ROLE OF VERBAL ENCODING IN SHORT-TERM AND LONG-TERM ODOR RECOGNITION

The role of verbal encoding in odor recognition memory was investigate d using odors of low familiarity to subjects before the experiment beg an. The experimental procedure included two phases-odor learning (firs t phase) and odor memory testing (second phase)-separated by a delay o f 7 days. Five experimental conditions were established: three conditi ons of odor learning with names (labeling conditions), one condition o f odor learning without names (sensory familiarization), and one condi tion of no learning prior to testing (control conditions). The labelin g conditions differed from each other regarding label characteristics. The names were those of odor sources (veridical names), those persona lly generated by subjects (generated names), or those derived from the chemical names of the odorants (chemical names). Subjects were requir ed to learn 20 fixed associations between odors (targets or distracter s) and 20 names during two daily sessions. The learning sessions inclu ded two identification tests and ended by a verbal memory test in whic h subjects recalled odor names. The odor memory test was split into tw o parts separated by a retention interval of either 20 min (short-term memory) or 24 h (long-term memory). Data showed that olfactory recogn ition memory was enhanced in subjects who associated veridical or gene rated names to odors during the learning session. Chemical names were not appropriate to facilitate odor recognition. Similarly, the level o f odor identification was higher for veridical and generated names tha n for chemical names, though the level of verbal memory for chemical n ames was substantial. Recognition response latencies were systematical ly longer for a target odor implying a positive response than for a di stractor odor implying a negative response. Together, these data sugge st that odor recognition and identification are sensitive to the seman tic content of labels associated with odors. Odor memory was adversive ly influenced by time, but this influence was less pronounced when the names were endowed with a rich semantic content.