The Minnesota Study of Twins Reared Apart and nature versus nurture

¶ … Nature/Nurture Debate

The long-standing debate about nature vs. nurture seeks to identify the greatest influence on one's intelligence, personality, and talents. Some believe that people inherit these characteristics, which will be manifest regardless of the circumstances under which one is raised. Others believe that one's environment shapes these factors. Talents and intelligence will languish if not nurtured; conversely, one born with average abilities and intelligence can benefit from enrichment. It is impossible to know to what extent nature vs. nurture shapes a child. Researchers could never conduct experiments in which groups of children were provided one type of upbringing over another; to do so would be shockingly unethical and immoral. However, scientists can study real-life cases and try to draw some conclusions.

The Minnesota Study of Twins Reared Apart commenced in 1979 for the purpose of trying to answer the nature/nurture question. Thomas Bouchard found that twins reared apart were as likely to share traits such as personality, interests, and attitudes as twins reared together. Bouchard surveyed both fraternal and identical twins. The findings suggest that these attributes are controlled by genetics, not environment. Further study by Bouchard and others have yielded some interesting results. Eckert, Bouchard, Bohlen and Heston (1986) found that homosexuality in male twins was likely genetically predisposed, while homosexuality in female twins was likely a learned behavior. Grove, Eckert, Heston, Bouchard, Segal and Lykken (1989) found both alcohol and drug abuse occurred with equal frequency among twins raised apart, suggesting a genetic disposition to addictive behaviors.

Ideal study conditions for the nature/nurture debate cannot be replicated in a laboratory. Researchers must seek twins who have been reared apart. They have no way to control the subjects and must rely on the anecdotal evidence subjects provide. The consequences of reaching a definitive answer would be far-reaching if it could be proven that genetics, rather than environment, made the greatest difference. Too many advances have been made in the United States with respect to equal education and opportunities for children of different races, genders, ethnicity, and socioeconomic groups. Children from traditionally underserved populations have made gains when provided opportunities their parents did not have. Genetics plays a role, but psychologists today believe that environment plays a greater factor.

2) Riding a Bicycle

The vestibular senses are awareness of body movement and balance. When startled, a person would make movements instinctively and not necessarily appropriately. One might slam on the brakes or jerk the handlebars in one direction or another. It would be easy to lose one's balance in such a circumstance. Kinesthetics is the sense that detects body position, weight, and the use of muscles and tendons. If one is startled, one can feel briefly disoriented and may feel too heavy and clumsy to get out of the way of disaster. Figure-ground perception refers to the seeming prominence of a target figure while the background recedes. In the case of the pursuing dogs, they seem huge to the cyclist because s/he is startled. In the mind's eye, the dogs assume extra large proportions, out of context with their surroundings. Closure is the emotional conclusion to an event. There are two possible scenarios for the bicycle rider. If the person were afraid of dogs, panic might ensue at the realization s/he was being chased. The person might try to ride faster or may fall or crash into something as a result of disorientation. On the other hand, if the person did not feel threatened by the dogs, then s/he might laugh in a self-deprecating way, regain balance and composure, and continue on with the bike trip. According to the law of common fate, one sorts out lines, curves and shapes perceived and makes meaning of them. When first startled by a pack of dogs, the bike rider would instantaneously wonder "What's that?" The person would detect movement and shapes and it would take a moment before those shapes made sense as dogs. The person would be startled by initial movement and startled a second time with the realization of what s/he saw. Size constancy refers to the perceived size of objects. Objects are the same size, obviously, whether they are near or far, but our minds perceive size relative to surroundings. The dogs appear much larger the closer they get. They may seem huge to a person who is afraid of dogs.

4) Sleep Cycle and Sleep Disorders

There are five stages in the sleep cycle: one through four and the rapid eye movement (REM) cycle. In stage one, sleep is light. One can move easily from sleep to wakefulness. The eyes move slowly and muscle movement slows. In stage two, eye movement stops. Brain waves become slower. In stage three, very slow brain waves (delta waves) are interspersed with smaller, faster waves. In stage four, almost all the waves are delta waves. Stages three and four are deep sleep, sometimes called delta sleep. There is no eye movement or muscle activity, and it is very difficult to wake someone during delta sleep. During REM, there is rapid eye movement, increased heart beat, more rapid breathing, and increased brain waves. During this stage, dreams occur; people who wake during this phase will remember their dreams.

Insomnia is a sleep disorder that can occur in one, or both, of two ways. People can have difficulty falling asleep initially, or they can fall asleep but have difficulty staying asleep. Doctors sometimes prescribe medication for insomnia, but some treatments can be habit-forming. Behavioral strategies may be a better option for many sufferers. These include limiting activities in the bedroom (e.g., removing the television), avoiding caffeine and alcohol, and relaxation techniques.

Another sleep disorder is sleep apnea. This is a physical problem in which the person breathes irregularly, with shallow breaths, or even stops breathing entirely for a few seconds. It is usually caused when the soft tissue in the back of the throat softens too much and blocks the airway. Sleep apnea can occur in anyone at any age, but is more common in men and in people of both genders who are overweight.

A third sleep disorder is one known as "restless leg syndrome." Sufferers feel a tingling or crawling sensation in their legs and they feel unable to keep their legs still. The sensation can also occur in the arms, although this is much less common. Movement can provide temporary relief to the crawling sensation, but it can resume once the person stops movement. Although medication has been shown to be effective in treating restless leg syndrome, many of the symptoms can be just as effectively treated as insomnia: avoidance of alcohol and caffeine, and relaxation techniques. Daily exercises and regular massages can also be beneficial.