Smell and taste function in the visually impaired

Surprisingly few quantitative studies have addressed the question of whether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outperform sighted subjects on a number of basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were administered the following olfactory and gustatory tests: the University of Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test; and a suprathreshold taste test in which measures of taste-quality identification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Philadelphia Water Department and trained to serve on its water quality evaluation panel. The primary findings of the study were that (a) the blind subjects did not outperform sighted subjects on any test of chemosensory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasantness ratings from the trained panel members than from the blind subjects, whose ratings did not differ significantly from those of the untrained sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a number of chemosensory tasks.     

An Exception to Mental Simulation: No Evidence for Embodied Odor Language

Do we mentally simulate olfactory information? We investigated mental simulation of odors and sounds in two experiments. Participants retained a word while they smelled an odor or heard a sound, then rated odor/sound intensity and recalled the word. Later odor/sound recognition was also tested, and pleasantness and familiarity judgments were collected. Word recall was slower when the sound and sound‐word mismatched (e.g., bee sound with the word typhoon). Sound recognition was higher when sounds were paired with a match or near‐match word (e.g., bee sound with bee or buzzer). This indicates sound‐words are mentally simulated. However, using the same paradigm no memory effects were observed for odor. Instead it appears odor‐words only affect lexical‐semantic representations, demonstrated by higher ratings of odor intensity and pleasantness when an odor was paired with a match or near‐match word (e.g., peach odor with peach or mango). These results suggest fundamental differences in how odor and sound‐words are represented.     

Familiarity,Cued and Free Odor Identification and Their Association with Cognitive Functioning in Middle Aged and Older Adults

ABSTRACT

The aim of the present study was to examine the association between familiarity of odors, cued and free odor identification performance and cognitive function in elderly adults. It was further investigated how age affects performance on the various odor tasks. A third aim was to investigate the role of familiarity in explaining performance on the free identification task. One hundred and thirty-six participants (aged 45–79 years) with normal olfactory sensitivity were assessed with the Scandinavian Odor Identification Test (SOIT) and standardized tests of cognitive function. Familiarity did not correlate with any measure of cognitive function, while verbal identification performance was associated with several cognitive measures, although correlations were modest. In this sample, free odor identification was affected by increasing age to a marginally larger extent than cued identification performance and familiarity ratings. The results suggest that the different olfactory tasks involve different levels of cognitive processing.     

年龄和性别对气味和词汇的语义识别的不同影响

本研究采用基于人口学特征的大规模取样, 通过线索气味识别测验和词汇测验考察了年龄和性别因素对嗅觉功能和语义知识的影响。1497位健康的成人(35岁~95岁)参与了气味识别和词汇熟练性测验。结果表明年龄对两项测验的成绩都有显著的负面影响, 尽管嗅觉测验的年龄效应更大。女性比男性识别出更多的气味且这种效应与年龄无关, 这进一步证实了先前的观察。本文详细讨论了这些发现的意义。     

Induced disgust affects implicit and explicit responses toward gay men and lesbians

In the current study, disgust was induced using a carefully controlled odor manipulation to observe its effect on participants' implicit and explicit responses to homosexuals. Participants were presented with a vial containing an odor that was described as “body odor” (n = 47) that induced a high level of disgust, or “parmesan cheese” (n = 43) that induced a moderate level of disgust, or an odor‐free vial (n = 53). Subsequently, participants viewed images of homosexual and heterosexual couples, and their viewing times and ratings of the images' pleasantness were recorded. Additionally, they completed a “feelings thermometer” task, the Attitudes Toward Lesbians and Gay Men scale that assessed feelings toward homosexuals, and the Three‐Domain Disgust Scale to measure sensitivity along three dimensions of disgust (pathogen, moral, and sexual). Results indicated that those in the body odor condition viewed images of gay (but not lesbian) couples for less time relative to images of heterosexual couples compared with participants in the other two conditions. With respect to explicit ratings, participants in the body odor condition reported colder feelings for gay relative to heterosexual men on the feelings thermometer compared with those in the no‐odor control condition. For pleasantness ratings, the odor manipulation served as a moderator, such that for those in the body odor condition only, higher sensitivity to sexual disgust predicted lower ratings for images of lesbian couples relative to straight couples. Thus, although induction of disgust biases implicit and explicit responses to gay couples, the degree to which this occurs for explicit ratings of lesbian couples depends on levels of sexual disgust. Copyright © 2013 John Wiley & Sons, Ltd.     

Odorous and pungent attributes of mixed and unmixed odorants

In order to explore functional properties of the olfactory and common chemical senses as well as their relation to the total nasal sensation experienced, various concentrations of two pungent odorants were presented alone and in the presence of different backgrounds of the other irritant. Stimuli comprised formaldehyde (at 1.0, 3.5, 6.9, and 16.7 ppm), ammonia (at 210, 776, 1,172, and 1,716 ppm), and their 16 possible binary mixtures. Subjects were asked to estimate the total nasal perceived intensity, and then to assess the olfactory (odor) and common chemical (pungency) attributes of the evoked sensations. The results showed that stimulus-response functions for pungency are steeper than those for odor. Furthermore, odor was always hypoadditive in mixtures (i.e., mixtures were perceived as less intense than the sum of their components), whereas pungency was, mainly, additive, and even suggested hyperadditivity. Total perceived intensity of the stimuli, alone and in mixtures, followed the stimulus-response patterns for pungency, which, therefore, emerged as the dominating attribute used by subjects in scaling the explored range of concentrations. The relationship between total nasal perceived intensity of the mixtures and that of their components reflected hypoaddition, resembling the outcome for the odor attribute.     

The nature and duration of adaptation following long-term odor exposure

Any individual living or working in an odorous environment can experience changes in odor perception, some of which are long lasting. Often, these individuals report a significant reduction in the perception of an odor following long-term exposure to that odor (adaptation). Yet, most experimental analyses of olfactory adaptation use brief odorant exposures which may not typify real-world experiences. Using a procedure combining long-term odor exposure in a naturalistic setting with psychophysical tests in the laboratory, we present evidence to show that reduced odor intensity following long-term exposure is accompanied by odorant-specific shifts in threshold. Subjects were exposed continuously to one of two odorants while in their home for a period of 2 weeks. Exposure produced an odorant-specific reduction in sensitivity and perceived intensity compared with preexposure baselines: Detection thresholds for the adapting odorant were elevated following exposure and perceived intensity ratings for weak concentrations were reduced. For most individuals, reduced sensitivity to the test odorant was still evident up to 2 weeks following the last exposure. The persistence of the change, as evidenced by the duration of recovery from adaptation, distinguishes this phenomenon from the adaptation seen following shorter exposures and highlights the need for the study of exposure durations that are more similar to real-world exposures.     

Paradoxical olfactory function in combat Veterans: The role of PTSD and odor factors

Stress- and trauma-related disorders, including posttraumatic stress disorder (PTSD), are characterized by an increased sensitivity to threat cues. Given that threat detection is a critical function of olfaction and that combat trauma is commonly associated with burning odors, we sought a better understanding of general olfactory function as well as response to specific trauma-related (i.e. burning) odors in combat-related PTSD. Trauma-exposed combat Veterans with (n = 22) and without (n = 25) PTSD were assessed for general and specific odor sensitivities using a variety of tools. Both groups had similar general odor detection thresholds. However, the combat Veterans with PTSD, compared to combat Veterans with comparable trauma exposure but without PTSD, had increased ratings of odor intensity, negative valence, and odor-triggered PTSD symptoms, along with a blunted heart rate in response to burning rubber odor. These findings are discussed within the context of healthy versus pathological changes in olfactory processing that occur over time after psychological trauma.     

Beyond intensity: Spectral features effectively predict music-induced subjective arousal

Emotions in music are conveyed by a variety of acoustic cues. Notably, the positive association between sound intensity and arousal has particular biological relevance. However, although amplitude normalization is a common procedure used to control for intensity in music psychology research, direct comparisons between emotional ratings of original and amplitude-normalized musical excerpts are lacking.

In this study, 30 nonmusicians retrospectively rated the subjective arousal and pleasantness induced by 84 six-second classical music excerpts, and an additional 30 nonmusicians rated the same excerpts normalized for amplitude. Following the cue-redundancy and Brunswik lens models of acoustic communication, we hypothesized that arousal and pleasantness ratings would be similar for both versions of the excerpts, and that arousal could be predicted effectively by other acoustic cues besides intensity.

Although the difference in mean arousal and pleasantness ratings between original and amplitude-normalized excerpts correlated significantly with the amplitude adjustment, ratings for both sets of excerpts were highly correlated and shared a similar range of values, thus validating the use of amplitude normalization in music emotion research. Two acoustic parameters, spectral flux and spectral entropy, accounted for 65% of the variance in arousal ratings for both sets, indicating that spectral features can effectively predict arousal. Additionally, we confirmed that amplitude-normalized excerpts were adequately matched for loudness. Overall, the results corroborate our hypotheses and support the cue-redundancy and Brunswik lens models.     

Invariance of odor strength with sniff vigor: an olfactory analogue to size constancy

Previous evidence has shown that detection threshold in humans and olfactory neural discharge rate in animal preparations both depend on flow rate of odorous vapor. But no data have been reported that show the effects of flow rate in humans on perceived odor strength at suprathreshold intensities. Subjects learned to inspire at two flow rates, one twice as great as the other, by adjusting (on a cathode ray tube) the transduced trace of a sniff-produced pressure change to match either of two target contours. They then made magnitude estimations of odor strength, while producing either weak or strong sniffs, for odorants presented over a wide range of concentrations via a specially designed sniff-bottle system. The odorant, diluted in diethyl phthalate, was n-butanol in two experiments and n-amyl acetate in two others. Subject-controlled flow rate had no effect on odor strength for either odorant. There was an apparent contradiction between these data and those on neural discharge rate that may, however, be resolved by adopting an odor constancy model: When sniff intensity varies during the olfactory exploration of an odor source, information about the rate at which odorant molecules are established at the receptor site is combined with information about sniff vigor so that the resulting percept is of invariant odor strength.     

Exploratory second-order analyses for components and factors

Abstract: Exploratory methods using second‐order components and second‐order common factors were proposed. The second‐order components were obtained from the resolution of the correlation matrix of obliquely rotated first‐order principal components. The standard errors of the estimates of the second‐order component loadings were derived from an augmented information matrix with restrictions for the loadings and associated parameters. The second‐order factor analysis proposed was similar to the classical method in that the factor correlations among the first‐order factors were further resolved by the exploratory method of factor analysis. However, in this paper the second‐order factor loadings were estimated by the generalized least squares using the asymptotic variance‐covariance matrix for the first‐order factor correlations. The asymptotic standard errors for the estimates of the second‐order factor loadings were also derived. A numerical example was presented with simulated results.     

Odors and the perception of hygiene

Although certain odors, such as lemon, are commonly associated with cleanliness and positive hygiene, empirical assessment of such associations for other odors and attributes is generally lacking. Moreover, differences between men and women in such associations have not been established. In this study of lemon, onion, pine, and smoke odors, ratings were obtained from 142 men and 336 women (M age= 30.1 yr., SD = 12.3) for odor intensity, gender association (masculine/feminine), and the success, sociability, intelligence, cleanliness, and attractiveness of a hypothetical person whose clothes smell like the odor in question. Ratings of the pleasantness or unpleasantness one would attribute to each odor in various rooms of the home were obtained, as well as a specification of whether such ratings are influenced by laundry habits, e.g., whether laundry is smelled before or after washing. Numerous associations were found. For example, a hypothetical person whose clothes smell of pine was rated as relatively more successful, intelligent, sociable, sanitary, and attractive than one whose clothes smelled of lemon, onion, or smoke. Sex differences, as well as differences between people who reported smelling their own laundry, were also found.     

Old-age deficits in the sense of smell as gauged by thresholds, magnitude matching, and odor identification

Twenty elderly subjects (70-90 years old) and 20 young control subjects (18-24 years old) underwent three kinds of olfactory testing: absolute thresholds to three odorants (d-limonene, iso-amyl butyrate, benzaldehyde), magnitude matching of these odorants to salt tastes, and odor identification of 30 common substances. For all three odorants elderly subjects' mean threshold significantly exceeded that of the young by about ninefold for d-limonene, about threefold for benzaldehyde, and about twofold for iso-amyl butyrate. These threshold differences predict approximate concentration differences necessary to arouse the same estimated odor strength above the threshold for the elderly and the young. Young subjects also scored better than the elderly in odor identification, even when subjects were given four alternatives from which to select the correct label. Unimpaired olfactory functioning is uncommon in the elderly; correlational tests show that as a group the young have better olfactory ability and show more interindividual uniformity.     

Physical effort biases the perceived pleasantness of neutral faces: A virtual reality study

The role of affective responses to effort in the regulation of physical activity behavior is widely accepted. Yet, to investigate these affective responses during physical activity, most studies used direct self-reported measures that are prone to biases (e.g., social desirability, ability to introspect). To reduce these biases, we used an indirect measure (i.e., an affect misattribution procedure) that assessed the implicit affective valence elicited by physical effort in 42 healthy young adults. Specifically, participants rated the pleasantness of neutral human faces presented in a virtual environment while cycling at different intensities. We used this rating as an indicator of implicit affective valence. Results showed that higher perceived effort was associated with lower pleasantness ratings of neutral faces, with this effect only emerging at moderate-to-high levels of perceived effort. Further analyses showed that higher actual effort was also associated with lower pleasantness ratings of neutral faces. Overall, these findings suggest that higher levels of perceived effort are associated with decreased affective valence during physical activity. Finally, this study presents a new indirect measure of affective valence during physical activity.     

Role of centrifugal projections to the olfactory bulb in olfactory processing

While there is evidence that feedback projections from cortical and neuromodulatory structures to the olfactory bulb are crucial for maintaining the oscillatory dynamics of olfactory bulb processing, it is not clear how changes in dynamics are related to odor perception. Using electrical lesions of the olfactory peduncle, sparing output from the olfactory bulb while decreasing feedback inputs to the olfactory bulb, we demonstrate here a role for feedback inputs to the olfactory bulb in the formation of odor-reward associations, but not for maintaining primary bulbar odor representations, as reflected by spontaneous odor discrimination.     

Attentional modulation of desensitization to odor

Subjective and behavioral responsiveness to odor diminishes during prolonged exposure. The precise mechanisms underlying olfactory desensitization are not fully understood, but previous studies indicate that the phenomenon may be modulated by central-cognitive processes. The present study investigated the effect of attention on perceived intensity during exposure to a pleasant odor. A within-subjects design was utilized with 19 participants attending 2 sessions. During each session, participants continuously rated their perceived intensity of a 10-minute exposure to a pleasant fragrance administered using an olfactometer. An auditory oddball task was implemented to manipulate the focus of attention in each session. Participants were instructed to either direct their attention toward the sounds, but still to rate odor, or to focus entirely on rating the odor. Analysis revealed three 50-second time windows with significantly lower mean intensity ratings during the distraction condition. Curve fitting of the data disclosed a linear function of desensitization in the focused attention condition compared with an exponential decay function during distraction condition, indicating an increased rate of initial desensitization when attention is distracted away from the odor. In the focused-attention condition, perceived intensity demonstrated a regular pattern of odor sensitivity occurring at approximately 1?2 minutes intervals following initial desensitization. Spectral analysis of low-frequency oscillations confirmed the presence of augmented spectral power in this frequency range during focused relative to distracted conditions. The findings demonstrate for the first time modulation of odor desensitization specifically by attentional factors, exemplifying the relevance of top-down control for ongoing perception of odor.     

An examination of relationships between the pleasantness,intensity, and concentration of 10 odorous stimuli

Relationships between physical concentration, perceived pleasantness, and perceived intensity were established by the method of magnitude estimation for 10 diverse chemical stimuli. Estimates of pleasantness significantly correlated with those of intensity for seven of the compounds examined. In all cases, the relationships between perceived intensity and physical concentration were described relatively well by power functions. However, this was not true for the pleasantness/concentration relationships. Intensity exponents correlated moderately with a number of common physicochemical parameters. Large differences were present between individual observer’s ratings of the perceived pleasantness of the odorants. These data indicate that the perceived pleasantness of some odorants may be systematically related to their perceived intensity, but do not support the notion that these dimensions are equivalent.

     

Measuring Competence and Dysfunction in Preschool Children: Source Agreement and Component Structure

Agreement between parents and teachers on ratings of three domains of behaviors exhibited by preschool children and the structural relations between these domains were measured. Parents and teachers rated the behaviors of a socioeconomically diverse sample of 610 children; ratings were obtained from parents at three time points and from teachers at two time points. The results indicated little agreement between sources on the ratings of individual child behaviors; however, ratings within a source were stable over time. Principal components analyses of source ratings combined and separately indicated virtually identical and independent three-component solutions comprised of a coping competence, externalizing behavior, and internalizing behavior component. These data suggest that competence and dysfunction develop in response to different contextual demands and underscore the importance of measuring each domain of behavior in clinical and research settings.