Where does contact collide?

In social psychology, the contact hypothesis holds that bringing members of different groups into contact can reduce prejudice between them, but only under favourable conditions: Allport specified equal status in the situation, common goals, intergroup cooperation, and the support of authorities or custom. Pettigrew and Tropp's meta-analysis of hundreds of studies later confirmed that contact typically reduces prejudice even when not all of Allport's conditions are met, though the effect is stronger when they are. The referent is a social relationship between groups and its attitudinal effect, with nothing in common with a rein connection or the stresses between pressed solids but the word.[1][2]

Unit

The amount and quality of contact between members of different groups

Recovery means

Not applicable

Measured by

Operationalised by the frequency and quality of intergroup contact and its association with reduced prejudice across studies

In engineering, contact mechanics studies the deformation, contact area, and stresses that arise when two solid bodies are pressed together. Hertzian theory, the classical starting point Johnson sets out, predicts the elliptical contact patch and pressure distribution between smooth elastic bodies from their geometry, load, and elastic moduli, and the field governs the design of bearings, gears, cams, and wheel–rail contact. The referent is a mechanical interface and its stress field, sharing nothing with intergroup contact or a rider's rein but the word for touching.[3]

Unit

The contact area and pressure distribution between touching bodies

Recovery means

Not applicable

Measured by

Predicted by Hertzian theory from load, geometry, and elastic moduli and checked against measured contact area and pressure