Nachshon Meiran

RECONFIGURATION OF PROCESSING MODE PRIOR TO TASK PERFORMANCE

Participants performed choice reaction time (RT) tasks on 2-dimensional stimuli such that each task was based on 1 stimulus dimension. A cue preceded the target stimulus and instructed the participant about which (randomly selected) task to perform. Shifting between tasks was associated with an RT cost, which was larger when the (randomly varying) cue-target interval was short as opposed to when it was long. Cue-target interval was not confounded with the remoteness from the previous trial. Hence, it affected the task-shift cost through preparation rather than by allowing carryover effects to dissipate. Similar results were obtained for 2 location tasks and for the object-based tasks (color and shape discrimination). They indicate a time-effort consuming process that operates after a task shift, precedes task execution, and presumably reflects the advance reconfiguration of processing mode.

Component Processes in Task Switching

Participants switched between two randomly ordered, two-choice reaction-time (RT) tasks, where an instructional cue preceded the target stimulus and indicated which task to execute. Task-switching cost dissipated passively while the participants waited for the instructional cue in order to know which task to execute (during the Response-Cue Interval). Switching cost was sharply reduced, but not abolished, when the participants actively prepared for the task switch in response to the instructional cue (during the Cue-Target Interval). The preparation for a task switch has shown not to be a by-product of general preparation by phasic alertness or predicting target onset. It is suggested that task-switching cost has at least three components reflecting (1) the passive dissipation of the previous task set, (2) the preparation of the new task set, and (3) a residual component.

On the origins of the task mixing cost in the cuing task-switching paradigm.

Poorer performance in conditions involving task repetition within blocks of mixed tasks relative to task repetition within blocks of single task is called mixing cost (MC). In 2 experiments exploring 2 hypotheses regarding the origins of MC, participants either switched between cued shape and color tasks, or they performed them as single tasks. Experiment 1 supported the hypothesis that mixed-tasks trials require the resolution of task ambiguity by showing that MC existed only with ambiguous stimuli that afforded both tasks and not with unambiguous stimuli affording only 1 task. Experiment 2 failed to support the hypothesis that holding multiple task sets in working memory (WM) generates MC by showing that systematic manipulation of the number of stimulus-response rules in WM did not affect MC. The results emphasize the role of competition management between task sets during task control.

Better Late Than Never? On the Dynamics of Online Regulation of Sadness Using Distraction and Cognitive Reappraisal

Real-life emotion regulation often occurs at some point after an emotion-triggering event (ETE) has been introduced, but most previous research has involved regulation before or after the ETE. In a series of experiments, the authors examined online regulation via distraction and cognitive reappraisal by manipulating the strategy initiation point in sadness-evoking films. Distraction was effective even when initiated late, presumably because it involves diluting the ETE contents by mixing them with a nonsad input. By contrast, reappraisal was less effective when initiated late, suggesting a possible point of no return for this strategy: Adopting a detached view late in the ETE may be difficult because it involves continued focus on the ETE and hence requires overcoming a previously formed tendency of identifying with the emotional content.

Divergent cognitive costs for online forms of reappraisal and distraction.

The present study was set out to evaluate the cognitive costs of two major emotion regulation strategies under conditions of increased challenge. Previous studies have established that cognitive reappraisal (construing an emotional event in nonemotional terms) has no cognitive costs. However, in all of these studies, reappraisal was initiated at the emotional situation onset, before emotional response tendencies sufficiently evolved. In the present study, the challenge of regulation strategies was increased by initiating strategies online at a late time point in an emotional situation. Applying this procedure revealed for the first time a cognitive cost for reappraisal and also provided double dissociation between reappraisal and another major cognitive emotion regulation strategy--distraction (diverting attention from an emotional situation via producing neutral thoughts). Specifically, late reappraisal, relative to distraction, resulted in an expenditure of self control resources. Late distraction but not reappraisal impaired memory encoding of the emotional situation.

Antecedents and consequences of maternal involvement in children's homework : A longitudinal analysis

Many parents are concerned with the desirability of helping their children with homework. Mothers and their childrens teachers filled out questionnaires twice, when children were in 1st and 3rd grade. The children did so in 3rd grade. Correlation matrices were analyzed by a Linear-Structural Relations model (LISREL). The predictions of 3rd grade by 1st grade variables were tested by hierarchical regressions. Maternal help with homework had no effect on the childs academic achievement. Mothers of weaker students helped more with homework, particularly in the 1st grade. In both grades, maternal help was related to her pedagogical belief in the value of helping and to her personal gratification from helping. Helping increased maternal emotional costs and caused tensions between her and the child, particularly when the latter was a poor student. Helping decreased with grade, as did maternal gratification and pedagogical belief.

Cognitive rigidity in unipolar depression and obsessive compulsive disorder: Examination of task switching, Stroop, working memory updating and post-conflict adaptation

Obsessive compulsive disorder (OCD) and depressive rumination are both characterized by cognitive rigidity. We examined the performance of 17 patients (9 suffering from unipolar depression [UD] without OCD, and 8 suffering from OCD without UD), and 17 control participants matched on age, gender, language and education, on a battery covering the four main executive functions. Results indicated that, across both disorders, patients required more trials to adjust to single-task conditions after experiencing task switching, reflecting slow disengagement from switching mode, and showed abnormal post-conflict adaptation of processing mode following high conflict Stroop trials in comparison to controls. Rumination, which was elevated in UD and not in OCD, was associated with poor working memory updating and less task preparation. The results show that OCD and UD are associated with similar cognitive rigidity in the presently tested paradigms.

The Task Rule Congruency Effect in Task Switching Reflects Activated Long-Term Memory.

Reaction time task rule congruency effects (RT-TRCEs) reflect faster responses to stimuli for which the competing task rules indicate the same correct response than to stimuli indicating conflicting responses. The authors tested the hypothesis that RT-TRCE reflects activated overlearned response category codes in long-term memory (such as up or left). The results support the hypothesis by showing that (a) RT-TRCE was absent for tasks for which there were no response codes ready beforehand, (b) RT-TRCE was present after these tasks were practiced, and (c) these practice effects were found only if the tasks permitted forming abstract response category codes. The increase in the RT-TRCE with response slowness, found only for familiar tasks, suggests that the abstract response category codes may be verbal or linguistic in these cases. The results are discussed in relation to task-switching theories and prefrontal functions.

Control by action representation and input selection (CARIS) : a theoretical framework for task switching

Control by action representation and input selection (CARIS) is a modeling framework for task-switching experiments, which considers action-related effects as critical constraints. It assumes that control operates by choosing control parameter values, representing input selection and action representation. Competing CARIS models differ in whether (a) control parameters are determined by current instructions or represent a perseveration, (b) current instructions apply to the input selection and/or to action representation. According to the chosen model (a) task execution results in a default bias in favor of the executed task thus creating perseverative tendencies; (b) control counteracts these tendencies by applying a transient momentary bias whose locus (input selection or action representation) changes as a function of task preparation time; (c) this happens because the task-cue (e.g., SHAPE) initially attracts attention to the immediately available cue-information (e.g., target shape) and then attracts it to inferred or retrieved information (e.g., “circle” is related to the right key press).

When the same response has different meanings: Recoding the response meaning in the lateral prefrontal cortex

The ability to adapt our behavioral repertoire to different situations and tasks is crucial for our behavioral control. Since the same motor behavior can have different meanings in different task situations, we often have to change the meaning of our responses when we get into a different task context. In a functional MRI experiment we manipulated this response recoding process. Subjects were required to execute two simple spatial tasks in a task switching paradigm. In one condition both tasks required the same set of responses, hence each response had two different meanings depending on the relevant task (bivalent condition). In the other condition subjects used a separate set of responses for each task (univalent condition). While subjects were required to recode the meaning when switching from one task to the next in the bivalent condition, response recoding was not required in the univalent condition. We demonstrate that the lateral prefrontal cortex is involved in recoding of response meaning. These results extend previous assumptions on the role of the prefrontal cortex in behavioral control.