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The Color of Odors

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Abstract

The interaction between the vision of colors and odor determination is investigated through lexical analysis of experts' wine tasting comments. The analysis shows that the odors of a wine are, for the most part, represented by objects that have the color of the wine. The assumption of the existence of a perceptual illusion between odor and color is confirmed by a psychophysical experiment. A white wine artificially colored red with an odorless dye was olfactory described as a red wine by a panel of 54 tasters. Hence, because of the visual information, the tasters discounted the olfactory information. Together with recent psychophysical and neuroimaging data, our results suggest that the above perceptual illusion occurs during the verbalization phase of odor determination.

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... Visual input holds a strong influence over taste, providing information about food products (de Liz Pocztaruk et al., 2011) and serving as the first and preferred sensory modality for customers (Morrot et al., 2001;Wadhera and Capaldi-Phillips, 2014). In low luminescence conditions, consumers' ability to perceive visual inputs becomes impaired. ...
Atmospheric factors within a retail environment provide efficient and effective methods for influencing customer behavior. Drawing on the concept of sensory compensation, this research investigates how ambient lighting influences taste perceptions. Three studies demonstrate that dim lighting enhances taste perceptions. The results of Studies 1a and 1b provide support that low lighting positively influences consumers' perceived taste of single taste dimension foods (e.g., sweet). Study 2 shows the number of taste dimensions (e.g., sweet vs. sweet and salty) stimulated serves as a boundary condition, attenuating the significant effect of dim lighting on taste perceptions.
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Most new products and almost all new brands fail in-market and are withdrawn as commercial failures, with all that this implies in terms of lost opportunity and wasted resources. This chapter takes a detailed look at the role played by concepts in motivating human behavior in general and purchasing and consumption behavior in particular. In doing so, it explores the complex relationships that exist between concepts, emotions and affect. One of the key learnings to be drawn from this is the distinction that should (and must) be drawn between concepts that are strongly associated with the valence dimension of affect and those concepts that are associated with the orthogonal, non-valence dimensions of affect. A study is described that clearly differentiates and identifies these two concept types. Based on these learnings, two case studies involving major international brands are presented, that demonstrate the greatly enhanced efficacy of concept profiling when implemented using orthogonal, non-valence concept terms. In doing so concept profiling has finally lifted the veil on what lies beyond liking.
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Pinking is the term used for describing the pink colouration that appears in white wines produced under reducing conditions when oxidised. The ability to predict the susceptibility of white wines for pinking is of utmost importance for wine producers. In this work, we critically compare the two most currently used methods for measuring pinking susceptibility and the use of the first derivative spectra and the CIEL*a*b* colour space method. The amplitude of the first derivative spectra in the 450–550 nm range has a good correlation with the values obtained by subtracting the extrapolate background at 500 nm (R2 = 0.927); therefore, first derivative spectroscopy seems to be a more straightforward approach for eliminating the background problem that occurs in this method. The CIEL*a*b* method using the a* value after oxidation seems to be the most appropriate method to measure the pinking susceptibility of white wines, showing a very good correlation with the amplitude of the first derivative spectra. The pink colouration visualisation is linearly related to the b* value of the white wine, showing that no universal cut-off value for predicting the pink visualisation should be used. Second derivative spectra allow the observation of the formation of different chromophores in wines after induced oxidation.
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Reinert Max - "Lexical worlds" and their "logic" through the statistical study of a body of nightmare narratives. The French school of data analysis, strongly influenced during the seventies by the work of J.P. Benzecri, owes much to his interest in language data. The development of desk-top publishing and the spreading of texts thanks to computers have revitalized this line of research by what is usually called the "statistical analysis of textual data" (Lebart, Salem, 1988). In this article, the author presents his work and questions in the field : the Alceste method and the notion of lexical worlds (which are central to the proposed strategy). The presentation is backed up by a specific application: the analysis of a body of 212 accounts of nightmares.
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Similarity-scaling approaches and INDSCAL analysis were used to survey 1976 Bordeaux wines presented to trained assessors in four ways: (i) in clear (colourless) glasses with instructions to assess both appearance and aroma attributes; (ii) in clear glasses with instruction to assess aroma, ignoring visual cues; (iii) in clear glasses but under red illumination; and (iv) in coloured glasses, with instruction to assess similarities using aroma only. The results indicated that when instructed to ignore appearance, assessors as a whole succeeded in doing so, providing similar information to that which was obtained in red glasses or under red illumination. When differences in wines are assessed using both appearance and aroma, there is evidence to indicate that some aroma attributes are being assessed differently from when the assessors could not see the wine or were instructed to ignore its appearance.
Article
The colour of Moravian white wines was evaluated instrumentally, using the trichromatic method, and by sensory analysis. The odour and flavour acceptancies could be predicted very well on the basis of sensory colour evaluation, and less efficiently by instrumental method. Consumers preferred wines with prevailing yellow hue, which was associated with sweet, fruity and floral flavour notes. Green hue was considered a negative factor, without any rational relation to negatively perceived flavour notes. Logarithmic relations fit moderately better experimental results than linear relations.
Article
Olfactory lateralization in humans: a reviewIn the field of human perception, the chemical senses (taste and smell) have received little attention from neuroscience research when compared with auditory, visual and tactile senses. In the case of olfaction, it would appear that the publications over the last few years have been trying to overcome this lack of research. Many investigations have been carried out on lateralization, mainly in relation to specific pathologies (i.e., epilepsy, split-brain, lobotomy, etc.), while there have been few studies of healthy subjects. The results are often contradictory due particularly to special features of the olfactory system. However, consensus is emerging concerning, first, the fact that if both hemispheres are involved in the olfactory process, it is probable that one is more dominant than the other (many studies have revealed a greater impact on the right hemisphere in the treatment of olfactory information, but the dominance has not been clearly established). Second, the simple detection process would appear not to be lateralized whereas the higher-order olfactory tasks which involve memory processes and lexical aspects could be. The exact conditions governing lateralization still require more clarification by systematically taking into consideration the characteristics of the individual subjects, as well as those of the odorant stimuli and the test conditions. Finally, currently available techniques used in neurosciences and particularly cerebral imagery will contribute to a better understanding of the complexity of cerebral asymmetry in olfaction.
Article
The cerebral blood flow velocity (CBFV) in the basal arteries during a word-generation task was assessed by functional transcranial Doppler ultrasonography (fTCD) and by functional magnetic resonance imaging (fMRI). The study investigates how event-related CBFV modulations in the middle cerebral artery (MCA) relate to regional cerebral blood flow (rCBF) changes. Both fMRI and fTCD were used in 13 subjects (7 men, 6 women, aged 21 to 44 years). The maximum difference of relative CBFV changes between the left and right MCA during the word-generation task was used as the language laterality index (LIfTCD). For the fMRI examination during the nearly identical language task, the corresponding index was defined by LIfMRI = 100(NL − NR)/(NL + NR), where NL and NR refer to the numbers of voxels activated in the left and right hemisphere, respectively. The evoked CBFV changes expressed by LIfTCD and the corresponding laterality index, LIfMRI, estimated by fMRI showed a close linear relation (regression analysis: r = 0.95, p < 0.0001). The results of this study demonstrate that language-related velocity changes in the MCAs relate to rCBF increases in a linear fashion. Since the laterality indices assessed by fMRI and fTCD are in such close agreement both techniques can therefore be used in a complementary way.Keywords: Functional transcranial Doppler ultrasound; Evoked flow; Functional magnetic resonance imaging; Language
Article
The influence of color on flavor was investigated using 310 untrained volunteers who each judged the flavor of 1 of 8 beverages. Artificially flavored raspberry and orange beverages were either left uncolored, or colored red, orange, or green. Color had a significant influence on the identification of both flavors, although every combination of color and flavor was identified correctly beyond the level expected by chance. Performance was degraded equally when beverages were uncolored, and facilitated equally when beverages were appropriately colored. Unusual color-flavor combinations reduced the identification of raspberry flavor more than that of orange flavor. The influence of color was particularly salient because tasters were aware that the color of the beverage might be inappropriate to its flavor.
Article
Twenty-nine subjects judged the aroma, flavor and texture of five pairs of foods that were normally colored and either uncolored or inappropriately colored. Subjects were tested during conditions of hunger and satiation and approximately half of the subjects were blindfolded during both test sessions. The data revealed that, in general, appropriately colored foods were perceived to have a stronger intensity and better quality aroma and flavor. The effects of color were significant only for aroma judgments although the same trend was evident for flavor judgments. The state of hunger significantly influenced flavor but not aroma judgments but the pattern of changes did not appear to be related to food color. Judgments of texture quality were not affected by the experimental manipulations.
Article
The aim of this study was to link the effects of odorants with the emotional process, through autonomic nervous system (ANS) responses. Taking Ekman's data and our previous results into account, we tried to verify a possible evocation by odorants of some basic emotions, i.e. anger, fear, sadness, surprise, disgust and happiness. The question investigated was: would it be possible to associate any of these emotions with a pattern of autonomic responses? A total of 15 subjects inhaled five odorants: lavender, ethyl aceto acetate, camphor, acetic acid and butyric acid acting as olfactory stimuli. After inhaling the odorant, subjects were requested to fill out an 11-point hedonic scale to rate its `pleasantness' vs. `unpleasantness'. ANS parameters monitored were skin potential and resistance, skin blood flow and temperature, instantaneous respiratory frequency and instantaneous heart rate. Simultaneous recording of these six autonomic parameters permitted the analysis of phasic responses through specific ANS patterns. An analysis of variance made it possible to differentiate among the five odorants. Two-by-two odorant comparisons for autonomic responses using Tukey's HSD multiple comparison test only permitted differentiation between `pleasant' and `unpleasant' odors. Camphor was differentiated from both types. For instance, long duration responses were associated with `unpleasant' odors whereas camphor elicited intermediate responses. Taking into account each subject's preferential channel, it was possible to associate each ANS pattern with a basic emotion by means of a decision tree. The computation of subjects' responses made it possible to associate an odorant with a basic emotion, over the whole group: lavender elicited mostly `happiness', as did, to a lesser degree ethyl aceto acetate; camphor induced either `happiness', `surprise' or `sadness' according to subjects' past histories; butyric and acetic acids mainly induced negative emotions: `anger' and `disgust'. A high correlation was evidenced between subjects' hedonic evaluation and autonomic estimation of basic emotions. These results obtained from 15 subjects were compared to those observed in two similar experiments. These approaches showed comparable results. Thus, more than 60 subjects showed similar autonomic responses which can be transcribed into basic emotions. Thus, a multiparametric autonomic analysis allows the identification of the quality of the response, i.e. the type of basic emotion in addition to the intensity.
Article
The primary sensory tool for specifying the characteristics of a complex aroma, fragrance, flavor or other odorous mixture of volatiles is descriptive analysis. Descriptive analysis uses a trained panel to specify the intensities of specific attributes, based on a psychophysical model for intensity scaling. However, the use of descriptive techniques for complex and well-blended aromas gives rise to several problems. The psychophysical intensity model based upon independent odor notes may be a poor way to characterize odor experience, bringing into question whether descriptive analysis is an adequate tool for sensory analysis of complex smells. These problems include the following: (1) disagreement among experts in the most prominent odor notes of a single product and other individual differences problems, (2) a correspondence between similarity scaling and intensity scaling, (3) the substitution of applicability measures for intensity, (4) the need to use mid-tier, general odor terms for profiling complex fragrances, and (5) blending and integration effects. Data will be presented on citrus–woody mixtures showing that ratings of similarity and intensity are highly correlated, suggesting a common underlying process for both ratings. A related issue concerns whether odors and their mixtures are perceived as unitary or analyzable percepts. With these same stimuli, the perception of singularity vs. mixed-ness of stimuli is difficult to predict. Sensory scientists should question the validity of descriptive data for such stimuli and avoid the simplistic mistake of equating data with perception. The use of simple and apparently independent intensity scales may produce the illusion that the odor experience is a collection of independent analyzable “notes” when it is not. ©
Article
We investigated the hypothesis that physiological limitations restrict the ability of humans to identify components in an odour mixture. Subjects were trained to identify the test odours, and were required to detect a single highly familiar odorant in stimuli consisting of one, four, eight, twelve, and sixteen odorants by using a selective-attention procedure. The stimuli were delivered by a computer-controlled sixteen-channel air-dilution olfactometer which provided samples of each of the sixteen odorants to be of equal perceived intensity for each subject. Identification fell to chance level when sixteen odorants were present. It is proposed that the profound loss of information was primarily due to inhibition of olfactory receptor cells by the odorants through competitive mechanisms, and the subsequent loss of odour identity through changes in the spatial code that may be used to identify odorants.
In a paired-associate paradigm using odors as stimuli and pictures for multiple-choice responses, the first of two associations to an odor was retained far better than the second over a 2-week period. The persistence of first-learned associations may be responsible for the long lasting nature of odor memories. Subjects reported constructing mediational schemes for mnemonic devices to link the odors and pictures. Latencies for a task of naming odors indicated that although naming odors is difficult, labels could be generated sufficiently fast that they could be employed as mediators in the paired-associate task. A third task investigated the phenomenon of knowing that an odor was familiar but being unable to name it. Subjects in this tip-of-the-nose state were questioned about the odor quality and the name of the odor and were given hints about the name. These subjects were found to have information available about the odor quality but none for the name as found in the tip-of-the-tongue state. However, as in the tip-of-the-tongue phenomenon, hints given to the subjects in the tip-of-the-nose state often led to the correct name.
Article
The effects of color on odor identification were tested under color appropriate, inappropriate, and blindfolded conditions. Subjects made fewer errors in identifying solutions that were colored appropriately (e.g., red-cherry) than in either the blindfolded condition, where there were no color cues, or the inappropriate color condition (e.g., red-lemon). Identification accuracy was greatest for typical odor-color combinations (e.g., red-cherry) compared with appropriate but nontypical odor-color combinations (e.g., red-watermelon). Response latencies were fastest for odors in the appropriately colored solutions. Subjects also rated appropriate color-odor combinations as most pleasant. However, this effect is probably due to the increase in identification accuracy of the appropriately colored solutions. In all three conditions, correctly identified odors were liked more than odors that were not correctly identified. Thus, color is an important perceptual variable in odor identification because it biases subjects toward a color category that facilitates identification if the color is "correct". This ability to identify an odor in turn influences the affective response to the odor.
Article
In Experiment 1, some odorous solutions (e.g., strawberry) were rated as smelling stronger when colored (e.g., red) than when colorless. Experiment 2 showed this effect to be due to a perceptual change rather than a response to experimental demand characteristics. Experiment 3 showed that the color-induced increase in odor intensity is not due to subjects' preexperimental experience with particular color-odor combinations, because the increase occurred with novel ones. We conclude that color induces a weak olfactory percept that combines with odorant-induced percepts. The effect may be due to conditioning or may be the result of residual intersensory neural connections left over from infancy.
Article
The present experiments explore whether there may be some forms of implicit memory for odors. In the first experiment, the elaborateness of olfactory encoding was varied at presentation. For (explicit) recognition memory testing we found positive effects of labeling responses to odors at encoding. Implicit memory measures (temporal and preference judgments) did not reveal reliable effects of prior odor presentation, however. The second experiment corroborated effects of levels of processing on r recognition memory. Again, perceptual or affective judgments remained insensitive for prior odor exposures. Implicit memory could only be detected with verbal measures at the testing stage (labeling accuracy or latency). These results are consistent with the proposal that odor information is represented at different levels of processing that are even with implicit memory measures only partly accessible.
Article
Berglund, B., Berglund, U., Engen, T., & Ekman, G.1 Multidimensional analysis of twenty-one odors. Scand. J. Psychol., 1973, 14, 131–137.-The present paper reports an experiment on the application of multidimensional scaling to the sense of smell for the purpose of revealing basic psychophysical dimensions of odorants matched in perceived intensity and varying only in perceived quality. The results showed clear evidence for the existence of individual odor spaces, but in apparent contradiction to related studies in the literature individual differences were too large to establish a representative odor space for the whole group. For nearly all individual subjects one of the factors extracted seemed to represent a unique hedonic dimension apparently unrelated to the physical attributes of the odorants. It is suggested that such psychological factors may be as important a basis for the judgment of the similarity of odors as the physical attributes of the odorants. Both the interpretation of multidimensional analysis and the extent to which the sense of smell is analytic or synthetic depend on an understanding of this problem.
Article
Retinal projections to several telencephalic structures have been demonstrated in a wide range of mammalian species following intraocular injections of tritiated amino acids and cholera toxin subunit-B conjugated to horseradish peroxidase. Since these regions are also innervated by olfactory fibers, we investigated the distribution of convergent projections using simultaneous injections of different anterograde tracers in the eye and olfactory bulbs. Convergent projections from the retina and from the olfactory bulbs were observed in the piriform cortex, olfactory tubercle, the cortical region of the medial amygdala, lateral hypothalamus, and the bed nucleus of the stria terminalis. A few retinal fibers also invade the nucleus of the lateral olfactory tract, the bed nucleus of the accessory olfactory bulb and the diagonal band of Broca. Injections of retrograde tracers in the medial amygdala, the bed nucleus or the lateral hypothalamus shows that the visuo-olfactory convergence mainly involves projections originating from the accessory olfactory bulb, and to a lesser extent from the ventromedial region of the main olfactory bulb. Fewer than 20 retinotelencephalic ganglion cells were identified in the retina, mainly located contralateral to the injection site. Ganglion cells were medium sized and possessed two long slender opposing dendrites. These retinal and olfactory projections could provide an anatomical substrate for the modulation of gonadotropin hormone levels and the olfactory influence on light mediated rhythms related to reproductive physiology.
Article
This study examined whether a previously established (D. G. Laing & G. W. Francis, 1989) limited capacity to discriminate and identify the components of olfactory mixtures resulted from the participants' lack of familiarity with the task, training designed to optimize cognitive and perceptual performance, or professional experience in odor discrimination. The participants were a trained panel of 10 women (23-43 years old), and an expert panel of 8 male professional perfumers and flavorists (25-55 years old). The individual chemical stimuli were 7 common dissimilar odorants of equal moderate intensity. An air dilution olfactometer delivered a single odorant or a mixture containing up to 5 odorants. The results indicated that for both panels only 3 or 4 components of a complex mixture could be discriminated and identified and that this capacity could not be increased by training. Therefore, the limit may be imposed physiologically or by processing constraints.
Article
We previously found that untrained subjects make nonrandom color matches to odors and that the color matches are stable over time (Gilbert, Martin, & Kemp, 1996). Here we investigate further aspects of the cross-modal associations between vision and olfaction: whether perceptual dimensions of odor vary systemically with those of vision. Subjects matched Munsell color chips to five odors presented at three concentrations; they also rated odor intensity. Significant negative correlations between Munsell value and perceived odor intensity were found for three odors. The results suggest that stronger odors were associated with darker colors. The cross-modal relationship between vision and olfaction appears to be dimensional: Color lightness varies inversely with perceived odor intensity. This finding parallels the dimensional relations found between other modalities (e.g., lightness varies with loudness).
Article
The study aimed to re-investigate differences in olfactory thresholds and odor discrimination between the left and right sides in relation to the handedness of healthy subjects. Twenty left- and 20 right-handers participated; all were in excellent health with no indication of any major nasal or health problems, and all were non-smokers. The two groups were comparable in terms of sex and age (left-handers: 11 women, 9 men, median age 25 years; right-handers: 9 women, 11 men, median age 26 years). Odor thresholds did not differ in relation to handedness. However, in the odor discrimination task the left-handers performed significantly better at the left side compared with the right nostril; this pattern was reversed in the right-handers. The data indicate that, similar to other sensory systems, higher olfactory functions exhibit a certain degree of lateralization.
Article
The colour of Moravian white wines was evaluated instrumentally, using the trichromatic method, and by sensory analysis. The odour and flavour acceptances could be predicted very well on the basis of sensory colour evaluation, and less efficiently by instrumental method. Consumers preferred wines with prevailing yellow hue, which was associated with sweet, fruity and floral flavour notes. Green hue was considered a negative factor, without any rational relation to negatively perceived flavour notes. Logarithmic relations fit moderately better experimental results than linear relations.
Article
To test the claim that odors are the 'best' cues to memory, several cross-modal experiments were conducted in which odors were compared with verbal, visual, tactile and musical stimuli as associated memory cues. Each experiment comprised two sessions (encoding and retrieval) separated by 48 hr. At the encoding session, a series of stimuli were incidentally associated to a set of emotionally arousing pictures. At the retrieval session, memory accuracy and emotionality were assessed. Across experiments, results revealed that odors were equivalent to other stimuli in their ability to elicit accurate recall, but that odor-evoked memories were always more emotional. Notably, emotional responses did not vary as a function of stimulus type at encoding. These data indicate that emotional saliency, rather than accuracy, is responsible for the impression that odors are superior reminders, and that retrieval processes (cf. encoding processes) are responsible for the distinctive emotionality of odor-evoked memories.
Article
In previous positron emission tomography (PET) studies we have shown significant regional cerebral blood flow (rCBF) increases during olfactory stimulation: unilaterally in the right orbitofrontal cortex, and bilaterally in the inferior frontal and temporal lobes (piriform cortex). In the present study we investigated brain function during different stages of olfactory memory processing. Subjects were scanned during four tasks: odor encoding, long-term odor recognition, short-term odor recognition and a no-odor sensorimotor control task. Subjects were 12 right-handed healthy volunteers (6 men, 6 women). Each subject underwent a training session four days prior to their PET scan to learn the six odors required for the long-term memory scan. PET scans were obtained with a Siemens Exact ECAT HR+ 3D system using H2(15)O methodology and 60-sec scanning intervals. PET images were coregistered with each subject's magnetic resonance imaging scan, averaged, and transformed into standard stereotaxic space. Paired image subtractions were analyzed for rCBF changes. Preliminary analyses have revealed significant activation of the right orbitofrontal region and bilateral piriform cortices during the long-term odor recognition task compared with the control task. Activation of the right piriform cortex was present during the short-term recognition task. Brain activity during encoding and retrieval tasks also involved prefrontal cortices. PET activation studies of memory in other modalities have led to hypotheses of a hemispheric encoding/retrieval asymmetry in frontal cortex; the generalizability of this theory to olfactory memory will be discussed.
Article
The objective of this study was to demonstrate hemispheric language dominance in normal children. Fifteen normal children were evaluated with functional magnetic resonance imaging (MRI) using an age-related silent word spelling paradigm. The data were analyzed with the cross-correlation method, and lateralization indices were calculated in language regions as determined by Talairach coordinates. Activation foci were detected in the left inferior frontal area and were strongly lateralized, with language lateralization indices of 0.74 +/- 0.21 (age 7-12 years, nine subjects), and 0.79 +/- 0.18 (13-18 years, six subjects). The indices were similar to those for adults (0.83 +/- 0.21, four subjects). Our study established that language is strongly lateralized to the left hemisphere in children as young as 7 years of age.
Article
The study of hemispheric asymmetry in olfaction in human subjects has given rise to many publications, but the findings have often been contradictory. This study used bilateral electrodermal activity recordings with unilateral stimulation as a measure of functional hemispheric asymmetry. A specific odorant (lavender) was used by monorhinic (single nostril) stimulation on 30 dextral subjects (20 females and 10 males). Intraindividually, the results showed no difference between the two nostrils, but all subjects exhibited a constant direction of electrodermal asymmetry: 20 subjects systematically showed a greater response amplitude for the right hand and 10 subjects systematically showed a greater response amplitude for the left hand, whatever hemisphere stimulated.
Article
The discriminatory capacity of the mammalian olfactory system is such that thousands of volatile chemicals are perceived as having distinct odors. Here we used a combination of calcium imaging and single-cell RT-PCR to identify odorant receptors (ORs) for odorants with related structures but varied odors. We found that one OR recognizes multiple odorants and that one odorant is recognized by multiple ORs, but that different odorants are recognized by different combinations of ORs. Thus, the olfactory system uses a combinatorial receptor coding scheme to encode odor identities. Our studies also indicate that slight alterations in an odorant, or a change in its concentration, can change its "code," potentially explaining how such changes can alter perceived odor quality.
Article
We tested the ability of human subjects to distinguish between members of homologous series of aliphatic alcohols (ethanol to n-octanol) and aldehydes (n-butanal to n-decanal). In a forced-choice triangular test procedure 20 subjects per series were repeatedly presented with all 21 binary combinations of the seven stimuli and asked to identify the bottle containing the odd stimulus. We found (i) that as a group, the subjects performed significantly above chance level in all tasks but two with the alcohols and all tasks but four with the aldehydes, and thus were clearly able to discriminate between most of the odor pairs presented; (ii) marked interindividual differences in discrimination performance, ranging from subjects who were able to significantly distinguish between all 21 odor pairs of a series to subjects who failed to do so with the majority of tasks; and (iii) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length for both homologous series. This suggests that carbon chain length may be one of presumably several determinants of the interaction between stimulus molecule and receptor, and thus may be a molecular property affecting odor quality of aliphatic alcohols and aldehydes.
Article
In the field of human perception, the chemical senses (taste and smell) have received little attention from neuroscience research when compared with auditory, visual and tactile senses. In the case of olfaction, it would appear that the publications over the last few years have been trying to overcome this lack of research. Many investigations have been carried out on lateralization, mainly in relation to specific pathologies (i.e., epilepsy, split-brain, lobotomy, etc.), while there have been few studies of healthy subjects. The results are often contradictory due particularly to special features of the olfactory system. However, consensus is emerging concerning, first, the fact that if both hemispheres are involved in the olfactory process, it is probable that one is more dominant than the other (many studies have revealed a greater impact on the right hemisphere in the treatment of olfactory information, but the dominance has not been clearly established). Second, the simple detection process would appear not to be lateralized whereas the higher-order olfactory tasks which involve memory processes and lexical aspects could be. The exact conditions governing lateralization still require more clarification by systematically taking into consideration the characteristics of the individual subjects, as well as those of the odorant stimuli and the test conditions. Finally, currently available techniques used in neurosciences and particularly cerebral imagery will contribute to a better understanding of the complexity of cerebral asymmetry in olfaction.