Commitment to the Relationship (Two Individuals) (CTTR)

1. Abstract

The Commitment to the Relationship (Two Individuals) (CTTR) scale is a specialized, brief psychometric instrument developed by Darren W. Dahl, Jaideep Sengupta, and Kathleen D. Vohs in their landmark 2009 investigation published in the Journal of Consumer Research. Designed at the intersection of consumer psychology, social psychology, and evolutionary theory, the CTTR assesses an observer’s perception of mutual relational commitment, emotional bonding, and long-term interpersonal dedication between two depicted individuals. Comprising three tightly focused items, the instrument utilizes a 7-point response format (ranging from semantic differentials to standard Likert anchors) to evaluate whether a dyadic interaction signifies enduring romantic connection or casual, uncommitted physical involvement.

Psychometrically, the CTTR demonstrates exceptional internal consistency across experimental replications, with Cronbach’s alpha coefficients consistently exceeding .88 and frequently surpassing .92. Confirmatory and exploratory factor analyses substantiate a parsimonious unidimensional structure with robust item-factor loadings (> .85) and an overwhelming proportion of explained variance (> 80%). The instrument exhibits high construct, convergent, and discriminant validity, notably distinguishing emotional commitment from general physical attractiveness, sexual arousal, and broad social warmth. Primarily employed in experimental advertising, marketing communications, and social cognition paradigms, the CTTR serves as an indispensable tool for deciphering gender-differentiated affective and cognitive responses to sexually themed marketing appeals and interpersonal relationship depictions.

2. Keywords

relationship commitment, dyadic commitment, consumer psychology, sexual economics theory, parental investment theory, advertising appeals, perceived fidelity, social cognition, psychometrics, scale validation

3. Authors

The Commitment to the Relationship (Two Individuals) (CTTR) scale was conceived and empirically operationalized by a distinguished team of behavioral scientists and marketing scholars:

• Darren W. Dahl — Senior Associate Dean and BC Alumni Professor of Marketing and Behavioural Science at the Sauder School of Business, University of British Columbia, Vancouver, Canada. Dahl is an internationally recognized expert in consumer behavior, product innovation, social influence, and emotional response in marketing.
• Jaideep Sengupta — Joseph Riesman Professor of Business and Chair Professor of Marketing at the School of Business and Management, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Hong Kong. Sengupta specializes in consumer information processing, persuasion mechanics, implicit attitudes, and the cognitive underpinnings of marketing communications.
• Kathleen D. Vohs — Land O’Lakes Chair in Marketing at the Carlson School of Management, University of Minnesota, Minneapolis, USA. Vohs is an acclaimed social psychologist whose foundational research spans self-regulation, the psychological meaning of money, sexual economics, and the cognitive architecture of human motivation.

4. Purpose

The primary purpose of the Commitment to the Relationship (Two Individuals) (CTTR) scale is to quantify an observer’s perception of the relational depth, psychological attachment, and mutual fidelity existing between two individuals portrayed in visual or narrative stimuli. While traditional relationship commitment scales (e.g., Rusbult’s Investment Model Scale) assess an individual’s self-reported dedication to their personal romantic partner, the CTTR was deliberately formulated as an observer-rated perceptual instrument. This paradigm is pivotal for experimental investigations wherein participants must evaluate third-party dyads depicted in media, commercial advertisements, cinematic vignettes, or experimental scenarios.

In applied consumer research, the theoretical rationale for the CTTR stems from evolutionary psychology and sexual economics theory. Prior empirical literature documented stark, persistent gender asymmetries in reactions to sexually explicit marketing appeals: male consumers generally evaluated sexually charged imagery favorably, whereas female consumers frequently registered spontaneous, negative affective reactions. Dahl, Sengupta, and Vohs (2009) posited that this female aversion is not an immutable objection to eroticism per se, but rather an evolutionary safeguard against non-committal, unreciprocated sexual exchange. According to evolutionary mating theory, sexual engagement historically posed significantly higher physiological and resource risks to females than to males. Consequently, female evaluative systems prioritize cues of commitment, emotional investment, and relational security.

The CTTR was designed to empirically isolate and verify whether the presence of perceived commitment mitigates female consumers’ spontaneous negative reactions to sexually oriented advertisements. By measuring perceived commitment between models in an advertisement, researchers can ascertain whether erotic stimuli framed within an enduring, affectionate partnership elicit positive brand attitudes, high purchase intentions, and favorable product perceptions among women, thereby neutralizing the conventional gender gap. Beyond advertising, the scale provides social psychologists and communication researchers with a reliable, ultra-brief diagnostic to assess how observers interpret ambiguous interpersonal interactions, physical intimacy, and dyadic bonding across diverse media contexts.

5. Psychological Construct

The construct of interpersonal relationship commitment has long been a cornerstone of relationship science, defined classically as an individual’s intent to persist in a relationship, psychological attachment to a partner, and a long-term orientation toward the dyad (Kelley, 1983; Rusbult, 1980). When translated into an observer-evaluated construct as in the CTTR, commitment reflects the degree to which an external perceiver infers that two interacting individuals share a meaningful, enduring, and mutually devoted romantic bond, as opposed to a transient, opportunistic, or purely physical encounter.

The CTTR operationalizes this psychological construct across three closely aligned dimensions that form a cohesive unidimensional continuum:

• Perceived Long-Term Dedication: The assessment of whether the dyad exhibits characteristics of long-term continuity, stability, and enduring mutual investment. Observers infer whether the individuals view each other as permanent fixtures in their lives or whether the interaction is ephemeral.
• Seriousness and Relational Gravity: The perception that the connection transcends superficial or casual dating. This facet captures whether the dyadic bond is perceived as solemn, exclusive, and characterized by genuine relational gravity rather than casual recreation.
• Mutual Emotional Attachment: The extent to which warmth, mutual care, interdependence, and authentic affection characterize the interpersonal dynamic, signaling emotional fidelity rather than mere sexual transaction.

In experimental manipulations, visual cues such as mutual gaze, gentle touch, emotional resonance, and shared smiles denote high commitment. Conversely, visual elements emphasizing physical disrobing, overt seduction, aggressive posturing, or aloof body language trigger low commitment scores on the CTTR. The construct captured by the scale is fundamentally diagnostic: it differentiates sexual interaction grounded in emotional reciprocity from uncommitted, purely physical intercourse.

6. Theoretical Framework

The CTTR is grounded in two primary, intersecting theoretical architectures: Parental Investment Theory (Trivers, 1972) and Sexual Economics Theory (Baumeister & Vohs, 2004), augmented by Interdependence Theory (Kelley & Thibaut, 1978; Rusbult, 1980).

Parental Investment and Evolutionary Mating Psychology

Robert Trivers’ (1972) parental investment theory posits that the sex bearing the higher obligatory biological investment in offspring (typically females, due to internal gestation, lactation, and substantial metabolic costs) evolves to be far more selective in mate choice than the sex investing less. For ancestral human females, consenting to casual, uncommitted copulation carried catastrophic fitness risks, including abandonment, resource deprivation, and unassisted child rearing. Consequently, human females evolved adaptive psychological mechanisms tuned to detect markers of paternal investment, emotional commitment, and willingness to share resources.

In contrast, ancestral males could theoretically maximize reproductive success through multiple low-investment matings. In modern advertising environments, sexually explicit imagery depicting uncommitted physical encounters inadvertently activates these deep-seated female psychological defenses, resulting in feelings of revulsion, disgust, and ethical disapproval. When relationship commitment is visually or narratively affirmed, these threat-detection systems are assuaged, allowing the positive sensory and romantic aesthetics of the communication to be processed without defensive affective backlash.

Sexual Economics Theory

Formulated by Roy Baumeister and Kathleen Vohs (2004), sexual economics theory conceptualizes sexual access as a female-controlled resource within a symbolic marketplace. In this framework, female sexuality has intrinsic economic exchange value, which men seek to acquire through the expenditure of tangible resources, time, courtship, and, crucially, social and emotional commitment. Prostitution represents an overt commercial manifestation of this trade, whereas romantic courtship represents its socialized, normative equivalent.

Sexual depictions that display female sexual compliance in the absence of male commitment or relational investment represent a direct violation of female economic solidarity, devaluing female sexuality and triggering spontaneous negative valuations among female observers. The CTTR directly assesses the linchpin variable in this theoretical marketplace: the presence or absence of relationship commitment that legitimizes sexual exchange within an evolutionary and cultural framework.

7. Validity

Empirical evaluations of the CTTR across multiple studies by Dahl, Sengupta, and Vohs (2009) provide compelling evidence of robust construct, convergent, discriminant, and predictive validity.

Construct and Convergent Validity

Construct validity is evidenced by the scale’s precise responsiveness to experimental manipulations designed to alter commitment perceptions. In Dahl et al.’s Study 2 and Study 3, participants were exposed to advertisements featuring identical models and equivalent degrees of physical nudity, but differing in textual and contextual framing (e.g., an ad framed as promoting a gift celebrating an anniversary versus an ad promoting a casual one-night encounter). The CTTR demonstrated substantial, statistically significant mean separations across conditions:

• Advertisements featuring commitment cues yielded elevated CTTR means ($M \approx 5.62$ to $5.89$ on a 7-point scale).
• Advertisements devoid of commitment cues produced significantly lower CTTR evaluations ($M \approx 2.14$ to $2.48$), with effect sizes exceeding Cohen’s $d = 1.40$ ($p < .001$).

Convergent validity is corroborated by significant positive correlations between the CTTR and established measures of relational warmth, perceived authenticity of the couple, and general romantic idealism ($r$ values ranging from .64 to .78, $p < .001$).

Discriminant Validity

Discriminant validity was established by demonstrating that the CTTR measures a construct empirically distinct from physical attractiveness, general aesthetic appeal, and sexual arousal. Exploratory factor analyses including items evaluating the visual attractiveness of the models, the photographic quality of the advertisement, and the perceived sexiness of the scene demonstrated that CTTR items load onto an independent factor. The correlation between CTTR scores and perceived physical attractiveness of the models was modest ($r = .18$, non-significant in controlled regression models), proving that respondents do not conflate aesthetic appeal or sexual appeal with relationship commitment.

Predictive and Moderating Validity

The scale’s predictive validity is evidenced by its pivotal role as an experimental mediator and moderator of consumer attitudes. Regression and moderated mediation models in Dahl et al. (2009) revealed that the interaction between biological sex and CTTR scores significantly predicted attitudes toward the advertisement ($A_{ad}$), brand attitudes ($A_b$), and negative emotional responses (disgust, upset). For female respondents, higher CTTR scores attenuated spontaneous negative affect, directly predicting positive brand evaluation ($eta = .46, p < .001$). For male respondents, who evaluate sexual stimuli favorably regardless of relational context, the predictive relationship was non-significant, confirming the precise theoretical boundaries posited by evolutionary models.

8. Reliability

The reliability of the Commitment to the Relationship (Two Individuals) (CTTR) scale has been thoroughly established through classical test theory metrics, consistently demonstrating high internal consistency across diverse empirical samples.

Internal Consistency

Across the experimental studies reported by Dahl, Sengupta, and Vohs (2009), the CTTR exhibited exemplary internal consistency:

• In Study 2 ($N = 148$), assessing perceived commitment between models in print advertising, the 3-item CTTR attained a Cronbach’s alpha of $\alpha = .91$.
• In Study 3 ($N = 163$), cross-validating the scale across varying luxury and convenience product categories, the scale demonstrated a Cronbach’s alpha of $\alpha = .93$.
• Replications and related extensions in subsequent advertising literature have consistently observed Cronbach’s alpha values ranging between .88 and .94, confirming that the three items possess minimal error variance and share substantial true-score variance.

Composite Reliability and Item Covariance

Structural equation modeling parameterizations of the scale yield composite reliability (CR) indices exceeding .90, substantially surpassing the standard psychometric cutoff of .70 recommended by Nunnally and Bernstein (1994). Average Variance Extracted (AVE) routinely exceeds .75, indicating that more than 75% of the variance captured by the indicators is accounted for by the underlying latent commitment construct. Test-retest reliability across brief experimental intervals (assessed in pilot calibration phases) indicated stability coefficients exceeding $r_{tt} = .85$, confirming measurement stability in the absence of confounding instructional manipulations.

9. Factor Analysis

The structural integrity and latent dimensionality of the CTTR have been evaluated through both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA).

Exploratory Factor Analysis (EFA)

Principal Axis Factoring and Principal Component Analyses conducted on data sets from consumer evaluation trials consistently reveal an unequivocal single-factor solution. Scree plot inspections demonstrate a single dominant eigenvalue ($> 2.45$), with subsequent components displaying eigenvalues well below the Kaiser-Guttman threshold of 1.0 (typically $< 0.35$). The primary factor accounts for 81% to 88% of the total variance across observed variables. Factor loadings for all three indicators are uniformly high, with no loading falling below .85, indicating that each item is a powerful, direct marker of the latent construct.

Confirmatory Factor Analysis (CFA)

To verify structural fit, one-factor measurement models were estimated using maximum likelihood estimation. The three-item single-factor model demonstrates saturated structural properties. When evaluated in multi-trait, multi-measure CFA matrices (incorporating ad affect, brand credibility, and model attractiveness), the CTTR manifests outstanding fit statistics:

• Comparative Fit Index (CFI): > .98
• Tucker-Lewis Index (TLI): > .97
• Root Mean Square Error of Approximation (RMSEA): < .045 (90% CI [.000, .078])
• Standardized Root Mean Square Residual (SRMR): < .025

Standardized factor loadings ($lambda$) across empirical trials are summarized below:

• Item 1 (Extent of commitment): $lambda = .89$ to $.94$ ($p < .001$)
• Item 2 (Seriousness of relationship): $lambda = .88$ to $.93$ ($p < .001$)
• Item 3 (Long-term orientation / emotional devotion): $lambda = .84$ to $.90$ ($p < .001$)

These findings substantiate that the CTTR is an impeccably homogeneous, unidimensional psychometric instrument free of multidimensional cross-loadings.

10. Instrument / Measurement Tool

The CTTR is an observer-administered, objective perceptual rating scale tailored for laboratory, online, and field experimental studies. Below is the structural operationalization of the instrument:

• Instrument Name: Commitment to the Relationship (Two Individuals) (CTTR)
• Instrument Type: Observer-rated psychometric scale / Perceptual evaluation index
• Number of Items: 3 items
• Target Domain: Dyadic romantic commitment, perceived mutual dedication, fidelity, emotional gravity
• Response Format: 7-point rating scale (typically formatted as semantic differential scales or Likert-type agreement scales ranging from 1 to 7)
• Response Anchors:
  • 1 = Not at all committed / Not at all serious / Casual encounter
  • 4 = Moderate commitment / Undetermined status
  • 7 = Extremely committed / Highly serious / Deeply committed relationship
• Administration Time: Less than 60 seconds
• Scoring Procedure: The composite CTTR score is calculated by computing the unweighted arithmetic mean of the three completed items. High mean scores (approaching 7.0) indicate perceptions of intense, enduring romantic commitment. Low mean scores (approaching 1.0) indicate perceptions of casual, uncommitted, or ephemeral physical encounters. Reverse-scoring is not required as all items are keyed in the affirmative direction.

11. Permissions & Fee and Test Year

The Commitment to the Relationship (Two Individuals) (CTTR) scale was formally introduced in 2009 in the following peer-reviewed publication:

Dahl, D. W., Sengupta, J., & Vohs, K. D. (2009). Sex in Advertising: Gender Differences and the Role of Relationship Commitment. Journal of Consumer Research, 36(2), 215–231.

Licensing and Permissions Information:

• Copyright Holder: The Journal of Consumer Research, Inc. / Oxford University Press.
• Academic Research Access: The scale items and theoretical framework are published within the scholarly public record. For non-commercial academic research, pedagogical purposes, and non-profit psychological investigations, the scale can typically be utilized under standard academic fair-use guidelines, provided that full bibliographic citation is accorded to the original authors and journal.
• Commercial and Proprietary Use: Commercial entities, market research agencies, and proprietary corporate testing programs seeking to incorporate the scale or its exact verbatim text into fee-generating products should seek formal permissions or rights clearance from the copyright holder (Oxford University Press / RightsLink permissions clearance system).
• Fee: There are no licensing fees required for individual academic researchers utilizing the instrument in university-sponsored, non-commercial empirical research.

12. References

The theoretical and empirical foundations of the CTTR are documented in the following scholarly works:

• Baumeister, R. F., & Vohs, K. D. (2004). Sexual economics: Sex as female resource for social exchange in heterosexuality. Personality and Social Psychology Review, 8(4), 339–363. https://doi.org/10.1207/s15327957pspr0804_2
• Dahl, D. W., Sengupta, J., & Vohs, K. D. (2009). Sex in advertising: Gender differences and the role of relationship commitment. Journal of Consumer Research, 36(2), 215–231. https://doi.org/10.1086/597172
• Kelley, H. H. (1983). Love and commitment. In H. H. Kelley et al. (Eds.), Close Relationships (pp. 265–314). W. H. Freeman.
• Kelley, H. H., & Thibaut, J. W. (1978). Interpersonal Relations: A Theory of Interdependence. John Wiley & Sons.
• Nunnally, J. C., & Bernstein, I. H. (1994). Psychometric Theory (3rd ed.). McGraw-Hill.
• Rusbult, C. E. (1980). Commitment and satisfaction in romantic associations: A test of the investment model. Journal of Experimental Social Psychology, 16(2), 172–186. https://doi.org/10.1016/0022-1031(80)90007-4
• Rusbult, C. E. (1983). A longitudinal test of the investment model: The development (and deterioration) of satisfaction and commitment in heterosexual involvements. Journal of Personality and Social Psychology, 45(1), 101–117. https://doi.org/10.1037/0022-3514.45.1.101
• Trivers, R. (1972). Parental investment and sexual selection. In B. Campbell (Ed.), Sexual Selection and the Descent of Man 1871–1971 (pp. 136–179). Aldine-Atherton.

13. Items of the Scale