Behavior genetics and disease.

Genetics make contributions to morphological and physiological traits as well as to behavior. The most obvious link between genetic heritage and phenotype (appearance) are physical characteristics. For example identical twins have identical genetic components and also identical appearance. Since cultural influences are also powerful it is particularly difficult to ascertain the influence of genes on human behavior. Nevertheless the etiology and function of genes in certain illnesses and associated behaviors is obvious. For example Downs syndrome is produced by genetic malfunction where instead of inheriting two number 21 chromosomes, the child inherits three.

Ongoing research has for some time linked genetic predispositions to mental disorders including depression and schizophrenia based on twin studies and other close familial relationships (Plomin, DeFries, McClearn, & Rutter, 1997). A genetic basis for these disorders is also supported by the fact that these mental disorders are universal although influenced also by cultural factors. More likely major mental illnesses are a result of an interaction between genetic factors and the environment. However, since no single gene is responsible for any behavior the gene-behavior pathway is very complex and difficult to establish. As for personality and intelligence the heritability of frequently occurring mental disorders like schizophrenia has largely been estimated from the frequency of occurrence in the patient’s closely related family. The fact that these illnesses occur worldwide would also strongly suggest a genetic influence, although different environments may still influence relative frequency and severity of symptoms (Plomin, DeFries, McClearn, & Rutter, 1997).

3.2.4 Hardwired optimism: The driver for cultural development.

Recent research (Sharot, 2011) has pointed toward the existence of a universal optimism bias. Research shows that humans are born with rose-colored glasses and more inherent optimism than justified by reality. For example ten percent of Americans believe they will live to be 100, whereas only 0.02 percent lives to that age. Assessments of the predictions of divorce shows that zero percent of U.S. marriage applicants expect to experience divorce whereas nearly half of married partners permanently end their marriages. Many respond with pessimism to contemporary economic conditions and 70 percent believe that other families in general are less successful compared to their parents generation. However when it comes to evaluating their own lives 76 percent are optimistic about the future of their own families. Research also showed profound optimism about their own driving ability as compared to others with 93 percent believing they were in the top 50 percentile in driving ability. The belief that somehow the future will always be better than the past is known as the “optimism bias” and is universal. One would think the contemporary conditions of wars, natural disasters, and economic collapse would affect personal prediction in a more pessimistic direction. However, as noted above our personal optimism remains high even while our expectations for society become pessimistic.

The obvious question is why personal optimism is so ubiquitous. It seems clear that persistent optimism is functional to our survival and cultural progress. Without optimism there would be nothing to stimulate innovation, produce new ideas, or encourage a willingness to persist despite conformity pressures. If not for optimism our ancestors might never have left Africa, or produced better ways to survive. We might still have remained cave dwellers if not for the motivational spark that made it possible to seek better ways. Our cognitive ability to anticipate alternative futures has been an essential component in the journey of mankind. A positive future may well be an illusion, but optimism provides clear benefits to the present. Optimists are more likely to look after their health whereas pessimistic cancer patients died earlier than those who had hope (Furnham and Heaven, 1999).

Now there is evidence that optimism may be hardwired into the brain as a trait selected by evolution with direct functional advantages. That opens a new perspective that our brains are not just related to the past, but may in fact be directed toward the future as well. Sharot’s research showed that the mere anticipation of the future colored even the most basic life events for the better. Could it be that optimism is the consequence of how our brains are wired? That our brains can anticipate the future has obvious survival functions as humans might better plan for contingencies and save resources for times of crisis or scarcity. Animals like squirrels and other species also have this function to anticipate winter and scarcity of food. This ability to mentally time travel is based on specific brain structures called the hippocampus. The research however shows that most people do not spend much time thinking about negative outcomes, but rather on how life might get better. Early research also points to the ability of the frontal cortex to communicate with subcortical regions as essential in directing our thoughts in a positive direction. Sharot suggest that without a neural mechanism that produces unrealistic optimism all humanity would be mildly depressed. However, on the contrary most of us find a silver lining in most events and find the positive even in negative outcomes. For example once a decision is made we all tend to evaluate the prospects positively and expect pleasure.

Sharot suggest that optimism was selected by evolutionary processes because positive expectations are motivating and increase our odds for survival. Optimists live longer and are healthier as they behave consistent with their positive expectations. The ubiquitous nature of optimism leads to an evaluation of the possibility that this trait is linked to specific gene structures - an area of future research. While optimism is irrational we would probably not get out of bed in the morning without future positive expectations.

Date: 2015-01-11; view: 685