Sharing a task or sharing space? On the effect of the confederate in action coding in a detection task

Area of Science:

• Cognitive Psychology
• Social Neuroscience

Background:

• The Simon effect is a well-documented phenomenon in reaction time tasks.
• Previous research indicated a 'social Simon effect' only in explicitly collaborative tasks.
• This effect was previously thought to require a representation of a partner's actions.

Purpose of the Study:

• To investigate if the social Simon effect occurs without explicit collaboration.
• To determine the role of peripersonal space in the social Simon effect.
• To re-evaluate the underlying mechanisms of the social Simon effect.

Main Methods:

• Participants performed a go-nogo task, a component of the two-choice reaction time task.
• The social Simon task was administered with and without explicit collaboration.
• Participant proximity was manipulated, specifically within and outside peripersonal space.

Main Results:

• A social Simon effect was observed even when participants did not collaborate.
• The social Simon effect was absent when participants were outside each other's peripersonal space.
• This suggests proximity, not collaboration, is key.

Conclusions:

• The social Simon effect can emerge without explicit collaboration.
• Peripersonal space is crucial for the social Simon effect.
• The effect may stem from proximity providing a spatial reference for self-action coding, rather than representing another's action.