Peter L. Hurd is an academic specialising in biology. He is an Associate Professor aligned to the Department of Psychology's Biocognition Unit, and the University's Centre for Neuroscience at the University of Alberta. His research primarily focuses on the study of the evolution of aggressive behaviour, including investigation of aggression, communication and other social behaviour which takes place between animals with conflicting interests. Major tools for this research are mathematical modeling (principally game theory and genetic algorithms).
He is also interested in how the process of sexual differentiation produces individual differences in social behaviour.
Some of Hurd's most cited papers deal with the evolution of mating displays, specifically the idea that sexually selected traits have evolved to exploit previously existing biases in the sensory, or recognition, systems of their receivers, rather than being handicapped displays[7][8] Hurd has argued against the handicap principle view of animal communication, demonstrating the evolutionary stability of conventional (non-handicap) threat displays using game theoretical models.[9][10][11] Adding empirical support to this theoretical work, Hurd has also argued that threat displays in birds,[12] and headbob displays in the lizard Anolis carolinensis[13] are conventional signals, rather than handicaps. Hurd attributes the preponderance of handicap models in biology to the use of simple signalling games which are incapable of modelling conventional signalling.[14]
Hurd has classified models of fighting behaviour into those driven by: 1) fighting ability (aka resource holding potential), 2) perceived value of winning, and 3) aggressiveness and argues that if variation in the last trait -aggressiveness- exists in a biologically meaningful way, it ought to be fixed for life at an early stage of development.[15] Many studies on both human, and non-human, animals suggest that inter-individual variation in adult aggressiveness is largely organised by prenatal exposure to androgens. Digit ratio (2D:4D, the ratio of index to ring finger length) is a widely used as a proxy measure for prenatal testosterone exposure. Hurd demonstrated that men with more feminine typical-digit ratios showed lower aggressive tendency than males with more masculine-typical digit ratios.[16]
Among his other research into digit ratio, Hurd has demonstrated that, while there is no difference in digit ratio between the sexes in most laboratory mice, that pups which gested[spelling?] next to brothers have higher digit ratios than those whose uterine neighbours were sisters,[17][18] and that the large differences in digit ratios between populations may be explained by Allen's rule and Bergmann's rule.[19]
^Hurd PL, Wachtmeister C-A & Enquist M, 1995. Darwin's principle of antithesis revisited: a role for perceptual biases in the evolution of intraspecific signals. Proceedings of the Royal Society of LondonB259: 201-205.
^Ryan MR, Rand W, Hurd PL, Phelps SM & Rand AS, 2003. Generalization in response to allopatric mate recognition signals. American Naturalist161: 380-394.
^Hurd PL, 1997. Is signalling of fighting ability costlier for weaker individuals? Journal of Theoretical Biology184: 83-88.
^Hurd PL & Enquist M. 1998. Conventional signalling in aggressive interactions: the importance of temporal structure. Journal of Theoretical Biology192: 197-211.
^Enquist M, Ghirlanda S, and Hurd, PL. 1998. Discrete conventional signalling of continuously varying resource value. Animal Behaviour56: 749--753.
^Hurd PL, 2004. Conventional displays: evidence for socially mediated costs of threat displays in a lizard. Aggressive Behavior30: 326-341.
^Hurd PL & Enquist M. 2005. A strategic taxonomy of biological communication. Animal Behaviour70: 1155-1170.
^Hurd PL. 2006. Resource holding potential, subjective resource value, and game theoretical models of aggressiveness signalling. Journal of Theoretical Biology241: 639-648.
^Bailey AA & Hurd PL, 2005. Finger length ratio predicts physical aggression in men but not women. Biological Psychology68: 215-222
^Bailey AA, Wahlsten D & Hurd PL, 2005. Digit ratio (2D:4D) and behavioral differences between inbred mouse strains. Genes, Brain & Behavior4: 318-323.
^Hurd PL, Bailey AA, Gongal PA, Yan RH, Greer JJ & Pagliardini S. 2007. Intrauterine position effects on anogenital distance and digit ratio in male and female mice. Archives of Sexual Behavior (in press).
^Hurd PL & van Anders SM. 2007. Latitude, digit ratios, and Allen's and Bergmann's rules: A comment on Loehlin, McFadden, Medland, and Martin (2006). Archives of Sexual Behavior36: 139-141.