The role of environmental familiarization in novel-object preference

The experiments in this report examined the behavioral variables modulating novel-object preference in a widely used 'object recognition' preparation. This preparation takes advantage of the tendency of rats to interact more with a novel than a familiar 'sample' object in a free-choice situation. Ex periment 1 examined the interaction between environmental familiarization a nd the duration of sample-object exposure in the development of a novel-obj ect preference. Interaction with the sample object during sample-object exp osure was increased when rats were given time in the environment prior to p resentation of the sample object. Also, provided that the sample-object exp osure was greater than 2 min, rats given environmental familiarization time prior to sample-object exposure displayed a novel-object preference. Rats that received the same amount of sample-object exposure without prior expos ure to the environment alone did not discriminate between the sample and no vel object. In Experiments 2 and 3, sample-object exposure occurred in a di fferent environment than the novel-object,test, Novel-object preference was not affected regardless of whether that testing environment was familiar o r novel. This result differs from previous work that finds that an object r ecovers some novelty when moved to a new spatial location. (C) 2000 Elsevie r Science B.V. All rights reserved.