Very short term recognition memory for odors

Abstract

An investigation of very short term olfactory recognition memory was made with odors of low familiarity to subjects. The experimental procedure was that currently used to make qualitative similarity judgments on odors delivered in paired succession. Subjects made similarity judgments in a yes/no recognition paradigm on odors that were either identical or different. The dependence of recognition performance upon the degree of qualitative similarity was assessed by using two sets of dissimilar odor pairs: slightly dissimilar pairs (S1) and very dissimilar pairs (S2). Performance in terms of correct judgments (hits, correct rejections) was rather good for identical pairs in both sets and was nearly perfect for very dissimilar pairs with a delay of 2-300 sec, suggesting no effect of time or similarity on performance. However, for slightly dissimilar pairs, false alarms increased in number, thereby indicating a dependence of the recognition score on the qualitative distance between odors. In addition, false alarms tended to increase with the lengthening of the retention interval. It was suggested that the subjects based their responses on their capability to detect differences between odors rather than recognizing their similarities. Correct identifications were thus preserved at the cost of increasing false alarms when the discrimination task was made more difficult by closer similarity between odors (S1) or by the fading of memory traces with time. Studying the congruence between the similarity judgments and the kind of evocations associated with paired odors gives some support to the view that recognition performances had some cognitive/semantic basis.

Odor discrimination and recognition memory as a

“…The decrease of false alarm scores with the increase in the number of familiarization sessions expresses the positive influence of familiarization on olfactory discrimination. Our false alarm data are in accord with those of a previous study (Jehl et al, 1994) showing that the production of false alarms is dependent on the qualitative proximity between odors to be compared.…”

“…An interval of 20 sec separated the presentation of two odors of a pair. The duration of this interval was thought to be adequate, since it was long enough to have the distractor not adversely modifi ed by sensory adaptation to the target and it was short enough to remain within the limits of short-term olfactory memo ry as previously explored (Jehl, Royet, & Holley, 1994). The presentation order of odor pairs was at random, but it was the same for all subjects.…”

A “Misfit” Theory of Spontaneous Conscious Odor Perception (MITSCOP): reflections on the role and function of odor memory in everyday life

“…It showed that the participants were significantly more certain of their correct rejections of the variants than of any of the other three possible responses (Hits and Misses: saying yes or no to the earlier experienced one; False alarms: saying yes to a variant). Support for the fact that novelty detection prevails over recollection comes also from the work of Jehl et al (1995), who showed that familiarization with odors did not affect the hit rate for these odors in a memory experiment, but significantly improved correct rejection of the distractors as shown in reduced false alarm rates. A similar support for novelty detection dominance was obtained in the interference experiments of Zucco (2003), who found that odor memory (in contrast to visual and auditory memory) was not affected by interference.…”

The functional profile of the human amygdala in affective processing: Insights from intracranial recordings

“…Authors considered unlikely any parasitic influence from sensory adaptation mechanisms (cf. Jehl, Royet, & Holley, 1994) but did not preclude the influence of attentional factors. These findings are in light of earlier iEEG evidence illustrating the amygdala to yield increased and statistically equal neural activity to initial odors and air (Halgren, Babb, & Crandall, 1977, Halgren, Babb, & Rausch, et al, 1977.…”