Introduction to the study

Harris and Fiske's 2006 study explores the biological underpinnings of social attitudes, focusing on how the brain processes images of people from marginalised groups. This research bridges psychology and neuroscience by examining neural responses to stereotypes – fixed, oversimplified ideas about particular groups – and prejudice – negative attitudes or feelings towards those groups. The study uses brain imaging to reveal how extreme out-groups, which are social groups perceived as very different from one's own, might trigger distinct brain activity compared to other humans or objects.

By investigating these processes, the study highlights potential biological correlates, meaning measurable brain activities linked to social biases. This approach helps explain why certain prejudices might feel instinctive, as they could involve automatic brain responses rather than just learned behaviours.

Aims of the study

The primary goal was to investigate how the brain responds to images of extreme out-groups, such as homeless people or drug addicts, compared to other humans or inanimate objects. Harris and Fiske aimed to identify biological markers of stereotypes and prejudice through brain scans.

Key research predictions:

• The medial prefrontal cortex (mPFC) – a brain region involved in social cognition, such as understanding others' thoughts and emotions – would activate when viewing images of typical humans.
• This activation would not occur when viewing objects, as they lack social relevance.
• For extreme out-groups, the researchers hypothesised reduced mPFC activity, potentially indicating dehumanisation, where individuals are perceived more like objects than people.

Procedure of the study

The study employed functional magnetic resonance imaging (fMRI), a technique that measures brain activity by detecting changes in blood flow, to scan participants' brains in real-time.

Participants

The sample consisted of university students.

Method and materials

• Participants underwent fMRI scans while viewing a series of images.
• Images included:
  • Pictures of humans from various social groups, including extreme out-groups (e.g., homeless individuals and drug addicts).
  • Pictures of everyday objects for comparison.
• The procedure involved presenting these images sequentially, allowing researchers to monitor brain responses to each category.

Results of the study

The fMRI data revealed distinct patterns of brain activity depending on the type of image viewed, supporting the idea that extreme out-groups elicit unique neural responses.

Key findings:

• Typical human images - As predicted, viewing pictures of people from non-extreme groups activated the medial prefrontal cortex, indicating engagement in social cognition processes like empathy or mentalising.
• Object images - No mPFC activity was observed, consistent with the lack of social relevance.
• Extreme out-group images - When participants viewed pictures of homeless people or drug addicts, there was no activation in the medial prefrontal cortex. Instead, brain regions associated with disgust – such as the insula and amygdala, which process negative emotions and threat detection – showed increased activity.

Conclusions and implications

From the results, Harris and Fiske concluded that stereotypes and prejudice towards extreme out-groups have a biological basis, involving reduced social brain activity and heightened disgust responses. This implies that such biases might bypass typical empathetic processing, making them harder to overcome through rational thought alone.

Broader implications for psychology

• Understanding prejudice - The findings highlight how biological factors could contribute to societal issues like discrimination, informing interventions that target neural pathways, such as empathy training.
• Limitations - The study relied on a student sample, which may not generalise to broader populations, and focused only on visual stimuli without measuring behavioural outcomes.
• Evaluation - Strengths include the objective use of fMRI for direct brain insights, but ethical concerns arise from potentially reinforcing stereotypes through the choice of out-group examples. Overall, this research advances biological explanations of social behaviour, encouraging further studies on reducing dehumanisation.