The Lopsided Ape
by Michael C. Corballis

He argues that it is significant that the human brain is structured somewhat asymmetrically with regard to where certain functions are performed. However, he fails to explain what the significance is. Even though he fails to make his point, he writes and explains things well and sorts through a lot of scientific information.

"Genes lying close on the DNA string to a change that proves to have survival value may also be selected in terms of their sheer proximity. This has been termed genetic hitch-hiking." p. 14

The earliest known mammals were primates. The opposable thumb is the main characteristic that distinguishes the primates from other mammals. p. 31

Bipedalism evolved before the increased brain size. p. 53

At the molecular lever, we are closer to the chimpanzee that the chimpanzee is to the gorilla. We are conspicuously more aquatic than our ape cousins. The decline in estrus and the more or less continuous sexual receptiveness of human females favor monogamy. p. 58

The human brain is the fourth largest, after whales, elephants, and dolphins. p. 66

Our brain is three times as large as we would expect for a primate of our build. p. 67

To hold to the pattern of primate development, women should give birth after a gestation of about a year and a half. This means that human babies are in effect embryos for about the first 9 months after they are born. Our large heads make birth difficult as it is. To delay birth beyond the nine month gestation period, when the brain is undergoing rapid growth, would make it impossible. The size of the pelvic canal is also limited by the structural requirements of bipedal walking. p. 68 The brain of a newborn chimpanzee is about 60% of its ultimate weight, while that of a newborn human is only 24% of an adult. p. 69

Most of the growth of the human brain therefore takes place after birth, when the child is exposed to the modifying influences of the environment, whereas the brains of apes are more than half developed at birth. p. 70

After 10 or 11 months, the superiority of the human infant begins to assert itself. p. 69

There is good evidence that if language is not learned before the age of puberty, it will never be learned properly at all. p. 72

Extending the period of infancy and childhood capitalizes on the period of greatest plasticity. Significant adaptive changes can therefore occur within a generation and are transmitted culturally rather than genetically. p. 72

The close sexual bonding between parents may also play a role here. Together with the helplessness of the human infant, it ensures a strong bond between parents and their children, and so maximizes the opportunity for children to learn from their elders (until the children become teenagers, that is). p. 72

The great majority of human beings are right handed. In most of us the left side of the brain controls speech. p. 80

Limbs are symmetrically placed so that movement, whether achieved by running, swimming, or flying, may proceed in a straight line. Any asymmetry in legs or wings would be likely to cause an animal or bird to proceed in fruitless (and perhaps meatless) circles. Sense organs, such as the eyes, ears, and nostrils, are symmetrically placed so that we may be equally alert to either side. Those parts of the brain that are concerned with these functions mirror the symmetry of the functions themselves. p. 81

Similarly, the asymmetrical placement of the internal organs of the body no doubt allows for more efficient packaging, and there in no survival value to be gained from bilateral symmetry in such matters. p. 82

There can be little doubt that handedness does have a structural basis, not in the hands themselves but in the brain structures that control them. p. 84

It seems likely that if cultural pressures were totally eliminated, right-handers would still constitute a substantial majority, with the proportion of left-handers reaching an asymptotic value of about 12 to 13 percent. p. 90

To find any asymmetry comparable to human right-handedness, we have to go to another talkative creature, the parrot. Most species of parrot seem to be left-footed in that they prefer to pick up bits of food with the left foot while perching on the right. p. 98

Phonemes may be combined to form morphemes, morphemes to form words, words to form sentences. p. 113

Modern theories of grammar, while still incomplete, are so complex that they take years to master. This is ironic, since the use of grammar is in fact easily achieved by most of us in early childhood. p. 118

The rules that children acquire are never the simplest, most obvious ones that an intelligent but "neutral" person would naturally infer. Only someone with a priori knowledge of what language is like could possibly extract the rules from the tangle of words available. Chomsky argued that every child is innately equipped with a language acquisition device (LAD) that guides the learning of linguistic rules. The LAD incorporates universal grammar and is uniquely as well as universally human. p. 120

Language is uniquely human. It depends heavily on the long period of postnatal growth that uniquely characterizes human development, and indeed is linked to specifically human developmental milestones. p. 133

Workers who have lost their larynxes are often unable to continue manual work. Difficult actions that require precise movement are usually performed with the breath held and the lips closed. After performing such actions, especially those involving considerable effort, the air is suddenly released, producing an audible grunt. p. 155

Pointing seems to be unique to human beings. p. 157

Reading disability is rare in Japan where script is laid out in vertical columns and symbols have the same meaning if left-right reversed. p. 199

Japanese symbols represent either syllables (kana) or whole words (kanji). p. 215

It is possible that only humans have the facility to use the concept of self recursively. p. 243 (This is important for a moral agent. RH)

Right-handed people have better control over the facial muscles on the left than the right. Emotions are more expressed more intensely on the left side of the face. p. 264

Almost all musicians who began their training before the age of 6 possess absolute pitch, compared with none of those who began after age 11. p. 268

The right hemisphere seems to play the more prominent role in our awareness of space and in the control of emotion, while the left hemisphere is dominant in the more abstract, propositional processes of language and reasoning. p. 311

The earlier forms of representation are, in humans, biased toward the right hemisphere are more holistic, and their intuitive quality may derive from the fact that they are preverbal. Many functions associated with the right hemisphere, such as emotion, the appreciation of music, or the perception of faces, are precisely the sorts of functions for which words often fail us. p. 272

After birth, most infants tend to sleep or lie with their heads turned to the right, an asymmetry that is readily noticeable in any hospital ward of healthy babies. p. 282

The message to new parents is that it might be better to speak to the infant from the right side of the crib but to play music from the left side. ... If just gazing fondly at your infant, then it might be advisable to do so from the left side of the crib, scurrying to the other side only if you wish to talk. p. 286

What we evolved was a more general capacity for adaptation itself. p. 312

Year Read: 1997


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