Testosterone, Attachment and the green-eyed monster Nicola J. Fussell & Angela C. Rowe School of Experimental Psychology, University of Bristol, UK. Are between-sex differences in the weightings men and women give to sexual versus emotional infidelity the result of a sex-specific psychological adaptation (Buss, Larsen, Westen & Semmelroth, 1992) or a more universal jealousy mechanism, based upon the attachment system, that interacts with proximal factors such as cultural norms and infidelity experience (Harris, 2003)? As there is some evidence to suggest a moderating role of attachment on between-sex differences, e.g. avoidant attachment is associated with a greater distress at sexual compared with emotional infidelity (Levy & Kelly, 2010; Treger & Sprecher, 2011), might between-sex differences in romantic jealousy be best conceptualised as the result of two competing biological mechanisms, the sexual reproduction and attachment systems? To test the interaction hypothesis we report on two experiments: Experiment 1 explored the effect of attachment style priming on jealousy and distress at sexual infidelity in women. Experiment 2 investigated the role of the sex steroid hormone testosterone as a potential biological marker of romantic jealousy and a possible interaction with attachment. Method Exp. 1: The effect of attachment style priming Exp. 2: Testosterone: a biological marker of jealousy? Experiment 1 adds to the literature showing an association between avoidant attachment orientation and distress at sexual infidelity compared to emotional infidelity. Experiment 2 is the first to report a moderating role for the sex steroid hormone testosterone on the relationship between anxious attachment and romantic jealousy. To the extent that distress at sexual infidelity represents greater sexual motivation, the results of both studies lend support to the interaction hypothesis. Summary and Conclusions Results Introduction Participants: 82 (men = 44), mean age ± 1.80 years, heterosexual with relationship experience. Male and female groups were matched for age, duration of previous relationship, experience of infidelity/cheating in a between-subjects design. Measures and procedure: Saliva samples for testosterone assay were taken at baseline and 15 minutes post manipulation. In order to trigger changes in testosterone participants were randomly assigned to ‘win’ vs ‘lose’ condition in a computer-based vicarious competitive task followed by self-report measures of attachment (ECR), jealousy and distress at sexual versus emotional infidelity. For men in the lose condition, increases in testosterone increased the strength of the relationship between anxious attachment orientation and romantic jealousy (Fig. 2). For the whole group, participants with extreme increases in testosterone self- reported higher jealousy than participants with extreme decreases in testosterone (t(53) = 2.318, p =.024). There were no differences in attachment orientation between the two groups (ps >.243). Grindley Grant Fig 2. Anxious attachment x % testosterone change group interaction regression lines on jealousy for men in the lose condition (F(1,20) = 5.467, p =.030, R 2 =.215; full model including anxious attachment orientation F(2,19) = , p <.001, R 2 =.678). Method Participants: 91 heterosexual women with relationship experience, mean age ± 1.87 years. Measures and procedure: Attachment orientation was measured at baseline using ECR. Participants randomly assigned to avoidant, anxious, secure or neutral priming task (8-minute visualisation) followed by self-report measures of jealousy and distress at sexual versus emotional infidelity (dichotomous and continuous rating). Differences in baseline anxious attachment between certain priming groups were controlled for. Results Fig 1. Rating of ease at choosing emotional versus sexual infidelity scenario as more upsetting (F(3,86) = 3.639, p =.016, η p 2 =.113) Participants in avoidant prime condition found it significantly harder to choose emotional infidelity as more upsetting than sexual infidelity (continuous rating) compared with all other conditions (Fig.1). Non-significant trend for participants in avoidant prime condition (compared with secure and anxious prime conditions) to choose sexual infidelity as more distressing than emotional infidelity (dichotomous task, F(3,86) = 2.347, p =.078). No effect of prime condition on jealousy (p =.892). Acknowledgements: