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37th IVU World Vegetarian Congress
Goa, India, September 10-16, 2006
Healthy Lifestyle - Vegetarian Way!

The Intelligence, Emotion, and Personality of Nonhuman Animals

Paper presented at the 37th IVU World Vegetarian Congress
September 10-16, 2006, Goa, India

George Jacobs, Vegetarian Society (Singapore)

With increased knowledge of the behaviour and cognitive abilities of the chicken has come the realization that the chicken is not an inferior species to be treated merely as a food source. (Leslie Rogers, 1995, p. 213)

People have many reasons to adopt a vegetarian diet, among which is compassion for our fellow animals. Vegetarians can strengthen the appeal of the compassion rationale for vegetarianism by providing evidence that other animals too display intelligence, emotion, and personality. This evidence can help convince humans that nonhuman animals are not mere objects to be used however we wish, like so many pieces of rock. Instead, nonhuman animals are thinking, feeling beings who deserve opportunities to live their lives according to their capabilities and dispositions.

The goal of this paper is to heighten the persuasive powers of vegetarians by bringing together a sampling of the growing amount of information that points to the sentience of our fellow animals. The paper is somewhat artificially divided into three sections: on intelligence, emotion, and personality. In addition to the normal list of works cited, the paper ends with other sources of further information, in hopes of making the paper as useful as possible.


Intelligence has been defined in many ways. The Merriam-Webster Online Dictionary defines it as, "the ability to learn or understand or to deal with new or trying situations" (Retrieved 24 January 2006 from Gardner (1993), in a now popular view, claims that there exist many intelligences, such as verbal-linguistic, visual-spatial, interpersonal, and bodily-kinesthetic. This section of the paper presents a small sample of the evidence for intelligence in other animals.


Memory may be considered an element of intelligence. A study reported in 2001 at the Babraham Institute in Cambridge, UK found that sheep can recognize the faces of as many as 50 other sheep as well as of familiar humans ( and, in some cases, sheep can even recognize the faces of individuals whom they have not seen for two years Goats, cattle, and horses are believed to have similar powers. In a follow-up study reported in 2004, researchers found that sheep could also recognize differences in emotions found in the faces of sheep and humans (


Another element of intelligence involves the ability to communicate. Although our fellow animals do not speak in the way humans do, they have many other means of communication (Pepperberg, 1991). A well-known example of communication among nonhumans are the dances that bees do to inform others about food sources: ( The dances and the sounds the bees make communicate the direction, distance, and even the height of food sources.

Tool use

The ability to use tools was once thought to belong exclusively to humans, but now we know that other animals also use tools. Examples are chimpanzees, elephants, dolphins, crows, and woodpecker finches. For instance, researchers observed a crow who learned to moisten his own food. In the case of this crow, humans had previously moistened food before giving it to him, but when they forgot, the crow used a cup to collect water from a trough and then poured the water onto his food (


Numeracy is another highly prized skill among humans that some other animals seem to possess to some extent. For example, research has shown that the ability to count and even to understand the concept of zero can exist among parrots: ( Chimpanzees have demonstrated a similar ability.


Another cognitive capacity is the ability to feel pain, as pain can act as an important aid to learning. Not everyone agrees about which of our fellow animals can feel pain. For example, a controversy exists over whether fishes can feel pain: However, less doubt exists about the pain experienced by mammals (CIWF, 2003). For instance, in lambs, levels of the stress hormone, cortisol, increase dramatically after tail-docking, the cutting off of part of their tails. Another example occurs among chickens who become lame because, as a result of being fed growth hormones, their bodies become unnaturally heavy and their legs cannot support the abnormal weight. These chickens have been found to prefer feed that contains a pain-killer. One last example of nonhuman animals' ability to experience pain involves calves who are de-horned by the meat and dairy industries: Dehorning is done to reduce injuries caused in part by the cramped conditions in which cows are forced to live: After dehorning, the calves' behavior differs markedly from calves who have not been subjected to this mutilation (CIWF, 2003).


Our fellow animals experience a range of emotions (Bekoff, 2000, 2002; Darwin, 1872; Goodall, 1990; Masson, 1997; Masson & McCarthy, 1995; Thomas, 1993, 1994, 2000). Unfortunately, negative emotions may predominate among the many billions of nonhuman animals forced to live on factory farms. This section of the paper presents a sampling of the evidence in the area of emotion.


Nonhuman animals have many reasons to feel fear, given the treatment that so many of them receive from the meat industry. For example, piglets separated from their mothers squeal in a distinctive manner, attempt to escape their enclosures, and may even seem to lose interest in living (Weary & Fraser, 1997). Sheep separated from their flock experience increased heart rate (Fraser & Broom, 1997). Calves and cows attempt to avoid people, such as those in the meat industry, who have attacked them in the past, for instance, with electric prods (Hemsworth & Coleman, 1998).


Another negative emotion is frustration. Due to factory farming practices, nonhuman animals often feel frustrated, because humans stop them from performing natural behaviors. Frustration arises because the nonhuman animals know what they want to or have to do, but are unable to fulfill their desires. An example occurs with chicken who are raised for reproduction. During a particular stage in their lives, they are allowed only a few minutes a day to eat. The resulting frustration leads to hyperactivity, aggression, and other unfortunate behaviors (CIWF, 2003).


Other than fear and frustration, our fellow animals also feel positive emotions, such as pleasure. One example is seen in calves after they have learned how to open a gate to enter an area where food is available. Their heart rate rises, and they exhibit excited behavior (CIWF, 2003). Perhaps more amazing is that one researcher believes that other animals, such as chimps, dogs, and rats, do something a bit like a human laugh:


Nonhuman animals seem to be able to empathize with others. Darwin may have been one of the first scientists to write about empathy among nonhuman animals. In The Descent of Man (1871), he maintains that many nonhuman animals are capable of sympathizing with others. de Waal (2001) cites the case of a psychologist who was studying the responses of young children to the emotions of others. When visiting human children in their homes, the researcher found that the other animals in the home, such as cats, responded as much as did the children, for example, cats would stay near to someone in distress and put their heads in the laps of those who were suffering.

Research with rats and primates, reported by de Waal (2001), offers further evidence that nonhuman animals react to the pain of others. When rats received food pellets for pressing a lever, they would at least temporarily stop pressing the lever when they saw other rats in distress. Similarly, when one rat saw another in an uncomfortable situation, the viewing rat would press a lever to change the other's circumstances. In a related study with monkeys, participants refused to pull a chain that would bring them food when they saw that pulling the chain caused another monkey to receive a shock.

In addition to laboratory studies, many examples of empathy can be found among nonhuman animals in nature. Here are a few examples:

a. All lions in a pride look after all the young, not just their own offspring (
b. Breeding birds receive help raising their young from helper birds, who protect nests from predators and help feed the fledglings (
c. Bees sacrifice themselves to save their hive (
d. Vampire bats regularly regurgitate blood and donate it to other members of their group who have failed to feed that night, ensuring they do not starve (
e. Vervet monkeys give alarm calls to warn fellow monkeys of the presence of predators, even though in doing so they attract attention to themselves, increasing their own chance of being attacked (
f. Dolphins support sick or injured compatriots, and even humans, swimming under them for hours at a time and pushing them to the surface so they can breathe (


Siebert (2006) reports the emergence of a new field of psychology, known as animal personality. Researchers in this and related fields have found that our fellow animals exhibit a wide variety of capabilities and behaviors that were once thought to be the exclusive domain of humans. An Animal Personality Institute has been established ( The institute's website contains a list of researchers and organization in this area, as well as a bibliography of works on the personalities of our fellow animals.

The institute's founder, Sam Gosling, began his work in the area after reading about personality among octopi. His first project was to give a modified personality measurement instrument used with humans to four people who worked with a group of hyenas. Gosling and John (1999) found that the people were able to use the instrument to attribute different personalities to each of the hyenas. After repeating the study with other species, Gosling and John (1999, p. 69) concluded that:

Scientists have been reluctant to ascribe personality traits, emotion and cognitions to animals, even though they readily accept that the anatomy and physiology of humans is similar to that of animals. Yet there is nothing in evolutionary theory to suggest that only physical traits are subject to selection pressures.

While, on one hand, some scientists may criticize Gosling and others who try to link our fellow animals and humans, on the other hand, what Siebert (2006) calls a "duh factor" often exists among humans who have spent large amounts of time with other animals. In other words, to many humans, especially ones who have a close relationship with individual nonhuman animals, it seems obvious that at least some species of our fellow animals think, feel, and have distinct personalities. In fact, until the rise of behaviorist psychology in the middle of the last century, many scientists agreed with Gosling's view, Darwin (1872) being an example.

One aspect of personality involves being a separate individual onto oneself, i.e., having a separate self. Irvine (2004) outlines four characteristics of self - agency, coherence, affectivity, and self-history - and explains how other animals possess these. These characteristics are important because they provide evidence of the selfhood of our fellow animals without them having to speak, at least not in the typical human sense of that term. Below, each of the four aspects of self is explained.

Agency involves deciding which actions to take, rather than being acted upon or acting in a pre-programmed manner. We see other animals exhibit agency when they interact with others of their species and when they search for food. A second characteristic of self is coherence, which means understanding oneself as an individual separate from others. One place we see evidence of coherence is when other animals hide. They may be prey hiding from predators or predators hiding in hopes of attacking unknowing prey.

Affectivity is a characteristic of self that has two main dimensions: emotion and vitality affects. While nonhuman animals may not have the range of facial expressions that humans possess, as discussed earlier in this paper, they do seem to exhibit many of the same emotions. For example, Irvine (2004) describes the grief that he witnessed in a female cat. The female and a male cat had formed a very close bond, sleeping, eating, and playing together. When the male died, the female grieved for an extended period of time, becoming withdrawn and disinterested in activities that had previously captured her attention. She would search for her friend, and failing to find him, stopped eating for a few days. This grieving continued until the cat moved to a new home.

A second aspect of affectivity involves what Bruner and Kalmar (1998) call "vitality affects." They explain that vitality effects concern a being's mood and zest for living. Thus, being lethargic, i.e., without much vitality, is one example of a vitality affect. In other words, the personalities of particular individuals manifest themselves in the way that they move and carry themselves.

The fourth characteristic of self is self-history, i.e., memory for what has happened to oneself in the past. This memory supplies meaning to the objects, places, individuals, and events of one's life. For instance, certain objects evoke certain emotions based on memory of past experiences, such as sheep may ignore most passing vehicles but come running when then see the vehicle which brings them food.


Anthropomorphism - Yes

Some critics of the ideas presented in this paper contend that those who credit other animals with intelligence, emotion, and personality are engaged in unwarranted anthropomorphism: giving human characteristics to nonhuman animals or to objects. These critics argue that we are superimposing a human frame of reference onto other animals in inappropriate ways. However, Irvine (2004) explains that anthropomorphism is actually a continuum, rather than an all-or-nothing attribution. To represent one end of the continuum, de Waal coined the term anthropodenial for the view that our fellow animals are very much different from us (Foster, 2001).

When vegetarians try to convince fellow humans that we should not eat other animals because these other animals, like us, possess intelligence, feel emotions, and have personalities, we are not saying that these characteristics are necessarily the same in other animals as they are in humans. Furthermore, a great deal of variation exists among different nonhuman animals. Perhaps, we can find a point somewhere in the middle of the anthropomorphism continuum. As Irvine (2004, p. 5) explains, this middle point, "[I]nvolves informed, systematic interaction with and observation of animals known as 'critical' or 'interpretive' anthropomorphism."

The future

Research into the intelligence, emotion, and personality of our fellow animals constitutes a growing field, with exciting new evidence emerging every year. Few of us are in a position to actually take part in this research. However, all vegetarians can play a crucial role in disseminating the results of the research. That has been the goal of this paper, for I believe that this research, along with humans' own personal experience with our fellow animals, offers strong grounds for the ending of human consumption of other animals.

In conclusion, please allow me to make two recommendations to those kind readers who have ventured this far into the paper:

  1. Be alert for further news of research into the intelligence, emotion, and personality of our fellow animals. The web sites mentioned here are among the many excellent resources. While some difficult technical terms and concepts will be encountered, the basics are not difficult to grasp with some effort.

  2. Share what you learn with others, vegetarians and non-vegetarians alike. This can be done via such means as word-of-mouth, email, newsletter, vegetarian society websites, posters, video showings, and talks. Let us show the bright side of human intelligence and emotion by bringing out the hard-working side of our personality to help our fellow animals.

I have no doubt that it is a part of the destiny of the human race, in its gradual improvement, to leave off eating animals (Henry David Thoreau, 1854, ch. 11)

Works Cited

Bekoff, M. (Ed.) (2000). The smile of a dolphin: Remarkable accounts of animal emotions. New York: Random House/Discovery.

Bekoff, M. (Ed.) (2000). Minding animals: Awareness, emotions, and heart. Oxford: Oxford University Press.

Bruner, J., & Kalmar, D. A. (1998). Narrative and metanarrative in the construction of self. In M. Ferrari & R. J. Sternberg (Eds.). Self-awareness: Its nature and development (pp. 308-331). New York: Guilford.

CIWF (Compassion in World Farming). (2003). Stop - look - listen: Recognising the sentience of farm animals. Petersfield, Hampshire: Author. Also available online at

Darwin, C. [1871] (1998). The descent of man. Amherst, NY: Prometheus Books.

Darwin, C. [1872] (1998). The expression of the emotions in man and animals (3rd ed.) New York: Oxford University Press.

de Waal, F. B. M. (2001, October 26). Do humans alone 'feel your pain'? Chronicle of Higher Education, B7. Retrieved 23 January 2006, from

Foster, (2001, April 8). Are you in antropodenial? New York Times on the Web. Retrieved 23 January 2006, from

Fraser, A. F., & Broom, D. M. (1997). Farm animal behaviour and welfare. Wallingford, Oxfordshire: CABI Publishing.

Gardner, H. (1993). Frames of mind: The theory of multiple intelligences (2nd ed.). NY: Basic Books.

Goodall, J. (1990). Through a window: My thirty years with the chimpanzees of Gombe. Boston: Houghton Mifflin.

Gosling, S. D., & John, O. P. (1999). Personality dimensions in non-human animals: A cross-species review. Current Directions in Psychological Science, 8, 69-75. Retrieved 23 January 2006, from

Hemsworth, P. H., & Coleman, G. J. (1998). Human-livestock interactions: The stockperson and productivity and welfare of intensively farmed animals. Wallingford, Oxfordshire: CABI Publishing.

Irvine, L. (2004). A model of animal selfhood: Expanding interactionist possibilities. Symbolic Interaction, 27(1), 3-21.

Masson, J. M. (1997). Dogs never lie about love: Reflections on the emotional world of dogs. New York: Three Rivers/Crown.

Masson, J. M., & McCarthy, S. (1995). When elephants weep: The emotional lives of animals. New York: Delta.

Pepperberg, I. (1991). A communicative approach to animal cognition: A study of conceptual abilities of an African Grey Parrot. In C. A. Ristau (Ed.), Cognitive ethology: The minds of other animals (pp. 153-186). Hillsdale, NJ: Lawrence Erlbaum.

Rogers, L. J. (1995). The development of brain and behaviour in the chicken. Wallingford, Oxfordshire: CAB International.

Siebert, C. (2006, January 22). The animal self. New York Times Magazine, retrieved January 22, 2006, from

Thomas, E. M. (1993). The hidden life of dogs. New York: Houghton Miffline.

Thomas, E. M. (1994). The tribe of tiger: Cats and their culture. New York: Simon & Schuster.

Thoreau, H. D. (1854). Walden. Retrieved 26 January 2006, from

Weary, D. M., & Fraser, D. (1997). Vocal response of piglets to weaning: Effect of piglet age. Applied Animal Behaviour Science, 54, 153-160.

Other Recommended Sources

Adams, C. J., & Donavan, J. (Eds.) (1995). Animals & women: Feminist theoretical explorations. Durham, NC: Duke University Press.

Animal Cognition & Learning website:

Animal Sentience website:

Barber, T. X. (1993). The human nature of birds. NY: St. Martin's Press.

Bonner, J. T. (1980). The evolution of culture in animals. Princeton, NJ: Princeton University Press.

Cromie, W. J. (2002, March 14). Scientists think that animals think. Harvard University Gazette. Retrieved January 24, 2006, from

Dawkins, M. S. (1998). Through Our Eyes Only? The Search for Animal Consciousness. Oxford: Oxford University Press.

de Waal, F. B. M. (1989). Peacemaking among primates. Cambridge: Harvard University Press.

de Waal, F. B. M. (1997). Bonobo: The forgotten ape. Berkeley: University of California Press.

de Waal, F. B. M. (2001). The ape and the sushi master. New York: Basic Books

de Waal, F. B. M., & Tyack, P. L. (Eds.). (2003). Animal social complexity: Intelligence, culture, and individualized societies. Cambridge: Harvard University Press

Dunayer, J. (2001). Animal equality: Language and liberation. Derwood, MD: Ryce Publishing.

Dunayer, J. (2004). Speciesism. Derwood, MD: Ryce Publishing.

Hauser, M. (2000). Wild minds: What animals really think. New York: Henry Holt.

International Vegetarian Union website:

Sanders, C. R., & Arluke, A. (1993). If lions could speak: Investigating the animal- human relationship and the perspectives of nonhuman others. Sociological Quarterly 34, 377-390.

Singer, P. (Eds.). (2006). In defense of animals: The second wave. Malden, MA: Blackwell.

United Poultry Concerns website:

Vegan Outreach website:

Webster, J. (1995). Animal welfare: A cool eye towards Eden. Oxford: Blackwell Science.

Wynne, C. D. L. (2001). Animal cognition: The mental lives of animals. Basingstoke, Hampshire: Palgrave Macmillan.

Wynne, C. D. L. (2004). Do animals think? Princeton, NJ: Princeton Un



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