Sequential modulation of (bottom-up) response activation and inhibition in a response conflict task: a single-pulse transcranial magnetic stimulation study.

Many cognitive tasks involve a response conflict between the response selected on the basis of the task-relevant attribute and that primed by an irrelevant attribute. Although response priming has been extensively investigated, we still have little evidence on whether it entails both excitatory and inhibitory processes and the way in which these processes are modulated by the prior occurrence of a conflict between-response alternatives. To shed light on these issues, we tested motor cortex excitability during a two-choice compatibility task (a Simon task) by delivering single pulses of transcranial magnetic stimulation and recording the resulting motor evoked potentials (MEPs).

Spatial parameters at the basis of social transfer of learning.

Recent research indicates that practicing on a joint spatial compatibility task with an incompatible stimulus-response mapping affects subsequent joint Simon task performance, eliminating the social Simon effect. It has been well established that in individual contexts, for transfer of learning to occur, participants need to practice an incompatible association between stimulus and response positions. The mechanisms underlying transfer of learning in joint task performance are, however, less well understood.

The influence of prior practice and handedness on the orthogonal Simon effect.

When stimuli are arranged vertically and responses horizontally, right-handed participants respond faster with right responses to stimuli presented above fixation and with left responses to stimuli presented below fixation, even when stimulus position is task-irrelevant (orthogonal Simon effect). The aim of the present work was twofold. First, we assessed whether the orthogonal Simon effect evident in right-handed participants is present also for left-handed participants (Experiment 1).

Facilitation and interference components in the joint Simon task.

Two experiments were conducted to assess whether the joint Simon effect is composed of facilitation and interference and whether facilitation is increased by a joint spatially compatible practice performed before performing the joint Simon task. In both experiments, participants were required to perform a Simon task along another person. Trials could be corresponding, non-corresponding, and neutral.

Contextual determinants of the social-transfer-of-learning effect.

A recent study (Milanese et al. in Cogn 116(1):15-22, 2010) showed that performing a spatial compatibility task with incompatible S-R links (i.e.

Influence on Simon and SNARC effects of a nonspatial stimulus-response mapping: between-task logical recoding.

In 4 experiments, we intermixed trials in which the stimulus color was relevant with trials where participants had to judge the stimulus shape or parity and found that the logical-recoding rule (Hedge & Marsh, 1975) applied to the relevant dimension in a task can generalize to the irrelevant dimension of the other task. The mapping assigned to participants in color-relevant trials modulated the Simon and SNARC (spatial-numerical association of response codes) effects (Simon & Small, 1969; Dehaene, Bossini, & Giraux, 1993) observed in shape- and parity-relevant trials. Standard effects were obtained when color-relevant trials required participants to respond by pressing a key of the same color as the stimulus, whereas an alternate-color mapping caused either the disappearance or reversal of the effects.

Shared learning shapes human performance: Transfer effects in task sharing.

We investigated whether performing a task with a co-actor shapes the way a subsequent task is performed. In four experiments participants were administered a Simon task after practicing a spatial compatibility task with an incompatible S-R mapping. In Experiment 1 they performed both tasks alongside another person; in Experiment 2 they performed the spatial compatibility task alone, responding to only one stimulus position, and the Simon task with another person; in Experiment 3, they performed the spatial compatibility task with another person and the Simon task alone; finally, in Experiment 4, they performed the spatial compatibility task alone and the Simon task with another person.