Lesion to the vmPFC abolishes intentionality (mis)attribution in the Knobe effect

Area of Science:

• Neuroscience
• Social Psychology
• Cognitive Science

Background:

• Intentionality attribution is vital for social interaction but its underlying mechanisms are not fully understood.
• The Knobe Effect describes a bias where negative side effects lead to greater intentionality attribution than positive ones.
• Previous research links this bias to emotional and moral judgments, but findings are inconsistent and neural underpinnings are underexplored.

Purpose of the Study:

• To investigate the causal role of the ventromedial prefrontal cortex (vmPFC) in the Knobe Effect.
• To examine how vmPFC lesions impact intentionality attribution, emotional responses, and moral judgments related to side effects.

Main Methods:

• Comparing intentionality and valence ratings of scenarios with negative or positive side effects in participants with vmPFC lesions and healthy controls.
• Assessing morality ratings, subjective emotional responses, and electrodermal activity during scenario evaluation.

Main Results:

• vmPFC patients did not exhibit the Knobe Effect, attributing similar intentionality to positive and negative side effects.
• This deficit occurred despite intact valence recognition but was associated with blunted emotional responses and altered moral judgments.
• Healthy controls demonstrated the typical Knobe Effect.

Conclusions:

• Emotional responses and moral judgments are fundamental to the Knobe Effect in healthy individuals.
• The vmPFC plays a causal role in mediating the Knobe Effect, highlighting its importance in social cognition and bias.