EXPRESS: Unveiling the boost in the sandwich priming technique

The masked priming technique (which compares #####-house-HOUSE vs. #####-fight-HOUSE) is the gold-standard tool to examine the initial moments of word processing. Lupker and Davis (2009) showed that adding a pre-prime identical to the target produced greater priming effects in the sandwich technique (which compares #####-HOUSE-house-HOUSE vs #####-HOUSE-fight-HOUSE). While there is consensus that the sandwich technique magnifies the size of priming effects relative to the standard procedure, the mechanisms underlying this boost are not well understood (i.e., does it reflect quantitative or qualitative changes?). To fully characterize the sandwich technique, we compared the sandwich and standard techniques by examining the RTs and their distributional features (delta plots; conditional-accuracy functions), comparing identity vs. unrelated primes. Results showed that the locus of the boost in the sandwich technique was two-fold: faster responses in the identity condition (via a shift in the RT distributions) and slower responses in the unrelated condition. We discuss the theoretical and methodological implications of these findings.

GABAergic modulation of performance in response inhibition and interference control tasks

Background: Inhibitory control is a crucial executive function with high relevance to mental and physical well-being. However, there are still unanswered questions regarding its neural mechanisms, including the role of the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Aims: This study examined the effects of lorazepam (0.5 mg and 1 mg), a positive allosteric modulator at the GABAA receptor, on response inhibition and interference control. We also explored the heterogeneity of inhibitory control and calculated delta plots to explore whether lorazepam affects the gradual build-up of inhibition and activation over time. Methods: N = 50 healthy participants performed antisaccade, Eriksen flanker and Simon tasks in a within-subjects, placebo-controlled, double-blind randomized design. Results: Lorazepam increased reaction time (RT) and error rates dose dependently in all tasks ( p ⩽ 0.005). In the antisaccade and Simon tasks, lorazepam increased congruency effects for error rate ( p ⩽ 0.029) but not RT ( p ⩾ 0.587). In the Eriksen flanker task, both congruency effects were increased by the drug ( p ⩽ 0.031). Delta plots did not reflect drug-induced changes in inhibition and activation over time. Delta plots for RT in the Simon task were negative-going, as expected, whereas those for the antisaccade and flanker tasks were positive-going. Conclusions: This study provides evidence for GABAergic involvement in performance on response inhibition and interference control tasks. Furthermore, our findings highlight the diversity of the broader construct of inhibitory control while also pointing out similarities between different inhibitory control tasks. In contrast to RT and error rates, the cognitive processes indexed by delta plots may not be sensitive to GABAergic modulation.

GABAergic Modulation of Response Inhibition and Interference Control

Background: Inhibitory control is a crucial executive function with high relevance to mental and physical wellbeing. However, there are still unanswered questions regarding its neural mechanisms, including the role of the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Aims: This study examined the effects of lorazepam (0.5 mg and 1 mg), a positive allosteric modulator at the GABAA receptor, on response inhibition and interference control. We also explored the heterogeneity of inhibitory control and calculated delta plots to explore whether lorazepam affects the gradual build-up of inhibition and activation over time. Method: A sample of N=50 healthy participants performed antisaccade, Eriksen flanker and Simon tasks in a within-subjects, placebo-controlled, double-blind randomised design. Results: Lorazepam increased mean reaction times (MRT) and error rates dose-dependently in all tasks (p≤.005). In the antisaccade and Simon tasks, lorazepam increased congruency effects for error rate (p≤.029) but not for MRT (p≥.587). In the Eriksen flanker task, both congruency effects were increased by the drug (p≤.031). Delta plots did not reflect any drug-induced changes in inhibition and activation over time. Delta plots for MRT in the Simon task were negative-going, as expected, whereas those for the antisaccade and flanker tasks were positive-going. Conclusions: This study provides clear evidence for GABAergic involvement in inhibitory control. Furthermore, our findings highlight the diversity of inhibitory control while also pointing out similarities between different inhibitory control tasks. In contrast to MRTs and error rates, the cognitive processes provided by delta plots appear not to be sensitive to GABAergic modulation.Draft version, 02.04.2020. This paper has not been peer reviewed. Please do not copy or cite without author's permission.

Space and Motion Stimulus-Response Correspondence (SRC) Effects in a Single Task

Previous research indicated that congruency between stimulus location and response position (spatial stimulus-response correspondence [SRC]) and stimulus motion and response movement congruency (motion SRC) are distinct SRC phenomena. This study further explored this issue and tested whether these two SRC effects are independent. This was conducted by investigating these two SRC effects in a single task. A stimulus with leftward or rightward motion was presented on the left or the right side of the screen and the participant had to move the joysticks held with the left and right hands leftward or rightward in response to the stimulus color. In this setting, the stimulus and response shared two types of correspondence: spatial and motion. The results demonstrated that two SRC effects occurred and interacted (interaction evident only in reaction times [RTs]). RT distribution analysis and accuracy delta plots for each SRC effect indicated that spatial and motion SRC are distinct phenomena based on different processes.