Task Rule-Congruency and Simon-Like Effects in Switching between Spatial Tasks

Testing Go/No-Go training effects on implicit evaluations of unhealthy and healthy snack foods

OBJECTIVE

Despite intending to eat healthy foods, people often yield to temptation. In environments rife with unhealthy food options, a positive implicit evaluation of unhealthy foods may inadvertently influence unhealthy choices. This study investigates if and under which conditions implicit evaluations of unhealthy and healthy foods can be influenced by a computer-based Go/No-Go (GNG) training.

DESIGN

Undergraduate student participants (N = 161 participants; 117 females, 44 males; Mage = 19 years, SD = 2 years) completed a GNG training with two healthy (grape and nut) and two unhealthy (potato chip and cookie) stimuli. Participants were either instructed to inhibit their responses to the potato chip (No-Go Chips/Go Grape) or to a grape (No-Go Grape/Go Chips).

MAIN OUTCOME MEASURE

Implicit evaluations of chips and grapes were assessed using the Extrinsic Affective Simon Task.

RESULTS

This GNG training impacted implicit evaluations of chips, but not grapes. GNG training effects were stronger for participants with lower sensitivity for behavioural inhibition measured with the Behavioural Inhibition System scale.

CONCLUSION

GNG training might help people change implicit food evaluations. More research is needed to understand how individual and training characteristics affect outcomes with the goal of tailoring and optimising the GNG training to produce the strongest effect.

Automatic price appraisals: why they matter and how to measure them

Accurately estimating consumers' willingness-to-pay (WTP) is crucial to product design, pricing decisions, and the design of competitive marketing strategies. However, traditional self-report measures of WTP are susceptible to many reporting biases, including tactical responding or an inability to make accurate estimates. Importantly, appraisals also occur automatically (i.e., in the absence of substantial time, intention, awareness, and/or substantial cognitive resources) and implicit measures used to capture automatic appraisals are less susceptible to the sort of reporting biases that self-report measures can be affected by. However, the only existing implicit measure for assessing automatic price appraisals (the Task Rule Congruency paradigm, 'TRC') is impractical because of the large number of trials and time it requires. Accordingly, here we introduce the Implicit Attribute Classification Task (IMPACT), test its effectiveness for the measurement of automatic price appraisals (Study 1), and directly compare its effectiveness and utility with that of the TRC (Study 2). We find that the IMPACT is an efficient measure of automatic price appraisals, that it produces considerably larger effects compared to the TRC, and that it does so while substantially shortening the procedure. We also discuss how the IMPACT scores can be used to derive an implicit measure of willingness to pay. Our findings make a substantial contribution to both research and practice by providing an effective tool that facilitates, for the first time, an efficient exploration of implicit WTP.

Contributions of Working Memory and Inhibition to Cognitive Flexibility in Nigerian Adolescents

This study used a novel approach that combined the latency and accuracy scores to examine the relative involvement of inhibition and working memory in two measures of cognitive flexibility – mixing cost and switch cost in 110 Nigerian adolescents. Results showed that inhibition was significantly associated with switch cost. On the other hand, working memory was negatively associated with mixing cost. These findings support the assumption that cognitive flexibility skills are dependent on inputs from inhibition and working memory processes. Inhibition is involved in the deactivation of irrelevant stimuli during switching trials while working memory is essential to maintain the current rule in sets that require no shifting.

Cognitive flexibility in adulthood and advanced age: Evidence of internal and external validity

Aging causes changes that affect functioning of cognitive processes such as cognitive flexibility (CF). Given it allows changing both behavior and thinking in dynamic contexts, it constitutes an essential trait of adaptive, goal-oriented behavior. Despite its importance, specific techniques to evaluate CF in older adults are lacking. The goal of this article is to describe and comparatively analyze the functioning of CF in a sample of 169 individuals representing three age groups-younger-age, middle-age and advanced-age adults-by obtaining evidence of internal and external validity. Using a correlational and cross-sectional research design, four studies were conducted in order to evaluate construct validity-fulfillment of experimental paradigm criteria and contrast between groups and tests with different methods. In addition to the Fingers Task, the study used the CAMBIOS Cognitive Flexibility Test, TAC's Conjunction Visual Search Task (which evaluates perceptual inhibition) and a verbal fluency task with changes. The results provide evidence of the functioning of CF in adulthood and advanced age, which has implications for neurocognitive clinical evaluation in these stages of life. Additionally, evidence was obtained in favor of the concurrent validity of the instruments used to measure CF, contributing to the solidity of future studies on this executive function.

Beyond asking: Exploring the use of automatic price evaluations to implicitly estimate consumers' willingness-to-pay

Explicit consumers responses are often adverse for the validity of procedures used to estimate consumers' willingness-to-pay (WTP). This paper investigates if price evaluations occur automatically and to what extent these automatic processes can be used to implicitly estimate consumers' WTP. An adapted version of the task-rule congruency (TRC) paradigm was used in two studies. Results of the first study provided evidence for the notion that prices are automatically evaluated. However, the used procedure had limitations that restricted its utility as an implicit WTP estimate. The procedure was adjusted, and an additional study was conducted. The results of the second study also indicated that prices were evaluated automatically. Additionally, the procedure used during the second study allowed to explore to what extent the observed TRC effects could be used to implicitly estimate consumers' WTP. Taken together, these studies provided evidence for the notion that prices are evaluated automatically. Furthermore, the procedure has the potential to be further developed into an implicit estimate of consumers' WTP.

Influences of Postural Control on Cognitive Control in Task Switching

The aim of the current study was to investigate the effects of postural control demands on cognitive control processes in concurrent auditory-manual task switching. To this end, two experiments were conducted using an auditory cued task-switching paradigm with different postural control demands (sitting vs. standing). This design allowed us to explore the effect of postural control on switch costs, mixing costs, and the between-task congruency effect. In addition, we varied the cue-based task preparation in Experiment 1 to examine whether preparation processes are independent of additional postural control demands or if the motor control processes required by the postural control demands interfere with task-specific cognitive preparation processes. The results show that we replicated the standard effects in task switching, such as switch costs, mixing costs, and congruency effects in both experiments as well as a preparation-based reduction of these costs in Experiment 1. Importantly, we demonstrated a selective effect of postural control demands in task switching in terms of an increased congruency effect when standing as compared to sitting. This finding suggests that particularly in situations that require keeping two tasks active in parallel, the postural control demands have an influence on the degree to which cognitive control enforces a more serial (shielded) mode or a somewhat less selective attention mode that allows for more parallel processing of concurrently held active task rules.

Functional brain and age-related changes associated with congruency in task switching

Alternating between completing two simple tasks, as opposed to completing only one task, has been shown to produce costs to performance and changes to neural patterns of activity, effects which are augmented in old age. Cognitive conflict may arise from factors other than switching tasks, however. Sensorimotor congruency (whether stimulus-response mappings are the same or different for the two tasks) has been shown to behaviorally moderate switch costs in older, but not younger adults. In the current study, we used fMRI to investigate the neurobiological mechanisms of response-conflict congruency effects within a task switching paradigm in older (N=75) and younger (N=62) adults. Behaviorally, incongruency moderated age-related differences in switch costs. Neurally, switch costs were associated with greater activation in the dorsal attention network for older relative to younger adults. We also found that older adults recruited an additional set of brain areas in the ventral attention network to a greater extent than did younger adults to resolve congruency-related response-conflict. These results suggest both a network and an age-based dissociation between congruency and switch costs in task switching.

Stimulus-Response Compatibility Effect in the Near-Far Dimension: A Developmental Study

The present study investigates the developmental aspect of stimulus-response compatibility (SRC) effect in 8-11-years-old children. The task consisted in manually responding to the color of a pawn presented on a chessboard at different distances. Manual responses were provided by reaching a proximal or distal location depending on the color of the stimulus. We found that reaction time was affected by the conflict generated by the response suggested by the location of the stimulus and the response required according to its color. This was not the case for movement time despite we found a higher rate of long duration movements in the incongruent than in the congruent spatial condition. The SRC effect was, however, observed in children older than 10 years old. These findings provide additional evidence for a reorganization of the perceptual system during the period of 8-10 years, integrating progressively multimodal information and preparing more efficiently the body to act in the environment.

Modality-specific effects on crosstalk in task switching: evidence from modality compatibility using bimodal stimulation

The present study was aimed at examining modality-specific influences in task switching. To this end, participants switched either between modality compatible tasks (auditory-vocal and visual-manual) or incompatible spatial discrimination tasks (auditory-manual and visual-vocal). In addition, auditory and visual stimuli were presented simultaneously (i.e., bimodally) in each trial, so that selective attention was required to process the task-relevant stimulus. The inclusion of bimodal stimuli enabled us to assess congruence effects as a converging measure of increased between-task interference. The tasks followed a pre-instructed sequence of double alternations (AABB), so that no explicit task cues were required. The results show that switching between two modality incompatible tasks increases both switch costs and congruence effects compared to switching between two modality compatible tasks. The finding of increased congruence effects in modality incompatible tasks supports our explanation in terms of ideomotor "backward" linkages between anticipated response effects and the stimuli that called for this response in the first place. According to this generalized ideomotor idea, the modality match between response effects and stimuli would prime selection of a response in the compatible modality. This priming would cause increased difficulties to ignore the competing stimulus and hence increases the congruence effect. Moreover, performance would be hindered when switching between modality incompatible tasks and facilitated when switching between modality compatible tasks.

Proactive control of irrelevant task rules during cued task switching

In task-switching paradigms, participants are often slower on incongruent than congruent trials, a pattern known as the task-rule congruency effect. This effect suggests that irrelevant task rules or associated responses may be retrieved automatically in spite of task cues. The purpose of the present study was to examine whether the task-rule congruency effect may be modulated via manipulations intended to induce variation in proactive control. Manipulating the proportion of congruent to incongruent trials strongly influenced the magnitude of the task-rule congruency effect. The effect was significantly reduced in a mostly incongruent list relative to a mostly congruent list, a pattern that was observed for not only biased but also 50 % congruent items. This finding implicates a role for global attentional control processes in the task-rule congruency effect. In contrast, enhancing the preparation of relevant (cued) task rules by the provision of a monetary incentive substantially reduced mixing costs but did not affect the task-rule congruency effect. These patterns support the view that there may be multiple routes by which proactive control can influence task-switching performance; however, only select routes appear to influence the automatic retrieval of irrelevant task rules.

Can time-based decay explain temporal distinctiveness effects in task switching?

In task switching, extending the response–cue interval (RCI) reduces the switch cost—the detriment to performance when switching compared to repeating tasks. This reduction has been used as evidence for the existence of task-set decay processes. Recently, this has been challenged by the observation of sequential dependencies on the RCI effect: switch cost is only reduced at longer RCIs when the previous trial had a short RCI. This trial-wise variation of RCI is thought to affect the temporal distinctiveness (TD) of a previous task's episodic trace, affecting the probability of its automatic retrieval on the current trial; importantly, TD is thought to be independent of the current trial's RCI. The present study highlights a dependency between the current RCI and TD, and demonstrates that a decay model can reproduce some patterns of data attributed to TD. Further, the decay account makes a strong prediction when TD is held constant: repetition response times should slow as the RCI increases, and switch response times should be facilitated. This prediction was tested via re-analysis of extant data and three experiments. The re-analysis provided some evidence for the decay account, but Experiments 1 and 2 report slowing for task repetition and switch trials, which cannot be explained by a task-set decay process. Experiment 3, which utilized tasks requiring perceptual judgements, showed small evidence for decay. We conclude that the data are largely consistent with the TD account and that the evidence for decay of higher-level task-sets is not convincing.

Modelling response selection in task switching: testing the contingent encoding assumption

The contingent encoding assumption is the idea that response selection in task-switching situations does not begin until the cue and the target have both been encoded. The authors tested the assumption by manipulating response congruency, stimulus order, and stimulus onset asynchrony (SOA) in two experiments. They found evidence of response selection prior to cue encoding for congruent targets with target-cue order at a long SOA, indicating that the contingent encoding assumption is invalid. The authors describe how contingent encoding can be removed from an existing task-switching model by introducing baseline evidence--task-neutral evidence that serves as a baseline for response selection prior to stimulus encoding. Simulations revealed that the modified model could reproduce the full pattern of response time data and generate responses prior to cue encoding. The authors conclude by discussing directions for further model development.

Task-Switching Methodology

In this paper, the authors review studies involving switching between an evaluative task and a nonevaluative task as a means to indirectly assess evaluative processes in the context of research of attitudes, psychopathology, and personality traits. Two task-switching indices, Switching Cost and Task Rule Congruency Effect, which represent two distinct sets of processes, have been used so far and can be assessed simultaneously. The authors suggest that using task-switching methodology as a platform provides significant methodological as well as theoretical advantages, which they attribute to the heightened involvement of the individual’s goal system, characterizing the task-switching paradigm.

When planning results in loss of control: intention-based reflexivity and working-memory

In this review, the authors discuss the seemingly paradoxical loss of control associated with states of high readiness to execute a plan, termed "intention-based reflexivity." The review suggests that the neuro-cognitive systems involved in the preparation of novel plans are different than those involved in preparation of practiced plans (i.e., those that have been executed beforehand). When the plans are practiced, intention-based reflexivity depends on the prior availability of response codes in long-term memory (LTM). When the plans are novel, reflexivity is observed when the plan is pending and the goal has not yet been achieved. Intention-based reflexivity also depends on the availability of working-memory (WM) limited resources and the motivation to prepare. Reflexivity is probably related to the fact that, unlike reactive control (once a plan is prepared), proactive control tends to be relatively rigid.

Flexible and inflexible task sets: asymmetric interference when switching between emotional expression, sex, and age classification of perceived faces

The present study investigated whether the processing characteristics of categorizing emotional facial expressions are different from those of categorizing facial age and sex information. Given that emotions change rapidly, it was hypothesized that processing facial expressions involves a more flexible task set that causes less between-task interference than the task sets involved in processing age or sex of a face. Participants switched between three tasks: categorizing a face as looking happy or angry (emotion task), young or old (age task), and male or female (sex task). Interference between tasks was measured by global interference and response interference. Both measures revealed patterns of asymmetric interference. Global between-task interference was reduced when a task was mixed with the emotion task. Response interference, as measured by congruency effects, was larger for the emotion task than for the nonemotional tasks. The results support the idea that processing emotional facial expression constitutes a more flexible task set that causes less interference (i.e., task-set "inertia") than processing the age or sex of a face.

Temporal distinctiveness and repetition benefits in task switching: Disentangling stimulus-related and response-related contributions

In cued task switching, decreasing switch costs with increasing response-to-cue interval (RCI) is a typical finding. The traditional account assumes an underlying process of task-set decay. In contrast, we suggest that these RCI effects are due to the influence of temporal distinctiveness on cue-based task retrieval (or reactivation). The present study explored the task-set components that are affected by temporal distinctiveness. According to the idea that a task set consists of response-related components and stimulus-related components, we manipulated response valence (bivalent vs. univalent) in Experiment 1. The results showed that lengthening the RCI leads to a loss of a task-repetition benefit, mainly when the RCI changed from the previous trial to the current trial, but this data pattern did not depend on response valence. In Experiment 2, stimulus valence was manipulated. The results revealed substantially stronger RCI effects with bivalent stimuli than with univalent stimuli. Taken together, the data are inconsistent with task-set decay accounts and suggest that the influence of RCI in task switching modulates cue-based retrieval of stimulus-related task components, such as biasing parameters.

Task switching and serial memory: looking into the nature of switches and tasks

Task switching research has so far focused on the impact of switching task-sets between two-choice classification tasks that require little or no memory load. Empirical work is lacking however to determine whether the switching cost can be extended to other cognitive activities and to different types of switches. In the present study, switching between the content - verbal to spatial - of the tasks was contrasted with switching cognitive processes - categorization to serial memory. Our pattern of results revealed the absence of local and general switch costs on serial memory tasks, while substantial costs were observed with two-choice judgement tasks. Such a finding challenges the widely accepted assumption that task alternation comes with a considerable cost in performance regardless of the cognitive tasks undertaken. Our results are discussed in context of the predominant models of task switching.

Response-specifying cue for action interferes with perception of feature-sharing stimuli

Perceiving a visual stimulus is more difficult when a to-be-executed action is compatible with that stimulus, which is known as blindness to response-compatible stimuli. The present study explored how the factors constituting the action event (i.e., response-specifying cue, response intention, and response feature) affect the occurrence of this blindness effect. The response-specifying cue varied along the horizontal and vertical dimensions, while the response buttons were arranged diagonally. Participants responded based on one dimension randomly determined in a trial-by-trial manner. The response intention varied along a single dimension, whereas the response location and the response-specifying cue varied within both vertical and horizontal dimensions simultaneously. Moreover, the compatibility between the visual stimulus and the response location and the compatibility between that stimulus and the response-specifying cue was separately determined. The blindness effect emerged exclusively based on the feature correspondence between the response-specifying cue of the action task and the visual target of the perceptual task. The size of this stimulus-stimulus (S-S) blindness effect did not differ significantly across conditions, showing no effect of response intention and response location. This finding emphasizes the effect of stimulus factors, rather than response factors, of the action event as a source of the blindness to response-compatible stimuli.

Stimulus–response compatibility for mixed mappings and tasks with unique responses

For two stimulus locations mapped to two keypresses, reaction time is shorter when the mapping is compatible than when it is not (the stimulus–response compatibility, SRC, effect). A similar result, called the Simon effect, occurs when stimulus location is irrelevant, and colour is relevant. When compatibly mapped trials are intermixed with incompatibly mapped trials or Simon task trials, the compatibility effect is eliminated, and the Simon effect is influenced by the location mapping. In five experiments, we examined whether similar mixing effects occur when the two spatial mappings or location-relevant and location-irrelevant tasks use distinct keypresses on the left and right hands. Mixing had considerably less influence on the SRC and Simon effects than it does when the intermixed trial types or tasks share the same responses, even though response time was lengthened to a similar extent. Mixing two tasks for which stimulus location was irrelevant yielded no within-task Simon effect, but the effect was also absent when four stimuli were assigned to two responses on a single hand. The relative lack of influence of mixing on the SRC and Simon effects when the tasks have unique responses implies that suppression of direct activation of the corresponding response occurs primarily when the tasks share responses.

Selecting a response in task switching: testing a model of compound cue retrieval

How can a task-appropriate response be selected for an ambiguous target stimulus in task-switching situations? One answer is to use compound cue retrieval, whereby stimuli serve as joint retrieval cues to select a response from long-term memory. In the present study, the authors tested how well a model of compound cue retrieval could account for a complex pattern of congruency effects arising from a procedure in which a cue, prime, and target were presented on each trial. A comparison of alternative models of prime-based effects revealed that the best model was one in which all stimuli participated directly in the process of retrieving a response, validating previous modeling efforts. Relations to current theorizing about response congruency effects and models of response selection in task switching are discussed.

The Dual Implication of Dual Affordance

In task switching experiments, comparing performance with bivalent stimuli (affording both tasks) to univalent stimuli (affording one task) confounds the need to change focus between dimensions and stimulus-task binding, because bivalent stimuli require focusing (and refocusing) but also appeared in the competing task before. To separate these influences, participants switched between vertical and horizontal judgments performed on bivalent (e.g., up-left) or univalent (e.g., left) actual locations or location words. In a critical condition involving bivalence without stimulus-task binding, actual locations and location words were each linked to a different task. Bivalence increased switch costs and preparation reduced switch costs only with bivalent stimuli. Stimulus-task binding affected performance in task repetitions, especially when little preparation time was afforded.

Preparation for horizontal or vertical dimensions affects the right-left prevalence effect

When stimulus and response simultaneously vary in both horizontal and vertical dimensions, the stimulus-response compatibility effect is often larger for the horizontal dimension. We investigated the role of preparation for each dimension in this right-left prevalence. In Experiment 1, tasks based on horizontal and vertical dimensions were mixed in random order, and the relevant dimension in each trial was cued with a variable cue-target stimulus onset asynchrony (SOA). A right-left prevalence effect was observed only when participants prepared for the upcoming task. Experiment 2 replicated the absence of the prevalence effect for the simultaneous presentation of cue and target using a fixed SOA of 0 msec. In Experiment 3, the right-left prevalence emerged with a 0-msec SOA when participants prepared for e achdimension basedon its frequency. These resultssuggest that participants' internal set can be greater for the horizontal dimension, leading to the right-left prevalence effect.

Is there a general task switching ability?

Participants were tested on two analogous task switching paradigms involving Shape/Size tasks and Vertical/Horizontal tasks, respectively, and three measures of psychometric intelligence, tapping fluid, crystallized and perceptual speed abilities. The paradigms produced similar patterns of group mean reaction times (RTs) and the vast majority of the participants showed switching cost (switch RT minus repeat RT), mixing cost (repeat RT minus single-task RT) and congruency effects. The shared intra-individual variance across paradigms and with psychometric intelligence served as criteria for general ability. Structural equations modeling indicated that switching cost with ample preparation ("residual cost") and mixing cost met these criteria. However, switching cost with little preparation and congruency effects were predominantly paradigm specific.

Response inhibition under task switching: its strength depends on the amount of task-irrelevant response activation

Under task switch conditions, response repetitions usually produce benefits if the task also repeats, but costs if the task switches. So far, it is largely undecided how to account for these effects. In the present study, we provide additional evidence in favor of the account that each response is inhibited in order to prevent its accidental re-execution. To test this hypothesis, the risk of an accidental re-execution of a given response was manipulated by modulating the activation of the response in the previous task. In Experiment 1, this was done by means of congruent and incongruent stimuli. As expected, on task switch trials, the repetition costs were larger if a congruent rather than an incongruent stimulus occurred in the previous task. In Experiment 2, the same effect occurred for stimulus-response compatible versus incompatible stimuli in the previous task. In Experiment 3, both manipulations were applied together, which produced almost additive effects. Altogether, the results support the inhibition account for the response repetition effects under task switch conditions.

Effects of precuing horizontal and vertical dimensions on right—left prevalence

When stimuli and responses can be coded along horizontal and vertical dimensions simultaneously, a right-left prevalence effect is often obtained for which the advantage for a compatible mapping is larger on the horizontal dimension than on the vertical dimension. The present study investigated the role of preparatory processes in this right-left prevalence effect using a method in which the relevant dimension was cued at short and long intervals prior to presentation of the target stimulus. In three experiments, the right-left prevalence effect did not vary significantly in magnitude as a function of cue-target interval, suggesting that the effect is due primarily to relative salience of the horizontal and vertical codes, as determined by the task structure, and not to a greater ease of attending to the horizontal dimension.

Spatial coding in two dimensions

There has been growing interest in exploring human performance for situations in which stimuli and/or responses vary along both horizontal and vertical dimensions. Earlier studies indicated that there is a prevalence of the horizontal dimension over the vertical dimension in the spatial codes that are used for response selection. We review evidence about spatial coding for 2-D stimulus-response sets and accounts that have been proposed for explaining how it takes place. Particular attention is devoted to the relative salience account, which provides the most comprehensive explanation of 2-D spatial coding. We also evaluate the influence of speed of spatial code formation, number of reference frames, and learning on subjects' performance in 2-D tasks.

Development of cognitive control and executive functions from 4 to 13 years: evidence from manipulations of memory, inhibition, and task switching

Predictions concerning development, interrelations, and possible independence of working memory, inhibition, and cognitive flexibility were tested in 325 participants (roughly 30 per age from 4 to 13 years and young adults; 50% female). All were tested on the same computerized battery, designed to manipulate memory and inhibition independently and together, in steady state (single-task blocks) and during task-switching, and to be appropriate over the lifespan and for neuroimaging (fMRI). This is one of the first studies, in children or adults, to explore: (a) how memory requirements interact with spatial compatibility and (b) spatial incompatibility effects both with stimulus-specific rules (Simon task) and with higher-level, conceptual rules. Even the youngest children could hold information in mind, inhibit a dominant response, and combine those as long as the inhibition required was steady-state and the rules remained constant. Cognitive flexibility (switching between rules), even with memory demands minimized, showed a longer developmental progression, with 13-year-olds still not at adult levels. Effects elicited only in Mixed blocks with adults were found in young children even in single-task blocks; while young children could exercise inhibition in steady state it exacted a cost not seen in adults, who (unlike young children) seemed to re-set their default response when inhibition of the same tendency was required throughout a block. The costs associated with manipulations of inhibition were greater in young children while the costs associated with increasing memory demands were greater in adults. Effects seen only in RT in adults were seen primarily in accuracy in young children. Adults slowed down on difficult trials to preserve accuracy; but the youngest children were impulsive; their RT remained more constant but at an accuracy cost on difficult trials. Contrary to our predictions of independence between memory and inhibition, when matched for difficulty RT correlations between these were as high as 0.8, although accuracy correlations were less than half that. Spatial incompatibility effects and global and local switch costs were evident in children and adults, differing only in size. Other effects (e.g., asymmetric switch costs and the interaction of switching rules and switching response-sites) differed fundamentally over age.

Advance task preparation reduces task error rate in the cuing task-switching paradigm

Advance preparation reduces RT task-switching cost, which is thought to be evidence of preparatory control in the cuing task-switching paradigm. In the present study, we emphasize errors in relation to response speed. In two experiments, we show that (1) task switching increased the rate at which the currently irrelevant task was erroneously executed ("task errors") and (2) advance task preparation reduced the task error rate to that seen in nonswitch trials. The implications of the results to the hypothesis concerning task-specific preparation are discussed.

Response execution, selection, or activation: What is sufficient for response-related repetition effects under task shifting?

Repetition effects are often helpful in revealing information about mental structures and processes. Usually, positive effects have been observed when the stimuli or responses are repeated. However, in task shift studies it has also been found that response repetitions can produce negative effects if the task shifts. Although several mechanisms have been proposed to account for this interaction between task shifting and response repetition, many details remain open. Therefore, a series of four experiments was conducted to answer two questions. First, are motor responses necessary to produce response-related repetition effects, or is response activation sufficient? Second, does the risk of an accidental re-execution of the last response affect the repetition costs? The results show that response activation alone can produce repetition effects. Furthermore, the risk of accidental response re-execution largely modulates these effects.