Date of Award

Spring 2007

Project Type


Program or Major


Degree Name

Doctor of Philosophy

First Advisor

Rebecca Warner


Although primatology research indicates that social grooming has broad social significance for primates, it has not been previously considered as a nonverbal communication channel among humans. Therefore, this research aimed to provide information about its social significance among humans in two ways. Participants completed a questionnaire in which they indicated the incidence of grooming others in several relationship contexts. Second, a different sample participated in an experiment in which they read one of several vignettes and gave their impressions. Impressions were targeted to presumed communicative functions of grooming: courtship/flirtation and attachment/pairbonding. Two variables were manipulated: type of action performed (grooming, non-grooming touch, no touch) and type of grooming performed (traditional, non-traditional, mimicry, and blemish-focused). A nested variable of three different examples was included for each type of grooming. Grooming was reported in a wide variety of relationships but was reported at a significantly higher incidence in romantic relationships. Dyads depicted grooming were identified as a romantically involved couple more often than chance would predict by women only, a fording that would be predicted by Error Management Theory (Haselton & Buss, 2000). Grooming is a tie-sign to women, and for men acts as a tie-sign only in the form of massage. Grooming has some psychological properties that further attest to its role in pairbonding. Fitting with the theory that grooming promotes pairbonding because it is a caregiving behavior, groomers are perceived to be better parents, more committed, more caring and more in love. Among people who attributed a romantic relationship to the depicted dyad, the pair was more often inferred to be an established couple rather than a newly formed one. Groomers did not convey significantly more sexual interest or flirtation. Therefore, grooming can best be characterized as an attachment behavior used for pairbonding rather than one used in courtship for flirtation purposes.