Harris · Psychological science 2006 · Cross-sectional experimental neuroimaging study · n=22

Dehumanizing the lowest of the low: neuroimaging responses to extreme out-groups.

Cited 983 times in the scientific literature.

Level 4 - case-series / case-control

Level assigned by design analogy; laboratory neuroimaging study in a small healthy volunteer sample.

PubMed 17100784 · doi:10.1111/j.1467-9280.2006.01793.x · record verified 2026-08-26

What was done

Functional magnetic resonance imaging (fMRI) was used to measure brain activation while 10 participants viewed 48 photographs depicting social groups across the four stereotype content model quadrants (combinations of low/high warmth and low/high competence) and 12 participants viewed photographs of objects.

What was found

The abstract reports no numerical values, effect sizes, or test statistics. Directionally, medial prefrontal cortex (mPFC) activation occurred in response to all social groups except extreme out-groups characterized by low warmth and low competence (such as addicts and homeless individuals). Extreme out-groups instead activated the insula and amygdala. Object stimuli did not activate the mPFC.

Why it matters

This study provides early neural evidence that extreme social prejudice may involve distinct neurocognitive processing where targets fail to elicit typical social cognition network activity.

Limits

The sample is extremely small (10 participants in the social condition, 12 in the object condition). The abstract does not report numerical data, effect sizes, or confidence intervals. Attributing specific emotional states like disgust based on insula and amygdala activation relies on reverse inference.

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