Psychological Bulletin 2015, Vol. 141, No. 1, 6-47
© 2014 American Psychological Association 0033-2909/15/$ 12.00 http://dx.doi.org/10.1037/a0038147
Toward a Psychology of Human-Animal Relations Catherine E. Amiot
Brock Bastian
Universite du Quebec a Montreal
University of New South Wales
Nonhuman animals are ubiquitous to human life, and permeate a diversity of social contexts by providing humans with food and clothing, serving as participants in research, improving healing, and offering entertainment, leisure, and companionship. Despite the impact that animals have on human lives and vice versa, the field of psychology has barely touched upon the topic of human-animal relations as an important domain of human activity. We review the current state of research on human-animal relations, showing how this body of work has implications for a diverse range of psychological themes including evolutionary processes, development, normative factors, gender and individual differences, health and therapy, and intergroup relations. Our aim is to highlight human-animal relations as a domain of human life that merits theoretical and empirical attention from psychology as a discipline. Keywords: human-animal relations, development and norms, individual differences, well-being and health, intergroup relations
of three Americans live with animals, spending more than $55 billion annually on their welfare (American Pet Products Associ ation, 2013). Dogs— a species that is particularly useful to humans (Serpell, 1995; Udell & Wynne, 2008) and sensitive to our non verbal behaviors (Hare, Brown, Williamson, & Tomasello, 2002; Hare & Tomasello, 2005)—play a central role in search and rescue and policing, and can be trained to guide the blind (Wells, 2009). Human-animal relations hence represent an important and com plex domain of human activity that merits theoretical and empir ical attention in its own right (Herzog, 2011; Rozin, 2006; Serpell, 2009). Throughout this review and on the basis of prior writings, we use the term animal to refer to species other than homo sapiens in order to distinguish nonhuman animals from human beings (e.g., Bekoff, 2007; S. Knight & Herzog, 2009; Pious, 2003). In this review we examine research focusing on human-animal relations, a field of enquiry that pertains specifically to the inter actions that exist between humans and animals. In this approach, and in contrast to most psychological research conducted up to now, animals are not used as a testing ground for psychological (human) theory nor are they attributed a passive role—they are investigated in the context of their interactions with humans. Indeed, traditionally, psychological research involving animals has been used to develop models of human behavior and to inform our understanding of fundamental human processes. The topic of human-animal relations hence differs from this comparative ap proach, as it directly captures the links and the dynamic interplay between humans and animals. The focus, therefore, of humananimal relations research is on reciprocal and interactive relations between humans and animals. Whereas this perspective contrasts sharply with prior psychological research where animals occupy a more instrumental role, it is needed to account for a large domain of human activity: how we interact with and relate to animals. Drawing on theoretical and empirical work conducted in soci ology, anthropology, neuroscience, medicine, veterinary studies, zoology, animal welfare, public health, psychiatry, criminology, and psychology, we aim to provide the first comprehensive review
Animals have accompanied humans for thousands of years, forging a strong interdependence between humans and other spe cies (de Waal, 2009). In fact, animals are ubiquitous to human lives: We currently eat an inordinate number of animals (i.e., approximately 9 billion each year in the United States; Joy, 2010) and use animals for clothing, for testing a range of human prod ucts, and for gaining basic insights into human biology and be havior. Animals entertain us, are represented in various forms of art, are part of our collective legends and histories, and they have been used as emblems and symbols of human attributes (e.g., Bryant, 1979; Herzog & Galvin, 1992; Leach, 1964; Levi-Strauss, 1966). Animals feature prominently in the socialization and enter tainment of children (Serpell, 1999a). Among animals, pets are attributed a special status, and they are recognized by approxi mately 90% of their owners as fully fledged family members (Cain, 1983; Carlisle-Frank & Frank, 2006; Cohen, 2002; Gallup, 1997; Voith, 1985; Voith, Wright, & Danneman, 1992). Two out
This article was published Online First November 3, 2014. Catherine E. Amiot, Department of Psychology, Universite du Quebec k Montreal; Brock Bastian, School of Psychology, University of New South Wales. This research was funded by grants from the Social Sciences and Humanities Research Council of Canada and the Fond pour la Recherche en Sante du Quebec to Catherine E. Amiot and by fellowships from the Australian Research Council to Brock Bastian (DPI 10102632). We would like to thank Matthew Hornsey and Harold Herzog, who provided con structive feedback on this article. We also thank Maude Roberge, Sarah Bourdeau, Moseni Mulemba, and Martin Roy, for their precious help with the literature search, downloading and managing the references, and put ting together Table 1; and Elsie Amiot, for serving as a source of inspira tion. Correspondence concerning this article should be addressed to Catherine E. Amiot, Department of Psychology, Universite du Quebec h Montreal, C.P. 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. E-mail: [email protected] 6
PSYCHOLOGY OF HUMAN-ANIMAL RELATIONS of this domain. Our review of this literature is selective, and in places interpretative, aiming to draw attention to the psychological themes and processes evident within this domain. To this extent we aim to address a critical gap within psychological knowledge and theorizing. To date, the discipline of psychology has been remark ably slow to investigate the topic of human-animal relations (S. Knight & Herzog, 2009; Melson, 2002; Pious, 1993a, 2003) and has been somewhat anthropocentric in its orientation. This is likely due to the peripheral status that animals have traditionally occu pied in our ethical frameworks, and the tendency not to recognize their psychological qualities (cf. Bastian, Loughnan, Haslam, & Radke, 2012; Epley, Waytz, & Cacioppo, 2007). Conversely, the field of anthrozoology—which focuses on human-animal interac tions— has provided a context within which these themes have been popularized (Hines, 2003; Podberscek, Paul, & Serpell, 2000). Furthermore, human-animal relations have been investi gated within different disciplines, including sociology, economics, geography, history, literature, and philosophy. Adopting a psycho logical approach brings a complementary perspective to the topic of human-animal relations. We believe that psychology is well positioned to contribute structured and comprehensive insights into human-animal rela tions. In this review we directly investigate the psychological processes that are involved in the interactions between humans and animals as a distinct domain of human behavior. By providing a comprehensive platform for thinking about human-animal rela tions, our aim is to provoke a range of novel research questions, focusing both on the causes and the broader consequences of human-animal relations. In fact, our relations with animals not only have consequences for animals (Pious, 1993a) but also have repercussions for human health (Fine, 2006; Herzog, 2011) and even impact on our associations with fellow humans (Ascione, 1992; Ascione & Weber, 1996; Bastian, Costello, Loughnan, & Hodson, 2012; Costello & Hodson, 2010). We believe that the current review is timely. Global concern for the treatment of animals, and how we relate to animals, is increas ing. Over the last 40 years, there has been a strong social move ment toward the recognition of animal rights (Pinker, 2011; Regan, 1983, 2001; Singer, 1981). Greenpeace and the World Wildlife Fund now have memberships exceeding 10 million. People for the Ethical Treatment of Animals counted 18 members in 1981, 250,000 in 1990, and more than 3 million in 2012. Growing animal welfare concerns motivate resistance to the impact of human activity on animals’ natural habitats and the use of animals for food and other resources (Foer, 2009; Singer, 2009). This in creased concern for animal rights is occurring in a context in which human (over)population of the planet is growing exponentially. Together, these two trends will continue to place pressure on already scarce resources and increase resource conflicts. Under standing the psychological factors that shape human-animal rela tions is necessary in order to effectively navigate this resource bottleneck. We organize the existing human-animal relations literature into six main sections that reflect traditional psychological themes. These themes are often used to organize psychological research as a field of study, and they allow coverage of a large and inclusive scope of psychological phenomena, ranging from themes that touch on biology up to societal and intergroup relations. Employ ing such a structure is particularly appropriate given the breadth of
7
literature on human-animal relations and, most importantly, the goal of the article, which is to demonstrate how a variety of psychological principles apply to the topic of human-animal rela tions. In line with this conventional organization of psychological research, we first cover evolutionary factors that lead us either to focus on and move toward animals or to fear some animals. Second, we present developmental evidence showing how the nature of our contacts with animals forges longer term humananimal relationships over the life span. Third, we review evidence showing how normative factors shape human-animal relations. Fourth, we analyze how individual differences, ideological beliefs, and gender operate in human-animal relations. Fifth, we review evidence showing how the presence of animals is linked to human health and vice versa. Sixth, we examine human-animal relations from an intergroup relations perspective. In keeping with our aim to provide a platform for more systematic psychological research into human-animal relations, following each of these six sections, we review the strength of the prior empirical evidence and make recommendations for future research.
Literature Search Procedure Our literature search involved two basic procedures: generating a pool of potentially relevant articles and selecting a subset of articles and book chapters for inclusion in the review. In the initial search cycle, we conducted searches in the PsycINFO database for all articles and chapters containing specific keywords or combi nations of keywords. When a keyword yielded too many refer ences (more than 1,000) and/or a majority of these references did not pertain to a psychological perspective per se, these keywords were crossed with another keyword to ensure a more focused search. The following combinations of keywords were used: ani mal welfare + attitudes, interspecies interactions + attitudes, interspecies interactions + identification, interspecies interac tions + well-being, interspecies interactions + quality o f life, morality + pets or animals, attachment + pets or animals, lone liness + pets or animals, terror management theory + pets or animals, social support + pets or animals, symbolism + animals, ritual + animals. The following keywords were also used on their own: animal-assisted therapy, animal cruelty, animal domestica tion, animal rights. The work of the following authors was sys tematically reviewed given their contribution to the psychological approach to human-animal relations and/or to the field of humananimal relations more generally: Erika Friedmann, Harold Herzog, Scott Pious, and James Serpell. These searches generated 1,744 articles, books, and book chap ters. We then examined the abstracts of the references generated by this literature search strategy. Given the focus of this review on psychological themes relevant to human-animal relations, refer ences were retained if they included psychological variables and covered direct interactions and interrelationships between humans and animals. We hence excluded ethological or animal cognition articles looking at the behavior of animals independent of human interactions. We also excluded work that employs animals as a control or baseline group, rather than as relational targets. To avoid redundancy, we excluded empirical articles and book chapters that overlapped in their conclusions and/or that presented less robust empirical data. In addition to these references, we included refer ences recommended by expert colleagues in the field of human-
8
AMIOT AND BASTIAN
animal relations, and articles that were cited in some articles (but that were not identified through the PsycINFO search) and that met our selection criteria. This resulted in 391 references on humananimal relations kept in the review; out of these, 199 were empir ical articles (see Table 1 for an overview). Table 1 presents the empirical articles that we relied on to review the evidence in the field, draw general conclusions for each of the six themes, and make recommendations for future research directions. In contrast, books and book chapters are cited in the review to make theoretical points. For topics that included a large number of articles (e.g., how the presence of animals is associated with human well-being), we also relied heavily on major reviews on the topic (i.e., Barker & Wolen, 2008; Friedmann, 2006; Her zog, 2011; Siegel, 2011). Prior to commencing our review, it is important to note the significant lack of cross-cultural research on human-animal rela tions, or for that matter converging evidence from non-Westem contexts. Table 1 reveals that although drawn from sometimes diverse populations, most of the evidence is from Western cul tures. Although it is tempting to interpret this culturally lopsided nature of the evidence as indicative that human-animal relations are of greater interest within Western contexts, this kind of cultural bias is not uncommon across a number of research domains, including psychology (Henrich, Heine, & Norenzayan, 2010). We return to a discussion of cultural differences and how they may shape human-animal relations at the end of this review.
Evolutionary Factors For more than 99% of human history, people have lived in hunter-gatherer bands totally and intimately involved with other living organisms (E. O. Wilson, 1993), suggesting that the evolu tion of human responses to animals was shaped by these interac tions.
Biophilia One of the most often cited theories as to why humans are interested in animals is the biophilia hypothesis (e.g., Kellert & Wilson, 1993; E. O. Wilson, 1984). Biophilia refers to the ten dency of humans to focus on life and lifelike processes (E. O. Wilson, 1984); it is the innately emotional affiliation that humans have toward other life forms (E. O. Wilson, 1993). Revised theo retical accounts of the biophilia hypothesis state that biophilia is not a single instinct but a complex of learning rules that trigger a variety of emotional reactions to animals, which are themselves shaped by culture (E. O. Wilson, 1993; see also Kahn, 1997, for a developmental perspective). Interestingly, the feelings molded by these learning rules fall along several emotional spectra: from attraction to aversion, from awe to indifference, from peacefulness to fear-driven anxiety. In this sense, biophilia refers to a selective attentiveness to other forms of life, which is neither inherently positive nor negative. In line with the biophilia hypothesis, the human mind may be wired to think differently about animals than inanimate objects, suggesting that part of the brain evolved to specialize in processing information about animals (Herzog, 2010; see also New, Cosmides, & Tooby, 2007). The biophilia hypothesis has received empirical support (e.g., for reviews, see DeLoache & Pickard, 2010; Kahn, 1997; cf. Joye
& De Block, 2011). For example, in a series of experiments, children were more attentive to animals than they were to inani mate objects. In free-play sessions, children aged 1-3 interacted more with live animals than with interesting toys. Further, they behaved differently toward the animals than the toys, talking about the animals more than the toys and asking more questions about them (LoBue, Bloom Pickard, Sherman, Axford, & DeLoache, 2013). According to Lorenz’s (1943) “cute response” (neoteny), hu mans are innately drawn to young animals, perhaps given that they share perceptual features with human infants, such as big eyes, large foreheads, and soft contours. In support of this contention, faces with infant features—including baby animal faces—were rated by adult participants as more attractive than those without (Archer & Monton, 2011). Providing some support for the notion that the cute response arises in conjunction with responsiveness to human infants or young animals, women’s greater appeal for a dog (compared to men’s) was stronger when the dog was a puppy than when the same dog got older (Fridlund & MacDonald, 1998). Relatedly, it has been argued that the human tendency to care and feel empathy for animals may have been a trait that was selected for, as it could reflect a more general capacity to care for human infants. Concern for animal welfare may have also given certain groups of humans an evolutionary advantage, as it allowed effi cient domestication of animals and herding (Bradshaw & Paul, 2010).
Fear Biological predispositions may also lead to distancing from animals. Modem humans remain “biologically prepared” to fear animals that threatened the survival of the human species during the course of evolution (Ohman & Mineka, 2001; Seligman, 1971). A large number of well-controlled laboratory studies support the evolutionary origins of human fear of some animals (for reviews, see Ohman & Mineka, 2001; Ulrich, 1993). For example, exper imental evidence revealed that participants were faster to detect the presence of a threatening animal (i.e., snake, spider) than a nonthreat-relevant stimulus (flower, mushroom; Ohman, Flykt, & Esteves, 2001; for a replication, see Lipp, Derakshan, Waters, & Logies, 2004). Participants also attributed more attentional re sources to and more rapidly recognized animals that typically elicit fear (snakes, spiders) than animals that do not (bird, fish; Waters, Lipp, & Randhawa, 2011; see also LoBue & DeLoache, 2008). In other experiments, infants and young children paid special atten tion to snakes and then also learned to fear snakes after listening to a frightened human voice paired with images of serpents (DeLo ache & LoBue, 2009; see LoBue, Rakison, & DeLoache, 2010, for a review), suggesting that fear responses can be acquired early.
Methodological Implications and Future Research Directions Together, these findings provide mostly experimental evidence for the fact that evolved responses to animals both orient us toward and propel us from animals: As can be seen in Table 1, 18 out of the 19 studies reviewed on this theme were experimental. Whereas the prior evidence reported in Table 1 has employed mostly cognitive ( n = 11 studies) and emotional measures (« = 7 studies)
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© 2014 American Psychological Association 0033-2909/15/$ 12.00 http://dx.doi.org/10.1037/a0038147
Toward a Psychology of Human-Animal Relations Catherine E. Amiot
Brock Bastian
Universite du Quebec a Montreal
University of New South Wales
Nonhuman animals are ubiquitous to human life, and permeate a diversity of social contexts by providing humans with food and clothing, serving as participants in research, improving healing, and offering entertainment, leisure, and companionship. Despite the impact that animals have on human lives and vice versa, the field of psychology has barely touched upon the topic of human-animal relations as an important domain of human activity. We review the current state of research on human-animal relations, showing how this body of work has implications for a diverse range of psychological themes including evolutionary processes, development, normative factors, gender and individual differences, health and therapy, and intergroup relations. Our aim is to highlight human-animal relations as a domain of human life that merits theoretical and empirical attention from psychology as a discipline. Keywords: human-animal relations, development and norms, individual differences, well-being and health, intergroup relations
of three Americans live with animals, spending more than $55 billion annually on their welfare (American Pet Products Associ ation, 2013). Dogs— a species that is particularly useful to humans (Serpell, 1995; Udell & Wynne, 2008) and sensitive to our non verbal behaviors (Hare, Brown, Williamson, & Tomasello, 2002; Hare & Tomasello, 2005)—play a central role in search and rescue and policing, and can be trained to guide the blind (Wells, 2009). Human-animal relations hence represent an important and com plex domain of human activity that merits theoretical and empir ical attention in its own right (Herzog, 2011; Rozin, 2006; Serpell, 2009). Throughout this review and on the basis of prior writings, we use the term animal to refer to species other than homo sapiens in order to distinguish nonhuman animals from human beings (e.g., Bekoff, 2007; S. Knight & Herzog, 2009; Pious, 2003). In this review we examine research focusing on human-animal relations, a field of enquiry that pertains specifically to the inter actions that exist between humans and animals. In this approach, and in contrast to most psychological research conducted up to now, animals are not used as a testing ground for psychological (human) theory nor are they attributed a passive role—they are investigated in the context of their interactions with humans. Indeed, traditionally, psychological research involving animals has been used to develop models of human behavior and to inform our understanding of fundamental human processes. The topic of human-animal relations hence differs from this comparative ap proach, as it directly captures the links and the dynamic interplay between humans and animals. The focus, therefore, of humananimal relations research is on reciprocal and interactive relations between humans and animals. Whereas this perspective contrasts sharply with prior psychological research where animals occupy a more instrumental role, it is needed to account for a large domain of human activity: how we interact with and relate to animals. Drawing on theoretical and empirical work conducted in soci ology, anthropology, neuroscience, medicine, veterinary studies, zoology, animal welfare, public health, psychiatry, criminology, and psychology, we aim to provide the first comprehensive review
Animals have accompanied humans for thousands of years, forging a strong interdependence between humans and other spe cies (de Waal, 2009). In fact, animals are ubiquitous to human lives: We currently eat an inordinate number of animals (i.e., approximately 9 billion each year in the United States; Joy, 2010) and use animals for clothing, for testing a range of human prod ucts, and for gaining basic insights into human biology and be havior. Animals entertain us, are represented in various forms of art, are part of our collective legends and histories, and they have been used as emblems and symbols of human attributes (e.g., Bryant, 1979; Herzog & Galvin, 1992; Leach, 1964; Levi-Strauss, 1966). Animals feature prominently in the socialization and enter tainment of children (Serpell, 1999a). Among animals, pets are attributed a special status, and they are recognized by approxi mately 90% of their owners as fully fledged family members (Cain, 1983; Carlisle-Frank & Frank, 2006; Cohen, 2002; Gallup, 1997; Voith, 1985; Voith, Wright, & Danneman, 1992). Two out
This article was published Online First November 3, 2014. Catherine E. Amiot, Department of Psychology, Universite du Quebec k Montreal; Brock Bastian, School of Psychology, University of New South Wales. This research was funded by grants from the Social Sciences and Humanities Research Council of Canada and the Fond pour la Recherche en Sante du Quebec to Catherine E. Amiot and by fellowships from the Australian Research Council to Brock Bastian (DPI 10102632). We would like to thank Matthew Hornsey and Harold Herzog, who provided con structive feedback on this article. We also thank Maude Roberge, Sarah Bourdeau, Moseni Mulemba, and Martin Roy, for their precious help with the literature search, downloading and managing the references, and put ting together Table 1; and Elsie Amiot, for serving as a source of inspira tion. Correspondence concerning this article should be addressed to Catherine E. Amiot, Department of Psychology, Universite du Quebec h Montreal, C.P. 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. E-mail: [email protected] 6
PSYCHOLOGY OF HUMAN-ANIMAL RELATIONS of this domain. Our review of this literature is selective, and in places interpretative, aiming to draw attention to the psychological themes and processes evident within this domain. To this extent we aim to address a critical gap within psychological knowledge and theorizing. To date, the discipline of psychology has been remark ably slow to investigate the topic of human-animal relations (S. Knight & Herzog, 2009; Melson, 2002; Pious, 1993a, 2003) and has been somewhat anthropocentric in its orientation. This is likely due to the peripheral status that animals have traditionally occu pied in our ethical frameworks, and the tendency not to recognize their psychological qualities (cf. Bastian, Loughnan, Haslam, & Radke, 2012; Epley, Waytz, & Cacioppo, 2007). Conversely, the field of anthrozoology—which focuses on human-animal interac tions— has provided a context within which these themes have been popularized (Hines, 2003; Podberscek, Paul, & Serpell, 2000). Furthermore, human-animal relations have been investi gated within different disciplines, including sociology, economics, geography, history, literature, and philosophy. Adopting a psycho logical approach brings a complementary perspective to the topic of human-animal relations. We believe that psychology is well positioned to contribute structured and comprehensive insights into human-animal rela tions. In this review we directly investigate the psychological processes that are involved in the interactions between humans and animals as a distinct domain of human behavior. By providing a comprehensive platform for thinking about human-animal rela tions, our aim is to provoke a range of novel research questions, focusing both on the causes and the broader consequences of human-animal relations. In fact, our relations with animals not only have consequences for animals (Pious, 1993a) but also have repercussions for human health (Fine, 2006; Herzog, 2011) and even impact on our associations with fellow humans (Ascione, 1992; Ascione & Weber, 1996; Bastian, Costello, Loughnan, & Hodson, 2012; Costello & Hodson, 2010). We believe that the current review is timely. Global concern for the treatment of animals, and how we relate to animals, is increas ing. Over the last 40 years, there has been a strong social move ment toward the recognition of animal rights (Pinker, 2011; Regan, 1983, 2001; Singer, 1981). Greenpeace and the World Wildlife Fund now have memberships exceeding 10 million. People for the Ethical Treatment of Animals counted 18 members in 1981, 250,000 in 1990, and more than 3 million in 2012. Growing animal welfare concerns motivate resistance to the impact of human activity on animals’ natural habitats and the use of animals for food and other resources (Foer, 2009; Singer, 2009). This in creased concern for animal rights is occurring in a context in which human (over)population of the planet is growing exponentially. Together, these two trends will continue to place pressure on already scarce resources and increase resource conflicts. Under standing the psychological factors that shape human-animal rela tions is necessary in order to effectively navigate this resource bottleneck. We organize the existing human-animal relations literature into six main sections that reflect traditional psychological themes. These themes are often used to organize psychological research as a field of study, and they allow coverage of a large and inclusive scope of psychological phenomena, ranging from themes that touch on biology up to societal and intergroup relations. Employ ing such a structure is particularly appropriate given the breadth of
7
literature on human-animal relations and, most importantly, the goal of the article, which is to demonstrate how a variety of psychological principles apply to the topic of human-animal rela tions. In line with this conventional organization of psychological research, we first cover evolutionary factors that lead us either to focus on and move toward animals or to fear some animals. Second, we present developmental evidence showing how the nature of our contacts with animals forges longer term humananimal relationships over the life span. Third, we review evidence showing how normative factors shape human-animal relations. Fourth, we analyze how individual differences, ideological beliefs, and gender operate in human-animal relations. Fifth, we review evidence showing how the presence of animals is linked to human health and vice versa. Sixth, we examine human-animal relations from an intergroup relations perspective. In keeping with our aim to provide a platform for more systematic psychological research into human-animal relations, following each of these six sections, we review the strength of the prior empirical evidence and make recommendations for future research.
Literature Search Procedure Our literature search involved two basic procedures: generating a pool of potentially relevant articles and selecting a subset of articles and book chapters for inclusion in the review. In the initial search cycle, we conducted searches in the PsycINFO database for all articles and chapters containing specific keywords or combi nations of keywords. When a keyword yielded too many refer ences (more than 1,000) and/or a majority of these references did not pertain to a psychological perspective per se, these keywords were crossed with another keyword to ensure a more focused search. The following combinations of keywords were used: ani mal welfare + attitudes, interspecies interactions + attitudes, interspecies interactions + identification, interspecies interac tions + well-being, interspecies interactions + quality o f life, morality + pets or animals, attachment + pets or animals, lone liness + pets or animals, terror management theory + pets or animals, social support + pets or animals, symbolism + animals, ritual + animals. The following keywords were also used on their own: animal-assisted therapy, animal cruelty, animal domestica tion, animal rights. The work of the following authors was sys tematically reviewed given their contribution to the psychological approach to human-animal relations and/or to the field of humananimal relations more generally: Erika Friedmann, Harold Herzog, Scott Pious, and James Serpell. These searches generated 1,744 articles, books, and book chap ters. We then examined the abstracts of the references generated by this literature search strategy. Given the focus of this review on psychological themes relevant to human-animal relations, refer ences were retained if they included psychological variables and covered direct interactions and interrelationships between humans and animals. We hence excluded ethological or animal cognition articles looking at the behavior of animals independent of human interactions. We also excluded work that employs animals as a control or baseline group, rather than as relational targets. To avoid redundancy, we excluded empirical articles and book chapters that overlapped in their conclusions and/or that presented less robust empirical data. In addition to these references, we included refer ences recommended by expert colleagues in the field of human-
8
AMIOT AND BASTIAN
animal relations, and articles that were cited in some articles (but that were not identified through the PsycINFO search) and that met our selection criteria. This resulted in 391 references on humananimal relations kept in the review; out of these, 199 were empir ical articles (see Table 1 for an overview). Table 1 presents the empirical articles that we relied on to review the evidence in the field, draw general conclusions for each of the six themes, and make recommendations for future research directions. In contrast, books and book chapters are cited in the review to make theoretical points. For topics that included a large number of articles (e.g., how the presence of animals is associated with human well-being), we also relied heavily on major reviews on the topic (i.e., Barker & Wolen, 2008; Friedmann, 2006; Her zog, 2011; Siegel, 2011). Prior to commencing our review, it is important to note the significant lack of cross-cultural research on human-animal rela tions, or for that matter converging evidence from non-Westem contexts. Table 1 reveals that although drawn from sometimes diverse populations, most of the evidence is from Western cul tures. Although it is tempting to interpret this culturally lopsided nature of the evidence as indicative that human-animal relations are of greater interest within Western contexts, this kind of cultural bias is not uncommon across a number of research domains, including psychology (Henrich, Heine, & Norenzayan, 2010). We return to a discussion of cultural differences and how they may shape human-animal relations at the end of this review.
Evolutionary Factors For more than 99% of human history, people have lived in hunter-gatherer bands totally and intimately involved with other living organisms (E. O. Wilson, 1993), suggesting that the evolu tion of human responses to animals was shaped by these interac tions.
Biophilia One of the most often cited theories as to why humans are interested in animals is the biophilia hypothesis (e.g., Kellert & Wilson, 1993; E. O. Wilson, 1984). Biophilia refers to the ten dency of humans to focus on life and lifelike processes (E. O. Wilson, 1984); it is the innately emotional affiliation that humans have toward other life forms (E. O. Wilson, 1993). Revised theo retical accounts of the biophilia hypothesis state that biophilia is not a single instinct but a complex of learning rules that trigger a variety of emotional reactions to animals, which are themselves shaped by culture (E. O. Wilson, 1993; see also Kahn, 1997, for a developmental perspective). Interestingly, the feelings molded by these learning rules fall along several emotional spectra: from attraction to aversion, from awe to indifference, from peacefulness to fear-driven anxiety. In this sense, biophilia refers to a selective attentiveness to other forms of life, which is neither inherently positive nor negative. In line with the biophilia hypothesis, the human mind may be wired to think differently about animals than inanimate objects, suggesting that part of the brain evolved to specialize in processing information about animals (Herzog, 2010; see also New, Cosmides, & Tooby, 2007). The biophilia hypothesis has received empirical support (e.g., for reviews, see DeLoache & Pickard, 2010; Kahn, 1997; cf. Joye
& De Block, 2011). For example, in a series of experiments, children were more attentive to animals than they were to inani mate objects. In free-play sessions, children aged 1-3 interacted more with live animals than with interesting toys. Further, they behaved differently toward the animals than the toys, talking about the animals more than the toys and asking more questions about them (LoBue, Bloom Pickard, Sherman, Axford, & DeLoache, 2013). According to Lorenz’s (1943) “cute response” (neoteny), hu mans are innately drawn to young animals, perhaps given that they share perceptual features with human infants, such as big eyes, large foreheads, and soft contours. In support of this contention, faces with infant features—including baby animal faces—were rated by adult participants as more attractive than those without (Archer & Monton, 2011). Providing some support for the notion that the cute response arises in conjunction with responsiveness to human infants or young animals, women’s greater appeal for a dog (compared to men’s) was stronger when the dog was a puppy than when the same dog got older (Fridlund & MacDonald, 1998). Relatedly, it has been argued that the human tendency to care and feel empathy for animals may have been a trait that was selected for, as it could reflect a more general capacity to care for human infants. Concern for animal welfare may have also given certain groups of humans an evolutionary advantage, as it allowed effi cient domestication of animals and herding (Bradshaw & Paul, 2010).
Fear Biological predispositions may also lead to distancing from animals. Modem humans remain “biologically prepared” to fear animals that threatened the survival of the human species during the course of evolution (Ohman & Mineka, 2001; Seligman, 1971). A large number of well-controlled laboratory studies support the evolutionary origins of human fear of some animals (for reviews, see Ohman & Mineka, 2001; Ulrich, 1993). For example, exper imental evidence revealed that participants were faster to detect the presence of a threatening animal (i.e., snake, spider) than a nonthreat-relevant stimulus (flower, mushroom; Ohman, Flykt, & Esteves, 2001; for a replication, see Lipp, Derakshan, Waters, & Logies, 2004). Participants also attributed more attentional re sources to and more rapidly recognized animals that typically elicit fear (snakes, spiders) than animals that do not (bird, fish; Waters, Lipp, & Randhawa, 2011; see also LoBue & DeLoache, 2008). In other experiments, infants and young children paid special atten tion to snakes and then also learned to fear snakes after listening to a frightened human voice paired with images of serpents (DeLo ache & LoBue, 2009; see LoBue, Rakison, & DeLoache, 2010, for a review), suggesting that fear responses can be acquired early.
Methodological Implications and Future Research Directions Together, these findings provide mostly experimental evidence for the fact that evolved responses to animals both orient us toward and propel us from animals: As can be seen in Table 1, 18 out of the 19 studies reviewed on this theme were experimental. Whereas the prior evidence reported in Table 1 has employed mostly cognitive ( n = 11 studies) and emotional measures (« = 7 studies)
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