Open Access Highly Accessed Research article

Selflessness is sexy: reported helping behaviour increases desirability of men and women as long-term sexual partners

David Moore14, Stuart Wigby2, Sinead English2, Sonny Wong2, Tamás Székely3 and Freya Harrison235*

Author Affiliations

1 Centre for Pain Research, University of Bath, Bath, UK

2 Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK

3 Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK

4 Current address: School of Natural Sciences & Psychology, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK

5 Current address: School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK

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BMC Evolutionary Biology 2013, 13:182  doi:10.1186/1471-2148-13-182

Published: 3 September 2013

Additional files

Additional file 1: Table S1:

Results of online surveys to define ‘altruistic’ behaviours. Items originally proposed as potentially altruistic traits and how they were scored by respondents to an online survey of a) 72 women with a mean age of 24.0±3.25 years, and b) 89 men with a mean age of 23.8±4.08 years. Survey respondents were asked the following: “In your opinion, are the following activities altruistic? Please rate each activity from 1–5, where 1 = not at all altruistic and 5 = very altruistic.” Responses to each item were analysed for skewness and items which did not show significant negative skew (p ≥ 0.05) were dropped from the list and not used inteh experiment. Items which had a modal rating of <4 were also dropped (no item had a mode of 5). Items dropped from the list are highlighted in grey. This left 20 items which we classed as altruistic for females and 12 for males. Internal consistency was assessed using Cronbach’s alpha. This measures the extent to which a set of variables measures a single, unidimensional underlying construct. Our values of alpha were high (0.99 for 20 items seen as altruistic by females and 0.94 for 12 items seen as altruistic by males), suggesting that the responses to different activities were consistent.

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Additional file 2: Table S2:

Results of online surveys to define ‘neutral’ behaviours. 80 men and 91 women aged 18–30 were asked whether each activity would affect how attractive they found a member of the opposite sex using a five-point Likert scale ranging from −2 to +2, where 0 indicated “no effect on attractiveness.” We retained traits which did not produce significant skew in responses (alpha=0.01) and these are listed below.

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Additional file 3:

Data supplement.

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Additional file 4: Figure S1.:

The effect of altruistic versus neutral traits on male attractiveness for long and short-term relationships, using only data collected from female participants aged ≤23 years. Cards were rated for attractiveness (on a 9-point Likert scale) and where the altruism card was shown in one trial, the neutral was shown in the other. The graphs show the least-square mean (± SE) change in attractiveness between trials (trial 2 value minus trial 1 value) with positive values indicating that the rating was higher in the 2nd trial than in the 1st trial. Bars with different letters above them are significantly different from each other using Tukey corrected multiple comparisons.

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