A Multilab Replication of the Ego Depletion Effect.

There is an active debate regarding whether the ego depletion effect is real. A recent preregistered experiment with the Stroop task as the depleting task and the antisaccade task as the outcome task found a medium-level effect size. In the current research, we conducted a preregistered multilab replication of that experiment. Data from 12 labs across the globe (N = 1,775) revealed a small and significant ego depletion effect, d = 0.10. After excluding participants who might have responded randomly during the outcome task, the effect size increased to d = 0.16. By adding an informative, unbiased data point to the literature, our findings contribute to clarifying the existence, size, and generality of ego depletion.

Causal underpinnings of working memory and Stroop interference control: Testing the effects of anodal and cathodal tDCS over the left DLPFC.

By means of transcranial direct current stimulation applied to the left dorsolateral prefrontal cortex, we investigated the causal role of increased or decreased excitability of this brain region for two facets of executive functions: working memory and Stroop interference control. We tested 1) whether anodal tDCS of the left DLPFC enhances working memory 15 minutes after termination of stimulation and in the absence of direct task practice under stimulation; 2) whether anodal tDCS of the left DLPFC enhances interference control, as evidenced by Stroop performance and Stroop sequence effects; and 3) whether cathodal tDCS leads to compromised executive functioning compared to anodal stimulation. In a between-subject design with 88 healthy psychology students, we compared the impact of anodal and cathodal stimulation against a sham condition, on performance on a Stroop task (during active stimulation) and on an n-back task (completed 15 minutes after active stimulation ended). We found significantly enhanced accuracy in the n-back task after anodal stimulation compared with sham, as well as speeded reactions in the Stroop tasks independent of trial type. By contrast, we found no modulation of Stroop interference effects or Stroop sequence effects. No inhibitory effects of cathodal stimulation were observed. These results support the causal role of the left DLPFC in working memory but lend no support to its involvement in Stroop interference control.

The blenderFace method: video-based measurement of raw movement data during facial expressions of emotion using open-source software.

This article proposes an optical measurement of movement applied to data from video recordings of facial expressions of emotion. The approach offers a way to capture motion adapted from the film industry in which markers placed on the skin of the face can be tracked with a pattern-matching algorithm. The method records and postprocesses raw facial movement data (coordinates per frame) of distinctly placed markers and is intended for use in facial expression research (e.g., microexpressions) in laboratory settings. Due to the explicit use of specifically placed, artificial markers, the procedure offers the simultaneous measurement of several emotionally relevant markers in a (psychometrically) objective and artifact-free way, even for facial regions without natural landmarks (e.g., the cheeks). In addition, the proposed procedure is fully based on open-source software and is transparent at every step of data processing. Two worked examples demonstrate the practicability of the proposed procedure: In Study 1(N= 39), the participants were instructed to show the emotions happiness, sadness, disgust, and anger, and in Study 2 (N= 113), they were asked to present both a neutral face and the emotions happiness, disgust, and fear. Study 2 involved the simultaneous tracking of 14 markers for approximately 12 min per participant with a time resolution of 33 ms. The measured facial movements corresponded closely to the assumptions of established measurement instruments (EMFACS, FACSAID, Friesen & Ekman, 1983; Ekman & Hager, 2002). In addition, the measurement was found to be very precise with sub-second, sub-pixel, and sub-millimeter accuracy.