Marc Hauser
Experiments washed by Marc Hauser convince him that animals take interesting thoughts, particularly chimps and monkeys, who lead relatively rich social lives. (Staff photograph by Stephanie Mitchell)

Do animals think?

"Of course they practice," answers Marc Hauser, a Harvard professor of psychology. "How could they not think and manage to survive in the world?"

Hauser has been studying fauna noesis since 1980, when a female spider monkey reached through the bars of her cage at Florida'south Monkey Jungle and gave him a hug. He was 19 years old at the fourth dimension. "She looked into my optics and cooed several times," he remembers. "The experience got me to thinking virtually what animals are thinking and how to discover out."

He now believes that animals conceive the world in means like to humans, especially species similar chimpanzees who alive a rich social life. His field and laboratory experiments propose that humans got their mechanisms for perception from animals. "Those mechanisms came free, courtesy of evolution," he says.

Hauser and his colleagues are trying to determine what sorts of thinking processes are unique to humans and what processes we share with animals. The i that comes immediately to heed is linguistic communication.

"Animals take interesting thoughts, but the only manner they can convey them is by grunts, shrieks, and other vocalizations, and by gestures," Hauser points out. "When humans evolved spoken communication, they liberated the kinds of thoughts nonhumans accept. Feedback between linguistic communication and thinking then boosted human cocky-awareness and other cognitive functions."

Can your pet think?

Most pet owners fervently believe that Fido or Fluffy has superior intelligence. Ane of the markers of intelligence is self-awareness, so here is a quick examination to run into if the animal has that power.

Position a mirror by your pet's nutrient dish, so it can come across its face and caput. Whenever you feed it pat the dog, true cat, or whatsoever on the head. Echo this routine for 3 to four days.

When you lot're ready, put some odorless light or nighttime powder in your manus and pat it onto your pet's head. You tin can use blistering soda or carbon black. Make certain you create a clearly visible spot on its head.

Watch the animal closely to encounter if it stares at itself, or tries to rub the spot. If it does, congratulations, your pet has some sense of self.

For more pet intelligence tests, consult "Wild Minds" by Marc Hauser (Henry Holt, 2000).

Monkeys get the rhythms

Clever experiments with monkeys and homo infants prove that they share thinking processes once thought to be in the minds of humans lonely. Babies just 3-4 days quondam can tell the difference between two languages such as Dutch and Japanese. When the infants hear someone saying sentences in Dutch, they express their interest past sucking rapidly on the nipples of pacifiers. After a while they go bored with the Dutch talk and stop sucking enthusiastically. If someone then starts speaking Japanese, they will show increased interest by upping their sucking rate.

The babies don't know what the speakers are talking about, of course, but they can discriminate between languages by the change in rhythms. They don't respond to languages with similar rhythms, such as Dutch and English language or French and Spanish. Likewise, if y'all play the same sentences backward, the infants neglect to react. "One explanation for this behavior is that they intuitively know that no human song tract can produce such sounds," Hauser explains.

If this is truthful, monkeys should not exist able to make the same distinctions because they don't know what rhythms and sounds human vocal tracts can produce. Only cotton-top tamarin monkeys easily distinguish between Dutch and Japanese. They look at a speaker dissemination sentences of Dutch, look abroad when they're bored, and then look dorsum when someone starts speaking Japanese. And they cannot make that stardom when the sentences are spoken backward.

"The monkeys have the same perceptual abilities as us," Hauser concludes. "That means such perception did not evolve with human speech communication; information technology existed earlier humans and speech evolved."

Babies do statistics

1 big mystery nigh man knowledge is how babies make up one's mind when one word ends and another begins when they listen to an adult'due south stream of speech. Experiments done in 1996 revealed that kids equally young as 8 months are capable of performing a kind of statistical analysis that seems pretty amazing.

The babies listen to a continuous stream of consonants and vowels, such as "dapikutilado…." Some combinations always cluster together, like "da-pi-ku," while others do not. If infants are aware of statistically familiar clusters, they show little involvement when they hear them. Merely when they hear something similar "da-ku-pi," they know something is unfamiliar. They look toward the sounds of unfamiliar triplets longer than they expect in the direction of those that are relatively familiar.

The youngsters don't know it, merely that's how they will get the hang of separating words in a stream of spoken communication. Linguists call this "computing transitional probabilities." It sounds too complicated for an 8-month-quondam, much less for a monkey. Even so, Hauser and his two collaborators, Elissa Newport and Richard Aslin, showed that cotton wool-top tamarins can do the same thing.

Perceptual and at least some ciphering mechanisms, therefore, lived in the brains of animals long earlier humans came along, even ancient humans who didn't do much more than grunt and bellow. "Some people wouldn't call these abilities 'thinking,'" Hauser admits. "That'southward fine with me. But it begs the question, 'What practise you mean by thinking?'"

How loftier can animals count

Additional tests by Hauser and other researchers reveal that monkeys can count up to four. The human ability to count to college numbers apparently came only later on we evolved language and developed words to describe quantities like 25 and one,000.

Some human cultures still don't apply large numbers. The Hadza people, hunter-gatherers in Tanzania, for example, have words only for "i," "two," and "three"; anything more than is "many." They are enlightened that a picture with 30 dots displays a larger number than one with twenty dots (as are monkeys), only they take no words for the precise numbers of dots.

The bottleneck between human and nonhuman thinking involves not just words, but the power to recombine words in an endless diverseness of new meanings. That appears to be a unique man capability. Chimpanzees take a rich social and conceptual life, Hauser maintains, but they tin't discuss it with each other.

The next pace in determining how much thinking ability humans share with other animals will involve scanning the brains of both while they do the aforementioned cognitive tasks. Harvard psychologists have already begun to practice this in a collaboration with researchers from the University of Massachusetts Medical School in Worcester and the Max Planck Institute in Germany. Monkeys may exhibit the same kind of intellectual behavior as humans, simply do they both employ the aforementioned areas of the brain?

"We have a great deal of data that show what areas of the encephalon are activated when humans respond to various situations," Hauser points out. "Now we will determine if monkeys and other animals use the same brain circuits."

So far, the monkeys are adapting well to experiments at the University of Massachusetts. They move into harnesses in brain scanning instruments, such as MRI machines, without difficulty. Measurements of their stress levels show that later on v days of training, marmoset monkeys feel equally comfy as they do in their home cages with their own social group.

For some people, such research will non provide a satisfactory answer to the question: Do animals really think? These people define thinking as having a sense of self, beliefs that go across raw perceptions, emotions such as empathy, and the ability to imagine a state of affairs remote in time and place and predict an outcome.

"Those capabilities cannot be illuminated by brain scanning," Hauser admits. "But experiments using other techniques are beginning to shed light on what kinds of perceptual and computation skills animals bring to analyzing the globe, and in what ways these skills are unlike from our own."

I recollect, therefore I am. – Descartes

For more information well-nigh nonhuman thinking, run into Hauser's book "Wild Minds," (Henry Holt, 2000). Hauser will debate distinguished linguist Noam Chomsky on March 30 at Harvard at a conference sponsored by the Language Evolution Society.