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“Animals are good to think with.” Claude Levi-Strauss. Why companion animals?.
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“It would be fair to argue that pet-keeping is genuinely ‘adaptive’ in the evolutionary sense of the word, since it contributes to individual health and survival by ameliorating stresses and strains of everyday life.” • James Serpell
Proximate Level Explanations • Immediate causes of behavior • “My dog is someone to care for” • “I love my cat” • Immediate benefits to individual • Pets help cope with stress • Cardiovascular benefits
Ultimate Level Explanations Evolutionary adaptations increase reproductive success.
Evolution - Model 1:Organic Evolution • Charles Darwin (1859) • Requires • Variation • Replication • Selection (?) • Time – lots • Units of replication– Genes
Theory 1. Attachment to pets is an evolved adaptation. • Need to show it pet-keeping is linked to genes (e.g., heritable). • Need to show that attachment to pets increases reproductive fitness.
Problems with the Evolutionary Adaptation Theory of Pet-Keeping 1. No evidence that pet-keeping is a heritable trait. 2. No evidence that pet owners have higher reproductive success. 3. Too much individual variation – many (perhaps most) people are not strongly attached to animals.
Theory 2. Pets are non-functional evolutionary byproducts (“spandrels”). • “Baby releasers” elicit feelings of parental care. • Attachment to pets is a misfiring of maternal instincts.
Theory 3: Pets are parasites • Cuckoos in the nest. • Pets use us to pass on their genes.
Evolutionary Model 2:Cultural Evolution • Richard Dawkins (1976) • Requires • Variation • Replication • Selection (?) • Time – not much • Units of replication - Memes • Examples – • Songs, Fashions, Ideas
Theory 4: Pet-keeping is a meme. Some predictions: 1. Potential for rapid cultural changes in forms of pet-keeping 2. Large cultural differences in pet keeping behaviors and attitudes 3. Pets run in families
American Kennel Club puppy registration data(Herzog, Bentley, and Hahn) • Every AKC registered dog in the United States (1926 – 2005) • N = 53,515,291 dogs • 154 breeds
1962 Social Epidemics • Epidemic of Irish Setters • Epidemic of “Girls Named Jennifer”
Dog breeds as memes: • 1.Breed preferences can change rapidly (like other forms popular culture). • 2. Breed preference are socially contagious. • 3. Popularity is independent of “quality”(?)
Are pets memes? • Memes requires a large brain and cultural transmission. • Uniquely human traits. • Symbolic language • Art • Religion • Pets(?)
2. Pet memes change in frequency. “If a sufficient amount of money is spent in advertising, a pet could be sold to every home” • 1929 “Pet Dealer Magazine””
Negative pet memes.50,000 dogs slaughtered in China this year.
3. Pet memes are transmitted from generation to generation. • Biggest predictor of pet ownership is family history with pets. • People raised with dogs have dog pets; people raised with cats have cat pets.
Biophilia: A Synthesis? • E.O. Wilson (1984) -- “Biophilia is the innate tendency to focus on life and life-like processes.” • E.O. Wilson (1993) • -- “Biophilia is not a single instinct but a complex set of learning rules”
Prepared and Counter-prepared Learning (Seligman) • Prepared pet memes -- kittens • Counter-prepared pet memes -- snakes
No evidence that pet-keeping increases reproductive fitness. Too much individual, cultural and historical variation. If there is selection for pet-keeping, it is weak. Pet-keeping is (probably) not an evolved adaptation.
Pet-keeping is (probably) spread by memes. • Pet-keeping memes are transmitted by imitation. • Non-adaptive cultural drift can produce changes in pet meme frequencies. • Some pet memes are more easily transmitted than others (gene-meme interactions). • Pets may have no evolutionary function.