The subjective evaluation of task switch cues is related to voluntary task switching.

Task switching refers to the effortful mental process of shifting attention between different tasks. While it is well-established that task switching usually comes with an objective performance cost, recent studies have shown that people also subjectively evaluate task switching as negative. An open question is whether this affective evaluation of task switching is also related to actual decision making. In this pre-registered study, we therefore examined whether individual differences in the negative evaluation of task switch cues are related to less voluntary task switching. To this end, participants first performed a cued task switching paradigm where abstract cues signaled task transitions (repetition or alternation). In a second phase, these transition cues were used as prime stimuli in an affective priming procedure to assess participants' affective evaluation of task switching. In a third phase, participants were allowed to freely choose whether to switch or repeat tasks. We found that a more negative evaluation of task switching cues was related to lower switch rates in the voluntary task switching phase. This finding supports neuroeconomic theories of value-based decision making which suggest that people use their subjective value of control to decide whether to engage in (different) tasks.

Learning to be in control involves response-specific mechanisms.

Conflict adaptation refers to our ability to modulate our attention in line with changing situational demands, so we can engage in goal-directed behavior. While there is ample evidence demonstrating that such adaptation in conflict tasks can be captured using different response modalities, it remains unknown whether these effects rely on domain-general mechanisms applied to different response modalities, or are the result of more inherently response-specific processes. Here, we used an individual-differences approach to evaluate whether conflict adaptation in two highly similar tasks using different response modalities are related. Specifically, participants performed two versions of a Stroop task, one in which they responded via key presses and one in which they responded via mouse movements. In both tasks, we manipulated the item-specific proportion of (in)congruent trials (80% vs. 20% congruent). This allowed us to evaluate the item-specific proportion congruency (ISPC) effect, a hallmark indicator of conflict adaptation. ISPC effects were observed in both response modalities. However, we found no indications that individual differences in the ISPC effects of the two response modalities were related. This raises the question whether findings from studies on conflict adaptation measured by different modalities can reliably be compared. Furthermore, these results suggest that response modality plays a more integrative role in these adaptive processes, rather than being the mere output of a domain-general control mechanism. This is consistent with contingency learning accounts of the ISPC effect and associative learning models of cognitive control.

Going, going, gone? Proactive control prevents the congruency sequence effect from rapid decay.

The congruency sequence effect, the finding of a reduced congruency effect following incongruent trials in conflict tasks, has received considerable attention in the research on cognitive control over the last two decades. This effect can reflect either the expectancy-guided, preparatory biasing of attention in anticipation of the upcoming stimulus (i.e. proactive control), or the phasic enhancement of the attentional set in response to conflict on the previous trial (i.e. reactive control). A recent study by Egner et al. in Front Psychol 1 (2010) set out to contrast these two alternatives, by exploring the congruency sequence effect across a wide range of inter-trial intervals. It was found that congruency sequence effects were subject to rapid decay over time. This decay fits well with the notion of reactive control, while at the same time speaking against the involvement of proactive regulation­which should also (and even mainly) be evident at longer intervals. In the present study, we first replicate the reduction of the congruency sequence effect with increasing inter-trial interval in a face-word Stroop task. In a second experiment, we show that congruency sequence effects are observed at longer intervals, too, when the proportion of trials with the longest inter-trial interval is increased. Our findings indicate that proactive control can prevent the congruency sequence effect from decaying rapidly.

Chemiluminescence assay for detection of anti-platelet antibodies.

A chemiluminescence (CL) assay for detection of antiplatelet antibodies was developed. Platelets sensitized with a xenogeneic antiplatelet serum or a potent anti-Pla1 serum stimulated granulocytes to produce CL. Other antibodies detectable by 51chromium release and immunofluorescent assays were not discerned by the CL assays.