Visual-cliff preference by infant rats: effects of rearing and test conditions

In monocular tests, normally reared infant rats, aged 21 to 22 days, fail to show a side preference on the visual-cliff apparatus. Rats of the same age, but reared in an "enriched" environment, prefer the shallow side of the apparatus. In binocular tests, even normally reared animals prefer the shallow side, although experimentally reared animals show a stronger preference. The results appear to reopen the question of what cues are employed on the visual cliff.