Detecting Transparent Barriers: Clear Evidence Against the Means-End Deficit Account of Search Failures.

The standard explanation of infants' search failures with hidden objects, despite an apparent sensitivity to them, is a deficit in the means-end skill for retrieving objects from occluders. Studies equating means-end demands for retrieving toys from transparent and opaque barriers challenge this account by showing that infants succeed more with visible objects. However, they suffer from a critical limitation: Infants may retrieve visible objects without noticing the transparent barriers in front of them. We addressed this concern by requiring infants to notice a barrier to retrieve a toy and specifically to pull down a rotating screen to retrieve a toy from behind it. Seven-month-olds used this means-end skill more often with a transparent barrier than an opaque one. Thus, neither a means-end deficit nor an ability to ignore transparent barriers fully accounts for search failures. Relations to other findings challenging the means-end deficit account and implications for approaches to studying cognitive development are discussed.