Thesis (Psy. D.)--Indiana University of Pennsylvania. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 157-172). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--University of Delaware, 2008. / Principal faculty advisor: Douglas W. Tallamy, Dept. of Entomology & Wildlife Ecology. Includes bibliographical references.

Thesis (M.S.)--Ohio University, June, 2005. / Includes bibliographical references (p. 73-85)

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 139-154).

Thesis (Ph. D.)--University of Louisville, 2004. / Department of Psychological and Brain Sciences. Vita. "May 2004." Includes bibliographical references (leaves 190-204).

Thesis (M.S.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 73-85)

Thesis (Ph.D.)--York University, 2004. Graduate Programme in Psychology. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99167

In this thesis, I aimed to explore vocal attractiveness from an evolutionary perspective: how listener's preferences for vocal qualities of potential partners could increase mating success and reproductive success. Chapters 1-4 outline the background to the thesis, reviews acoustics, sexual selection theory, and human mate-choice. In chapter 5, I correlated attributions made to voices to the acoustic properties of the voices. In men's voices, pitch negatively predicted vocal attractiveness. Attributions of masculinity, size, age, health and vocal attractiveness were all positively correlated. In women's voices, pitch, formant dispersion and perceived health positively predicted vocal attractiveness. Masculinity, size and age negatively predicted vocal attractiveness. In chapter 6, I measured the effect of manipulating fundamental and/or formant frequencies (apparent vocal-tract length) on vocal attributions. Women found men's voices with lowered voice pitch and decreased formant dispersion more attractive, masculine, large, older and healthier. Women's size predicted preference for male vocal- tract length. In chapter 7, I explored attitudes to voices speaking vowels and whole sentences using a correlation design and acoustic manipulations. Women's self-rated attractiveness positively predicted vocal masculinity preferences. Most of the remaining studies focus on how hormones relate to vocal production and perception. Women with less oestrogen showed the biggest menstrual cycle shifts in vocal masculinity preferences, preferring masculinity most in the fertile phase (chapter 8). Men's testosterone levels predicted the size of changes in attributions of dominance to men's voices (chapter 9). Women's voice pitch correlated with facial-metric masculinity and facial attractiveness (chapter 10). Men preferred women's voices with raised pitch to lowered pitch at multiple levels of starting pitch (chapter 11). These findings indicate men preferred femininity to averageness. In chapter 12, I relate the work in this thesis to other work and the broader evolutionary perspective.

Altruism and cooperation have been troubling concepts for theorists. Where altruism towards kin is well-researched, altruism towards non-kin is an evolutionary puzzle. There have been advances in evolutionary psychology where theorists have explored the evolution of altruism through the lens of sexual selection theory, hypothesising that altruism leads to increased chances of being chosen as a mate, particularly as females value altruistic tendencies in a romantic partner. As a result, it was hypothesised males would be more cooperative and altruistic towards those they were attracted to. In study 1, it was found that females placed more importance on altruism and cooperativeness in a mate, far more than males. In addition, males placed more importance on physical attractiveness in a mate, far more than females. In study 2, it was found that people were altruistic and cooperative towards attractive members of the opposite sex when viewing images in response to moral scenarios. When I aimed to replicate this finding, using a game-theoretic framework in studies 3, 4 and 5, I found that people were fair, and altruistic when allocating stakes, and attractiveness did not predict altruism. This consistent fair behaviour led me to further investigate the role of fairness in mate attraction. In studies 6 and 7, it was found that third-parties found fairness to be more attractive than altruism, particularly female participants. In study 8, I further delved into the role of fairness in mate choice, where I found that fairness could be attractive because it increases relationship maintenance in the short-term, but it is altruism that increases relationship longevity in long-term relationships. Furthermore, it was found that people perceive short-term, fair couples to have less intention to cheat than long-term altruistic couples. This thesis opens a new and exciting door in the field of evolutionary psychology, providing evidence that fairness could play a role in mate choice.