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Dehumanizing the Lowest of the Low Neuroimaging Responses to Extreme Out-Groups Article by Lasana T. Harris & Susan T. Fiske. By Stephanie Clogg. Summary:. Introduction Method Results Discussion My opinion on the paper. Introduction.
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Dehumanizing the Lowest of the Low Neuroimaging Responses to Extreme Out-GroupsArticle by Lasana T. Harris & Susan T. Fiske By Stephanie Clogg
Summary: • Introduction • Method • Results • Discussion • My opinion on the paper
Introduction • Aim: To investigate through neuroimaging if extreme out-groups are perceived as less than human • Prejudice is not just a simple animosity! • Out-group Infrahumanization Theory • Medial prefrontal cortex (mPFC): necessary for social cognition • Activated when thinking about a person or making social judgements
Stereotype Content Model (SCM) • High vs. low levels of perceived warmth and competence • 4 stereotype dimensions (Pity, Pride, Disgust, Envy) • SCM predicts extreme out-groups (low warmth/low competence) will be dehumanized Competence Warmth
Hypothesis: • HYPOTHESIS: Extreme out-groups (low warmth/ low competence) may NOT significantly activate the mPFC • No social cognition - not perceiving these groups as fully human???
Method: Participants: • 22 Princeton undergraduates • Included 6 ethnic minorities Scanning parameters: • 3T Siemens Allegra head-dedicated MR scanner • Participant responded with manual response pads • Functional echoplanar imaging (EPI) sequence used • Participants were familiarized with a similar task before entering scanner • Series of 6 runs of 10 photos
Image of social group depicting 1 of the 4 SCM categories Example of procedure for Study Group 1 Response screen Baseline fixation task Second image in series... 6 seconds 2 seconds 12 seconds 6 seconds
Results: Data analysis: • BOLD signal response recorded from each SCM quadrant • Subtracted activation during exposure to image from activation during black screen display (baseline task) • Resulting contrast maps were averaged across participants • Study 1 participants evaluated predicted SCM quadrant of image well above chance (0.25)
Brain regions involved: Study 1 • Significant mPFCactivations was revealed for pride, pity, and envy but NO significant mPFC activation for disgust • Red circled areas indicate mPFC activation R=Right
Brain regions involved: Disgust • No mPFC activation, supporting the hypothesis! • Disgust images (in study) were associated with activation in theright amygdala &left insula
Discussion and summary: • Due to absence of mPFC activation in low-low social groups, suggesting lack of social cognition, members of some social groups are dehumanized. • Low-low social groups also ellicit neural patterns of disgust (insula) and fear (amygdala) according to meta-analyses • The proof of neural mechanisms involved in dehumanization may help explain hate crimes and genocide
My Opinion on this study: • Strengths: • Using fMRI and EPI monitors activity in the whole brain, which allowed them to find activation in the left insula for disgust category. (This would not have been found if they were only looking at localized activation in the mPFC) • Provided neurological evidence for previous theories • Weaknesses: • Low number of participants all from similar backgrounds and ages • Further research: • Use more people from different age groups, demographic and racial backgrounds.