Emotion in animals

[2][3][4][5] Cognitive bias tests and learned helplessness models have shown feelings of optimism and pessimism in a wide range of species, including rats, dogs, cats, rhesus macaques, sheep, chicks, starlings, pigs, and honeybees.

While emotions in nonhuman animals is still quite a controversial topic, it has been studied in an extensive array of species both large and small including primates, rodents, elephants, horses, birds, dogs, cats, honeybees and crayfish.

The behaviourist argument is, why should humans postulate consciousness and all its near-human implications in animals to explain some behaviour, if mere stimulus-response is a sufficient explanation to produce the same effects?

There is considerable uncertainty and difficulty related to the interpretation and ambiguity of emotion: an animal may make certain movements and sounds, and show certain brain and chemical signals when its body is damaged in a particular way.

In 1903, C. Lloyd Morgan published Morgan's Canon, a specialised form of Occam's razor used in ethology, in which he stated:[19][20] In no case is an animal activity to be interpreted in terms of higher psychological processes, if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development.Charles Darwin initially planned to include a chapter on emotion in The Descent of Man but as his ideas progressed they expanded into a book, The Expression of the Emotions in Man and Animals.

[22] A domestic dog's simple tail wag may be used in subtly different ways to convey many meanings as illustrated in Darwin's The Expression of the Emotions in Man and Animals published in 1872.

The same individual is trained to anticipate that stimulus B, e.g. a 10 Hz tone, precedes a negative event, e.g. bland food is delivered when the animal presses a lever.

Cognitive biases have been shown in a wide range of species including rats, dogs, rhesus macaques, sheep, chicks, starlings and honeybees.

[32] The exact function of spindle cells in whale brains is still not understood, but Hof and Van Der Gucht believe that they act as some sort of "high-speed connections that fast-track information to and from other parts of the cortex".

[32] They compared them to express trains that bypass unnecessary connections, enabling organisms to instantly process and act on emotional cues during complex social interactions.

[9] Beginning with Darwin and his research, it has been known that chimpanzees and other great apes perform laugh-like vocalizations, providing scientists with more symbolic self-reports of their emotional experiences.

[1] Research with rats has revealed that under particular conditions, they emit 50-kHz ultrasonic vocalisations (USV) which have been postulated to reflect a positive affective state (emotion) analogous to primitive human joy; these calls have been termed "laughter".

[36][37] The 50 kHz USVs in rats are uniquely elevated by hedonic stimuli—such as tickling, rewarding electrical brain stimulation, amphetamine injections, mating, play, and aggression—and are suppressed by aversive stimuli.

[38] Some vocalizations of domestic cats, such as purring, are well known to be produced in situations of positive valence, such as mother kitten interactions, contacts with familiar partner, or during tactile stimulation with inanimate objects as when rolling and rubbing.

[39] Low pitched bleating in sheep has been associated with some positive-valence situations, as they are produced by males as an estrus female is approaching or by lactating mothers while licking and nursing their lambs.

[39] Neuroscientific studies based on the instinctual, emotional action tendencies of non-human animals accompanied by the brains neurochemical and electrical changes are deemed to best monitor relative primary process emotional/affective states.

[45] Koko, a gorilla trained to use sign language, was reported to have expressed vocalizations indicating sadness after the death of her pet cat, All Ball.

The authors suggest this responsiveness to the pain of others demonstrated by mice is indicative of emotional contagion, a phenomenon associated with empathy, which has also been reported in pigs.

I suffered many bruised toes and nipped fingers before I could detect a curious swivel of the ears, irritated flick of the tail, or concerned crinkle above a long-lashed eye.'

[65] The following is an excerpt from his book: A few years ago my friend Rod and I were riding our bicycles around Boulder, Colorado, when we witnessed a very interesting encounter among five magpies.

Then, all four magpies stood vigil for a few seconds and one by one flew off.Bystander affiliation is believed to represent an expression of empathy in which the bystander tries to console a conflict victim and alleviate their distress.

Mother hens show one of the essential underpinning attributes of empathy: the ability to be affected by, and share, the emotional state of their distressed chicks.

[70] Some research indicates that domestic dogs may experience negative emotions in a similar manner to humans, including the equivalent of certain chronic and acute psychological conditions.

The corresponding characteristic in humans has been found to correlate highly with an explanatory style and optimistic attitude that views the situation as other than personal, pervasive, or permanent.

Immediately after training, half of the honeybees were subjected to vigorous shaking for 60 s to simulate the state produced by a predatory attack on a concealed colony.

This shaking reduced levels of octopamine, dopamine, and serotonin in the hemolymph of a separate group of honeybees at a time point corresponding to when the cognitive bias tests were performed.

The researchers of the study stated that, "Although our results do not allow us to make any claims about the presence of negative subjective feelings in honeybees, they call into question how we identify emotions in any non-human animal.

It is logically inconsistent to claim that the presence of pessimistic cognitive biases should be taken as confirmation that dogs or rats are anxious but to deny the same conclusion in the case of honeybees.

Crayfish which experienced an electric shock displayed enhanced fearfulness or anxiety as demonstrated by their preference for the dark arms more than the light.

Furthermore, shocked crayfish had relatively higher brain serotonin concentrations coupled with elevated blood glucose, which indicates a stress response.