The effects of pre-exposure on escape from a Morris pool

In two experiments rats were pre-exposed to the landmarks surrounding a Mor ris pool while they swam to a platform with a beacon attached to it. They w ere then required to escape from the pool by finding the platform, without the beacon, in a new position. When the platform remained in the same place for each pre-exposure session, but was moved from session to session, then subsequent escape from the pool was more rapid than when the landmarks wer e not visible during pre-exposure (Experiment 1). But when the platform was moved from trial to trial during preexposure, then subsequent escape from the pool was disrupted (Experiments 1 and 2). It is proposed that pre-expos ure to the landmark alters the attention that is paid to them, which then i nfluences how readily the landmarks can be used to identify the new positio n of the platform.