Thinking Pigs: A Comparative Review of Cognition, Emotion, and Personality in Sus domesticus

Lori Marino,Christina M Colvin

doi:10.46867/ijcp.2015.28.00.04

Abstract

While relatively little is known about the psychology of domestic pigs, what is known suggests that pigs are cognitively complex and share many traits with animals whom we consider intelligent. This paper reviews the scientific evidence for cognitive complexity in domestic pigs and, when appropriate, compares this literature with similar findings in other animals, focusing on some of the more compelling and cutting-edge research results. The goals of this paper are to: 1) frame pig cognition and psychology in a basic comparative context independent of the livestock production and management setting; and 2) identify areas of research with pigs that are particularly compelling and in need of further investigation. We summarize and discuss several areas of comparative psychology, including nonsocial and social cognition, self-awareness, emotion, and personality. We conclude that there are several areas of research in which the findings are suggestive of complex psychology in pigs. We conclude by calling for more noninvasive cognitive and behavioral research with domestic pigs in non-laboratory settings that allow them to express their natural abilities.

Highlights

While relatively little is known about the psychology of domestic pigs, what is known suggests that pigs are cognitively complex and share many traits with animals whom we consider intelligent
While some studies have been done that do not frame pigs within an applied setting, these are far less numerous than those with direct reference to behavioral management in an agricultural or laboratory setting. This paper examines both categories of research – applied and basic – in an effort to begin to fill out and reframe our understanding of pig intelligence, cognition, and overall psychology on a basic comparative-evolutionary level
In this paper we have identified a number of findings from studies of pig cognition, emotion, and behavior which suggest that pigs possess complex ethological traits similar, but not identical, to dogs and chimpanzees

Summary

Introduction

While relatively little is known about the psychology of domestic pigs, what is known suggests that pigs are cognitively complex and share many traits with animals whom we consider intelligent. No ungulate groups are well-studied compared with the aforementioned animals who are, in contrast, frequently considered Because of their status as an under-represented ungulate group, there exists a very basic need to bring together what we do know about pigs in order to build on our current understanding and gain further insights into the distribution of various cognitive and behavioral levels of sophistication in mammals and other taxa. We have chosen to focus on the more complex capacities in pigs that are arguably at the leading edge of intelligence and sentience and to identify compelling and promising areas of cognition, emotion, and sociality which, we contend, should be investigated in future studies. While dogs were selected for traits promoting human companionship and work, pigs were selected for the ability to produce meat

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Conclusion