Merely labeling categories makes people exaggerate real differences between them.

Evidence

One famous piece of evidence for the biasing impact of categorization on perception comes from a study by Tajfel and Wilkes (1963). Like Allport, Tajfel and Wilkes conceived categorization (and stereotyping) to result in the overestimation of intergroup differences and intragroup resemblances. Participants estimated the length of a series of lines that varied from each other by regular increments. When shorter lines (As) were systematically given a different label than longer lines (Bs), participants overestimated the differences between the categories. This basic categorization effect applies to estimates about attitudes, traits, or even physical values (e.g., Krueger & Clement, 1994) and points to the biasing influence of categorization. However, it seems most pronounced when the judgment is uncertain, such as when participants communicate their estimates in an unfamiliar measurement unit (Corneille, Klein, Lambert, & Judd, 2002). — , Rudman, Laurie A - On the Nature of…, 1155

Categorization

Category: Factual Claims

• XREF: The Tajfel-Wilkes line experiment is the classic minimal demonstration that mere labels distort perceived category differences.
• SEED: The finding that categorization bias peaks under uncertainty suggests an essay angle on how ambiguous or new situations amplify stereotyping.

Related

• Merely labeling objects into two categories makes perceivers exaggerate differences between the groups. (similarity 0.94)
• Mere labeling of groups induces perceived intergroup differences even for neutral stimuli (similarity 0.91)
• Categorization enables thought but inevitably blurs the individual features it generalizes. (similarity 0.81)
• Categorization distorts perception and memory by increasing within-group confusion (similarity 0.81)
• Categorization reduces uncertainty at a predictable cost to accuracy (similarity 0.80)
• Categorization both enables judgment and necessarily biases it (similarity 0.79)
• Categorization inherently produces prejudgment that cannot be avoided (similarity 0.79)
• Categorizing people into groups minimizes perceived within-group differences (similarity 0.79)
• Categorization renders outgroups more homogeneous and ingroups more varied (similarity 0.79)
• Repeated, common features of things are not necessarily deeper or more significant than particulars. (similarity 0.78)