Order effects in stimulus discrimination challenge established models of comparative judgement: A meta-analytic review of the Type B effect.

This paper provides a comprehensive review of the Type B effect (TBE), a phenomenon reflected in the observation that discrimination sensitivity varies with the order of stimuli in comparative judgment tasks, such as the two-alternative forced-choice (2AFC) paradigm. Specifically, when the difference threshold is lower (higher) with the constant standard preceding rather than following the variable comparison, one speaks of a negative (positive) TBE. Importantly, prominent psychophysical difference models such as signal detection theory (Green & Swets, 1966) cannot easily account for the TBE, and are hence challenged by it. The present meta-analysis provides substantial evidence for the TBE across various stimulus attributes, suggesting that the TBE is a general feature of discrimination experiments when standard and comparison are presented successively. Thus, inconsistent with psychophysical difference models, subjective differences between stimuli are not merely a function of their physical differences but rather also depend on their temporal order. From the literature, we identify four classes of potential candidate theories explaining the origin of the TBE, namely (1) differential weighting of the stimulus magnitudes at the two positions (e.g., Hellström, Psychological Research, 39, 345-388 1977), (2) internal reference formation (e.g., Dyjas, Bausenhart, & Ulrich, Attention, Perception, & Psychophysics, 74, 1819-1841 2012), (3) Bayesian updating (e.g., de Jong, Akyürek, & van Rijn, Psychonomic Bulletin and Review, 28, 1183-1190 2021), and (4) biased threshold estimation (García-Pérez & Alcalá-Quintana, Attention, Perception & Psychophysics, 72, 1155-1178 2010). As these models, to some extent, make differential predictions about the direction of the TBE, investigating the respective boundary conditions of positive and negative TBEs might be a valuable perspective for diagnostic future research.

The effect of transcutaneous auricular vagus nerve stimulation (taVNS) on cognitive control in multitasking.

Current research in brain stimulation suggests transcutaneous auricular vagus nerve stimulation (taVNS) as a promising tool to modulate cognitive functions in healthy populations, such as attention, memory, and executive functions. Empirical evidence in single-task contexts, suggests that taVNS promotes holistic task processing, which strengthens the integration of multiple stimulus features in task processing. However, it is unclear how taVNS might affect performance in multitasking, where the integration of multiple stimuli leads to an overlap in stimulus response translation processes, increasing the risk of between-task interference (crosstalk). In a single-blinded, sham-controlled, within-subject design, participants underwent taVNS while performing a dual task. To assess the effects of taVNS, behavioral (reaction times), physiological (heart rate variability, salivary alpha-amylase), and subjective psychological variables (e.g., arousal) were recorded over three cognitive test blocks. Our results revealed no overall significant effect of taVNS on physiological and subjective psychological variables. However, the results showed a significant increase in between-task interference under taVNS in the first test block, but not in the subsequent test blocks. Our findings therefore suggest that taVNS increased integrative processing of both tasks early during active stimulation.

Valence moderates the effect of stimulus-hand proximity on conflict processing and gaze-cueing.

An effective interaction with the environment requires adaptation of one's own behaviour to environmental demands. We do so by using cues from our environment and relating these cues to our body to predict the outcomes of events. The recent literature on embodied cognition suggests that task-relevant stimuli, presented near the hands, receive more attentional capacity and are processed differently than stimuli, presented spatially more distant to our body. It has also been proposed that near-hand processing is beneficial to conflict resolution. In the current study, we tested the assumption of an attentional bias towards the near hand space in the context of our previous work by combining a cueing paradigm (allocation of visual attention) with a conflict processing paradigm (Simon task) in the near vs far hand space. In addition, the relevance of processing was manipulated by using affective (angry vs neutral smileys) gaze cues (i.e., varying the valence of the cues). Our results indicate that (a) the interaction of valence × cue congruency × hand proximity was significant, indicating that the cueing effect was larger for negative valence in the proximal condition. (b) The interaction of valence × Simon compatibility × stimulus-hand proximity interaction was significant, indicating that for negative valence processing, the Simon effect was smaller in the proximal than in the distal stimulus-hand condition. This effect was at least numerically but not significantly reversed in the neutral valence condition. (c) Overall, cue congruency, indicating the correct vs incorrect attention allocation to the target stimulus onset, did not reveal any effect on Simon compatibility × stimulus-hand proximity. Our results suggest that valence, the allocation of attention, and conflict, seem to be decisive factors determining the direction and strength of hand proximity effects.

Opposing influences of global and local stimulus-hand proximity on crosstalk interference in dual tasks.

In contrast to traditional dualistic views of cognition, visual stimulus processing appears not independent of bodily factors such as hand positioning. For example, reduced crosstalk between two temporally overlapping tasks has been observed when the hands are moved into the attentional window alongside their respective stimuli (i.e., establishing global stimulus-hand proximity). This result indicates that hand-specific attentional processing enhancements support a more serial rather than parallel processing of the two tasks. To further elucidate the nature of these processing modulations and their effect on multitasking performance, the present study consisted of three interrelated crosstalk experiments. Experiment 1 manipulated global stimulus-hand proximity and stimulus-effect proximity orthogonally, with results demonstrating that hand proximity rather than effect proximity drives the crosstalk reduction. Experiment 2 manipulated the physical distance between both hands (i.e., varying local stimulus-hand proximity), with results showing weak evidence of increased crosstalk when both hands are close to each other. Experiment 3 tested opposing influences of global and local stimulus-hand proximity as observed in Experiment 1 and 2 rigorously within one experiment, by employing an orthogonal manipulation of these two proximity measures. Again, we observed slightly increased crosstalk for hands close to each other (replicating Experiment 2); however, in contrast to Experiment 1, the effect of global stimulus-hand proximity on the observed crosstalk was not significant this time. Taken together, the experiments support the notion of hand-specific modulations of perception-action coupling, which can either lead to more or less interference in multitasking, depending on the exact arrangement of hands and stimuli.

Action prediction modulates self-other integration in joint action.

People often coordinate actions with others, requiring an adjustable amount of self-other integration between actor's and co-actor's actions. Previous research suggests that such self-other integration (indexed by the joint Simon effect) is enhanced by agent similarity of the co-actor (e.g., high in intentionality). In this study, we aimed to extend this line of research by testing whether experiencing agency over a co-actor's actions (vicarious agency) and/or action prediction strengthens the joint Simon effect. For this purpose, we manipulated experienced agency by varying the experienced control over a co-actor's actions (Experiment 1), and action prediction regarding the co-actor's actions (Experiment 2). Vicarious agency could effectively be induced, but did not modulate the size of the joint Simon effect. The joint Simon effect was decreased when the co-actor's actions were unpredictable (vs. predictable) during joint task performance. These findings suggest social agency can be induced and effectively measured in joint action. Action prediction can act as an effective agency cue modulating the amount of self-other integration in joint action.

The role of action inhibition for behavioral control in joint action.

When two individuals share a task with a common goal, coordinating one's own and the other's actions is pivotal. Inhibition of one's own actions when it is the other's turn to act is assumed to play a crucial role in this process. For instance, in the joint Simon task, two individuals share a two-choice task such that one of them responds to one stimulus type and ignores the stimulus type to which the other responds. Because stimuli can either appear on one's own or on the other's side, stimulus location can conflict with stimulus identity, thus slowing response time. It has previously been shown that such conflict leads to a reduction of the detrimental effects of conflict on immediately upcoming trials both following own responses and even more so following the other's responses. This amplified trial-to-trial adjustment following the other's responses has been assumed to reflect the inhibition of own responses on the other's trials. The present study tested this hypothesis by comparing sequential trial-to-trial adjustments following correct responses and commission errors on which the inhibition of own responses has failed. As expected, adjustments were stronger following the other's correct responses than following own correct responses. Crucially, such amplification of sequential adjustment was not observed following own commission errors on the other's trials. This shows that amplification of sequential adjustments following the other's trials depend on successful inhibition of own responses on these trials and points to a crucial role of response inhibition for behavioral control in joint action.

Top-Down Modulation of Motor Priming by Belief About Animacy.

Research has shown that people automatically imitate others and that this tendency is stronger when the other person is a human compared with a nonhuman agent. However, a controversial question is whether automatic imitation is also modulated by whether people believe the other person is a human. Although early research supported this hypothesis, not all studies reached the same conclusion and a recent meta-analysis found that there is currently neither evidence in favor nor against an influence of animacy beliefs on automatic imitation. One of the most prominent studies supporting such an influence is the study by Liepelt and Brass (2010), who found that automatic imitation was stronger when participants believed an ambiguous, gloved hand to be human, as opposed to wooden. In this registered report, we provide a high-powered replication of this study (N = 199). In contrast to Liepelt and Brass (2010), we did not find an effect of animacy beliefs on automatic imitation. However, we did find a correlation between automatic imitation and perceived self-other similarity. Together, these results suggest that the gloved hand procedure does not reliably influence automatic imitation, but interindividual differences in perceived similarity do.

Evidence for a modulating effect of transcutaneous auricular vagus nerve stimulation (taVNS) on salivary alpha-amylase as indirect noradrenergic marker: A pooled mega-analysis.

BACKGROUND: Non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) has received tremendous attention as a potential neuromodulator of cognitive and affective functions, which likely exerts its effects via activation of the locus coeruleus-noradrenaline (LC-NA) system. Reliable effects of taVNS on markers of LC-NA system activity, however, have not been demonstrated yet. METHODS: The aim of the present study was to overcome previous limitations by pooling raw data from a large sample of ten taVNS studies (371 healthy participants) that collected salivary alpha-amylase (sAA) as a potential marker of central NA release. RESULTS: While a meta-analytic approach using summary statistics did not yield any significant effects, linear mixed model analyses showed that afferent stimulation of the vagus nerve via taVNS increased sAA levels compared to sham stimulation (b = 0.16, SE = 0.05, p = 0.001). When considering potential confounders of sAA, we further replicated previous findings on the diurnal trajectory of sAA activity. CONCLUSION(S): Vagal activation via taVNS increases sAA release compared to sham stimulation, which likely substantiates the assumption that taVNS triggers NA release. Moreover, our results highlight the benefits of data pooling and data sharing in order to allow stronger conclusions in research.

Motor cognition in schizophrenia: Control of automatic imitation and mapping of action context are reduced.

The ability to imitate is considered impaired in schizophrenia patients. This assumption, however, is based on heterogeneous studies mostly targeting voluntary imitation, e.g., pantomime. Studies on automatic imitation, however, and on underlying mechanisms of top-down inhibition of automatic imitation and contextual modulation in schizophrenia are highly limited. We employed two sensorimotor paradigms to examine imitation-inhibition and action context mapping in 37 schizophrenia patients and 36 matched controls. In the first experiment, participants performed finger lifts while observing a hand executing compatible or incompatible finger lifts from the third-person perspective. The compatibility or incompatibility of these finger lifts affected participants' reaction times (RTs). The comparison of between-condition RT differences shows a larger movement compatibility effect in schizophrenia than in controls. The second experiment involved finger lifts while watching a still hand, from the first-person perspective, with constrained fingers that either corresponded or did not correspond to the participants' response fingers. Here, schizophrenia patients showed a diminished RT slowing in corresponding constraint trials. While the former results provide evidence for an impaired control of imitation in patients with schizophrenia, the latter results indicate a reduced encoding of action context. In conclusion, this study provides the first evidence for deficits of top-down control of imitation and motor context processing in the same sample of schizophrenia patients.

Metacontrol and joint action: how shared goals transfer from one task to another?

In most of our daily activities and in team sports, we interact with other individuals and do not act in isolation. Using a social variant of the standard two-choice Simon task, this study aims to test if competitive/cooperative processing modes (i.e., metacontrol states) change the degree of bodily self-other integration between two persons in joint action. In addition, and more exploratory the study tested if this effect depends on a shared group experience with the partner. Two participants shared a visual Simon task, so that each person basically performed complementary parts of the task, which transfers the paradigm into a go/no-go Simon task for each person. Before running this joint Simon task, we set both participants either in a competitive or a cooperative control state by means of a dyadic game, a manipulation aimed at testing possible goal transfer across tasks. We found significant joint Simon effects for participants who were in a competitive state and for participants who were in a cooperative state. The joint Simon effect for participants being in a competitive state was significantly smaller than for participants being in a cooperative state. When experiencing the goal induction together with the partner, the joint Simon effect was significantly decreased as when the induction was performed alone. Both effects (metacontrol state induction and shared experience) seem to be statistically independent of each other. In line with predictions of metacontrol state theory, our study indicated that abstract cognitive goal states can be transferred from one task to another task, able to affect the degree of bodily self-other integration across different task situations.

Embodied cognition in multitasking: increased hand-specific task shielding when stimuli are presented near the hand.

The proximity of hand position alters the processing of visual stimuli. Stimuli presented close (proximal) to hands receive an enhanced allocation of visual attention compared to stimuli presented far (distal) from hands. In the present dual-task study we studied the consequences of this preferential processing when the stimulus for Task 1 (S1) and the stimulus for Task 2 (S2) were presented together and were assigned to specific response hands (R1 and R2) located proximal (at the monitor) versus distal (in the lap) to the stimuli. In two experiments, we tested whether stimulus-hand proximity affected the extent of between-task interference (i.e., influence of additional Task 2 processing on primary Task 1 processing). In Experiment 1, results showed that stimulus-hand proximity reduced the amount of between-task interference compared to the distal stimulus-hand condition. Extending these findings, in Experiment 2 a further reduction of between-task interference was obtained when a single hand was located at the monitor instead of two hands. These results are inconsistent with the assumption of a generally increased attentional processing benefit for multiple stimuli within hand space. Instead, these findings speak for a hand-specific processing benefit that supports more separate processing of two tasks. Together these findings demonstrate that stimulus-hand proximity affects the quality of multiple task performance, which is discussed in the context of both, basic and applied cognitive research.

Saccadic eye movements do not trigger a joint Simon effect.

Although the joint Simon task (JST) has been investigated for more than a decade, its cause is still unclear. According to ideomotor views of action control, action effects are a commonly cited explanation. However, action effects are usually confounded with the actions producing such effects. We combined a JST with eye tracking and asked participants to respond by performing specific saccades. Saccades were followed by visual feedback (central vs. lateral feedback), serving as the action effect. This arrangement allowed us to isolate actions from action effects and, also to prevent each actor from seeing the reciprocal actions of the other actor. In this saccadic JST, we found a significant compatibility effect in the individual setting. The typical enhanced compatibility effect in the joint setting of the JST was absent with central action feedback and even when lateralized visual action feedback was provided. Our findings suggest that the perception of action effects alone might not be sufficient to modulate compatibility effects for eye movements. The presence of a compatibility effect in the individual setting shows the specific requirements of a saccadic compatibility task - the requirement to perform prosaccades to compatible and antisaccades to incompatible target locations. The lack of a difference between compatibility effects in joint and individual settings and the lack of a modulation of the compatibility effect through lateralized visual action feedback shows that the finding of a joint Simon effect that has frequently been reported for manual responses is absent for saccadic responses.

A matter of you versus me? Experiences of control in a joint go/no-go task.

When interacting with others, people represent their own as well as their interaction partners' actions. Such joint action representation is essential for action coordination, but may also interfere with action control. We investigated how joint action representations affect experienced control over people's own actions and their interaction partners' actions. Participants performed a joint go/no-go task, which is commonly used to measure to what extent people represent their own actions in spatial reference to their interaction partner (e.g., as 'left' vs. 'right'). After each second trial, participants indicated experienced control over their own action, their interaction partner's action, or over action inhibition. Despite this frequent interruption of the go/no-go task, we found strong evidence for the spatial representation of joint actions. However, this joint action representation did not affect experiences of control. Possible explanations and implications of these findings are discussed.

It's not me, it's you - Differential neural processing of social and non-social nogo cues in joint action.

This study used a joint flanker task to investigate differences in processing of social and non-social nogo cues, i.e., between cues indicating that a co-actor should respond and cues signaling that neither actor nor co-actor should respond, using event-related potentials (ERPs) and trial-to-trial response times (RTs). It was hypothesized that a social co-actor's response should be reflected in stronger modulation (slower RTs on subsequent trials; augmented neural responses) for social compared to non-social nogo. RTs and ERPs replicated flanker compatibility effects, with faster responses and increased P3a on compatible trials. In line with the hypotheses, ERPs revealed distinct coding of social and non-social nogo in the conflict-sensitive N2 which showed a compatibility effect only for social nogo, and in the attention/memory-related P3b which was larger for social relative to non-social nogo. The P3a did not distinguish between social and non-social nogo, but was larger for compatible and smaller for go trials. Contrary to our hypotheses, RTs were faster after social relative to non-social nogo. Hence, the representation of the co-actor's response in joint action modulates conflict processing reflected in the N2 and response discrimination and evaluation reflected in the P3b and may facilitate subsequent responses in the context of social versus non-social nogo.

The Multimodal Go-Nogo Simon Effect: Signifying the Relevance of Stimulus Features in the Go-Nogo Simon Paradigm Impacts Event Representations and Task Performance.

Numerous studies have shown that stimulus-response-compatibility (SRC) effects in the go-nogo version of the Simon task can be elicited as a result of performing the task together with another human or non-human agent (e.g., a Japanese-waving-cat, a working-clock, or a ticking-metronome). A parsimonious explanation for both social and non-social SRC effects is that highlighting the spatial significance of alternative (non-/social) action events makes action selection more difficult. This holds even when action events are task-irrelevant. Recent findings, however, suggest that this explanation holds only for cases of a modality correspondence between the Simon task as such (i.e., auditory or visual) and the alternative (non-/social) action event that needs to be discriminated. However, based on the fact that perception and action are represented by the same kind of codes, an event that makes the go-nogo decision more challenging should impact go-nogo Simon task performance. To tackle this issue, the present study tested if alternative stimulus events that come from a different sensory modality do impact SRC effects in the go-nogo version of the Simon task. This was tested in the presence and absence of alternative action events of a human co-actor. In a multimodal (auditory-visual) go-nogo Simon paradigm, participants responded to their assigned stimulus - e.g., a single auditory stimulus while ignoring the alternative visual stimulus or vice versa - in the presence or absence of a human co-actor (i.e., joint and single go-nogo condition). Results showed reliable SRCs in both, single and joint go-nogo Simon task conditions independent of the modality participants had to respond to. Although a correspondence between stimulus material and attention-grabbing event might be an efficient condition for SRCs to emerge, the driving force underlying the emergence of SRCs rather appears to be whether the attentional focus prevents or facilitates alternative events to be integrated. Thus, under task conditions in which the attentional focus is sufficiently broad to enable the integration and thus cognitive representation of alternative events, go-nogo decisions become more difficult, resulting in reliable SRCs in single and joint go-nogo Simon tasks.

Dual-Tasking in the Near-Hand Space: Effects of Stimulus-Hand Proximity on Between-Task Shifts in the Psychological Refractory Period Paradigm.

Two decades of research indicate that visual processing is typically enhanced for items that are in the space near the hands (near-hand space). Enhanced attention and cognitive control have been thought to be responsible for the observed effects, amongst others. As accumulating experimental evidence and recent theories of dual-tasking suggest an involvement of cognitive control and attentional processes during dual tasking, dual-task performance may be modulated in the near-hand space. Therefore, we performed a series of three experiments that aimed to test if the near-hand space affects the shift between task-component processing in two visual-manual tasks. We applied a Psychological Refractory Period Paradigm (PRP) with varying stimulus-onset asynchrony (SOA) and manipulated stimulus-hand proximity by placing hands either on the side of a computer screen (near-hand condition) or on the lap (far-hand condition). In Experiment 1, Task 1 was a number categorization task (odd vs. even) and Task 2 was a letter categorization task (vowel vs. consonant). Stimulus presentation was spatially segregated with Stimulus 1 presented on the right side of the screen, appearing first and then Stimulus 2, presented on the left side of the screen, appearing second. In Experiment 2, we replaced Task 2 with a color categorization task (orange vs. blue). In Experiment 3, Stimulus 1 and Stimulus 2 were centrally presented as a single bivalent stimulus. The classic PRP effect was shown in all three experiments, with Task 2 performance declining at short SOA while Task 1 performance being relatively unaffected by task-overlap. In none of the three experiments did stimulus-hand proximity affect the size of the PRP effect. Our results indicate that the switching operation between two tasks in the PRP paradigm is neither optimized nor disturbed by being processed in near-hand space.

The Psychophysiology of Action: A Multidisciplinary Endeavor for Integrating Action and Cognition.

There is a vast amount of literature concerning the integration of action and cognition. Although this broad research area is of great interest for many disciplines like sports, psychology and cognitive neuroscience, only a few attempts tried to bring together different perspectives so far. Our goal is to provide a perspective to spark a debate across theoretical borders and integration of different disciplines via psychophysiology. In order to boost advances in this research field it is not only necessary to become aware of the different areas that are relevant but also to consider methodological aspects and challenges. We briefly describe the most relevant theoretical accounts to the question of how internal and external information processes or factors interact and, based on this, argue that research programs should consider the three dimensions: (a) dynamics of movements; (b) multivariate measures and; (c) dynamic statistical parameters. Only with an extended perspective on theoretical and methodological accounts, one would be able to integrate the dynamics of actions into theoretical advances.

When a Social Experimenter Overwrites Effects of Salient Objects in an Individual Go/No-Go Simon Task - An ERP Study.

When two persons share a Simon task, a joint Simon effect occurs. The task co-representation account assumes that the joint Simon effect is the product of a vicarious representation of the co-actor's task. In contrast, recent studies show that even (non-human) event-producing objects could elicit a Simon effect in an individual go/no-go Simon task arguing in favor of the referential coding account. For the human-induced Simon effect, a modulation of the P300 component in Electroencephalography (EEG) is typically considered as a neural indicator of the joint Simon effect and task co-representation. Showing that the object-induced Simon effects also modulates the P300 would lead to a re-evaluation of the interpretation of the P300 in individual go/no-go and joint Simon task contexts. To do so, the present study conceptually replicated Experiment 1 from Dolk et al. (2013a) adding EEG recordings and an experimenter controlling the EEG computer to test whether a modulation of the P300 can also be elicited by adding a Japanese waving cat to the task context. Subjects performed an individual go/no-go Simon task with or without a cat placed next to them. Results show an overall Simon effect regardless of the cat's presence and no modulatory influence of the cat on the P300 (Experiment 1), even when conceivably interfering context factors are diminished (Experiment 2). These findings may suggest that the presence of a spatially aligned experimenter in the laboratory may produce an overall Simon effect overwriting a possible modulation of the Japanese waving cat.

Barriers to success: physical separation optimizes event-file retrieval in shared workspaces.

Sharing tasks with other persons can simplify our work and life, but seeing and hearing other people's actions may also be very distracting. The joint Simon effect (JSE) is a standard measure of referential response coding when two persons share a Simon task. Sequential modulations of the joint Simon effect (smJSE) are interpreted as a measure of event-file processing containing stimulus information, response information and information about the just relevant control-state active in a given social situation. This study tested effects of physical (Experiment 1) and virtual (Experiment 2) separation of shared workspaces on referential coding and event-file processing using a joint Simon task. In Experiment 1, participants performed this task in individual (go-nogo), joint and standard Simon task conditions with and without a transparent curtain (physical separation) placed along the imagined vertical midline of the monitor. In Experiment 2, participants performed the same tasks with and without receiving background music (virtual separation). For response times, physical separation enhanced event-file retrieval indicated by an enlarged smJSE in the joint Simon task with curtain than without curtain (Experiment1), but did not change referential response coding. In line with this, we also found evidence for enhanced event-file processing through physical separation in the joint Simon task for error rates. Virtual separation did neither impact event-file processing, nor referential coding, but generally slowed down response times in the joint Simon task. For errors, virtual separation hampered event-file processing in the joint Simon task. For the cognitively more demanding standard two-choice Simon task, we found music to have a degrading effect on event-file retrieval for response times. Our findings suggest that adding a physical separation optimizes event-file processing in shared workspaces, while music seems to lead to a more relaxed task processing mode under shared task conditions. In addition, music had an interfering impact on joint error processing and more generally when dealing with a more complex task in isolation.

Multitasking as a choice: a perspective.

Performance decrements in multitasking have been explained by limitations in cognitive capacity, either modelled as static structural bottlenecks or as the scarcity of overall cognitive resources that prevent humans, or at least restrict them, from processing two tasks at the same time. However, recent research has shown that individual differences, flexible resource allocation, and prioritization of tasks cannot be fully explained by these accounts. We argue that understanding human multitasking as a choice and examining multitasking performance from the perspective of judgment and decision-making (JDM), may complement current dual-task theories. We outline two prominent theories from the area of JDM, namely Simple Heuristics and the Decision Field Theory, and adapt these theories to multitasking research. Here, we explain how computational modelling techniques and decision-making parameters used in JDM may provide a benefit to understanding multitasking costs and argue that these techniques and parameters have the potential to predict multitasking behavior in general, and also individual differences in behavior. Finally, we present the one-reason choice metaphor to explain a flexible use of limited capacity as well as changes in serial and parallel task processing. Based on this newly combined approach, we outline a concrete interdisciplinary future research program that we think will help to further develop multitasking research.