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Are Animals Conscious?

Animals seems to have emotions, intentions, plans, and personalities, all things we humans associate with conscious­ness. How much can we read into animal behavior, before we start to make mistakes like the animal researchers of the 1880s?

Can we acknowledge that animals have experiences, emotions, an inner life? Most people do. If we grant there is something to be investigated, how do we investigate it?

One thing we can say with assurance: animals do not think in words. This means that cats and dogs and horses do not possess anything quite like human intelligence or reflective self-conscious­ness, which is dominated by language.

Animal awareness, whatever it is like, must be more immediate and reactive. Humans have belief systems composed of verbal descriptions, assertions, and explanations. Animals must live more "in the moment."

What can we "say with assurance" about animal awareness?

After our family moved from one house to another, one of my children asked me whether our cat "remembered the old house." I replied that we have good evidence that cats dream, so our cat might dream about the old house.

If she was brought back to the old house, she would remember it and know how to navigate around it. But I also explained that cats do not have language, so the cat never thinks, "I wonder what is going on at the old house" or, "I miss the old house."

Possibly our closest experience of consciousness without language happens on those rare occasions when we wake up quickly and the language areas of the brain are not fully engaged. That might happen, for example, in the moments after being awakened in response to an alarm clock.

We see our environment and react well enough to get out of bed and start the morning routine. However, for a few minutes we may not feel much like talking or experience much inner chatter.

While gradually waking up, we may greet a friendly dog or cat and give it a pat, treating it as an alinguistic equal. During that time our consciousness is direct and sensory-oriented, although we may perform goal-oriented activities showing an awareness of the future.

When it comes to emotions, there is more reason to think our states of mind resemble those of animals. Emotions are supported by the limbic system, and most mammals have limbic systems rival the size of human limbic system, or even greater in proportion to the size of their brains.

Why is it reasonable to assume we understand animal emotions?

Therefore it is not surprising that we can read the emotions of other mammals. Animals like horses and dogs can read ours also, making them skilled at adjusting to humans.

Owners will tell you that sociable birds such as parrots and penguins are transparent in displays of mood and emotion. Any devoted pet owner could draw up the equivalent of an ethogram, a list of species-typical behaviors, and a list of displays such as intention movements and submission postures, readily understood by the human owner.

The problem is not our inability to read emotion or intention into animal behavior; it is our tendency to overdo it. As shown by the case of Clever Hans and countless other examples, humans are prone to mistakenly anthropomorphizing (projecting human qualities into other species).

For purposes of advancing our know­ledge, it is not enough to say animal awareness is obvious or transparent or that animal emotions and personalities are evident, even if it is true. Any sort of objective measure that sheds a light on animal cognition is valued by research psychologists.

The Mirror Test

Gallup (1977) is famous for arguing that animals, particularly the great apes (chimpanzees and gorillas) do indeed have human-like consciousness. In one famous series of experiments, he studied the reactions of apes to mirror images of themselves.

Gallup assumed that if apes recognized their image in the mirror, they had some kind of self-awareness. That inference can be debated, but the mirror test itself is an objective measure.

Behavioral responses make it clear whether a creature treats a mirror image as a different animal or itself. If it charges the mirror or looks behind it, it thinks the image is of another animal.

If it sits in front of the mirror picking things out of its teeth, or makes other self-referencing behaviors, it knows it is looking at its own reflection. Responses tend to be one way or the other.

In Gallup's classic research, he first gave chimpanzees 10 days of exposure to full-length mirrors. During the 10 days, frequency of "other-directed behaviors" such as threat displays directed toward the mirror rapidly fell to near zero.

Then Gallup anesthetized the chimps and painted the top half of an eyebrow ridge with "bright red, odorless, non-irritating, alcohol-soluble dye." The marks were located so the animals could not see them without the mirror.

When the chimps awoke from the anesthesia, they were placed in front of the mirror. They increased their frequency of mirror-looking behavior by over 25 times. They touched the red spot, and they smelled and examined their fingers after touching the red area "even though the dye had long since dried and was indelible" (Gallup, 1977).

What was Gallup's experiment on self-recognition in apes?

Gallup and other investigators found that a variety of other primates, such as baboons, macaques, mandrills, and two species of gibbons did not respond this way. Gallup and his colleagues con­cluded that this ability was unique to humans and great apes.

A team of behaviorists, Epstein, Lanza, and Skinner (1981), could not leave the claim of animal consciousness unchal­lenged. What if a pigeon could be taught to do the same thing? Would we attribute self-consciousness to a bird?

They decided to use conditioning techniques to see if they could teach pigeons to behave like Gallup's apes. First the researchers taught pigeons to peck white flecks of paper off their own bodies, using a shaping procedure. Then they taught them to peck at things they could see only in a mirror.

How did Epstein and Skinner respond to Gallup's experiment?

Finally they fitted the pigeons with collars so the birds could not see their own bodies except in a mirror. Then they put flecks of paper on their bodies where they could not see them, except in the mirror.

Sure enough, the pigeons reached around the collar and pecked off the flecks of paper that they could see only in the mirror. Evidently they referred the mirror image to their own bodies.

The researchers triumphantly concluded that Gallup was wrong to use this task as an operational definition of self-awareness, because (obviously? transparently?) pigeons would not have self-consciousness of the sort Gallup was claiming for apes.

What is "one problem" with the Epstein and Skinner rebuttal to Gallup?

There are problems with the logic of Epstein, Lanza, and Skinner (1981) rebuttal to Gallup. The researchers seemed to be making the same assumption in their own work that they were criticizing in the work of Gallup: that similar behaviors in two different species represented the same sub­jective events.

The argument seemed to be: Pigeons could do the mirror task, and pigeons probably lack self-consciousness, ergo apes who could do the mirror task were not necessarily self-conscious. This logic only works if pigeons and apes go through the same cognitive processes in performing the task, and we do not know that.

An entirely different line of argument is that pigeons, being birds and therefore very visual animals, might indeed have the ability to relate a visual image to their bodies, especially when trained systematically to perform the compo­nent behaviors of the task. It is not clear (to me, anyway) whether this relates to the issue of animal consciousness.

Gallup's experiment has been criticized on various other grounds. Westergaard and Hopkins (1994) noted, "Only 20%...of the chimpanzees he actually tested actually passed the notorious mark test." They also pointed out that "effects of human contact on the development of self-recognition in chimpanzees and orangutans have yet to be assessed."

In other words, they were suggesting the mirror recognition might not be spont­aneous or natural. They also pointed out that monkeys readily learn to use mirrors to guide their own hand movements to obtain hidden food, so perhaps the discontinuity between monkey and apes (emphasized by Gallup) was not so great as first appeared.

What are criticisms of Gallup's research or conclusions?

Despite the criticisms, Gallup's research caught people's imaginations. It inspired new research, and the mirror test was tried on a wide variety of species.

Many species passed the mirror test at least occasionally, using mirrors to inspect their bodies after being marked. The list includes asian elephants, the great apes (bonobos, chimpanzees, orangutans, gorillas), bottleneck dolphins (porpoises), orcas, the Eurasian magpie, and possibly manta rays (Pachniewska, 2016).


Epstein, R., Lanza, R. P., & Skinner, B. F. (1981). Self-awareness in the pigeon. Science, 212, 695-696.

Gallup, G. G. (1977). Self-recognition in primates. American Psychologist, 32, 329-338.

Pachniewska, A. (2016) Animal Cognition. [blog] List of animals that have passed the mirror test. Retrieved from:

Westergaard, G. C., & Hopkins, W. D. (1994). Theories of mind and self recognition. American Psychologist, 8, 761-762.

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