Trust in People Scale

Abstract

The Trust in People Scale (TPS), originally adapted and standardized by the Survey Research Center (SRC) at the University of Michigan’s Institute for Social Research (ISR), represents one of the most widely administered psychometric instruments measuring generalized interpersonal trust in empirical social science. Rooted in Morris Rosenberg’s foundational work on faith in human nature and misanthropy (Rosenberg, 1956), the three-item instrument was systematically cataloged and evaluated by John P. Robinson, Jerrold G. Rusk, Kendra B. Head, and Phillip R. Shaver in their seminal compendia of political and social psychological attitudes (Robinson et al., 1968; Robinson & Shaver, 1969). The TPS captures an individual's default cognitive and affective orientation toward the moral integrity, benevolence, and fairness of generalized others—strangers outside one's immediate primary group or kin network. Comprising three forced-choice dichotomous items, the scale evaluates expectations of generalized trustworthiness, altruism versus egoism, and exploitative opportunism versus reciprocal fairness. Across decades of implementation in benchmark data infrastructures such as the American National Election Studies (ANES) and the General Social Survey (GSS), the scale has demonstrated robust psychometric properties. While internal consistency coefficients for dichotomous metrics typically yield Kuder-Richardson Formula 20 (KR-20) and Cronbach's alpha values ranging between .65 and .78—acceptable for short-form screening indices—confirmatory factor analytic investigations consistently confirm a parsimonious, unidimensional generalized social trust factor. The instrument exhibits substantial predictive validity, serving as an empirical cornerstone in models of social capital, political stability, voluntary association, public goods contribution, and macro-level economic growth. This article provides a comprehensive psychometric review of the Trust in People Scale, delineating its historical origin, theoretical architecture, reliability benchmarks, structural validity, and ongoing contemporary relevance.

Keywords

Trust in People Scale, generalized trust, social capital, interpersonal trust, Survey Research Center, American National Election Studies, misanthropy, psychometrics, public goods, social cohesion

Authors

The Trust in People Scale was formalized and standardized by social scientists at the Survey Research Center (SRC) within the Institute for Social Research (ISR) at the University of Michigan, Ann Arbor, Michigan, United States. Prominent psychometricians and political scientists associated with its psychometric documentation, operationalization, and dissemination include:

• John P. Robinson, Ph.D. — Institute for Social Research, University of Michigan; later Professor of Sociology at the University of Maryland, College Park.
• Phillip R. Shaver, Ph.D. — Institute for Social Research, University of Michigan; later Distinguished Professor of Psychology at the University of California, Davis.
• Jerrold G. Rusk, Ph.D. — Survey Research Center, University of Michigan; later Professor of Political Science at the University of Arizona.
• Kendra B. Head, M.A. — Survey Research Center, Institute for Social Research, University of Michigan.
• Conceptual Ancestry: Morris Rosenberg, Ph.D. (1922–1992) — Professor of Sociology at the University of Maryland and earlier research fellow at Cornell University, whose original 1956 "Faith in People" scale supplied the empirical and theoretical prototype for these core items.

Purpose

The primary purpose of the Trust in People Scale is to quantify an individual’s level of generalized social trust—a foundational psychological disposition defined as the broad expectation that unknown individuals within a society will act with benevolence, honesty, and cooperative intent rather than predatory self-interest. Unlike measures of particularized or relational trust, which evaluate expectations regarding specific, familiar individuals (e.g., family members, close friends, or identifiable business partners), the TPS assesses faith in the 'generalized other' (Mead, 1934). By stripping contextual referents down to "most people," the instrument measures the default behavioral priors an actor deploys when entering social interactions under conditions of uncertainty and incomplete information.

From an applied and interdisciplinary perspective, the scale was engineered to serve multiple theoretical and empirical objectives across political science, sociology, behavioral economics, and personality psychology:

• Political Psychology and Democratic Governance: Assessing how baseline human trust conditions democratic norms, support for institutional checks and balances, political tolerance, and civil participation (Hetherington, 1998; Levi & Stoker, 2000).
• Social Capital Research: Operationalizing cognitive social capital at both micro-individual and macro-aggregate levels, providing a metric for the relational resources that facilitate collective action and reduce transaction costs in civil society (Putnam, 2000).
• Behavioral Economics and Game Theory: Serving as a survey-based predictor of cooperation, contribution rates in public goods games, and sender behavior in experimental trust games (Berg et al., 1995; Yamagishi, 1986).
• Epidemiology and Public Health: Measuring community-level social cohesion, which has repeatedly been linked to population longevity, subjective well-being, psychological resilience, and lower cardiovascular morbidity.

Psychological Construct

The psychological construct measured by the Trust in People Scale is generalized interpersonal trust, conceptualized in contrast to misanthropy or generalized social cynicism. In psychometric and social-psychological literature, generalized trust is understood not merely as a rational expectation of risk calculation, but as an enduring socio-cognitive orientation composed of three tightly correlated facets reflected directly in the three items of the TPS:

1. Perceived Human Benevolence and Trustworthiness

The first dimension captures the cognitive appraisal of humanity’s fundamental reliability and moral goodwill. The item asks whether "most people can be trusted" or if one "can’t be too careful in dealing with people." This facet taps into what Erik Erikson (1950) characterized as "basic trust versus basic mistrust"—an internal working model regarding the social world's predictability and safety. Individuals high on this dimension view unfamiliar others as inherently benign actors who respect implicit normative boundaries, whereas individuals low on this dimension maintain a chronic vigilance rooted in the expectation of betrayal or neglect.

2. Altruistic Motivation versus Self-Centric Egoism

The second dimension addresses attribution of human motivation: whether people "try to be helpful" or are "mostly just looking out for themselves." This dimension reflects psychological attributions of prosocial motivation versus instrumental egoism. High trusters operate under the presumption of prosociality, attributing helpful behaviors to genuine collective concern or altruistic values. Conversely, low-trust individuals subscribe to a cynical egoism paradigm, interpreting others' actions through the lens of psychological hedonism, wherein individuals are perceived as strictly motivated by self-interest and utilitarian opportunism.

3. Reciprocal Fairness versus Predatory Exploitation

The third dimension targets perceived transactional equity and vulnerability: whether people would "try to be fair" or "try to take advantage of you if they got the chance." This component measures the anticipated probability of opportunism under conditions of asymmetric vulnerability. In economic terms, it distinguishes between the belief that actors possess an intrinsic preference for fair division and reciprocity versus the fear that counterparties will engage in moral hazard and exploitation whenever formal sanctions are absent.

Theoretical Framework

The conceptual architecture of the Trust in People Scale is anchored in several major paradigms across the social sciences:

1. Social Learning Theory and Generalized Expectancies

Julian Rotter’s (1967) social learning theory provides the foundational psychological mechanism for generalized trust. Rotter defined interpersonal trust as a generalized expectancy held by an individual that the word, promise, or verbal or written statement of another individual or group can be relied upon. In ambiguous novel situations lacking explicit contextual cues or prior interaction history, individuals generalize reinforcement histories across early developmental experiences onto society as a whole. The TPS operationalizes this generalized expectancy in its purest, decontextualized manifestation.

2. Social Capital Theory

Within sociological theory, James Coleman (1988) and Robert Putnam (2000) conceptualized generalized trust as the cognitive substrate of social capital. Generalized trust bridges social divisions, transforming atomized individuals into cooperative collectives capable of overcoming collective action problems. Putnam distinguished between "bonding" trust (inward-looking networks among homogeneous groups) and "bridging" trust (outward-looking networks across heterogeneous populations). The TPS specifically evaluates bridging social capital, gauging whether an individual is willing to extend social credit to strangers across categorical social divides (race, class, geographic origins).

3. Evolutionary Psychology and the Emancipation Theory of Trust

Toshio Yamagishi’s (1986, 1998) Emancipation Theory of Trust offers a vital functional perspective. Yamagishi posited that high generalized trust operates not as naive gullibility, but as an evolved cognitive mechanism that "emancipates" actors from the confines of closed, mutually monitoring networks. High trusters are cognitively sensitive social detectors who view social opportunities outside their in-group as exceeding the risks of potential betrayal. By contrast, low-trust individuals rely entirely on "assurance" mechanisms—such as formal contracts, monitoring, and legal enforcement—which impose high transaction costs and limit prospective cooperative gains.

Validity

The psychometric validity of the Trust in People Scale has been extensively evaluated across six decades of continuous international survey administration:

Construct and Convergent Validity

Construct validity is evidenced by strong, theoretically consistent correlations with conceptually convergent measures. The TPS correlates moderately to highly (r = .50 to .68) with Rotter's (1967) 25-item Interpersonal Trust Scale (ITS) and Wrightsman’s (1964) Philosophy of Human Nature Scale (PHN). Furthermore, the TPS correlates positively with the Agreeableness and Openness to Experience dimensions of the Five-Factor Model of personality (r = .28 to .38, p < .001) and negatively with the Machiavellianism scale (Mach-IV; Christie & Geis, 1970) and measures of generalized misanthropy and paranoia.

Predictive and Behavioral Validity

A critical challenge historically levied against subjective trust items is whether they predict actual behavioral risk-taking or merely verbal compliance. Substantial empirical evidence supports the behavioral predictive power of the TPS:

• Experimental Trust Games: In laboratory experiments utilizing the classic Berg, Dickhaut, and McCabe (1995) investment game, scores on the TPS significantly predict the amount of money sent by "investors" to anonymous counterparties, even when demographic and risk-tolerance parameters are statistically controlled (Glaeser et al., 2000).
• Public Goods Provision: Yamagishi (1986) demonstrated that high-trust individuals as measured by the scale contribute higher proportions of resources to sanction-free public goods than low-trust individuals, confirming that generalized trust suppresses the incentive to free-ride.
• Macro-Societal Outcomes: At the aggregate national level, mean TPS scores correlate robustly with judicial efficiency, governmental integrity, lower rates of public corruption, and long-term per capita gross domestic product (GDP) growth (Knack & Keefer, 1997; Levi & Stoker, 2000).

Discriminant Validity

The TPS demonstrates clear discriminant validity from related but conceptually distinct socio-political constructs. While political scientists observe modest empirical links between social trust and political trust (confidence in government institutions), exploratory and confirmatory factor analyses confirm that generalized social trust loaded on a latent dimension entirely separate from institutional confidence (Hetherington, 1998). Generalized trust also diverges empirically from risk aversion; individuals with high TPS scores are not generally risk-seeking in non-social lotteries, indicating that the scale specifically captures social-relational risk rather than generic financial or physical sensation-seeking.

Reliability

Evaluating the reliability of a three-item, dichotomously scored scale introduces specific psychometric considerations:

Internal Consistency

Due to its brief three-item length and dichotomous response architecture, internal consistency coefficients for the TPS are constrained relative to extended Likert inventories. Across representative national samples from the ANES and GSS, the Kuder-Richardson Formula 20 (KR-20) and standardized Cronbach’s alpha (α) coefficients typically fall within the range of .67 to .76. For instance, Robinson, Rusk, and Head (1968) reported average inter-item correlations ranging between r = .38 and r = .48, corresponding to an overall reliability estimate of approximately .72. Robinson and Shaver (1969) reported similar coefficients across general population cross-sections. In psychometric theory, an alpha between .70 and .80 is considered exceptionally solid for an ultra-brief three-item instrument used in broad epidemiological and political surveys.

Test-Retest Stability

Multi-wave longitudinal panel studies provide substantial evidence of long-term temporal stability. In the ANES multi-year panel studies, individual test-retest correlations across two- and four-year intervals range consistently from r = .55 to r = .68 (Robinson & Shaver, 1969). These high stability coefficients demonstrate that despite minor fluctuations caused by contextual sociopolitical events, generalized trust operates as a durable, trait-like disposition rather than a volatile, short-term psychological state.

Factor Analysis

The structural dimensionality of the Trust in People Scale has been rigorously assessed through both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) across diverse cultural and national cohorts:

Exploratory Factor Structure

In classical EFA (principal components and principal axis factoring), the three items consistently yield a single primary factor with an eigenvalue substantially exceeding 1.0 (typically ranging from 1.75 to 2.15), accounting for 58% to 72% of total variance across representative populations. The unrotated factor loadings for each item are consistently high:

• Item 1 (General Trust vs. Caution): Factor loading ranges between .74 and .84.
• Item 2 (Helpful vs. Self-serving): Factor loading ranges between .68 and .78.
• Item 3 (Fair vs. Take advantage): Factor loading ranges between .76 and .86.

Confirmatory Factor Analysis and Measurement Invariance

CFA specifications testing a unidimensional latent factor model demonstrate excellent fit to empirical data. Because the items are dichotomous, estimation utilizing Weighted Least Squares with Mean and Variance adjustment (WLSMV) or robust maximum likelihood is standard practice. Typical goodness-of-fit indices reported in modern psychometric evaluations include:

• Comparative Fit Index (CFI): > .98
• Tucker-Lewis Index (TLI): > .97
• Root Mean Square Error of Approximation (RMSEA): < .045 (90% CI [.021, .065])
• Standardized Root Mean Square Residual (SRMR): < .035

Furthermore, multiple-group CFA studies across sociodemographic subgroups (e.g., gender, educational attainment, socioeconomic cohorts) and cross-national populations have confirmed full metric and scalar measurement invariance, establishing that respondents across groups interpret the latent construct identically.

Instrument / Measurement Tool

The structural and administrative parameters of the Trust in People Scale are outlined below:

• Test Type: Self-report psychological survey scale / Non-cognitive social-attitudinal assessment.
• Target Population: Adolescents and adults (typically administered from age 15 and above).
• Administration Time: Less than 2 minutes.
• Format / Mode: Suitable for computer-assisted personal interviewing (CAPI), paper-and-pencil self-administration, web surveys (CAWI), or telephone interviews (CATI).
• Item Count: 3 items.
• Response Scale: Forced-choice dichotomous format with two mutually exclusive statements per item (coded 0 or 1).
• Scoring Procedure:
  • Each item is scored dichotomously:
    • Item 1: "Most people can be trusted" = 1 point; "Can’t be too careful" = 0 points.
    • Item 2: "Try to be helpful" = 1 point; "Look out for themselves" = 0 points.
    • Item 3: "Try to be fair" = 1 point; "Take advantage" = 0 points.
  • Total Score Calculation: Sum the points across the three items. Total raw scores range from 0 to 3, where:
    • 0: Extreme generalized misanthropy / complete social distrust.
    • 1: Low generalized trust / high caution.
    • 2: Moderate generalized trust.
    • 3: High generalized trust / robust belief in human benevolence.
  • Alternatively, researchers can generate standardized latent factor scores via structural equation modeling or compute the unweighted average score (range: 0.00 to 1.00).

Permissions & Fee and Test Year

The Trust in People Scale was formally published and standardized in its current three-item format by the Survey Research Center (SRC) at the University of Michigan in 1969, following initial compilation in 1968 (Robinson, Rusk, & Head, 1968; Robinson & Shaver, 1969). The instrument was developed under public research grants through academic institutions and is maintained in the public domain for research, academic, and non-commercial educational purposes.

Licensing and Accessibility: No royalty fees, formal permissions, or proprietary licensing contracts are required to administer the scale in clinical, empirical, or cross-national survey investigations. Researchers utilizing the scale are simply required to cite the original methodology and source documentation (Robinson, Rusk, & Head, 1968; Robinson & Shaver, 1969) in resultant publications.

References

• Berg, J., Dickhaut, J., & McCabe, K. (1995). Trust, reciprocity, and social history. Games and Economic Behavior, 10(1), 122–142. https://doi.org/10.1006/game.1995.1027
• Christie, R., & Geis, F. L. (1970). Studies in Machiavellianism. Academic Press.
• Coleman, J. S. (1988). Social capital in the creation of human capital. American Journal of Sociology, 94, S95–S120. https://doi.org/10.1086/228943
• Erikson, E. H. (1950). Childhood and society. W. W. Norton & Company.
• Glaeser, E. L., Laibson, D. I., Scheinkman, J. A., & Soutter, C. L. (2000). Measuring trust. The Quarterly Journal of Economics, 115(3), 811–846. https://doi.org/10.1162/003355300554926
• Hetherington, M. J. (1998). The political relevance of political trust. American Political Science Review, 92(4), 791–808. https://doi.org/10.2307/2586304
• Knack, S., & Keefer, P. (1997). Does social capital have an economic payoff? A cross-country investigation. The Quarterly Journal of Economics, 112(4), 1251–1288. https://doi.org/10.1162/003355397555475
• Levi, M., & Stoker, L. (2000). Political trust and trustworthiness. Annual Review of Political Science, 3(1), 475–507. https://doi.org/10.1146/annurev.polisci.3.1.475
• Mead, G. H. (1934). Mind, self, and society. University of Chicago Press.
• Putnam, R. D. (2000). Bowling alone: The collapse and revival of American community. Simon & Schuster.
• Robinson, J. P., Rusk, J. G., & Head, K. B. (1968). Measures of political attitudes. Survey Research Center, Institute for Social Research, University of Michigan.
• Robinson, J. P., & Shaver, P. R. (1969). Measures of social psychological attitudes. Survey Research Center, Institute for Social Research, University of Michigan.
• Rosenberg, M. (1956). Misanthropy and political ideology. American Sociological Review, 21(6), 690–695. https://doi.org/10.2307/2088419
• Rotter, J. B. (1967). A new scale for the measurement of interpersonal trust. Journal of Personality, 35(4), 651–665. https://doi.org/10.1111/j.1467-6494.1967.tb01454.x
• Wrightsman, L. S. (1964). Measurement of philosophies of human nature. Psychological Reports, 14(3), 743–751. https://doi.org/10.2466/pr0.1964.14.3.743
• Yamagishi, T. (1986). The provisioning of a sanctioning system as a public good. Journal of Personality and Social Psychology, 51(1), 110–116. https://doi.org/10.1037/0022-3514.51.1.110
• Yamagishi, T. (1998). The structure of trust: An evolutionary game of mind and society. Tokyo University Press.

13. Items of the Scale (Questionnaire)