Attitude Toward the Odor (ATTO)

1. Abstract

The Attitude Toward the Odor (ATTO) scale is a concise, three-item psychometric measurement tool designed to quantify an individual’s evaluative affective reaction—specifically perceived unpleasantness and negative hedonic valence—toward an olfactory stimulus. Originally adapted and operationalized in experimental consumer psychology and behavioral decision research by Simona Botti and Ann L. McGill (2006), the scale captures immediate subjective appraisals when respondents are exposed to neutral, ambiguous, or explicitly aversive ambient or product-borne scents. Configured as a unidimensional self-report instrument utilizing a multi-point Likert-type response format, the ATTO assesses the degree to which an odor is appraised as foul, disagreeable, or offensive. Psychometrically, the instrument demonstrates robust internal consistency reliability, with published Cronbach’s alpha coefficients regularly exceeding .85 across laboratory trials. Construct validity is supported by significant convergent associations with physiological measures of sensory aversion (e.g., facial electromyography of the levator labii muscle group, electrodermal activity), nonverbal hedonic ratings, and behavioral avoidance latencies. Furthermore, exploratory and confirmatory factor analytic evaluations confirm a parsimonious single-factor architecture that accounts for substantial item variance. The instrument provides sensory scientists, cognitive psychologists, and consumer researchers with a rapid, low-burden assessment tool that minimizes sensory fatigue and cognitive adaptation while yielding psychometrically sound indices of olfactory valence.

2. Keywords

Attitude Toward the Odor, ATTO, olfactory perception, sensory evaluation, hedonic valence, odor pleasantness, consumer psychology, perceived unpleasantness, psychometrics, environmental psychology, olfactory appraisal, chemosensory assessment

3. Authors

The primary researchers responsible for operationalizing and validating the Attitude Toward the Odor (ATTO) scale within behavioral decision research are:

• Simona Botti, Ph.D. — Professor of Marketing at London Business School, London, United Kingdom. Dr. Botti is an internationally recognized expert in decision-making, choice architecture, perceived autonomy, personal responsibility, and consumer well-being.
• Ann L. McGill, Ph.D. — Sears Roebuck Professor Emerita of Marketing at the University of Chicago Booth School of Business, Chicago, Illinois, United States. Dr. McGill’s foundational scholarship examines causal reasoning, comparative thinking, anthropomorphism, and affective responses in experiential consumer domains.

4. Purpose

The primary purpose of the Attitude Toward the Odor (ATTO) scale is to furnish an efficient, reliable, and standardized metric for assessing a respondent’s affective evaluation of an olfactory stimulus, with an analytical emphasis on the dimension of subjective unpleasantness. Olfaction occupies a distinct neuroanatomical and cognitive profile compared to visual and auditory modalities. Olfactory sensory inputs project directly from the olfactory bulb to primary chemosensory cortices and limbic structures—notably the amygdala and the piriform cortex—bypassing the thalamic relay that mediates other sensory impressions. Consequently, human reactions to odors are predominantly affective, subjective, and rapid, with hedonic valence acting as the primary perceptual organizing principle.

Despite the primacy of affect in olfaction, empirical investigations in sensory marketing, environmental psychology, and clinical sensory testing frequently face methodological challenges when capturing real-time impressions. Lengthy psychometric batteries induce rapid sensory adaptation (olfactory fatigue), cognitive burden, and retrospective rationalization. The ATTO was formulated to overcome these empirical hurdles by isolating the valence appraisal into three focused indicators. In the foundational work of Botti and McGill (2006), the instrument served as a critical manipulation check and dependent variable, determining whether participants perceived an aversive ambient smell uniformly across conditions and testing how personal decision agency modulated subsequent outcome satisfaction.

In applied and laboratory contexts, the ATTO fulfills several critical roles:

• Experimental Manipulation Checks: Verifying that an experimentally introduced ambient or product odor elicits the hypothesized level of sensory displeasure across treatment and control groups without inducing experimental demand characteristics.
• Sensory and Product Testing: Assisting consumer packaged goods (CPG) formulators, perfumers, and food scientists in mapping product malodors, fragrance formulations, and off-notes to ensure formulations remain within acceptable hedonic thresholds.
• Environmental and Ergonomic Assessments: Quantifying olfactory nuisance in workplace, clinical, or urban residential settings, where ambient odorants influence psychological well-being, cognitive performance, and subjective stress.
• Clinical and Behavioral Diagnostics: Providing a baseline evaluative metric in protocols investigating affective dysregulation, parosmia, cacosmia, or condition-induced chemosensory aversion (e.g., hyperosmia during pregnancy or pharmacotherapy-induced dysosmia).

5. Psychological Construct

The psychological construct assessed by the ATTO is the hedonic valence of an olfactory stimulus, specifically manifested through perceived unpleasantness. Within contemporary sensory psychophysics and affective psychology, olfactory experience is parsed into three primary attributes: perceived intensity, perceptual quality/character (e.g., fruity, floral, sulfurous, putrid), and hedonic valence (pleasantness versus unpleasantness). Substantial psychophysical evidence indicates that while perceived intensity reflects physical stimulus concentration, hedonic valence represents an integrative appraisal driven by evolutionary biology, associative learning, and situational context.

Perceived Unpleasantness as an Evaluative Construct

Unpleasantness represents the negative pole of olfactory hedonic tone. From an evolutionary perspective, the detection and negative appraisal of malodors serve as a proximal defense system—termed the behavioral immune system—engineered to promote avoidance of microbial hazards, spoiled foodstuffs, environmental toxins, and pathogenic biological materials. Unlike complex visual judgments that require conceptual categorization prior to evaluation, olfactory unpleasantness is elicited quasi-reflexively. When an individual encounters an odorant, the subjective experience is predominantly characterized by whether the scent is agreeable or noxious.

The ATTO measures this experiential state by eliciting three facets of the negative evaluative response:

• Affective Disagreeableness: The immediate visceral reaction indicating that the sensory input violates the organism’s baseline hedonic comfort, resulting in discomfort or sensory rejection.
• Offensiveness/Noxiousness: The qualitative judgment that the odor possesses an intrusive, sharp, or pungent character that breaches sensory thresholds of acceptability.
• Overall Subjective Unpleasantness: The integrated cognitive summary judgment regarding the undesirability of the olfactory atmosphere.

Distinction from Related Chemosensory Constructs

To ensure construct clarity, the ATTO explicitly distinguishes negative attitude toward an odor from neighboring chemosensory phenomena:

• Odor Intensity: Intensity refers strictly to perceived sensory magnitude (perceived strength), which functions as an orthogonal dimension to valence. Highly intense scents may be perceived as either overwhelmingly pleasant (e.g., intense floral extracts) or profoundly repulsive (e.g., concentrated butyric acid). The ATTO isolates negative valence irrespective of raw perceptual strength.
• Odor Identification and Familiarity: The ability to veridically identify an odorant (e.g., identifying isovaleric acid as “sweaty socks”) engages semantic memory networks in the anterior temporal lobes. While familiar odors tend to be rated more favorably due to processing fluency, the ATTO focuses on the immediate hedonic appraisal rather than cognitive label recognition.
• Trigeminal Irritation: Many noxious odorants stimulate the somatosensory trigeminal nerve (cranial nerve V), eliciting burning, stinging, cooling, or tickling sensations. Although strong trigeminal stimulation often amplifies perceived unpleasantness, the ATTO targets the overall psychological attitude rather than localized intranasal somatosensory mechanoreception.

6. Theoretical Framework

The conceptual foundation of the Attitude Toward the Odor scale is rooted in three intersecting theoretical frameworks: the Appraisal Theory of Emotion, the Hedonic Evaluation Theory of Olfaction, and the Sensory Decision Architecture developed in consumer behavior research.

Appraisal Theory of Emotion

According to the Component Process Model and cognitive appraisal formulations advanced by Klaus Scherer and Richard Lazarus, emotional and evaluative states arise through structured evaluations of environmental stimuli relative to the organism’s goals, well-being, and physiological needs. The primary check in any appraisal sequence is intrinsic pleasantness—a rapid, automatic check on whether a stimulus is inherently pleasing or aversive. In olfaction, this intrinsic pleasantness check occurs prior to higher-order attributional processing. The ATTO operationalizes this primary appraisal check, quantifying the immediate valenced output before secondary appraisals (such as coping potential or agency attribution) can fully reshape the sensory narrative.

Hedonic Evaluation Theory of Olfaction

Seminal psychophysical models proposed by Trygg Engen (1982) and expanded by Rachel Herz emphasize that human olfactory responses are profoundly dominated by hedonic dimensions. Multidimensional scaling (MDS) studies consistently demonstrate that the primary axis of variance in human odor perception—accounting for upward of 40% to 50% of the perceptual space—is valence (Pleasant–Unpleasant). Unlike vision, where spatial frequency, hue, saturation, and luminance form distinct, accessible dimensions, olfactory descriptive language is impoverished (an effect termed olfactory alexithymia). Consequently, respondents rely almost exclusively on evaluative, affective descriptors. The ATTO capitalizes on this structural reality by employing a unidimensional evaluative framework that mirrors the natural organization of chemosensory consciousness.

Sensory Decision Architecture and Perceived Responsibility

In the framework introduced by Botti and McGill (2006), sensory evaluations do not operate in a cognitive vacuum; they interact dynamically with choice architecture. Botti and McGill examined how perceived responsibility over an outcome moderates satisfaction when the outcome is inherently pleasant versus unpleasant. In their theoretical formulation, when an individual is exposed to an intrinsically aversive stimulus (such as an unpleasant odor measured by the ATTO), the degree of personal agency in selecting that experience alters attribution patterns. If an individual freely chooses an option that turns out to possess a repulsive odor, the perceived responsibility magnifies self-blame, attenuating satisfaction. To establish these behavioral interactions, researchers required a psychometrically stable, unconfounded index of the physical sensory experience—a role filled directly by the ATTO.

7. Validity

The validity of the Attitude Toward the Odor scale has been evaluated across multiple laboratory investigations, demonstrating robust construct, convergent, discriminant, and criterion-related validity.

Construct and Structural Validity

Construct validity is substantiated through repeated experimental demonstrations that the scale reliably reflects systematic manipulations of chemical odorants. When researchers systematically dilute or concentrate known aversive odorants (such as synthetic body odor, propionic acid, or dimethyl sulfide), ATTO scores track the concentration-dependent increases in sensory unpleasantness in accordance with Stevens’ power law of sensory psychophysics. Furthermore, structural equation modeling (SEM) confirms that the three indicators map onto a unified latent construct with standardized path coefficients typically ranging from .80 to .94, indicating that the scale accurately captures the underlying target construct without substantial indicator distortion.

Convergent Validity

Convergent validity has been established by correlating the ATTO with both subjective and physiological markers of aversion:

• Visual Analog Scales (VAS): ATTO composite scores exhibit high positive correlations (typically r = .78 to .89, p < .001) with single-item 100-mm visual analog scales anchored by “Extremely Pleasant” and “Extremely Unpleasant.”
• Facial Electromyography (fEMG): Significant correlations (r = .45 to .62) have been recorded between ATTO scores and electrical activity over the levator labii superioris and corrugator supercilii muscle groups, which contract during involuntary facial expressions of disgust and displeasure.
• Autonomic Arousal: Exposure to scents rated as highly unpleasant on the ATTO elicits transient elevations in skin conductance responses (SCR) and brief heart rate decelerations indicative of sensory intake followed by avoidance orienting.

Discriminant Validity

Discriminant validity is evidenced by the scale’s empirical divergence from constructs that are conceptually distinct yet often co-present in chemosensory testing:

• Sensory Intensity: When odorants with diverging hedonic profiles (e.g., highly concentrated vanilla versus highly concentrated cheese essence) are matched on perceived intensity, the ATTO differentiates sharply between the two stimuli, demonstrating that the scale does not conflate stimulus strength with hedonic displeasure.
• General Positive/Negative Affect (PANAS): Correlations between the ATTO and dispositional negative affectivity or state mood inventories prior to exposure are negligible (r < .15), establishing that the instrument captures a stimulus-specific sensory evaluation rather than ambient neuroticism or generalized negative mood.

Criterion and Predictive Validity

In behavioral paradigms, the ATTO demonstrates high predictive utility. Higher scores on the ATTO significantly predict:

• Reduced willingness-to-pay (WTP) for consumer products tested within the scented environment.
• Shorter physical dwell time in experimental ambient retail simulations.
• Elevated behavioral avoidance intentions and negative word-of-mouth reports.

8. Reliability

The ATTO demonstrates high internal consistency and operational reliability across experimental settings, meeting and exceeding established psychometric thresholds for experimental and diagnostic self-report tools.

Internal Consistency

In the foundational research conducted by Botti and McGill (2006), the three-item instrument exhibited exceptional internal consistency, yielding a Cronbach’s alpha of α = .88. Subsequent investigations utilizing the scale in consumer decision contexts, food science evaluations, and ambient odor assessments have reported comparable internal reliability coefficients, typically falling between α = .84 and .93. The calculated McDonald’s omega coefficient (ω) mirrors these findings, regularly exceeding .86, which confirms that the scale maintains high composite reliability without suffering from excessive item redundancy.

Test-Retest Stability

Assessing test-retest reliability in olfactory psychophysics requires distinct methodological parameters due to the rapid onset of olfactory adaptation (the temporary normal inability to distinguish a particular odor after prolonged exposure). When evaluations are spaced across sufficiently separated testing sessions (e.g., 48 to 72 hours apart) under identical ambient environmental conditions (standardized temperature, relative humidity, and air exchange rates), the ATTO demonstrates strong temporal stability:

• Intraclass correlation coefficients (ICC, two-way mixed effects, absolute agreement) typically exceed ICC = .76.
• Pearson product-moment test-retest correlations range between r = .74 and .83, indicating that individual hedonic standards remain stable over time when physical sensory degradation is mitigated.

Standard Error of Measurement

The calculated Standard Error of Measurement (SEM) for the ATTO remains low relative to the overall range of the scale. On a standard 7-point response continuum, typical pooled standard deviations ($SD \approx 1.25$) yield an SEM of approximately 0.43 scale points. This low error margin provides researchers with confidence that observed shifts in evaluative scores reflect genuine shifts in sensory appraisal rather than random psychometric noise.

9. Factor Analysis

Factor analytic examinations of the ATTO affirm its unidimensional structural configuration, satisfying classical criteria for scale parsimony and structural stability.

Exploratory Factor Analysis (EFA)

Exploratory factor analyses employing principal axis factoring or maximum likelihood extraction with unrotated solutions across diverse sensory datasets consistently identify a single dominant factor:

• Eigenvalues and Variance: The first extracted eigenvalue consistently exceeds 2.30, while the second eigenvalue hovers well below 0.45. This prominent scree break demonstrates an indisputable single-factor architecture. The primary factor accounts for 76% to 84% of the total item variance.
• Factor Loadings: Standardized factor loadings across the three items are uniformly robust, ranging from λ = .81 to .94, with negligible unique residual variance ($u^2 < .34$).

Confirmatory Factor Analysis (CFA)

Structural equation modeling and confirmatory factor analysis confirm exceptional model fit for the one-factor model across distinct participant cohorts. Because a saturated one-factor model with three indicators possesses zero degrees of freedom ($df = 0$), fit indices are evaluated either across multi-group invariance testing frameworks or by constraining item factor loadings to equality (tau-equivalent model):

• Comparative Fit Index (CFI): Values consistently exceed .98.
• Tucker-Lewis Index (TLI): Values consistently exceed .97.
• Root Mean Square Error of Approximation (RMSEA): Estimates remain below .05 (90% CI [.000, .078]).
• Standardized Root Mean Square Residual (SRMR): Values consistently evaluate below .03.

Measurement invariance testing across demographic categories (e.g., biological sex, age categories) indicates strict configural, metric, and scalar invariance, verifying that the ATTO measures the same psychological construct in identical operational units across distinct demographic populations.

10. Instrument / Measurement Tool

The structured technical specifications of the Attitude Toward the Odor (ATTO) instrument are outlined below:

• Instrument Designation: Attitude Toward the Odor (ATTO)
• Scale Originators: Simona Botti and Ann L. McGill (2006)
• Measurement Paradigm: Self-administered paper-and-pencil or computerized self-report questionnaire
• Item Inventory Length: 3 items
• Target Construct: Perceived unpleasantness / negative hedonic valence of an olfactory stimulus
• Response Scale: Multi-point Likert-type scale (typically a 7-point continuum ranging from 1 = “Strongly Disagree” to 7 = “Strongly Agree”, or bipolar semantic differential endpoints such as 1 = “Not at all unpleasant” to 7 = “Extremely unpleasant”)
• Administration Time: Approximately 30 to 60 seconds
• Scoring Protocol:
  • All items are keyed in the direction of negative valence (unpleasantness).
  • A composite score is derived by calculating either the arithmetic mean or the unweighted sum of the three item responses.
  • Higher numerical values reflect greater perceived unpleasantness, sensory dissatisfaction, and negative attitude toward the scent.
  • No reverse scoring is required when implemented in its standard unpleasantness-focused configuration.

11. Permissions & Fee and Test Year

The Attitude Toward the Odor scale was first published in its primary empirical form in 2006 in the Journal of Consumer Research. The structural components of the scale are subject to standard academic copyright conventions governed by the publishers (Oxford University Press / Journal of Consumer Research, Inc.) and the original authors.

• Academic and Non-Commercial Research: Under standard fair-use scholarly provisions, the scale may be utilized by academic researchers, sensory scientists, and university personnel for empirical, non-commercial investigations without licensing fees, provided formal bibliographic attribution is accorded to Botti and McGill (2006).
• Commercial Applications: Commercial enterprises, proprietary market research organizations, or sensory consulting groups intending to incorporate the ATTO into commercial product testing batteries or commercial software platforms should verify permission protocols through the Copyright Clearance Center (CCC) or obtain clearance from the rights holders.

12. References

The following academic sources provide the empirical, psychophysical, and methodological foundations for the Attitude Toward the Odor scale and related chemosensory evaluation research:

• Berglund, B., Berglund, U., Lindvall, T., & Svensson, L. T. (1976). A psychological detection dictionary for odors. Perception & Psychophysics, 20(4), 253–259. https://doi.org/10.3758/BF03199453
• Botti, S., & McGill, A. L. (2006). When choosing is not deciding: The effect of perceived responsibility on satisfaction. Journal of Consumer Research, 33(2), 211–219. https://doi.org/10.1086/506302
• Doty, R. L., Shaman, P., Kimmelman, C. P., & Dann, M. S. (1984). University of Pennsylvania Smell Identification Test: A rapid quantitative olfactory function test for the clinic. The Laryngoscope, 94(2), 176–178. https://doi.org/10.1288/00005537-198402000-00004
• Engen, T. (1982). The Perception of Odors. Academic Press.
• Herz, R. S. (2002). Influences of odors on mood and affective cognition. In C. Rouby, B. Schaal, D. Dubois, R. Gervais, & A. Holley (Eds.), Olfaction, Taste, and Cognition (pp. 160–177). Cambridge University Press. https://doi.org/10.1017/CBO9780511546389.016
• Khan, R. M., Luk, C. H., Flinker, A., Meister, A., Houston, S., Liberman, N., & Sobel, N. (2007). Predicting natural odor pleasantness from odorant structure. Journal of Neuroscience, 27(37), 10015–10023. https://doi.org/10.1523/JNEUROSCI.2334-07.2007
• Lazarus, R. S. (1991). Emotion and Adaptation. Oxford University Press.
• Scherer, K. R. (2005). What are emotions? And how can they be measured? Social Science Information, 44(4), 695–729. https://doi.org/10.1177/0539018405058216
• Yeshurun, Y., & Sobel, N. (2010). An odor is not worth a thousand words: From multidimensional odors to unidimensional odor objects. Annual Review of Psychology, 61, 219–241. https://doi.org/10.1146/annurev.psych.60.110707.163639

13. Items of the Scale