Shared learning shapes human performance: Transfer effects in task sharing

We investigated whether performing a task with a co-actor shapes the way a subsequent task is performed. In four experiments participants were administered a Simon task after practicing a spatial compatibility task with an incompatible S-R mapping. In Experiment 1 they performed both tasks alongside another person; in Experiment 2 they performed the spatial compatibility task alone, responding to only one stimulus position, and the Simon task with another person; in Experiment 3, they performed the spatial compatibility task with another person and the Simon task alone; finally, in Experiment 4, they performed the spatial compatibility task alone and the Simon task with another person. The incompatible practice eliminated the Simon effect in Experiments 1 and 4. These results indicate that when a task is distributed between two participants with each one performing a different part of it, they tend to represent the whole task rather than their own part of it. This experience can influence the way a subsequent task is performed, as long as this latter occurs in a social context.     

Pending intentions: Effects of prospective task encoding on the performance of another task

A number of recent studies casts doubt on the empirical separability of processes of task preparation from the actual execution of the respective task. We report two experiments in which we separated the precueing of a task from its execution by an intervening task. In addition, for the precued task we employed imperative stimuli that in most cases were associated with a competing task, making the execution of this task dependent on an internal representation of the information provided by the precue. Under these conditions, the performance of the intervening task suffered specific interference as a function of its relation to the precued task. This suggests that the encoding of the precue resulted in specific preparation for the precued task. Furthermore, the transition between the intervening task and the precued task was associated with relatively small costs that did not vary as a function of the interval that separated the two tasks. This also suggests that a great deal of preparation for the second task already took place during the encoding of the precue. Further observations suggest that the resolution of the interference between a memory-based task representation, as well as a perceptually induced task representation, and the representation of the currently relevant task took place on the level of individual task features.     

Verbal representation in task order control: An examination with transition and task cues in random task switching

Recent task-switching studies in which a predictable task sequence has been used have indicated that verbal representation contributes to the control of task order information. The present study focused on the role of verbal representation in sequential task decisions, which are an important part of task order control, and examined the effects of articulatory suppression in a random-task-cuing paradigm with two different types of cues presented just before the presentation of a stimulus: a transition cue and a task cue. The former cue provided information only about switching or repeating the task, whereas the latter was associated directly with the identity of the task (i.e., indicating a parity or a magnitude task). In Experiment 1, in which transition cues guided task sequences, articulatory suppression impaired performance in both repetition and switch trials, thereby increasing the mixing costs. In Experiment 2, in which a task cue, rather than a transition cue, was presented to examine the influence of a cue-decoding process, articulatory suppression had no specific effect on task performance. Experiment 3, in which the transition cue and the task cue were randomly presented in the same block to equalize the memory load and task strategy for the two types of cues, confirmed that articulatory suppression significantly increased the mixing costs only in transition cue trials. The results from the three experiments indicated that the use of verbal representation is effective in sequential task decision—that is, in selecting a task set on the basis of transient task order information in both repetition and switch trials.     

No ego-depletion effect without a good control task

The ego-depletion effect refers to a temporary failure of self-control exertion after first performing an effortful task. This phenomenon has experienced a replication crisis in the past few years. In the present series of experiments, we tried to replicate the ego-depletion effect using a 30-min modified Stroop task tapping two executive functions (inhibitory control and cognitive flexibility) as the depleting task. In the first study, we compared the performance of a handgrip endurance task after this depleting task or after a classic control task (i.e., reading color words) and failed to replicate the ego-depletion effect. We showed that the control task induced boredom and subjective fatigue. In a second study, we looked for a better control task and compared the color-word reading task to another possible control task used in the literature (i.e., watching a documentary). Controlling for boredom, subjective fatigue, motivation and affective state, we found that the video task was not boring and did not induce fatigue, drop in motivation or negative affective state, whereas the color-word reading task did. In a third study, we used the video task as the control task and the modified effortful Stroop task used in the first study as the depleting task and succeeded in replicating the ego-depletion effect. This series of experiments illustrates that the choice of an appropriate control task is crucial to observe an ego-depletion effect and that boredom is costly. Consequently, it appears necessary to control for boredom in any future replication study aiming to observe an ego-depletion effect.     

Suppression of brain activity related to a car-following task with an auditory task: An fMRI study

Driving a car in daily life involves multiple tasks. One important task for safe driving is car-following, the interference of which causes rear-end collisions: the most common type of car accident. Recent reports have described that car-following is hindered even by hands-free mobile telephones. We conducted functional MRI with 18 normal volunteers to investigate brain activity changes that occur during a car-following task with a concurrent auditory task. Participants performed three tasks: a driving task, an auditory task, and a dual task in an fMRI run. During the driving task, participants use a joystick to control their vehicle speed in a driving simulator to maintain a constant distance from a leading car, which moves at varying speed. Language trials and tone discrimination trials are presented during the auditory task. Car-following performance was worse during the dual task than during the single-driving task, showing positive correlation with brain activity in the bilateral lateral occipital complex and the right inferior parietal lobule. In the medial prefrontal cortex and left superior occipital gyrus, the brain activity of the dual task condition was less than that in the single-driving task condition. These results suggest that the decline of brain activity in these regions may induce car-following performance deterioration.     

Prospective memory in young and older adults: The effects of task importance and ongoing task load

Remembering to perform an action in the future, called prospective memory, often shows age-related differences in favor of young adults when tested in the laboratory. Recently Smith, Horn, and Bayen (2012; Aging, Neuropsychology, and Cognition, 19, 495) embedded a PM task in an ongoing color-matching task and manipulated the difficulty of the ongoing task by varying the number of colors on each trial of the task. Smith et al. found that age-related differences in PM performance (lower PM performance for older adults relative to young adults) persisted even when older adults could perform the ongoing task as well or better than the young adults. The current study investigates a possible explanation for the pattern of results reported by Smith et al. by including a manipulation of task emphasis: for half of the participants the prospective memory task was emphasize, while for the other half the ongoing color-matching task was emphasized. Older adults performed a 4-color version of the ongoing color-matching task, while young adults completed either the 4-color or a more difficult 6-color version of the ongoing task. Older adults failed to perform as well as the young adults on the prospective memory task regardless of task emphasis, even when older adults were performing as well or better than the young adults on the ongoing color-matching task. The current results indicate that the lack of an effect of ongoing task load on prospective memory task performance is not due to a perception that one or the other task is more important than the other.     

Task switching versus cue switching: using transition cuing to disentangle sequential effects in task-switching performance

Recent methodological advances have allowed researchers to address confounds in the measurement of task-switch costs in task-switching performance by dissociating cue switching from task switching. For example, in the transition-cuing procedure, which involves presenting cues for task transitions rather than for tasks, cue transitions (cue switches and cue repetitions) and task transitions (task switches and task repetitions) can be examined in a complete factorial design. Transition cuing removes the confound between cue transitions and first-order task transitions, but it introduces a confound between cue transitions and longer task sequences. In the present study, transition cuing was studied with two cues per transition (REPEAT and AGAIN for task repetitions; SWITCH and CHANGE for task switches), enabling a partial deconfounding of cue transitions and task sequences. Two experiments revealed robust sequential effects, with higher order task transitions affecting performance when cue transitions were held constant and with cue transitions affecting performance when task sequences were held constant. Methodological and theoretical implications of these findings for research on task switching are discussed.     

Reliability and generalizability of an acted-out false belief task in 3-year-olds

The current study tested the reliability and generalizability of a narrative act-out false belief task held to reveal Theory of Mind (ToM) competence at 3 years of age, before children pass verbal standard false belief tasks (the “Duplo task”; Rubio-Fernández & Geurts, 2013, Psychological Science). We conducted the task across two labs with methodologically improved matched control conditions. Further, we administered an analogue intensionality version to assess the scope of ToM competence in the Duplo task. 72 3-year-olds participated in a Duplo change-of-location task, a Duplo intensionality task, and half of them in a matched verbal standard change-of-location task, receiving either false belief or matched true belief scenarios. Children performed at chance in the false belief Duplo location change and intensionality tasks as well as in the standard false belief task. There were no differences to the standard task, and performance correlated across all three false belief tasks, revealing a rather unified competence and no task advantage. In the true belief conditions of both Duplo tasks, children performed at ceiling and significantly different from the false belief conditions, while they were at chance in the true belief condition of the standard task. The latter indicates that a pragmatic advantage of the Duplo task compared to the standard task holds only for the true belief scenarios. Our study shows that the Duplo task measures the same ToM competence as the standard task and rejects a notion of earlier false belief understanding on the group level in 3-year-old children.     

Inhibition of response mode in task switching

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.     

Task conflict effect in task switching

A part of action preparation is deciding what the relevant task is. This task-decision process is conceptually separate from response selection. To show this, the authors manipulated task conflict in a spatial task-switching paradigm, using conflict stimuli that appeared during trials with univalent targets (affording 1 task). The conflict stimuli afforded task identity because they were used as task cues with bivalent targets (affording 2 tasks) that were intermixed with the univalent targets. Thus, for univalent targets, irrelevant stimuli either caused low task conflict or high task conflict. In three experiments, the authors found poorer performance in high task conflict trials than in low task conflict trials. Task conflict was introduced during target appearance (Experiment 1) or task preparation (Experiments 2 and 3). In the latter case, the task conflict effect decreased with increasing task preparation time showing that task preparation involves task decision.     

The modality effect of ego depletion: Auditory task modality reduces ego depletion

An initial act of self‐control that impairs subsequent acts of self‐control is called ego depletion. The ego depletion phenomenon has been observed consistently. The modality effect refers to the effect of the presentation modality on the processing of stimuli. The modality effect was also robustly found in a large body of research. However, no study to date has examined the modality effects of ego depletion. This issue was addressed in the current study. In Experiment 1, after all participants completed a handgrip task, one group's participants completed a visual attention regulation task and the other group's participants completed an auditory attention regulation task, and then all participants again completed a handgrip task. The ego depletion phenomenon was observed in both the visual and the auditory attention regulation task. Moreover, participants who completed the visual task performed worse on the handgrip task than participants who completed the auditory task, which indicated that there was high ego depletion in the visual task condition. In Experiment 2, participants completed an initial task that either did or did not deplete self‐control resources, and then they completed a second visual or auditory attention control task. The results indicated that depleted participants performed better on the auditory attention control task than the visual attention control task. These findings suggest that altering task modality may reduce ego depletion.     

Joint Relationships of Task Proficiency With Aptitude,Experience, and Task Difficulty: A Cross-Level,Interactional Study

We adopted a cross-level interactional perspective in investigating the prediction of United States Air Force (USAF) jet engine mechanic task-level proficiency from aptitude, experience, and task difficulty. Aptitude, job and task experience, and task difficulty measures all were significant predictors of task proficiency. An hypothesis that task difficulty would moderate the aptitude-task proficiency relationship received no support. Similarly, hypothesized moderating effects of job experience on relationships of task proficiency with aptitude and task difficulty received little support. lhsk-level experience, however, had significant moderating effects on relationships of task proficiency with both aptitude and task difficulty. Aptitude and task difficulty had weaker relationships with task proficiency with increased task experience. We recommend that future research on performance determinants (a) clarify further the experience construct and (b) exploit theoretical and analytic advantages of cross-level and multilevel research designs.     

Preparation time modulates pro-active control and enhances task conflict in task switching

Performance in the Stroop task reflects two conflicts—informational (between the incongruent word and ink color) and task (between relevant color naming and irrelevant word reading). Neuroimaging findings support the existence of task conflict in congruent trials. A behavioral indication for task conflict—Stroop reverse facilitation—was found in previous studies under low task-control conditions. Task switching also causes reduction in task control because the task set frequently changes. We hypothesized that it would be harder to efficiently manage task conflicts in switching situations and, specifically, as cue–target interval (CTI) decreases. This suggestion was examined in two experiments using a combined Stroop task-switching design. We found a large interference effect and reverse facilitation that decreased with elongation of CTI. Results imply that task switching reduces pro-active task control and thereby enhances the informational and the task conflicts. This calls for a revision of recent control models to include task conflict.     

Exploring task-set reconfiguration with random task sequences

Switching between two different tasks normally results in an impairment in people's performance known as a switch cost, typically measured as an increase in reaction time (RT) and errors compared to a situation in which no task switch is required. Researchers in task switching have suggested that this switch cost is the behavioural manifestation of the task set reconfiguration processes that are necessary to perform the upcoming task. However, an examination of the literature in task switching reveals apparently contradictory results about the nature of task set reconfiguration processes. In Experiment 1, we addressed this issue by comparing participants' performance in two different experimental conditions: predictable task switching and random task switching. In the predictable switch condition the switch cost completely vanished after the first repetition of the new task. However, in the random switch condition, while the difference between switch and repetition trials was not significant, we observed a significant reduction in RT between the first and second repetition of the new task. In Experiment 2, we further investigated the pattern of task set reconfiguration in the random switch situation. The results showed a progressive reduction of participants' response latencies across repetitions of the same task. The present study demonstrates that, whereas the results in predictable switching conditions are compatible with an exogenous-reconfiguration hypothesis, random task switching produces a more gradual, decay-like switch cost reduction with task repetition.     

Individual differences in secondary task performance

The purpose of this research was to use secondary task performance as a predictor of performance on a difficult primary task. Reaction time (RT) to secondary probes that occurred during the rehearsal period of an easy memory task were used to measure spare capacity associated with the memory task. This measure was then correlated with performance on a harder version of the same memory task. Experiments 1-4 involved a paired associate memory task. Probe RT was sensitive to the difficulty of the paired associate task, and analysis of individual differences showed that probe RT during the easy version of the task was correlated with performance on a harder version of the task. Experiment 4 also utilized a spatial memory task. Probe RT was less sensitive to the demands of the spatial memory task, and in that case, the "easy-to-hard" prediction was not successful.     

Sequential ordering in children's representations of rotation movements

This study compared Marmor's state-comparison mental rotation task and a movement recognition task with respect to the level of sequence knowledge required for correct performance. The movement recognition task assessed children's understanding that pivot position and the shape of a rotating object remain invariant throughout the movement. Based on an analysis of development in children's counting, we hypothesized that explicit knowledge of sequence relations is not needed on the state-comparison task but is needed on the pivot and shape recognition task. In Experiment 1, 5- and 7-year-old children performed on the state-comparison task and an ordering task involving a Mickey Mouse figure. In Experiment 2, children between the ages of 5 and 13 years performed on a pivot and shape recognition task and an ordering task involving rotating squares. As predicted, the results indicated that 5-year-olds can execute a mental rotation on the state-comparison task but cannot sequence states in the rotation movement, whereas sequencing was a prerequisite for identification of incorrect movement sequences on the recognition task. The implications of these findings for development in children's kinetic imagery were discussed.     

Investigating the visual span in comparative search: the effects of task difficulty and divided attention

In three experiments, participants' visual span was measured in a comparative visual search task in which they had to detect a local match or mismatch between two displays presented side by side. Experiment 1 manipulated the difficulty of the comparative visual search task by contrasting a mismatch detection task with a substantially more difficult match detection task. In Experiment 2, participants were tested in a single-task condition involving only the visual task and a dual-task condition in which they concurrently performed an auditory task. Finally, in Experiment 3, participants performed two dual-task conditions, which differed in the difficulty of the concurrent auditory task. Both the comparative search task difficulty (Experiment 1) and the divided attention manipulation (Experiments 2 and 3) produced strong effects on visual span size.     

Anchoring in time estimation

In two experiments, an anchoring account of the misestimation of future task duration was tested. This account states that such misestimation occurs because previous task duration serves as an anchor for predictions, leading to underestimation when a longer task follows a shorter one and overestimation when a shorter task follows a longer one. Before estimating the duration of a focal task, participants selected a figure (anchor) of a longer or shorter duration produced by other participants in previous research on the same task (Experiment 1) or a different task (Experiment 2). In both experiments, misestimation differed according to the relative duration of the anchor to the focal task. Underestimation occurred with the shorter anchor and overestimation occurred with the longer one, suggesting that estimates were distorted in the direction of the anchors. This finding is discussed in relation to the role of prior task experience in moderating this anchoring effect.     

Timing in a dual-task in children and adults: when the interference effect is higher with concurrent non-temporal than temporal information

This study used a dual task with participants of different levels of cognitive capacities, assessed with neuropsychological tests, to examine the attentional cost on time judgment of processing concurrent temporal and non-temporal information. Children and adults performed a temporal reproduction task with either an interfering temporal or non-temporal discrimination task. The results showed an underestimation of time in the dual task compared to the single task, the extent of which was directly linked to individual attentional capacities. However, the non-temporal task interfered more than the temporal task on the reproduced durations. Nonetheless, the temporal reproduction task equally affected performance in the non-temporal and the temporal discrimination task. These results reveal the predominant role of the cost of dual-tasking in interference effects on time judgment, and the lesser role of concurrent information, especially of temporal information. This suggests a lack of competition for attentional resources in the processing of multiple durations.     

Cue-based preparation and stimulus-based priming of tasks in task switching

In this study, we investigated the interaction of three different sources of task activation in precued task switching. We distinguished (1) intentional, cue-based task activation from two other, involuntary sources of activation: (2) persisting activation from the preceding task and (3) stimulus-based task activation elicited by the task stimulus itself. We assumed that cue-based task activation increases as a function of cue-stimulus interval (CSI) and that task activation from the preceding trial decays as a function of response-stimulus interval Stimulus-based task activation is thought to be due to involuntary retrieval of stimulus-associated tasks. We manipulated stimulus-based task activation by mapping each of the stimuli consistently to only one or the other of the two tasks. After practice, we reversed this mapping in order to test the effects of item-specific stimulus-task association. The mapping reversal resulted in increased reaction times and increased task shift costs. These stimulus-based priming effects were markedly reduced with a long CSI, relative to a short CSI, suggesting that stimulus-based priming shows up in performance principally when competition between tasks is high and that cue-based task activation reduces task competition. In contrast, lengthening the response-cue interval (decay time) reduced shift costs but did not reduce the stimulus-based priming effect The data are consistent with separable stimulus-related and response-related components of task activation. Further theoretical implications of these findings are discussed.