On the role of familiarity with units of measurement in categorical accentuation: Tajfel and Wilkes (1963) revisited and replicated.

The present article provides evidence for the role of participants' familiarity with units of measurement in categorical accentuation with unidimensional physical estimates. Belgian and American participants estimated the lengths of lines varying in length. Depending on the condition, the lines were or were not systematically associated with categorical labels, and the estimates were made either in inches or in centimeters. Consistent with our predictions, (a) categorical accentuation was higher when the lines were systematically categorized than when they were not, and (b) this effect was stronger when participants reported their estimates in an unfamiliar measurement unit (i.e., Belgian participants using inches, and American participants using centimeters). These findings support the view that people's reliance on categorical information is more likely to emerge given uncertain contexts of judgment. Additionally, they may help explain why researchers have had difficulties replicating the categorical accentuation effect in the past.