Chapter 12 Outline - 12 Motivation Motivation a process...

12. Motivation
Motivation - a process within a person or animal that causes that organism to move toward a goal or
away from an unpleasant situation
• Intrinsic motivation – the desire to do something for its own sake and the pleasure it
brings
• Extrinsic motivation – the desire to do something for external rewards
The Hungry Animal: Motives to Eat
• The biology of weight
o Genetic influences on weight and body shape
 Set point – the genetically influenced weight range for an individual; it is
maintained by biological mechanisms that regulate food intake, fat reserves, and
metabolism
 Everyone has a genetically programmed basal metabolism rate , the rate at which
the body burns calories for energy, and a fixed number of fat cells, which store
fat for energy and can change in size
 A complex interaction of metabolism, fat cells, and hormones keeps people at the
weight their bodies are designed to be
 Genes set the set point
 Numerous other genes are linked to being overweight or obese
o The overweight debate
 More than half of all American adults, and at least 25 percent of all children and
teenagers, are now overweight or obese
 Health researchers are worried about this trend because obesity is considered a
leading risk factor in diabetes, high blood pressure, heart disease, stroke, cancer,
infertility, sleep apnea, and many other disorders
 Lately some scientists have been arguing that for most people, the real health
culprit is not overweight but lack of fitness
• Environmental Influences on Weight
o The increased abundance of fast food and processed foods
o The widespread consumption of high-sugar, high-calorie soft drinks
o The sharp decline in exercise and other expenditures of energy
o The increased portion sizes of food and drink
o The abundance of highly varied foods
• The Body as Battleground: Eating Disorders
o Bulimia nervosa – an eating disorder characterized by episodes of excessive eating
(bingeing) followed by forced vomiting or use of laxatives (purging)
o Anorexia nervosa – an eating disorder characterized by fear of being fat, a distorted
body image, radically reduced consumption of food, and emaciation
o People with binge-eating disorder binge without purging; others chew whatever food
they want but spit it out without swallowing; others are normal weight but take no joy
in eating because they worry obsessively about gaining a pound; some develop
phobias about eating certain kinds of food
o Most disorders are generated by psychological factors, including depression and
anxiety, low self-esteem, perfectionism, and a distorted body image
o Cultural factors can also generate dissatisfaction with one’s body

o Just as anorexic women see their gaunt bodies as being too fat, some men have the
delusion that their muscular bodies are too puny, so they abuse steroids and exercise
or pump iron compulsively
• In sum, within a given environment, genetic predispositions for a certain body weight and