1. Introduction to Motivation: Hunger Modules 37 and 38

2. Motivation Motivational Concepts Instincts and Evolutionary Psychology
Drives and Incentives
Optimum Arousal
A Hierarchy of Motives

3. Motivation Hunger The Physiology of Hunger The Psychology of Hunger
Obesity and Weight Control

4. Motivation
Motivation is a need or desire that energizes behavior and directs it towards a goal.
Arises from interplay of nature and nurture
Aron Ralston was motivated to cut his arm in order to free himself from a rock that pinned him down
watch?v=B2XLoQ1xYB0&s afe=activen
Nature—pushes us
Nurture—pulls us
AP Photo/ Rocky Mountain News, Judy Walgren
Aron Ralston

5. Perspectives on Motivation
Four perspectives used to explain motivation include the following:
Instinct Theory (replaced by the evolutionary perspective)
Drive-Reduction Theory
Arousal Theory
Hierarchy of Motives

6. Instincts & Evolutionary Psychology
Instincts are complex behaviors that have fixed patterns throughout different species and are not learned (Tinbergen, 1951).
Preview Question 1: What underlying assumption is shared by instinct theory and evolutionary psychology?
The more complex the NS, the more adaptable the species.
Tony Brandenburg/ Bruce Coleman, Inc.
© Ariel Skelley/ Masterfile
Where the woman builds different kinds of houses
the bird builds only one kind of nest.

7. Evolutionary Psychology
Underlying assumption is that genes predispose species-typical behavior
Perpetuation of species

8. Drives and Incentives
When the instinct theory of motivation failed, it was replaced by the drive-reduction theory. A physiological need creates an aroused tension state (a drive) that motivates an organism to satisfy the need.
Preview Question 2: How does drive-reduction theory help us understand the forces that energize and direct some of our behavior?

9. Drive Reduction
The physiological aim of drive reduction is homeostasis
Maintenance of a steady internal state
Operates through feedback loops

10. Incentive Need+Incentive=Strong Drive
Where our physiological needs push, incentives (positive or negative stimuli) pull us in reducing our drives.
A food-deprived person who smells baking bread
(incentive) feels a strong hunger drive.
Need+Incentive=Strong Drive

11. Optimum Arousal
Human motivation aims to seek optimum levels of arousal, not to eliminate it. Young monkeys and children are known to explore the environment in the absence of a need-based drive.
Preview Question 3: What type of motivated behavior does arousal theory attempt to explain?
Harlow Primate Laboratory, University of Wisconsin
Randy Faris/ Corbis

12. Optimum Level of Arousal
“Infovores”: we seek new information
Bored? We look for ways to increase arousal
Too stimulated? We are stressed and look for ways to decrease arousal
Yerkes-Dodson Law: moderate arousal leads to optimum performance
More difficult tasks require lower arousal for best performance

13. A Hierarchy of Motives
Abraham Maslow (1970) suggested that certain needs have priority over others. Physiological needs like breathing, thirst, and hunger come before psychological needs such as achievement, self-esteem, and the need for recognition.
Preview Question 4: What is the basic idea behind Maslow’s hierarchy of needs?
( )

14. Hierarchy of Needs Hurricane Survivors Joe Skipper/ Reuters/ Corbis
Mario Tama/ Getty Images
Joe Skipper/ Reuters/ Corbis
David Portnoy/ Getty Images for Stern
Menahem Kahana/ AFP/ Getty Images
Hurricane Survivors

15. Self-Transcendence
Maslow added self-transcendence to the top of the pyramid
Self-actualization: people seek to realize their own potential
Self-transcendence: people strive for meaning, purpose, and communion that is beyond the self

16. MASLOW’S HIERARCHYAND MISCONCEPTIONS
There are exceptions to the order. Martyrs for example, sacrifice life itself for an ideal.
For some people the need for respect must be satisfied before they can enter into a love relationship.
A given motive does not have to be 100% satisfied before we turn to a higher need.—Our needs are only partially satisfied at any given moment
The means of satisfying a particular need varied across cultures. In our society, respect from others may come from being a doctor-in other societies it might come from being a hunter or farmer.

17. MASLOW AND MISCONCEPTIONS
Maslow did not actually believe that any given behavior is motivated by a single need.
He said that behavior is a result of multiple motivations.
Sexual behavior, for example, may be motivated by the need for sexual release, by a need to win or express affection, by a sense of conquest or mastery, and or a desire to feel feminine or masculine.

18. Hunger When do we eat? When we are hungry. When are we hungry?
When there is no food in our stomach.
How do we know when our stomach is empty?
Our stomach growls. These are also called hunger pangs.

19. The Physiology of Hunger
Stomach contractions (pangs) send signals to the brain making us aware of our hunger.
Preview Question 5: What physiological factors cause us to feel hungry?

20. Stomachs Removed
Tsang (1938) removed rat stomachs, connected the esophagus to the small intestines, and the rats still felt hungry (and ate food).

21. Body Chemistry & the Brain
Levels of glucose in the blood are monitored by receptors (neurons) in the stomach, liver, and intestines. They send signals to the hypothalamus in the brain.
Rat Hypothalamus

22. Hypothalamic Centers
The lateral hypothalamus (LH) brings on hunger (stimulation). Destroy the LH, and the animal has no interest in eating. The reduction of blood glucose stimulates orexin in the LH, which leads rats to eat ravenously.

23. Hypothalamic Centers
The ventromedial hypothalamus (VMH) depresses hunger (stimulation). Destroy the VMH, and the animal eats excessively.
Richard Howard

24. Lateral hypothalamus: “Lunch!”
(Involved in “hunger messages”)
Ventromedial hypothalamus: “Vomit!!!”
(The “satiety center”; “You’ve had enough!”)

25. Hypothalamus & Hormones
The hypothalamus monitors a number of hormones that
are related to hunger.
Hormone
Tissue
Response
Orexin increase
Hypothalamus
Increases hunger
Ghrelin increase
Stomach
Insulin increase
Pancreas
Leptin increase
Fat cells
Decreases hunger
PPY increase
Digestive tract

26. MUD PIES IN HAITI
uE&playnext=1&list=PL10E9A14679D15FD1 &feature=results_main

27. Set Point
Manipulating the lateral and the ventromedial hypothalamus alters the body’s “weight thermostat.” Heredity influences set point and body type. Researchers now describe it more as a “settling point”
If weight is lost, food intake increases and energy expenditure decreases. If weight is gained, the opposite takes place.

28. Basal Metabolic Rate
Measure of how much energy we use to maintain basic body functions when the body is at rest
Varies between individuals
Food intake decreases=BMR decreases

29. The Psychology of Hunger
Memory plays an important role in hunger. Due to difficulties with retention, amnesia patients eat frequently if given food (Rozin et al., 1998).
Preview Question 6: What psychological influences affect our eating behavior and feelings of hunger?

30. Taste Preference: Biology or Culture?
Body chemistry and environmental factors influence not only when we feel hunger ded
but what we feel hungry for!
Richard Olsenius/ Black Star
Victor Englebert

31. Hot Cultures like Hot Spices
Countries with hot climates use more bacteria-inhibiting spices in meat dishes. ccstart=100666&pt=0&vid=pbssaf904&entire=No

32. The Ecology of Eating
Situations often have a great deal of control over our eating.
Social facilitation: People eat more when eating with others.
Unit bias: Explored how the French waistlines are smaller than American waistlines.
Look at the portions!

33. Eating Disorders
Anorexia Nervosa: A condition in which a normal-weight person (usually an adolescent woman) continuously loses weight but still feels overweight. (.6 people in lifetime)
Reprinted by permission of The New England
Journal of Medicine, 207, (Oct 5, 1932),
Lisa O’Connor/ Zuma/ Corbis

34. Eating Disorders
Bulimia Nervosa: A disorder characterized by episodes of overeating, usually high-calorie foods, followed by vomiting, using laxatives, fasting, or excessive exercise. (1% life-time) Binge Eating disorder: Those who do significant binge eating, followed by remorse—but do not purge, fast, or exercise excessively. (2.8% life-time)

35. Reasons for Eating Disorders
Sexual Abuse: Childhood sexual abuse does not cause eating disorders.
Family: Younger generations develop eating disorders when raised in families in which weight is an excessive concern.
Genetics: Twin studies show that eating disorders are more likely to occur in identical twins rather than fraternal twins.
Culture: body images vary (Western cultures vs. India vs. Africa)

36. Obesity and Weight Control
Why do some people gain weight while others eat the same amount and seldom add a pound???
Fat is an ideal form of stored energy and is readily available. In times of famine, an overweight body was a sign of affluence.
Preview Question 7: What factors predispose some people to become and remain obese?

37. Obesity
A disorder characterized by being excessively overweight. Obesity increases the risk for health issues like cardiovascular diseases, diabetes, hypertension, arthritis, and back problems.

38. Body Mass Index (BMI)
Obesity in children increases their risk of diabetes, high blood pressure, heart disease, gallstones, arthritis, and certain types of cancer, thus shortening their life-expectancy.

39. Obesity and Mortality
The death rate is high among very overweight men. In 2004, the US Medicare system began recognizing obesity as an illness.

40. Obesity and Cognitive Performance
Link between women’s obesity and their risk of late-life cognitive decline
Alzheimer’s and tissue loss

41. Social Effects of Obesity- can be socially toxic.
When women applicants were made to look overweight, subjects were less willing to hire them.

42. Physiology of Obesity
Fat Cells: There are billion fat cells in the body. These cells can increase in size (2-3 times their normal size) and number (75 billion) in an obese individual (Sjöstrum, 1980).

43. Set Point and Metabolism
When reduced from 3,500 calories to 450 calories, weight loss was a minimal 6% and the metabolic rate a mere 15%.
Once we become fat, we require less food to maintain our weight than we did to attain it—because fat has a lower metabolic rate than other tissues so it takes less food energy to maintain.
The obese defend their weight by conserving energy.

44. REVERSE EXPERIMENT
Overfed volunteers an extra 1000 calories a day for eight weeks.
Those who gained the least weight tended to spend the extra caloric energy by fidgeting more.
Lean people are naturally disposed to fidget and move about than are energy-conserving overweight people who tend to sit longer.

45. Identical twin studies reveal that body weight has a genetic basis.
The Genetic Factor
Identical twin studies reveal that body weight has a genetic basis.
Courtesy of John Soltis, The Rockefeller University, New York, NY
The obese mouse on the left has a defective gene for the hormone leptin. The mouse on the right sheds 40% of its weight when injected with leptin.

46. Activity
Lack of exercise is a major contributor to obesity. Just watching TV for two hours resulted in a 23% increase of weight when other factors were controlled (Hu & others, 2003).

47. Food Consumption
Over the past 40 years, average weight gain has increased. Health professionals are pleading with US citizens to limit their food intake.

48. Losing Weight
In the US, two-thirds of the women and half of the men say they want to lose weight. The majority of them lose money on diet programs.

49. Plan to Lose Weight
When you are motivated to lose weight, begin a weight-loss program, minimize your exposure to tempting foods, exercise, and forgive yourself for lapses.
Joe R. Liuzzo

50. Summary