Noninvasive brain stimulation reduces prejudice scores on an implicit association test

Area of Science:

• Neuroscience
• Social Psychology
• Cognitive Science

Background:

• The anterior temporal lobe (ATL) plays a crucial role in semantic conceptualization.
• Damage to the left ATL is linked to semantic dementia.
• Repetitive transcranial magnetic stimulation (rTMS) can inhibit brain regions, but its effect on negative conceptual schemata is understudied.

Purpose of the Study:

• To investigate if rTMS applied to the ATLs can reduce prejudice.
• To assess the impact of bilateral ATL inhibition on implicit bias scores.

Main Methods:

• Forty neurologically normal undergraduates participated in a randomized controlled trial.
• Participants received rTMS to the left ATL, right ATL, motor cortex (control), or sham stimulation.
• A modified Implicit Association Test (IAT) measuring prejudice was administered before and after stimulation.

Main Results:

• A one-way ANOVA revealed significant differences in IAT score changes between groups.
• Both left and right ATL rTMS significantly reduced IAT scores, indicating decreased prejudice.
• No significant differences were found in control or sham groups.

Conclusions:

• Inhibitory rTMS delivered to the bilateral ATLs effectively reduces prejudice.
• The ATLs may be involved in the conceptual associations underlying stereotyping and overgeneralization.
• This study suggests a potential neuroscientific intervention for reducing social biases.