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.     

Primacy and recency effects in task analyses: Preliminary results

Performance for three independent living tasks were examined via task analyses. Given the relatively small sample size (n = 56) of individuals with intellectual and developmental disabilities, we simulated 1000 replications based upon observed results using Monte Carlo techniques. The results of the current study suggest that: (1) adaptive behavior was more related to task performance than IQ; and (2) after statistically controlling for adaptive behavior, task performance was influenced by the first step. Task performance appear to be over-estimated with the inclusion of the first step.     

N-backer: an auditory n-back task with automatic scoring of spoken responses

The n-back task is commonly used to load working memory (WM) in dual-task and neuroimaging experiments. However, it typically involves visual presentation and buttonpress responses, making it unsuitable for combination with primary tasks that involve vision and action, such as sequential object use and other tasks of daily living. The N-backer software presented here will automatically present and score auditory–verbal n-back sequences utilising the standard speech synthesis and recognition facilities that come with Microsoft Windows. Data are presented from an experiment in which 12 student participants carried out three tasks from the Naturalistic Action Test (NAT) while their attention was divided between the primary task and a continuous auditory–verbal 2-back secondary task. The participants’ 2-back performance was scored in two ways: by hand, from video recordings, and automatically, using the software, allowing us to evaluate the accuracy of N-backer. There was an extremely high correlation between these scores (.933). The videos were also used to obtain a comprehensive error score for the NAT. Significantly more errors were made in the more complex NAT tasks when participants were 2-backing, as compared with when they were not, showing that the auditory–verbal n-back task can be used to disrupt sequential object use. This dual-task method may simulate the attentional deficits of patients with brain injury, providing insights into the difficulties they face in tasks of daily living.     

Micro- and macro-adjustments of task set: activation and suppression in conflict tasks

Macro- and micro-adjustment of task set was studied using distributional analyses of performance data (reaction time and accuracy) obtained in a new experiment using the Simon task. Macro-adjustments involved the long-term strategic modifications in response to the relative probability of conflict trials, while micro-adjustment involved trial-by-trial modifications invoked by the commission of incidental errors. These adjustments were examined in detail in distributional analyses of RT and accuracy, which have been shown to be particularly useful in studying the role of activation and suppression in conflict tasks. The modification of behavioral strategies incurred by the commission of errors and by the relative probability that the irrelevant location corresponded to the incorrect response was found to involve a reduced location-driven direct response activation (as reflected in the early portions of the delta plots for accuracy) and a stronger selective suppression of that direct activation (as reflected in the delta plot slopes for RT). When the probability of conflict trials was high, the effects of irrelevant location were already precluded by macro-adjustment, so that error commission had no further micro-adjustment effect on subsequent behavior. These patterns were not disclosed by analysis of overall performance.     

Learning a procedural task: effectiveness of multimedia presentations

Three experiments investigated the effectiveness of presenting procedural information through different media and their combinations. Experiment 1 examined the effectiveness of text, line drawings, text and line drawings, video. and video stills for learning a first aid task. The results showed an advantage of text and line drawings and of the video presentation over the other three conditions for both bandaging performance and answering questions about the task. Experiment 2 showed that the beneficial effect of the combination of text and pictures could not be accounted for simply in terms of a dual coding explanation. Rather, the effectiveness of the media and their combinations was influenced by the extent to which they conveyed action information. Finally, Experiment 3 showed no evidence of a contiguity effect: text and pictures were as effective when presented together on the same screen as when they were presented separately. Copyright © 2000 John Wiley & Sons, Ltd.     

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.     

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.     

Irrelevant thoughts,emotional mood states,and cognitive task performance

In two experiments, we investigated the relationship shared by irrelevant thoughts, emotional mood states, and cognitive task performance. At an empirical level, irrelevant thoughts were defined as thoughts that did not facilitate successful task performance. We used the same general procedure for both experiments: three groups of college students received happy-, neutral-(control), or sad-mood inductions and performed a memory task. The procedure for obtaining thoughts varied between experiments. The subjects in Experiment 1 listed their thoughts after the memory recall task. In Experiment 2, the subjects were tape-recorded while performing a memory task and producing concurrent verbal protocols. The subjects in both experiments then judged their thoughts in terms of frequency, intensity, and irrelevance. We found a similar pattern of results in both experiments: (1) The proportions of irrelevant thoughts and recall performance were negatively related, and (2) happy and sad students produced reliably greater proportions of irrelevant thoughts than did neutral (control) students.     

Video game practice optimizes executive control skills in dual-task and task switching situations

We examined the relation of action video game practice and the optimization of executive control skills that are needed to coordinate two different tasks. As action video games are similar to real life situations and complex in nature, and include numerous concurrent actions, they may generate an ideal environment for practicing these skills (Green & Bavelier, 2008). For two types of experimental paradigms, dual-task and task switching respectively; we obtained performance advantages for experienced video gamers compared to non-gamers in situations in which two different tasks were processed simultaneously or sequentially. This advantage was absent in single-task situations. These findings indicate optimized executive control skills in video gamers. Similar findings in non-gamers after 15 h of action video game practice when compared to non-gamers with practice on a puzzle game clarified the causal relation between video game practice and the optimization of executive control skills.     

Effects of response selection on the task repetition benefit in task switching

A task switch typically leads to worse performance than a repetition does. This shift cost can be reduced with sufficient task preparation time, but a residual cost usually remains. We propose that a large part of this residual cost is caused by an activation bias produced by response selection processes in the preceding trial. In our experiments, we manipulated response selection requirements using a go/no-go methodology. The residual shift cost disappeared after no-go trials, suggesting that response selection is crucial to establish an activation bias for the current category-response rules and that this bias persists into the next trial. A comparison with a go-only group confirmed this analysis by revealing no differences in preparatory strategy due to the inclusion of no-go trials. In addition, no-go trials had no significant effects on subsequent trials in a single-task experiment, suggesting that no-go trials are not coded as a task different from go trials and that there is no inhibition of the prepared task in a no-go trial. We thus conclude that a persisting activation bias of response rules plays a major role in task switching.     

On the link between mind wandering and task performance over time

Here we test the hypothesis that fluctuations in subjective reports of mind wandering over time-on-task are associated with fluctuations in performance over time-on-task. In Study 1, we employed a singleton search task and found that performance did not differ prior to on- and off-task reports, nor did individual differences in mind wandering predict differences in performance (so-called standard analytic methods). Importantly however, we find that fluctuations in mind wandering over time are strongly associated with fluctuations in behavior. In Study 2, we provide a replication of the relation between mind wandering and performance over time found in Study 1, using a Flanker interference task. These data indicate (1) a tight coupling between mind wandering and performance over time and (2) that a temporal-analytic approach can reveal effects of mind wandering on performance in tasks where standard analyses fail to do so. The theoretical and methodological implications of these findings are discussed.     

Long-range correlation properties in motor timing are individual and task specific

1/f (β) noise represents a specific form of (long-range) correlations in a time series that is pervasive across many sensorimotor variables. Recent studies have shown that the precise properties of the correlations demonstrated by a group of test participants may vary as a function of experimental conditions or factors characterizing the group. Our purpose in the present study was to clarify whether long-range correlations affect sensorimotor performance generally or in a task-specific manner and whether each individual produces characteristic long-range correlations that are reliable across several runs of the same task. We analyzed the series of time intervals produced by 43 participants in two timing tasks: unimanual rhythmic tapping and circle drawing. We found that a participant's 1/f (β) properties in tapping were not related to the 1/f (β) properties in circle drawing. However, within each task, individual differences were reliable, and a Cronbach's alpha of .59 showed a high degree of within-subjects reproducibility of the long-range correlations. Thus, long-range correlations represent a consistent and distinctive characteristic of individuals performing a particular task, rather than a ubiquitous generic property of sensorimotor time series. The implications of these results are discussed from both a theoretical and a methodological perspective.     

Motor learning by observation: Evidence from a serial reaction time task

This study sought evidence of observational motor learning, a type of learning in which observation of the skilled performance of another person not only facilitates motor skill acquisition but does so by contributing to the formation of effector-specific motor representations. Previous research has indicated that observation of skilled performance engages cognitive processes similar to those occurring during action execution or physical practice, but has not demonstrated that these include processes involved in effector-specific representation. In two experiments, observer subjects watched the experimenter performing a serial reaction time (SRT) task with a six-item unique sequence before sequence knowledge was assessed by response time and/or free generation measures. The results suggest that: (1) subjects can acquire sequence information by watching another person performing the task (Experiments 1-2); (2) observation results in as much sequence learning as task practice when learning is measured by reaction times (RTs) and more than task practice when sequence learning is measured by free generation performance (Experiment 2, Part 1); and (3) sequence knowledge acquired by model observation can be encoded motorically--that is, in an effector-specific fashion (Experiment 2, Part 2).     

The role of verbal short-term memory in task selection: How articulatory suppression influences task choice in voluntary task switching

The roles of verbal short-term memory (vSTM) in task selection and task performance processes were examined when individuals were asked to voluntarily choose which of two tasks to perform on each trial randomly. Consistent with previous voluntary task-switching (VTS) research, we hypothesized that vSTM would support random task selection by maintaining a sequence of previously executed tasks that would be used by a representativeness heuristic. Furthermore, because using a representativeness heuristic requires sufficient time for updating and comparison processes, we expected that vSTM would have a greater effect on task selection when more time was available. Participants completed VTS under concurrent articulatory suppression and foot tapping at short and long response-to-stimulus intervals (RSIs). Task selection in VTS was more repetitive under suppression than under foot tapping, but this effect did not vary with RSI, suggesting that vSTM does not maintain the sequence of executed tasks to guide task selection. Instead, vSTM is critical for maintaining the intended task and ensuring that it is carried out. In contrast to the finding that a working memory load impairs task performance, we found no difference in reaction times and no switch costs between suppression and foot-tapping conditions, suggesting that vSTM is not critical for task performance.     

Group Learning Curves: The Effects of Turnover and Task Complexity on Group Performance1

This study examined the effects of turnover and task complexity on group performance. Two hundred and forty subjects arranged into three-person groups performed a production-type task for six experimental periods. The design was a 2 (Turnover vs. No Turnover) × 2 (Simple vs. Complex Task) × 2 (Male vs. Female) × 6 (Periods) factorial with repeated measures on the last factor. The analysis revealed that group performance improved markedly as groups gained experience with the task. Groups which did not experience turnover (closed groups) produced significantly more products than did groups which experienced turnover (open groups). The superior performance of closed over open groups was amplified over periods. Groups produced more of the simple than of the complex product, and this difference was also amplified over periods. The gap in the performance of closed versus open groups increased over periods, and the increase in the gap was greater for the simple than for the complex task. The lesser impact of turnover on the complex task is consistent with an innovation hypothesis, according to which increases in the production of complex tasks are due more to innovation than to repetition. Supportive analyses of innovation data are reported.     

The relative importance of task, citizenship, and counterproductive performance to global ratings of job performance: a policy-capturing approach

A review of research on job performance suggests 3 broad components: task, citizenship, and counterproductive performance. This study examined the relative importance of each component to ratings of overall performance by using an experimental policy-capturing design. Managers in 5 jobs read hypothetical profiles describing employees' task, citizenship, and counterproductive performance and provided global ratings of performance. Within-subjects regression analyses indicated that the weights given to the 3 performance components varied across raters. Hierarchical cluster analyses indicated that raters' policies could be grouped into 3 homogeneous clusters: (a) task performance weighted highest, (b) counterproductive performance weighted highest, and (c) equal and large weights given to task and counterproductive performance. Hierarchical linear modeling indicated that demographic variables were not related to raters' weights.     

Deconstructing the tower: Parameters and predictors of problem difficulty on the Tower of London task

The Tower of London (TOL) task has been widely used in both clinical and research realms. In the current study, 104 healthy participants attempted all possible moderate- to high-difficulty TOL problems in order to determine: (1) optimal measures of problem solving performance, (2) problem characteristics, other than the minimum moves necessary to solve the problem, that determine participants’ difficulty in solving problems successfully, quickly, and efficiently, and (3) effects of increased task experience on which problem characteristics determine problem difficulty. A factor analysis of six performance measures found that, regardless of task experience, problem difficulty could be captured well either by a single factor corresponding to general quality of solution or possibly by three subordinate factors corresponding to solution efficiency, solution speed, and initial planning speed. Regression analyses predicting these performance factors revealed that in addition to a problem’s minimum moves three problem parameters were critical in determining the problem difficulty: goal position hierarchy, start position hierarchy, and number of solution paths available. The relative contributions of each of the characteristics strongly depended on which performance factor defined performance. We conclude that TOL problem performance is multifaceted, and that classifying problem difficulty using only the minimum moves necessary to solve the problem is inadequate.     

Examining the moderating effects of time on task and task complexity on the within person self-efficacy and performance relationship

ObjectivesThe study examined two moderating variables that may influence the direction of the effect of self-efficacy upon performance, namely; time spent on task and task complexity.DesignMultilevel analysis was conducted to examine within person and between group relationships.MethodEighty eight novice golfers putted in 4 sessions over a period of 2 days (completing 800 putts in total). Each session contained 10 trials of 20 putts. The golfers were split into 2 conditions; a stable task condition where task requirements remained constant across time and a dynamic task condition, where task complexity changed across time.ResultsIn early learning (i.e., the first 10 trials) results revealed a slight negative effect between self-efficacy and subsequent performance. However, across the 40 trials self-efficacy had a positive effect upon subsequent performance. Further, there was a significant task condition (stable vs. dynamic) interaction. In the easy task condition, self-efficacy showed a slight (but non-significant) positive effect upon performance. However, in the dynamic learning condition, self-efficacy had a positive and significant effect upon subsequent performance.ConclusionPrevious tests of the within person self-efficacy relationship tend to limit learning to 10 trials or less. The study is the first to examine the reciprocal relationship between self-efficacy and performance as a result of task experience (i.e., time spent on the task) and task complexity simultaneously. Positive effects emerged as a result of extended time learning the task and by varying the degree of task complexity whilst learning.     

Brainstorming and task performance in groups constrained by evidence

Group brainstorming is usually considered a task of divergent thinking, and the ideas produced in most research on brainstorming are counted and scored for creativity but put to no further use. We studied brainstorming by embedding it in a rule induction task that initially requires divergent thinking but increasingly requires convergent thinking as evidence accumulates across trials. We also tested whether brainstorming facilitated performance on the induction task itself. The experimental design was a 2 (nominal or interacting groups) × 3 (brainstorming early in the task, late in the task, or none) factorial. For brainstorming performance, nominal groups of 4 individuals outperformed face-to-face groups of 4 individuals. But as predicted from an analysis of the effects of constraining hypotheses by evidence, the advantage for nominal groups declined when brainstorming took place late in the task where there was a large amount of accumulated evidence to consider. Brainstorming did not generally affect performance on the induction task, although early group brainstorming resulted in more correct hypotheses than late group brainstorming. Group brainstorming was perceived as more effective than individual brainstorming by both interacting and nominal group members, a finding that extends the illusion of group productivity in brainstorming to tasks of convergent thinking.