The social intelligence hypothesis states that the main selection pressures driving increases in brain-to-body ratio are social rather than ecological. The domestic horse is an ideal animal to study within this framework because horses possess rich social lives but inhabit simple ecological environments. Here I assess the abilities of horses within two broad areas of social cognition; the classification of, and the use of information obtained from, social partners. In Section One I demonstrate that horses are capable of cross-modal individual recognition of conspecifics, an ability not previously demonstrated conclusively outside of humans. This ability extends to identifying familiar human companions suggesting that recognition systems are highly plastic in the individuals they can encode. These results also provide the first insights into the brain mechanisms involved in this process by revealing a clear left hemisphere bias in discriminatory ability. In Section Two I investigate the extent to which horses are capable of reading human attentional and communicative cues. It has been suggested that this skill was selected for through the process of domestication, however there have been no systematic studies of domestic animals other than the domestic dog. I found that horses were indeed highly skilled at determining if people were paying attention to them. In contrast they tended to only use basic stimulus enhancement cues to choose a rewarded bucket. A further study of young horses indicated that the ability to detect human attention requires significant experience to develop fully whereas the ability to use stimulus enhancement cues in an object choice task appears to require far less (if any) experience to develop. Overall my thesis extends our knowledge of comparative social cognition and in particular our knowledge of social cognition in horses. Taken together, these results clearly demonstrate that horses do indeed possess some complex socio-cognitive skills.

Thesis (M.S.)--Ohio University, June, 2008. / Title from PDF t.p. Includes bibliographical references.

Thesis (PH.D.)--Michigan State University. Animal Science, 2008. / Title from PDF t.p. (viewed on Aug. 11, 2009) Includes bibliographical references (p. 201-211). Also issued in print.

Thesis (Ph. D.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 31, 2007) Includes bibliographical references.

Typescript, etc. / Digitized by Kansas State University Libraries

LD2668 .T4 1947 T5 / Master of Science

Call number: LD2668 .T4 1948 S5 / Master of Science

by Daron Adam Fincham. / Bibliography: leaves [183]-[210] / Thesis (Ph.D.)--Chinese University of Hong Kong, 1985

Living in complex societies is thought to promote the development of sophisticated social, cognitive, and communicative skills. Investigating the extent of these skills across taxa is critical to understanding the evolution of the advanced abilities found in some species, including humans. Facial expressions are rich sources of social information for humans and some primates; however whether this is true for other animals is largely unknown. Horses are an ideal study species for these questions: they form valuable social relationships and display some advanced socio-cognitive skills, but are phylogenetically distant from primates and so might be expected to communicate quite differently. Here I present a method for quantifying and coding horse facial movements (EquiFACS), which reveals that horses have an extensive capacity for producing facial expressions. I then utilise EquiFACS to demonstrate that horses produce facial actions that mirror the emotional content of auditory stimuli, providing evidence for a perception-action representation of emotional information. Through my experiments on the perception of facial expressions in horses I show that these expressions display meaningful information to conspecifics, which influences their behaviour in functionally relevant ways. I also shed light on the physiological processes involved in the perception of emotional conspecific facial expressions, showing that viewing negatively valenced conspecific emotional expressions raises resting heart rate. This is indicative of emotional contagion, which may be a mechanism through which information is obtained and social interactions are regulated. Collectively, my research demonstrates the ability to produce and use complex facial expressions as a source of social information is not limited to primates, but is present in at least two phylogenetically distant groups. This suggests these skills may either be an evolutionarily conserved trait or have evolved under common selective pressures. As well as their scientific significance, these findings have implications for horse management and welfare.

Graduation date: 1997