A detailed and challenging read.
This book looks at how the brain works, and in particular the division of activity within the right (RH) and left (LH) hemispheres of the brain. Below are some interesting points I noted.
- Frontal lobes are c. 7% of the total brain in dogs, c. 17% in the lesser apes and c. 35% in both the greater apes and humans. However, humans have more white matter (the myelin sheath which greatly speeds transmission of signals along neurones).
- RH focuses on 'the new' - broad vigilant attention, bonding in social animals, detailed discrimination and topography. LH) has a narrower focus on 'the known' - categorising stimuli and fine control of motor response. In problem solving, RH presents an array of possible solutions, LH takes a single solution that best fits what it already knows.
- RH open to interconnectedness - empathy and self-awareness. This capacity emerges in primates. Children only acquire this capacity fully at age 4, though elements are present from around 12 to 18 months. Autistic children never fully acquire it, and lacking empathy and not understanding social language, irony and metaphor, they lack prosodic skill - the ability to convey meaning and feeling through intonation and voice inflection.
- RH faster and more accurate in discriminating facial expression and emotion. LH reads emotion in mouth (but not eyes where signs of emotion are more subtle).
- Disturbances in RH lead to body dysmorphia and anorexia nervosa. RH stroke more disabling than LH, despite LH loss of speech; RH stores words in songs. Apraxia - the inability to carry out action, despite no impairment of sensory or motor function is most severe after RH lesions.
- Language - each hemisphere uses language differently. Some great apes show the same R/L brain asymmetry. Homo heidelbergiensis (common ancestor of H.sapiens and H.neanderthalensis) had a large brain and vocal apparatus comparable to modern humans.
- All known spoken language needs brain space, vocal cords, control of tongue and mouth. Monkeys and apes lack such control. Only birds can mimic human voices.
- Significant similarities in music and language suggest a common origin. Music has a simpler syntax, and is less highly evolved, indicating an earlier origin. Newborns are sensitive to the rhythms of language (the prosody of speech) as seen in infant directed speech (baby talk or 'motherese'). No human culture is without music, in which people join together to dance and sing. Poetry evolved before prose, and early poetry was sung.
- Altruism. Most subjects in Prisoners' Dilemma tests prefer mutual cooperation over unilateral defection, but will punish selfishness by others in following rounds.
- Mutual gaze, especially shared, averted gaze at an object - highly evolved characteristic. Apart from humans, only some apes and monkeys with prolonged contact with humans may be capable of this. But dogs are very sensitive to human attention, especially direction of gaze and expression of eyes (most cats are not).
- The function of the corpus callosum - the band of tissue connection RH and LH - is to inhibit inter-hemispheric nerve impulses. This inhibition is disrupted in strokes and neurological injury, and also fails to develop in up to 1% of the population.
- Schizophrenia - many aspects may be due to this. Condition only noted from 18th century (in contrast to melancholia and bipolar behaviour, which are both recorded in ancient Egypt, Greece and Rome). Increased in prevalence with industrialization, but still relatively rare, steep increase in first half 20th century. More common in urban situations. Same trends in various nations.
- Universal natural music responses at physiological level. Activation of brain areas: harmony slows heart beat, brain areas associated with pleasant experiences, while dissonance stimulates areas dealing with noxious stimuli. Babies as young as 4 months prefer harmony.
- Increases in material well-being have little or nothing to do with human happiness, once basic material needs are met. Happiness is best predicted by the breadth and depth of one's social connections. This also correlates with rates of colds, heart attacks, strokes, cancer, depression and premature death of all sorts.
- In West, religion has declined in 20th century. But when we stop worshiping divinity, we find something else to worship.
- Eastern cultures - self-improvement is less about getting what one wants, and more about confronting one's own shortcomings. While setting higher personal standards, they rarely feel depressed about failure to measure up.
- In West, people tend to over-estimate their abilities, exaggerate their capacity to control essentially uncontrollable events and hold over-optimistic views of the future.
