Beyond this, more general principles of object categorization may be applied to odor perception. The act or process of smelling. Ashby
2000): In 4 studies, participants received 6 microencapsulated odorants and were asked to describe each odor with only 1 attribute from an 11-item list. . Classification studies have strongly focused on the number and character of perceptual dimensions and thus mainly applied PCA, EFA, or MDS on their data. Lundstrom
The entire list of interference factors is impossible to consider, but odor researchers are asked to both choose the very limited number of test odors thoroughly and to control for biases—not primarily to fully eliminate them, but to improve the understanding and valid interpretation of outcomes (Lawless and Heymann 2010). For 10 odors, significant differences in familiarity ratings were found between both groups. New data for assessing observer metamerism, The use of exploratory factor analysis and principal components analysis in communication research. . 1999; Conway and Huffcutt 2003; Costello and Osborne 2005). Thus, when people are unable to identify an odor, they normally express their olfactory perceptions by experiences they have gained with it: places or situations (“Christmas”), activities (“cleaning,” “baking”), effects (“relaxing”), or—on the most basic level—hedonic ratings (“pleasant”) (Schleidt et al. Sobel
Experience has been shown to influence quality perception by providing facts on the identity, function, or effect of an odor. EV
Out of 175 different descriptors, the vast majority pointed to odor sources (84.3%), 8.4% represented sense-specific qualities (fragrant, aromatic, rancid), and 6.7% described nonolfactory percepts (dry, heavy, sweet); 1 descriptor referred to pleasantness, 1 to an odor effect (full list is available from first author).
One reason for preferring PCA over EFA may be to determine the position of odors in an olfactory space in addition to identifying its relevant dimensions. C
However, one should not simply assume 1) that olfactory perceptions are generally stable over time, 2) that different people perceive identical odorants in the same way, and 3) that different … HR
n 1. the sense of smell 2. the act or function of smelling n. 1. the act of smelling. Although similarity ratings had been collected from odor experts, the appropriateness of these labels remains questionable. C
An odor or odour is a chemical dissolved in air, generally at a very low concentration, which we perceive by the sense of olfaction.Odors are also called smells, which can refer to both pleasant and unpleasant odors.In contrast, stench and stink are used specifically to describe an unpleasant odor. They rather allow panelists to apply an individual definition of relevant quality features. Hummel
In addition to the direct impact of labels’ odor quality, numerous studies have confirmed an effect of verbal information on hedonic ratings (Moskowitz 1979; Lorig and Roberts 1990; Distel and Hudson 2001; Herz and von Clef 2001; Herz 2003; Lundström et al. S
Chrea et al. Gilbert
. NLM (2000) reviewed a large body of research and reported that many of the proposed perception-based classification systems are vague or even contradictory. 2004, 2005), whereas those by odor professionals have usually not applied pleasantness as comparison criterion (Ennis et al.
Beyond that, experts have only rarely stated pleasantness as substantial perceptual quality of odors, whereas studies with nonprofessionals have almost always yielded a hedonic dimension.
However, both approaches are based on distinct mathematical assumptions even though often yield fairly similar results.
Although Chastrette (2002) assumed a high-dimensional olfactory space, most of the reviewed studies reported between 2 and 4 perceptual dimensions. P
Hence, it remains largely unknown how exactly each odor has been characterized and by whom. Robinson
Evidence for this assumption has been provided by the results of nonverbal classification studies: All but one of the reviewed studies that applied pairwise similarity ratings revealed a primary pleasantness dimension, whereas verbal methods found a hedonic factor considerably less frequent.
Elderly subjects might be excluded from classification studies to reduce the impact of physiological impairments. In summary, olfactory ratings appear to be stable over short periods of time. They established an extensive data set based on 307 test odors and 30 standards that has been reanalyzed by several researchers (Ennis et al.
These results suggest that humans prefer the smells they have frequently experienced due to their culture-specific eating habits and hence demonstrate a substantial impact of cultural experience on perceptual ratings of odors.
Odor profiles have usually been developed by odor professionals and contain verbal descriptions for hundreds or thousands of odors.
Even though the study was conducted with 7 perfumers, the panel “disagreed significantly on the odor profile of certain odorants” (Boelens and Haring 1981). Pleasantness may have also been introduced to classification systems by researcher expectations. Despite these measures, expectations remain a central issue of most classification studies: Especially the search for a pleasantness factor has considerably affected numerous odor arrangements. Amoore (1967, 1977) assumed an increased detection threshold for specific odorants along with otherwise normal olfactory sensitivity as indication for the malfunction of a particular receptor type. Odor classification: a review of factors influencing perception-based odor arrangements. (2012) reported that within-individual variability does not increase with longer time intervals. However, other studies reported differences in verbal ratings of experts and laymen and indicated that linguistic expressions of odor perceptions are inconsistent: 1) When compared with laymen, experts use further and more specific descriptors to verbalize their perceptions (Lawless 1984; Solomon 1990, 1997).
However, as the organization of this space is under investigation, the matter of representativeness is vague and classification studies have dealt differently with this issue: Several studies of the works we reviewed did not report selection criteria at all (Wright and Michels 1964; Woskow 1968; Jeltema and Southwick 1986; Stevens and O’Connell 1996; Dalton et al.
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