The impact of MRI scanner environment on perceptual decision-making

Despite the widespread use of functional magnetic resonance imaging (fMRI), few studies have addressed scanner effects on performance. The studies that have examined this question show a wide variety of results. In this article we report analyses of three experiments in which participants performed a perceptual decision-making task both in a traditional setting as well as inside an MRI scanner. The results consistently show that response times increase inside the scanner. Error rates also increase, but to a lesser extent. To reveal the underlying mechanisms that drive the behavioral changes when performing a task inside the MRI scanner, the data were analyzed using the linear ballistic accumulator model of decision-making. These analyses show that, in the scanner, participants exhibit a slow down of the motor component of the response and have less attentional focus on the task. However, the balance between focus and motor slowing depends on the specific task requirements.     

Dissecting stimulus–response binding effects: Grouping by color separately impacts integration and retrieval processes

In selection tasks, target and distractor features can be encoded together with the response into the same short-lived memory trace, or event file (see Hommel, 2004), leading to bindings between stimulus and response features. The repetition of a stored target or distractor feature can lead to the retrieval of the entire episode, including the response—so-called “binding effects.” Binding effects due to distractor repetition are stronger for grouped than for nongrouped target and distractor stimulus configurations. Modulation of either of two mechanisms that lead to the observed binding effects might be responsible here: Grouping may influence either stimulus–response integration or stimulus–response retrieval. In the present study we investigated the influences of grouping on both mechanisms independently. In two experiments, target and distractor letters were grouped (or nongrouped) via color (dis)similarity separately during integration and retrieval. Grouping by color similarity affected integration and retrieval mechanisms independently and in different ways. Color dissimilarity enhanced distractor-based retrieval, whereas color similarity enhanced distractor integration. We concluded that stimulus grouping is relevant for binding effects, but that the mechanisms that contribute to binding effects should be carefully separated.     

(Not) Thinking about you: Differences in victims’ and perpetrators’ self-focus after interpersonal and intergroup transgressions

We tested the hypothesis that, following a transgression, victims and perpetrators differ in their focus of attention. In three studies (total N = 740), we manipulated participants’ social role (victim vs. perpetrator) in a hypothetical scenario (Studies 1 and 2) and in a perceived real conflict (Study 3) in an interpersonal (Studies 1 and 2) and an intergroup (Study 3) context. Results from all studies confirmed that victims show a stronger self-focus than perpetrators. Moreover, results suggest victims’ higher self-focus as a predictor of willingness to reconcile. Participants’ self-focus mediated the effect of social role on reconciliation intentions as a single mediator (Study 2), or in sequence with their motivation to consider the other party's needs (Study 3). Overall, the present research suggests that victims and perpetrators differ in their focus of attention, and that this difference has important theoretical and practical implications for reconciliation between individuals and between groups.     

Lost time: Bindings do not represent temporal order information

Psychonomic Bulletin & Review - Many accounts of human action control assume bindings between features of stimuli and responses of individual events. One widely accepted assumption about these...