Quarterly Journal of Experimental Psychology

Dual tasks are a common phenomenon in everyday life. In dual-task contexts, we perform two-component tasks in temporal overlap, which usually results in impaired performance in one or both of these component tasks relative to single-task contexts. Numerous studies have examined dual-task interference at the level of response selection, but only a few studies have addressed the cognitive representation of a dual task and the cognitive mechanisms controlling these representations. The present review outlines recent empirical findings and theoretical developments concerning these two issues. In detail, the review focuses on different components of a cognitive dual-task representation, including the representation of component-task-specific information (i.e., information about the goal and stimulus-response mapping of a component task), the representation of component-task order information (i.e., information about the order in which the component tasks have to executed), and the representation of dual-task identity information (i.e., information about which two-component tasks have to be performed). A particular emphasis is placed on the cognitive representation of dual-task identity information, which is examined in a recent research line employing the task-pair switching logic as an empirical approach. By conceptualising a dual-task representation as a hierarchical multi-component representation, the review integrates the research line on the cognitive representation of dual-task identity information with the research lines on the representation of component-task-specific information and component-task order information. Based on this conceptualisation, the review provides a new theoretical contribution to dual-task research and highlights an integrative perspective on the different components of cognitive dual-task representations.

Adaptive behavior in the real world involves navigating competing goals in a constantly changing environment. Doing so requires cognitive flexibility across multiple domains, including flexibility for switching between tasks, that is, activating the appropriate rules for stimulus-response associations, and flexibility for shifting attention between different sources of sensory inputs. Previous work in task switching and attention shifting has separately shown that people are capable of strategically modulating both types of flexibility based on the current demands. That is, people become better at switching between tasks (e.g., digit magnitude vs. parity tasks) when switches are frequently cued and better at shifting attention between different stimulus locations when shifts are frequently cued. Across five experiments in the current study, we investigated the possibility of cognitive flexibility transfer between the domains of task switching and attention shifting when the frequency of switches/shifts is orthogonally manipulated within the same context. We implemented a novel paradigm that involved concurrent cued task switching and attention shifting. We varied either the proportion of task switches or attention shifts across blocks of trials, while keeping the proportion of the other constant. If flexibility adaptations in biased contexts transferred across domains, switch/shift frequency manipulations in one domain should affect flexibility across both domains. Instead, in Experiments 1 to 3, we found that performance costs of attention shifts remained constant across task-switch biased contexts despite adjustments in task-switch costs; likewise, in Experiments 4 to 5, we found that costs of switching between tasks remained constant across blocks that varied in attention-shift frequency despite adaptations in attention-shift costs. These results suggest that probabilistic learning and adjustments of attention-shifts and task switches to meet contextual demands occur independently.

Convergent evidence suggests that the transfer effects engendered by training studies are tied to specific task features. The present study examined transfer in a set of three hierarchically nested change-detection tasks (CDTs) using a tightly controlled adaptive training paradigm. These CDT paradigms all required participants to remember arrays of stimuli, and then report the change (in colour, orientation or both) of a probed item. The three tasks were identical except for the response judgement requirements: colour, orientation or dual (both colour and orientation). We also included a retro-cue – a spatial cue within the retention period – allowing us to test whether training impacts the allocation of attention during maintenance. Each training group made significantly greater on-task gains relative to the active control group (digit-span training). Between-task transfer patterns were present but limited and largely feature-specific. Training gains on the orientation task did not transfer to the colour variant and vice versa; in fact, there was some evidence of negative transfer. However, those trained on the colour variant did show benefits to both variants within the dual-task context. The dual-CDT trainees also showed transfer to the simple orientation and colour variants. Finally, we found no compelling evidence to distinguish whether training gains and transfer effects are due to improved capacity or the improved precision with which representations are held. In short, participants learn to better represent and report specific features, but it is not clear if this is driven by changes in capacity or precision.

Executing a response results in bindings between features of present stimuli and features of the response, a compound often called “event file”. If features of an event file repeat in a later episode, the event file is assumed to be retrieved and to affect the current action (so-called “binding effects”). Feature binding and retrieval are considered to be fundamental processes in human action control. However, to date, it is not clear whether the concept of a reinitiating retrieval process, as opposed to the additional involvement of residual activity (as suggested by recent neurophysiological studies), provides a more accurate description of how previously formed bindings can influence current action. In this study, we investigated the short time window immediately following integration and its modulation on binding effects in three experiments. We measured response–response binding effects after 0, 100, 300, and 500 ms after integration in an adapted response–response binding paradigm and measured distractor–response binding effects 0 and 500 ms after integration in an adapted distractor–response binding paradigm. We found evidence for binding effects even at response–stimulus intervals as short as 0 ms, both for response–response binding and distractor–response binding. Our findings suggest that the concept of residual activation seems to play an additional role next to the process of retrieval.

Acting means changing the environment according to one’s own goals, and this often requires bodily movements as responses. How these responses are selected is a central question in contemporary cognitive psychology. The ideomotor principle offers a simple answer based on two assumptions: An agent first learns an association between a response and its effects. Later, this association can be used in a reverse way: When the agent wants to achieve a desired effect and activates its representation, the associated response representation becomes activated as well. This reversed use of the learned association is considered the means to select the required response. In three experiments, we addressed two questions related to the first assumption: First, we tested whether effect representations generalise to more abstract conceptual knowledge. This is important, because outside the laboratory and in novel situations, effects are variable and not always exactly identical, such that generalisation is necessary for successful actions. Second, the nature of the response–effect relation has been debated recently, and more data are necessary to put theorising on firm empirical ground. Results of our experiments suggest that (a) abstraction to conceptual knowledge seems to occur only under very restricted situations, and (b) it seems that no (implicit) associations between responses and effects are learned, but rather (explicit) propositional knowledge in the form of rules.

Many accounts of instruction-based learning assume that initial declarative representations are transformed into executable procedural ones, so as to enable instruction implementation. We tested the hypothesis that declarative-procedural transformation should be bound to a specific response modality and not transferable across different modalities. In Experiment 1, novel stimulus-response instructions had to be implemented either verbally or manually either once or three times. Modality-specific procedural encoding was probed via a subsequent implicit priming test. This involved the same stimuli but required a response that could be either compatible or incompatible with the originally instructed response using either the same or a different response modality. We found that procedural encoding was modality-specific as indicated by a stronger repetition-dependent increase of the compatibility effect when response modality was unchanged. Explicit test performance, serving as a marker of declarative encoding, was independent of modality transition and it was uncorrelated with implicit test performance. Unexpectedly, the implicit priming test also revealed a small yet significant transfer to the response modality that was previously not overtly implemented, likely reflecting covert response “simulation”. To examine if covertly simulated responding occurs even when instruction implementation is omitted altogether, we conducted Experiment 2. Subjects merely viewed novel stimulus-response instructions prior to testing. Again, we found evidence for procedural encoding of the non-implemented instructions. Moreover, a direct comparison of both experiments revealed higher test scores (both implicit and explicit) for previously non-implemented instructions than for previously implemented instructions. This calls for theoretical reconciliation with diverging previous study results.

Automatic effects of instructions (AEIs) are typically reported with simple instructions that specify stimulus-response (S-R) mappings. Evidence in support of AEIs for instructions that specify more complex rules is less consistent. Here, we investigated whether instructions communicating context-specific strategic control routines designed to reduce evidence accumulation from the target stimulus can affect AEIs in the NEXT paradigm (Meiran et al., 2015). In each mini-block, participants were first instructed on the S-R mappings that should be implemented in the two GO trials at the end of the mini-block. In the intervening NEXT trials (0–3 trials), participants responded to each stimulus with the same (e.g. left) NEXT response. Importantly, the instructions also indicated the probability that each stimulus would be presented during the critical GO trials (e.g. 90% vs. 10%). We reasoned that this would strategically reduce the amount of information accumulated from the target stimulus prior to selecting a response, thereby reducing the magnitude of AEIs. GO performance was modulated by the context, suggesting that the strategic aspects of the instructions had been implemented. However, AEIs were broadly consistent across contexts, suggesting that the adopted strategy did not affect automatic behaviour. This pattern of results was consistent across three experiments (one preregistered), suggesting that complex instructions do not automatically trigger strategic control in dynamic environments.

Congruency effects in conflict tasks are typically larger after congruent compared to incongruent trials. This congruency sequence effect (CSE) indicates that top-down adjustments of cognitive control transfer between processing episodes, at least when controlling for bottom-up memory processes by alternating between stimulus-response (S-R) sets in confound-minimised designs. According to the control-retrieval account, cognitive control is bound to task-irrelevant context features (e.g., stimulus position or modality) and retrieved upon subsequent context feature repetitions. A confound-minimised CSE should therefore be larger when context features repeat rather than change between two trials. This study tested this prediction for a more abstract contextual stimulus feature, speaker gender. In two preregistered auditory prime-probe task experiments, participants classified colour words spoken by a female or male voice. Across both experiments, we found confound-minimised CSEs that were not reliably affected by whether the speaker gender repeated or changed. This indicates that speaker transitions have virtually no influence on the transfer of control adjustments in the absence of S-R repetitions. By contrast, when allowing for bottom-up memory processes by repeating the S-R set, CSEs were consistently larger when the speaker gender repeated compared to changed. This suggests that speaker transitions can in principle influence transfer between processing episodes. The discrepancy also held true when considering learning and test episodes separated by an intervening episode. Thus, the present findings call for a refinement of the control-retrieval account to accommodate the role of more abstract contextual stimulus features for the maintenance of memory traces in auditory conflict processing.

Learning-guided reactive control is the flexible biasing of attention that is triggered by external cues, such that more focused control settings are retrieved and executed in response to cues predicting higher attentional demands. We investigated whether race/ethnicity is harnessed as a cue to guide control using a social Stroop task in which participants named the race/ethnicity of a face (e.g., Asian) while ignoring a superimposed word that was congruent (e.g., Asian) or incongruent (e.g., White). In the first four experiments, we manipulated item-specific proportion congruence. Faces of some races/ethnicities (e.g., Asian, Black) were mostly congruent, and faces of others (e.g., White, Latina) were mostly incongruent. We observed the item-specific proportion congruence effect showing a smaller Stroop effect for mostly incongruent faces. Critically, we found transfer of the effect to faces of each race/ethnicity that were 50% congruent, indicating control at the more abstract, category level (i.e., more focused control setting retrieved and executed for racial/ethnic categories associated with higher attentional demands). Individuating faces did not disrupt category-level control but recategorisation of the faces into racially/ethnically diverse teams did, as indicated by the lack of transfer. In a final experiment, we associated proportion congruence (attentional demands) with the conjunction of two social categories (race/ethnicity and gender) and found novel evidence of conjunctive learning-guided control. The findings demonstrate that race/ethnicity (and conjunctions with gender) cues control adjustments, people transfer learned control settings to other members of race/ethnicity categories, and recategorisation creates an important boundary condition for transfer.

People learn associations between attentional demands (e.g., conflict likelihood) and predictive cues and then reactively retrieve relatively relaxed or focused control settings upon reoccurrence of a predictive cue, which is referred to as learning-guided control. A key theoretical question concerns whether learning-guided control transfers to novel situations in which the cues are no longer predictive of attentional demands. Using a picture-word Stroop task, we examined whether learning-guided control settings acquired when responding with one response modality (i.e., manual keypress) were evidenced when subsequent transfer items required a different response modality (i.e., vocal response). For training items, an item-specific proportion congruence manipulation was employed such that some predictive cues (pictures) were mostly congruent, and others were mostly incongruent. Transfer items were visibly identical to training items, but critically, all cues were 50% congruent. In Experiment 1 in which training occurred prior to a separate transfer phase, we did not observe transfer. In Experiment 2, we intermixed manual modality training items and vocal modality transfer items within blocks throughout the experiment. In this case, transfer was observed. These novel findings demonstrate that learning-guided control settings can generalize from one response modality to another under select conditions. We discuss the roles of modality-specific processes and boundaries between training items and transfer items in modulating transfer, and implications for automaticity.

The ability to spontaneously access knowledge of relational concepts acquired in one domain and apply it to a novel domain has traditionally been explored in the analogy literature via the problem-solving paradigm. In the present work, we propose a novel procedure based on categorisation as a complementary approach to assess spontaneous analogical transfer—using one category learning task to enhance learning of the same underlying category structures in another domain. In Experiment 1, we demonstrate larger improvements in classification performance across blocks of training in a target category learning task among participants that underwent a base category learning task relative to a separate group of participants learning the target category structures for the first time, thus providing evidence for spontaneous transfer of the category structures. In Experiment 2, we demonstrate similar evidence of spontaneous transfer for participants that underwent a comparison-based base category learning task under a more rigorous context shift between the base and target category learning tasks. Additional exploratory analyses across both experiments showcase ways in which this paradigm can be used to answer questions regarding the analogical transfer of relational category structures and generate promising paths for future work.

Even though spontaneous retrieval of analogous cases lacking surface similarity with a target situation typically requires achieving an abstract representation of the target situation, recent studies on analogical argumentation suggest that the deliberate disposition to search for analogous cases in long-term memory (LTM) suffices to increase cross-domain retrieval significantly. However, a limitation of these studies concerns the impossibility to determine whether the analogous situations reported were invented rather than retrieved, and whether there were instances of analogical retrieval that were not reflected in participants’ arguments. To overcome these shortcomings, Experiment 1 resorted to a traditional transfer paradigm where a base analogue is learned prior to the presentation of the target situation during a contextually-separated phase. Results confirmed that an explicit indication to base persuasive arguments on analogous situations increases distant retrieval as compared to a baseline condition where the instruction to generate persuasive arguments did not include an indication to think of analogous cases. Experiment 2 generalised the retrieval advantage of voluntary search to the activity of generating explanatory hypotheses for a counterintuitive phenomenon, a more prototypical variety of knowledge transfer that has been somewhat overlooked within analogy research. The theoretical and educational implications of the present findings are discussed.

In choice–reaction tasks, responses are faster if stimuli and responses are spatially compatible than if they are incompatible, even when the locations of the stimuli are irrelevant to the task. This stimulus–response (S-R) compatibility effect that occurs based on task-irrelevant stimulus and response features is known as the Simon effect. The Simon effect can be eliminated or even reversed after training with spatially incompatible S-R mappings only for a short duration, indicating that newly acquired incompatible S-R associations transfer to the Simon task. This transfer effect is usually reduced when the context of the training task is altered at test, suggesting that the expression of learned S-R associations depends on the similarity between the learning and test contexts. However, there can be cases where transfer occurs from one context to another but not in the reverse direction (i.e., transfer asymmetry). Transfer asymmetry is problematic for many models of psychological similarity, which would predict that transfer is symmetrical between two contexts. This study shows that Tversky’s set-theoretic model of similarity—the contrast model—is a useful framework for understanding how transfer symmetry arises in human perceptual-motor learning. The results of the two experiments imply that the similarity of contexts depends not only on features that overlap between the contexts but also on features that are distinctive to them.