ODOR DISCRIMINATION AND RECOGNITION MEMORY AS A FUNCTION OF FAMILIARIZATION

The role of olfactory familiarization in short-term recognition of odo rs was investigated. Subjects were asked to make qualitative similarit y judgments regarding either identical or dissimilar odors delivered i n pairs. Except for control groups, subjects got familiarized with eit her the first (target) or the second (distracter) or both odors from a pair. Groups also differed according to the number of familiarization sessions-one, two, or three-taking place prior to the discrimination judgments. There was no significant influence of familiarization on co rrect recognition scores for pairs of identical odors. The most salien t finding was a marked decrease of false alarms as a function of the n umber of familiarization sessions, which evidenced a positive effect o f familiarization on discrimination for pairs of dissimilar odors. The se judgments were not dependent on an intensity criterion. False alarm s did not vary according to whether subjects had been familiarized wit h the target or the distracter or both odors from a pair. A positive c orrelation found between discrimination performances and the number of odors correctly remembered as being presented during familiarization suggested that familiarization resulted in long-term storing of memory traces for familiarized odors. Since familiarization was effective de spite conditions unfavorable to the use of semantic encoding, the resu lts argue in favor of a predominantly perceptual encoding of odors in the investigated task.