Incidental memory of differently processed odors.

10 odors were presented to three different groups of 20 subjects each (10 men and 10 women) to investigate the relationships among encoding conditions and both immediate and delayed incidental recognition of odors. Subjects who were not told to memorize the material and not informed of the final recognition test had to evaluate the intensity of each odor (Task 1), to judge the similarity of each odor to mint (Task 2), or to score each odor for pleasantness and sourness (Task 3). The subjects had to recognize test odors, represented one at a time, together with some distractors, immediately thereafter (Immediate Test) and one week later (Delayed Test). Task 1 and Task 2 produced better performances (77% and 75% of items recognized immediately; 66% and 69% recognized after a week) than Task 1. The performance on Task 3, more conceptually driven, was the worst, both immediately (67%) and a week later (52%). Sex and task reliably interacted: women performed better than men on Tasks 1 and 3, men on Task 2. Accuracy did not vary by task but by test time (immediate or delayed). Better performance on Tasks 1 and 2 may depend not only on more effective storage but also on the better fit between the task and the test.

Recognition of nonexplicitly presented odors.

This research was designed to check to what extent naive subjects can recognize odors in a situation similar to those of daily life. The odors were presented nonexplicitly and without any warning to memorize them for a later recognition task. Different intensities of noise were used to verify whether these affect the olfactory recognition task by modifying arousal and check whether a situation made more unpleasant by a louder noise produces changes in subjects' evaluations of the pleasantness of the odors presented. Also, subjects' personality traits were measured on extraversion-introversion and self-monitoring questionnaires. The three odors (Eucalyptolus, linalile acetate, bornile acetate) were recognized just under 50% of the time and were recognized differently. The number of recognitions did not vary significantly by sex or noise conditions; the most intense noise affected only the number of false alarms. Pleasantness scores differed only among the different odors. High self-monitoring subjects tended to have fewer recognitions; scores on extraversion-introversion produced no significant effect.

Odour memory and odour hedonics in children.

The characteristics of olfactory memory during development were investigated and the hypothesis that the pleasantness of smells may be affected by previous associations with pleasant or unpleasant objects or events was tested. This type of emotional memory was compared in the immediate and long-term recognition of olfactory stimuli. Children from three different age groups (mean ages: 6 years 6 months; 8 years 9 months; and 10 years 5 months) were subdivided into two groups. One group was presented with six different odours, each with a slide depicting a pleasant picture. The other group was presented with the odours accompanied by unpleasant pictures. Immediately after stimulus presentation the subjects underwent a recognition test. One month later the subjects underwent a second recognition test, at the end of which they were required to give an evaluation of the pleasantness of each odour on a nine-point scale. At no age level did the pictures matched to the odours affect the recognition score. Olfactory memory varied with age, chiefly because memory decay increased with age, perhaps because of greater proactive interference. With increasing age more rapid decay was set against better immediate recognition. The hypothesis that the hedonic characteristics of odours are partially learned and are affected by events experienced in other modalities was supported.

Subjective intensity of the lily-of-the-valley scent.

14 blind-folded subjects were requested to give numerical judgments of the perceived intensities of 1/4, 1/2, 1, 2, 4, 8, lily-of-the-valley bunches, according to a naturalistic approach. The psychophysical function conforms to a power law. The exponent, smaller than 1, is in the same range as those commonly found for smell.