"Off with the old": mindfulness practice improves backward inhibition

Mindfulness practice has been linked to reduced depressive rumination and described as involving inhibition of information that has been relevant in the past and is no longer relevant in the present moment. Backward inhibition (BI) is considered to be one of the purest measures of task set inhibition, and impaired BI has been linked to depressive rumination. BI was contrasted with Competitor Rule Suppression (CRS), which is another phenomenon observed in task switching, yet one which involves episodic memory tagging of information that is currently conflicting rather than active inhibition. Although similar at baseline level, a randomly assigned group (n = 38) who underwent an eight session mindfulness training program exhibited improved BI but not CRS compared to a waiting list group (n = 38). Findings indicate that mindfulness improves the specific component of task set inhibition, which has previously been linked to reduced rumination. Implications regarding the potential role of task set inhibition in mediating between mindfulness and reduced rumination, as well as the role of mindfulness in "being in the present moment" are discussed.

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.

Episodic retrieval and decaying inhibition in the competitor-rule suppression phenomenon

The Competitor Rule Suppression (CRS) effect is the performance impairment observed in task switching when the currently relevant task rule is the same rule that had generated a response conflict in the preceding trial. This effect could reflect (a) episodic tagging, in which a competitor rule is retrieved with relative difficulty in subsequent trials or (b) residual active inhibition of the competing rule. In order to help distinguishing between the two accounts, the authors manipulated the Response-Cue Interval (RCI), which may influence both processes. CRS increased with increasing temporal distinctiveness between the previous and current episode (operationalized by the ratio of the current RCI to the previous RCI, RCI/pRCI), thus supporting episodic tagging. CRS additionally decreased numerically with increasing RCI even when the RCI/pRCI ratio was fixed, thereby providing suggestive support for the decay account.

"Mind the trap": mindfulness practice reduces cognitive rigidity

Two experiments examined the relation between mindfulness practice and cognitive rigidity by using a variation of the Einstellung water jar task. Participants were required to use three hypothetical jars to obtain a specific amount of water. Initial problems were solvable by the same complex formula, but in later problems ("critical" or "trap" problems) solving was possible by an additional much simpler formula. A rigidity score was compiled through perseverance of the complex formula. In Experiment 1, experienced mindfulness meditators received significantly lower rigidity scores than non-meditators who had registered for their first meditation retreat. Similar results were obtained in randomized controlled Experiment 2 comparing non-meditators who underwent an eight meeting mindfulness program with a waiting list group. The authors conclude that mindfulness meditation reduces cognitive rigidity via the tendency to be "blinded" by experience. Results are discussed in light of the benefits of mindfulness practice regarding a reduced tendency to overlook novel and adaptive ways of responding due to past experience, both in and out of the clinical setting.

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.

Selective attention to perceptual dimensions and switching between dimensions

In the present experiments, the question being addressed was whether switching attention between perceptual dimensions and selective attention to dimensions are processes that compete over a common resource? Attention to perceptual dimensions is usually studied by requiring participants to ignore a never-relevant dimension. Selection failure (Garner's Interference, GI) is indicated by poorer performance in the filtering condition (when this dimension varies) as compared with baseline (when it is fixed). Switching between perceptual dimensions is usually studied with the task switching paradigm. In the present experiments, attention switching was manipulated by using single-task blocks and blocks in which participants switched between tasks or dimensions in reaction to task cues, and attention to dimensions was assessed by including a third, never-relevant dimension that was either fixed or varied randomly. In Experiments 1 (long cue-target interval, CTI) and 2 (short CTI), the tasks involved shape and color and the never-relevant dimension (texture) was chosen to be separable from them. In Experiments 3 (long CTI) and 4 (short CTI), the tasks involved shape and brightness and the never-relevant dimension, saturation, was chosen to be separable from shape and integral with brightness. Task switching did not generate GI but a short CTI did. Thus, switching and filtering generally do not compete over central limited resources unless under tight time pressure. Experiment 3 shows GI in the brightness task but not in the shape task, suggesting that participants switched their attention between brightness and shape when they switched tasks.

Working memory load but not multitasking eliminates the prepared reflex: further evidence from the adapted flanker paradigm

The prepared reflex (PR) metaphor (Exner, 1879; Woodworth, 1938) suggests that stimulus-response (S-R) instructions held in working memory (WM) can lead to autonomous response activation without any practice. Cohen-Kdoshay and Meiran (2007) showed flanker compatibility effects immediately following the instructions (First Trials Flanker Compatibility Effect, FTFCE) and also showed that FTFCE was eliminated when participants had to hold an additional novel task rule in mind. They attributed the elimination of the FTFCE to WM load, but did not rule out multitasking and associated increased control demands as a possible alternative explanation. In the present experiment, the authors compared a no-load condition, a load condition involving a secondary task that was changed in every block (thus requiring WM) and a multi-tasking condition involving a secondary that remained the same throughout the experiment. The results show FTFCE without load and in the multi-tasking condition but no FTFCE in the WM load condition, establishing the critical involvement of WM storage capacity in the FTFCE.

Anger and the speed of full-body approach and avoidance reactions

The notion that anger is linked to approach motivation received support from behavioral studies, which measured various motor responses to angering stimuli. However, none of these studies examined full-body motions which characterize many if not most everyday instances of anger. The authors incorporate a novel behavioral motor task that tests motivational direction by measuring the reaction times (RTs) of stepping forward and backward in response to the words “toward” and “away.” The results show that, relative to anxiety and control conditions, anger induction resulted in a steeper approach–avoidance RT gradient which was shifted in favor of approach.

Objects and events as determinants of parallel processing in dual tasks: evidence from the backward compatibility effect

The backward-compatibility effect (BCE) is a major index of parallel processing in dual tasks and is related to the dependency of Task 1 performance on Task 2 response codes (Hommel, 1998). The results of four dual-task experiments showed that a BCE occurs when the stimuli of both tasks are included in the same visual object (Experiments 1 and 2) or belong to the same perceptual event (Experiments 3 and 4). Thus, the BCE may be modulated by factors that influence whether both task stimuli are included in the same perceptual event (objects, as studied in cognitive experiments, being special cases of events). As with objects, drawing attention to a (selected) event results in the processing of its irrelevant features and may interfere with task execution.

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 reaction-time task-rule congruency effect is not affected by working memory load: further support for the activated long-term memory hypothesis

Previous studies claimed that task representation is carried out by the activated long-term memory portion of working memory (WM; Meiran and Kessler in J Exp Psychol Human Percept Perform 34:137-157, 2008). The present study provides a more direct support for this hypothesis. We used the reaction-time task-rule congruency effect (RT-TRCE) in a task-switching setup, and tested the effects of loading WM with irrelevant task rules on RT-TRCE. Experiment 1 manipulated WM load in a between-subject design. WM participants performed a color/shape task switching, while having 0, 1 or 3 numerical task rules as WM load. Experiment 2 used a similar load manipulation (1 or 3 rules to load WM) in a within-subject design. Experiment 3 extended these results by loading WM with perceptual tasks that were more similar to the shape/color tasks. The results show that RT-TRCE was not affected by WM load supporting the activated long-term memory hypothesis.

Choosing to switch: spontaneous task switching despite associated behavioral costs

The literature shows that switching among simple cognitive tasks is difficult and involves a performance cost. Accordingly, cost-benefit considerations seem to predict that task switching would not occur spontaneously. Here we show that spontaneous task switching is a robust phenomenon, despite its costs. In Experiment 1, participants had to judge shapes according to one of three possible dimensions. Importantly, they were given the option to choose another relevant dimension or let the computer program change the dimension for them, but only if they wanted to do so. The results showed that spontaneous task switching was prevalent, despite robust switching costs. Experiment 2 extended this finding in showing spontaneous switching from an easy task to a more difficult task. The authors provide two possible explanations for the phenomenon that posit that spontaneous switching may be unpreventable or even advantageous.

The representation of instructions operates like a prepared reflex: flanker compatibility effects found in first trial following S-R instructions

The prepared reflex (PR) metaphor (Woodworth, R. S. (1938). Experimental psychology. New York: Holt, Rinehart and Winston) suggests that stimulus-response (S-R) instructions held in working memory (WM) can lead to autonomous response activation even without any practice. Cohen-Kdoshay and Meiran (Cohen-Kdoshay, O., & Meiran, N. (2007). The representation of instructions in working memory leads to autonomous response activation: Evidence from the first trials in the flanker paradigm. The Quarterly Journal of Experimental Psychology, 60 (8), 1140-1154) showed that the flanker compatibility effect (FCE) is found in the eight trials following S-R instructions supporting the PR hypothesis. Nonetheless, performance in the first trials forms long-term memory (LTM) traces which link abstract categories with responses and the retrieval of these LTM traces may be the reason for the autonomous response activation seen in the FCE. This account predicts FCEs to be absent in the first trial and present afterwards. The authors show that the FCE was present in the first trial immediately following the instructions, thus providing unequivocal support for the PR metaphor.

Attention, intention, and strategy in preparatory control

The neural mechanisms underlying different forms of preparatory control were examined using event-related fMRI. Preparatory brain activation was monitored in relation to different types of advance information: (1) random task cues indicating which of two possible tasks to perform upon subsequent target presentation; (2) task-ambiguous target stimuli; or (3) targets for which the correct response could be pre-determined. Three types of activation pattern were observed in different brain regions. First, more posterior regions of lateral prefrontal cortex (LPFC) and parietal cortex were activated by both advance task cues and advance targets, but with increased and more sustained activation for the latter. Second, more anterior regions of LPFC and parietal cortex were selectively activated by advance targets. Importantly, in these regions preparatory activation was not further modulated by the availability of advance response information. In contrast, preparatory activation in a third set of brain regions, including medial frontal cortex, reflected the utilization of advance response information, but by only a subset of participants. These results suggest three types of preparatory control: attentional (stimulus-oriented), intentional (action-oriented), and a possibly strategic component that might determine inter-individual differences in response readiness. Notably, the absence of regions selectively or even preferentially activated during cue-based preparation argues against certain conceptualizations of task-selective attention under cued task-switching conditions.