Looking for jealousy in animals

SciAm reports:

Man's best friend does not like anything muscling in on that friendship. The first experimental test of jealousy in dogs shows that canines nip even at stuffed pooches when these fakes take away the attention of the dogs' owners.

This new findings support the view that jealousy is a primordial emotion seen not only in humans, but in other animals as well, researchers said. The results also show that jealousy does not require especially complex minds, the scientists said. ...

The owners were instructed to treat the fake dog and the jack-o'-lantern like they were real dogs, by petting the objects and talking to them sweetly. When it came to the book, the owners were asked to read the text out loud.

The scientists found dogs acted far more jealous when their owners displayed affection to the stuffed dog compared with the other items. The canines were nearly twice as likely to push or touch the owner when the owner was playing with the fake dog compared with the jack-o'-lantern, and more than three times as likely to do so when compared with the book. Furthermore, about one-third of the dogs tried to get between their owners and the stuffed toy. And while one-quarter of the dogs snapped at the fake dog, only one did so at the jack-o'-lantern and book.

This is anthropomorphism. Maybe it would be jealousy if the dog destroyed the fake dog, but I am not sure this has anything to do with jealous. Maybe the dog just wanted to be petted by the owner.

Yes, the dog liked being petted, and asked for it when he say that the owner was petting a fake dog. But maybe the dog was just deducing that the owner was available for petting. I might decide that I want an ice cream cone after seeing someone else with an ice cream cone, but that does not mean that I am jealous.

A professor says:

The sociologist, Davis (1948) defined jealousy as a fear and rage reaction fitted to protect, maintain, and prolong the intimate association of love. In a pair-bonding species like our own that lives in social groups, jealousy is a logical prediction from evolutionary theory. In fact, if jealousy did not exist as a universal human characteristic, it would represent an oddity that demanded scientific explanation.

The function of jealousy is somewhat different between the two sexes. In males, jealousy revolves around the issue of uncertainty of paternity. Whereas women have always known if an infant is hers or not, until the advent of modern DNA testing techniques men could never be certain that a child was the product of their loins.

Although paternal uncertainty is a problem in all primate species, true jealousy may be unique to the evolution of the human line. ...

Based on evolutionary logic, it was predicted that male jealousy would be more concerned with sexual infidelity and female jealousy would be more concerned with emotional infidelity. Buss, Larson, Westen, & Semmelroth (1992) used a series of forced choice experiments to demonstrate that men indicated greater distress to a partner’s sexual, rather than emotional infidelity, whereas women showed the reverse response displaying greater distress to a partner’s emotional infidelity rather than their sexual infidelity.

This video claims to demonstrate jealousy in capuchins (New World monkeys). Others say that it shows fairness or entitlement. But there is a leaner explanation -- maybe the monkey just prefers grapes to cucumbers and is trying to get grapes. Further research has attempted to address the objections, but it is still limited. It always finds a monkey that prefers grapes to cucumber, showing the monkey that it could be getting a grape instead of cucumber, and watch the monkey reject the cucumber in an effort to get a grape.

I have posted similar criticism of mindreading crows, cats, and rats, and suggested that many people have a cognitive bias for rich explanations.