A model-based approach to disentangling facilitation and interference effects in conflict tasks.

Abstract

Conflict tasks have become one of the most dominant paradigms within cognitive psychology, with their key finding being the conflict effect: That participants are slower and less accurate when task-irrelevant information conflicts with task-relevant information (i.e., incompatible trials), compared to when these sources of information are consistent (i.e., compatible trials). However, the conflict effect can consist of two separate effects: Facilitation effects, which is the amount of benefit provided by consistent task-irrelevant information, and interference effects, which is the amount of impairment caused by conflicting task-irrelevant information. While previous studies have attempted to disentangle these effects using neutral trials, which contrast compatible and incompatible trials to trials that are designed to have neutral task-irrelevant information, these analyses rely on the assumptions of Donder’s subtractive method, which are difficult to verify and may be violated in some circumstances. Here, we develop a model-based approach for disentangling facilitation and interference effects, which extends the existing diffusion model for conflict tasks (DMC) framework to allow for different levels of automatic activation in compatible and incompatible trials. Comprehensive parameter recovery assessments display the robust measurement properties of our model-based approach, which we apply to nine previous data sets from the flanker (6) and Simon (3) tasks. Our findings suggest asymmetric facilitation and interference effects, where interference effects appear to be present for most participants across most studies, whereas facilitation effects appear to be small or nonexistent. We believe that our novel model-based approach provides an important step forward for understanding how information processing operates in conflict tasks, allowing researchers to assess the convergence or divergence between experimental-based (i.e., neutral trials) and model-based approaches when investigating facilitation and interference effects.

Separating facilitation and interference in backward crosstalk.

“…The relatively symmetric facilitation and interference effects in the BCE, especially with respect to RTs, is also particularly interesting when considering the regular finding of a larger interference than facilitation effect in conflict tasks (see also Evans & Servant, 2022). Smith and Ulrich (2023) recently summarized the respective literature on the Simon, flanker, and Stroop tasks and concluded that 42 of the 52 studies considered showed a larger interference than facilitation effect.…”

“…The present study investigated the extent to which the BCE is the result of facilitation in compatible trials or interference in incompatible trials, and thereby, whether the implicit assumption of symmetrical response activation is reasonable. To this end, we introduced neutral trials into a dual task, with the assumption that T2 stimuli or responses in these trials neither interfered with nor facilitated T1 response selection (similar to neutral, task-irrelevant stimuli in the context of conflict tasks; see, e.g., Evans & Servant, 2022; Smith & Ulrich, 2023). Specifically, in Experiments 1 and 2, T1 required a left or right key press (R1) to indicate the color of a letter (S2), while T2 required the utterance of the German words for “left,” “middle,” or “right” (R2) to indicate the identity of the letter (S2).…”

“…incomp = incompatible; comp = compatible. the context of conflict tasks; see, e.g., Evans & Servant, 2022;Smith & Ulrich, 2023). Specifically, in Experiments 1 and 2, T1 required a left or right key press (R1) to indicate the color of a letter (S2), while T2 required the utterance of the German words for "left," "middle," or "right" (R2) to indicate the identity of the letter (S2).…”

“…Disentangling their unique contributions, however, is certainly important because current descriptive and quantitative models (Hommel, 1998; Janczyk, Renas, & Durst, 2018; Koob et al, 2023) of the BCE implicitly assume T2 response activation to be similar in both compatible and incompatible conditions. It would require an explicit reformulation of the models or the introduction of a separate control mechanism to argue why T2 response activation should differ between compatible and incompatible trials (see Evans & Servant, 2022, for some arguments in favor of asymmetry in response activation in the context of conflict tasks). Thus, the present study provides an important test of the current set of BCE models.…”

“…First, the predictions depend on the peak latency of T2 response activation, which could not be identified precisely in the study by Koob et al (2023, p. 113). Second, the predictions depend on the architecture of DMC, our specific simulation settings (e.g., see Evans & Servant, 2022, for arguments favoring a stronger influence of incompatible than compatible information in conflict tasks), and the applicability of DMC to dual tasks.…”