Everyday Lies in Close and Casual Relationships

DePaulo and Kashy (1998) used a week-long diary methodology with 77 undergraduates and 70 community members to examine how relationship closeness shapes both the frequency and character of everyday lying. The study found that people tell significantly fewer lies per social interaction to those with whom they share greater emotional closeness, with subjective emotional closeness emerging as the dominant predictor over relationship duration or interaction frequency. Altruistic (other-oriented) lies were disproportionately more common in close relationships, while lies told to closer partners were also more likely to be discovered and more emotionally distressing to the liar.

Two-sample diary study in which 147 total participants (77 undergraduates and 70 community members) recorded all social interactions and lies daily for seven days, with relationship closeness operationalized via subjective ratings, duration, and interaction frequency analyzed using multilevel two-step regression.

This foundational study addressed how relationship closeness shapes deceptive behavior by having participants record all social interactions and lies for one week. Using both college student and community samples, researchers operationalized closeness through multiple measures including subjective ratings, relationship duration, and interaction frequency. Results showed that while people lie less frequently to close relationship partners, the lies they do tell in close relationships tend to be more serious and emotionally significant. The study provided crucial baseline data about the social ecology of deception, demonstrating that lying patterns vary systematically with relationship context.

These findings establish important baseline parameters for polygraph practice by demonstrating that deceptive behavior varies systematically with relationship context, suggesting that examiner understanding of relational dynamics may be relevant to case preparation and result interpretation.

Background & Context

Deception research in the late twentieth century was largely focused on the mechanics of lying — how people do it, whether they can be caught, and what physiological signals accompany it. What remained comparatively underexplored was a more fundamental social question: does the closeness of a relationship shape both the rate and the character of the lies told within it? DePaulo and Kashy's 1998 study, published in the Journal of Personality and Social Psychology, was designed to fill precisely this gap.

Prior diary studies of lying, including the authors' own landmark 1996 work, had established that lying is a routine feature of social life — but they had not systematically examined how relationship type and emotional closeness modulate deceptive behavior. Earlier studies were also methodologically limited: most focused on a single selected lie or conversation rather than capturing the full ecology of a person's social interactions across time. Critically, nearly all prior work had relied exclusively on college student samples.

This study extended and deepened the foundational 1996 research by bringing in both undergraduate and community participant samples, operationalizing "closeness" in three distinct ways, and examining lying not merely as a frequency count but as a relational phenomenon embedded in the emotional fabric of different kinds of human bonds. For polygraph research, these findings matter because they illuminate the baseline social context of deception — the environment in which all subsequent lie-detection efforts operate.

Research Design & Methodology

The study comprised two diary investigations in which 77 undergraduates and 70 community members recorded their social interactions and lies for a week. The college student sample (Study 1) consisted of 30 male and 47 female undergraduates ranging in age from 17 to 22, who participated in partial fulfillment of an introductory psychology course requirement. The community sample (Study 2) was recruited via posted advertisements, continuing education lists, and random selection from a local telephone directory, ranging in age from 18 to 71 — making it one of the very few non-student samples in the lying literature at the time.

The procedure unfolded across three phases. Participants attended an initial 90-minute session in which key terms were defined — a lie was operationalized as any intentional attempt to mislead someone. They then completed daily social interaction records and deception records for seven consecutive days. The deception record was printed alongside the social interaction record; participants indicated to whom they told the lie and then used a blank space to briefly describe the lie and its reason, followed by nine 9-point rating scales covering variables including degree of planning, importance of not getting caught, feelings of comfort before, during, and after the lie, perceived seriousness, and whether the target appeared to believe the lie.

Relationship closeness was operationalized in three independent ways — making this the most methodologically comprehensive design in the lying-in-relationships literature to that point:

• Subjective closeness — a composite of how close participants felt to each partner and how much they liked that person, averaged from 15-point scales (college sample: r = .84 between the two items; community sample: r = .81)
• Relationship duration — the number of months or years the participant had known each partner (square-root transformed to correct for skew)
• Frequency of interaction — the number of dyadic social interactions recorded with each partner over the week, adapted from the Rochester Interaction Record
• Relationship category — participants classified each partner as stranger, acquaintance, friend, best friend, romantic partner, spouse, parent, child, sibling, or other relative

The primary statistical approach was a two-step multilevel regression designed to handle the hierarchically nested structure of the data (multiple partners nested within participants). The first step estimated the closeness-to-lying relationship for each participant individually; the second step aggregated these estimates across participants, weighting by the precision of each first-step regression. This approach allowed the researchers to examine both whether closeness predicted lying overall and whether that relationship differed by participant gender or partner gender.

Results & Key Findings

The headline finding was unambiguous: people tell significantly fewer lies per social interaction to those to whom they feel emotionally closer. Because lying violates the openness and authenticity that people value in their close relationships, participants told fewer lies per social interaction to the people to whom they felt closer and felt more uncomfortable when they did lie to those people. This held across both the college and community samples and across multiple operationalizations of closeness.

When all three closeness variables were entered simultaneously in a multivariate regression, subjective emotional closeness emerged as the only significant independent predictor of lying rate — outpacing both relationship duration and interaction frequency. The standardized regression coefficients for subjective closeness predicting rate of lying were b = –0.084 (t = 4.99, p < .001) for college students and b = –0.063 (t = 3.00, p < .01) for community members in single-variable analyses, remaining significant when all three relationship variables were entered simultaneously.

Rates of lying varied substantially by relationship category:

• Strangers: college students lied in approximately 77% of social interactions; community members in 56%
• Acquaintances: college ~48%; community ~33%
• Friends: college ~28%; community ~26%
• Best friends: college ~28%; community ~17%
• Spouses (community sample): only ~10% — the lowest of all adult categories
• Romantic partners (non-spouse): surprisingly high at ~34% for college, ~32% for community — comparable to acquaintance rates despite high reported closeness
• Mothers (college students): nearly one lie in every two interactions (~46%), a notable exception to the closeness hypothesis

Because altruistic lies can communicate caring, relatively more of the lies told to best friends and friends were altruistic than self-serving, whereas the reverse was true of lies told to acquaintances and strangers. Also consistent with predictions, lies told to closer partners were more often discovered. For college students, subjective closeness predicted lie discovery (b = .092, p < .01), and the combined analysis across both samples was significant (p = .01). Participants also felt more distressed before and after telling lies to emotionally closer partners — for distress before telling the lie, the combined p across samples reached .04.

Discussion & Significance

The findings carry important theoretical weight for understanding the social ecology of deception. The dominance of subjective emotional closeness over objective measures like relationship duration or interaction frequency reveals that what deters lying is not simply familiarity or opportunity — it is the felt emotional bond itself. People who have known each other for years, or who interact daily, do not necessarily lie less to each other unless they also feel emotionally close. The emotional quality of the relationship appears to be the critical inhibitor of deceptive behavior.

Equally significant is the finding about the nature of lies within close relationships. Even though people lie less frequently to close partners, when they do lie to them, those lies are disproportionately altruistic (other-oriented) rather than self-serving. This finding has implications for how we conceptualize deception: within intimate relationships, lying can sometimes function as a form of relational maintenance and care — a social lubricant rather than a purely antisocial act. The study also reframes the well-documented "truth bias" in deception detection: the finding that people default to believing others more than is statistically warranted makes adaptive sense, because in real close relationships, the base rate of truth-telling is genuinely higher.

The notable exceptions — high lying rates to mothers among college students and to non-spouse romantic partners — point to the important moderating roles of power asymmetry and self-presentational motivation. Romantic partners who are not yet spouses may elicit particularly high rates of self-centered lying because people are uncertain whether their "true selves" are appealing enough to sustain the relationship, driving impression-management behavior. This nuance adds sophistication to what might otherwise appear to be a simple inverse relationship between closeness and lying.

Limitations & Considerations

Several methodological considerations temper the conclusions of this study:

• Self-report validity: The data rest entirely on participants' willingness to accurately record their own lies — a socially stigmatized behavior. The authors took extensive precautions (anonymity, detailed instructions, multiple data collection points, broad definition of lies), but the possibility of underreporting cannot be eliminated.
• Reactive measurement: Diary methodology may itself be reactive — participants who observed patterns in their own lying behavior may have retroactively adjusted their closeness ratings accordingly.
• Cross-sectional relationship structure: The study captures one week of lying behavior; whether these patterns remain stable across time, across seasons of a relationship, or in response to major relational events is unknown. Longitudinal designs would be needed to address developmental questions about how lying evolves as relationships deepen.
• Sample demographics: Both samples were predominantly White, limiting generalizability across cultural contexts in which norms about deception, relationship closeness, and social obligation may differ substantially.
• Causal direction: The study is correlational by design. It is possible that people who lie more also tend to experience less relationship closeness as a consequence, rather than closeness causally suppressing lying — a direction the authors acknowledge.

The study's authors openly discuss these constraints and argue persuasively that the diary methodology, despite its limitations, remains the most appropriate tool for studying theoretically motivated questions about everyday deception — because the fundamental social phenomena (spousal lying, parental lying, lying to strangers) simply cannot be randomly assigned and experimentally manipulated.

Practical Applications

For polygraph practitioners and deception researchers, this study provides invaluable contextual grounding. It establishes that deception is not a stable trait deployed uniformly across social contexts — it is a relational behavior modulated by emotional investment. A subject arriving for a polygraph examination carries a lifetime of deception patterns shaped by their relationships. Examiners who understand that the same individual may be highly honest in close personal relationships but routinely deceptive in more impersonal ones are better positioned to interpret examinees' baselines, pre-test interview disclosures, and emotional responses. The finding that lies told to close partners are more emotionally distressing — producing measurable discomfort before, during, and after — directly relates to the physiological arousal that forms the basis of polygraph measurement.

The study also has implications for post-conviction sex offender testing (PCSOT) and relationship-disclosure polygraph contexts, where the target of deception is often a close family member or supervised treatment provider. The evidence that altruistic lies — protective, other-oriented deceptions — are actually more common in close relationships suggests that examiners should be attentive to the possibility that some non-disclosure or minimization in therapeutic settings may reflect deeply habituated relational care-taking behavior rather than purely self-protective concealment. Understanding the baseline social ecology of lying in human relationships is not peripheral to polygraph science — it is foundational to it.