete task-order preparation but also requires exogenous, stimulus-driven components.

The study investigated practice effects, instruction manipulations, and the associated cognitive architecture of dual-memory retrieval from a single cue. In two experiments, we tested predictions about the presence of learned parallelism in dual-memory retrieval within the framework of the set-cue bottleneck model. Both experiments included three experimental laboratory sessions and involved computerized assessments of dual-memory retrieval performance with strategy instruction manipulations. In Experiment 1, subjects were assigned to three distinct dual-task practice instruction groups: (1) a neutral instruction group without a specific direction on how to solve the task (i.e., neutral instruction), (2) an instruction to synchronize the responses (i.e., synchronize instruction), and (3) an instruction to use a sequential response style (i.e., immediate instruction). Results indicate that strategy instructions are able to effectively influence dual retrieval during practice. Mainly, the instruction to synchronize responses led to the presence of learned retrieval parallelism. Experiment 2 provided an assessment of the cognitive processing architecture of dual-memory retrieval. The results provide support for the presence of a structural bottleneck that cannot be eliminated by extensive practice and instruction manipulations. Further results are discussed with respect to the set-cue bottleneck model.

The present study asks how behavioral (dual-action) demands in dual tasks are mentally represented and whether changes in representation might govern practice-related dual-task performance improvements. Three different representation accounts were empirically tested based on the idea that dual-action demands required in a dual-task trial might be represented in different ways. According to a compositional (Structuralist) account, component tasks remain structurally intact when combined with another task. In contrast, a holistic (Gestalt) account posits that dual-action requirements in dual tasks are represented holistically and entirely distinct from its component action requirements. Finally, a contextual change account assumes that a change in context (e.g., from single- to dual-action requirement) generally impedes response retrieval, similar to repeating a response while the task context switches. To address this issue, we analyzed trial-by-trial effects in a single/dual switch paradigm (SDS paradigm, involving a randomized mix of single- and dual-task trials within blocks). Specifically, we analyzed performance in an extensive dual-task training setting (involving training sessions across several days) combining an auditory-vocal task and a visual-manual task. The results indicated that, throughout practice, nearly all relevant comparisons of performance between complete switch trials (e.g., between the two single tasks) and partial repetition trials (e.g., from dual to single task) revealed partial repetition benefits, that is, for both the auditory-vocal and the visual-manual task, and for both single- and dual-task performance analyses. Therefore, dual-action requirements in the present dual-task setting are mentally represented in a compositional, Structuralist fashion, probably due to low between-task dimensional overlap.

In this study, we investigated whether alertness training in healthy older adults increases visual processing speed (VPS) and whether functional connectivity in the cingulo-opercular network predicts training gain. Using the theory of visual attention, we derived quantitative estimates of VPS before and after training. In Study 1, 75 healthy older adults participated in alertness training, active-control training, or no training ( n = 25 each). A significant Group × Session interaction indicated an increase in VPS in the alertness-training group but not in the control group, despite VPS not differing significantly between groups before training. In Study 2, 29 healthy older adults underwent resting-state functional MRI and then participated in alertness training. Pretraining functional connectivity in the cingulo-opercular network correlated with the individual training-induced change in VPS. In conclusion, results indicate that alertness training improves visual processing in older adults and that functional connectivity in the cingulo-opercular network provides a neural marker for predicting individual training gain.

Dual-process theories assume that physical activity (PA) behavior is regulated by two different processes: impulsive (i.e., automatic, fast) and reflective (i.e., effortful, slow) processes. In thi...

Performing two tasks simultaneously involves the coordination of their processing. Task coordination is particularly required in dual-task situations with varying order of the component tasks. When task order switches between subsequent trials, task-order coordination leads to order switch costs in comparison to task order repetitions (i.e., worse performance in trials associated with an order switch compared to an order repetition). However, the adaptive characteristics of task-coordination processes and order switch costs are underspecified so far. For example, studies on conflict control have shown that these coordination processes can be modulated in response to changes in task demands. The present study investigated therefore whether task-order coordination processes are modulated by the previous experience of a task-order switch. To investigate order switch costs in a dual-task situation with two sensorimotor tasks with variable task-order, we analyzed performance in current trials with task-order switches and with task-order repetitions following task-order switches and task order repetitions in the preceding trial. The data of four different experimental conditions showed that order switch costs were reduced in trials following task-order switches compared to task-order repetitions; resembling the Gratton effect commonly observed in conflict adaptation paradigms. We discussed the present results in the context of task-order set representations, cognitive control theories, and dual-task models.

Working memory (WM) is a limited capacity system which is responsible for simultaneously maintaining and processing information. Reliable individual differences in this capacity place limiting constraints for performing other cognitive activities. Thus, WM training might even benefit a wide range of cognitive functions. This prospect makes WM training very prominent and also controversial. In the present chapter, we briefly illustrated common training regimes and reviewed the empirical evidence for training effects on the trained WM tasks, near transfer to nontrained WM tasks, and far transfer to different cognitive functions. Consistent evidence across different age groups from all over the lifespan and across several meta-analyses speaks in favor of significant average training effects and significant near transfer to nontrained WM tasks. However, evidence for far transfer to, for example, fluid intelligence, executive functions, and academic achievement, is mixed. We reviewed current topics of discussion in the field and concluded that a greater focus on variables possibly moderating transfer effects (e.g., individual differences and situational characteristics during training) is necessary to better understand conflicting findings. More research on far transfer effects is needed because even small effects could actually make a difference relevant to everyday life.

In the past 10 years, commercial computerized brain trainings became increasingly popular on the digital market. These programs are readily available, easy to administer, motivating, and adaptive. However, their effectiveness based on randomized controlled (RCT) studies with an active control group in healthy populations is hotly debated. Therefore, in this review, we report the characteristics and study outcomes of currently available commercial brain training programs. We critically assess the number and quality of RCT studies evaluating their empirical evidence for enhancing cognitive functioning in healthy adults and discuss their effectiveness.

Dual-task (DT) situations require task-order coordination processes that schedule the processing of two temporally overlapping tasks. Theories on task-order coordination suggest that these processes rely on order representations that are actively maintained and processed in working memory (WM). Preliminary evidence for this assumption stems from DT situations with variable task order, where repeating task order relative to the preceding trials results in improved performance compared to changing task order, indicating the processing of task-order information in WM between two succeeding trials. We directly tested this assumption by varying WM load during a DT with variable task order. In Experiment 1, WM load was manipulated by varying the number of stimulus–response mappings of the component tasks. In Experiment 2A, WM load was increased by embedding an additional WM updating task in the applied DT. In both experiments, the performance benefit for trials with repeated relative to trials with changed task order was reduced under high compared to low WM load. These results confirm our assumption that the processing of the task-order information relies on WM resources. In Experiment 2B, we tested whether the results of Experiment 2A can be attributed to introducing an additional task per se rather than to increased WM load by introducing an additional task with a low WM load. Importantly, in this experiment, the processing of order information was not affected. In sum, the results of the three experiments indicate that task-order coordination relies on order information which is maintained in an accessible state in WM during DT processing. Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659 Martin-Luther-Universität Halle-Wittenberg (1043)

Previous studies demonstrated that dual-task impairments (i.e., dual-task costs) are higher in children than in young adults. However, these studies did not specify the mechanisms explaining higher dual-task costs and did not assess the specific task processes that particularly impair simultaneous task performance in children. We assessed sources of higher dual-task costs in children (n = 32) as compared with young adults (n = 32) by combining auditory (Task 1) and visual (Task 2) sensorimotor tasks into dual tasks of the psychological refractory period (PRP) type. Both tasks are separated by a varying stimulus onset asynchrony (SOA). In Visual Task 2, we manipulated task difficulty at the perceptual stage (contrast manipulation) and response selection stage (mapping manipulation) in order to identify age-related changes in capacity limitations during dual-task performance. The results showed that the response selection manipulation and SOA yielded additive effects in children and young adults, providing evidence for interference at response selection processes in both age groups. In contrast, the perceptual stage manipulation and SOA resulted in underadditive effects in young adults and additive effects in children. This age-related difference is consistent with the assumption that limitations in central processing are present in both age groups, whereas perceptual interference between tasks seems to be larger in children than in young adults.

When two overlapping tasks are processed, they hit a bottleneck at a central processing stage that prevents simultaneous processing of the two tasks. Thus far, however, the factors determining the processing order of the tasks at the bottleneck are unknown. The present study was designed to (re)investigate whether the arrival times of the two tasks at the central bottleneck are a key determinant of the processing order (cf. Sigman & Dehaene, 2006). To this end, we implemented a visual-auditory dual task with a random stimulus order, in which we manipulated arrival time by prolonging the initial, perceptual processing stage (stimulus analysis) of the visual task and compared the effects of this manipulation with those of one impacting the central bottleneck stage of the visual task. Additionally, we implemented two instruction conditions: Participants were told to respond either in the order of stimulus presentation or in the order they preferred. The manipulation of the visual perception stage led to an increase in task response reversals (i.e., the response order was different from the order of stimulus presentation), whereas there was no such increase when the bottleneck stage was manipulated. This pattern provides conclusive evidence that the processing order at the bottleneck is (at least in part) determined by the arrival times of the tasks at that point. Reaction time differences between the two instruction conditions indicated that additional control processes are engaged in determining task processing order when the participants are expressly told to respond in the order of stimulus presentation.

There is evidence in the literature that two retrievals from long-term memory cannot occur in parallel. To date, however, that work has explored only the case of two retrievals from newly acquired episodic memory. These studies demonstrated a retrieval bottleneck even after dual-retrieval practice. That retrieval bottleneck may be a global property of long-term memory retrieval, or it may apply only to the case of two retrievals from episodic memory. In the current experiments, we explored whether that apparent dual-retrieval bottleneck applies to the case of one retrieval from episodic memory and one retrieval from highly overlearned semantic memory. Across three experiments, subjects learned to retrieve a left or right keypress response form a set of 14 unique word cues (e.g., black—right keypress). In addition, they learned a verbal response which involved retrieving the antonym of the presented cue (e.g., black—“white”). In the dual-retrieval condition, subjects had to retrieve both the keypress response and the antonym word. The results suggest that the retrieval bottleneck is superordinate to specific long-term memory systems and holds across different memory components. In addition, the results support the assumption of a cue-level response chunking account of learned retrieval parallelism.

Executive functioning of two simultaneous component tasks in dual-task situations is primarily associated with activation of the lateral prefrontal cortex (PFC), as demonstrated in functional imaging studies. However, the precise role of the lateral PFC and the causal relation between this area's activity and executive functioning in dual tasks has exclusively been demonstrated for the left lateral PFC so far. To investigate this relation for the right lateral PFC, we used anodal transcranial direct current stimulation (atDCS; 1 mA, 20 min) in contrast to sham stimulation (1 mA, 30 s) in Experiment 1 (N = 30) as well as cathodal transcranial direct current stimulation (ctDCS; 1 mA, 20 min) in contrast to sham stimulation (1 mA, 30 s) in Experiment 2 (N = 25) over the right inferior frontal junction under conditions of random task order in dual tasks; random dual tasks require decisions on task order and thus high demands on executive functioning. Across these experiments, our results showed different tDCS-related effects: while atDCS improved performance evident from reduced error rates (Experiment 1), ctDCS impaired dual-task performance and increased these rates (Experiment 2). Moreover, baseline performance correlated with tDCS-induced performance changes, indicating that baseline performance was associated with atDCS-induced improvement. Our findings suggest that dual-task performance is causally related to right lateral PFC activation under conditions that require executive functioning as well as cognitive control of task sets and task order.

Commercial brain games are home- and computer-based cognitive trainings that are industrially offered and promise to enhance cognitive functioning by repeating cognitive tasks. Despite compelling evidence for the effectiveness of cognitive trainings in various domains and populations, the assumption of brain games’ effects on people’s minds has been challenged. However, there are only very few attempts to systematically evaluate the effectiveness of such games under ecologically valid training conditions. To approach this gap in the literature, we applied commercially available training tasks assumed to tap into working memory updating and capacity. The effectiveness of this training was measured by utilizing pre- and post-tests in trained tasks (criterion tasks), untrained transfer tasks from the assumed training domains (near-transfer tasks), as well as from the domains processing speed, shifting, inhibition, reasoning, and self-reported cognitive failures (far-transfer tasks). Training as well as pre-post-tests were completely administered home-based. In contrast to an active control group, a training group improved performance in the criterion tasks and near-transfer tasks. Improved performance was also evident in processing speed and shifting tasks (i.e., far-transfer tasks), but these improvements were not as conclusive as those in near-transfer tasks. Further, the number of reported cognitive failures was reduced in the training in contrast to the control group at post-test. Performance improvements were more pronounced for high-performing participants (i.e., magnification effects). In general, this study provides an evaluation of the effectiveness of a particular set of working-memory training tasks in an ecologically valid setting in the context of brain games.

Dual tasks (DTs) are characterized by the requirement for additional mechanisms that coordinate the processing order of two temporally overlapping tasks. These mechanisms are indicated by two types of costs that occur when comparing DT blocks with fixed and random orders of the component tasks. On a block level, task-order control costs are reflected in increased reaction times (RTs) in random-order compared to fixed-order blocks, indicating global, monitoring-based, coordination mechanisms. On a trial level, within random-order blocks, order-switch costs are indicated by increased RTs on order switch compared to order repetition trials, reflecting memory-based mechanisms that guide task-order in DTs. To test the nature of these mechanisms in two experiments, participants performed DTs in fixed- and random-order blocks. In random-order blocks, participants were either instructed to respond to both tasks according to the order of task presentation (sequential-order instruction) or instructed to freely decide in which order to perform both tasks (free-order instruction). As a result of both experiments, we demonstrated that task-order control costs were reduced under the free-order compared to the sequential-order instruction, whereas order-switch costs were not affected by our instruction manipulation. This pattern of results suggests that the task-order control costs reflect global processes of task-order regulation such as engaging monitoring processes that are sensitive to changes in order instructions, while order-switch costs reflect rather local memory-based mechanisms that occur irrespective of any effort to coordinate task-order.