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2 Introduction to Motivation: Hunger Module 26 This is a very wordy unit, I strongly recommend paraphrasing. Link: Battle at Kruger 8:24 Link

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4 Motivation Overview Motivational Concepts  Instincts and Evolutionary Psychology  Drives and Incentives  Optimum Arousal  A Hierarchy of Motives

5 Think about why you did the following things based on your experience during the past 4 weeks. 1.Drank water 2.Ate healthy food 3.Ate unhealthy food 4.Selected a piece of new clothing or shoes 5.Got in a fight with a family member or friend 6.Drove faster than the speed limit or other dangerous driving 7.Study for a test 8.Take a test without studying 9.Did something exciting or risky like ride a rollercoaster, walk through a rough part of the hood, etc.

6 Motivation a need or desire that energizes behavior and directs it towards a goal. -Specific need or desire, such as hunger, thirst, or achievement, that prompts goal- directed behavior Aron Ralston AP Photo/ Rocky Mountain News, Judy Walgren

7 Perspectives on Motivation Four perspectives are used to explain motivation: 1.Instinct/Evolutionary Theory 2.Drive-Reduction Theory 3.Arousal Theory 4.Hierarchy of Motives

8 Instincts & Evolutionary Psychology Instincts are complex behaviors that have fixed patterns throughout different species and are not learned (Tinbergen, 1951). Where the woman builds different kinds of houses the bird builds only one kind of nest. © Ariel Skelley/ Masterfile Tony Brandenburg/ Bruce Coleman, Inc.

9 Drive Reduction Theory Instinct theory of motivation 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 (Hull, 1951). Tension

10 Drive Reduction Theory Cont. Primary Drives –Unlearned Food Water Temperature regulation Food Drive Reduction Organism Stomach Full Empty Stomach (Food Deprived) Secondary Drives –Learned Money Shelter Job

11 Homeostasis -tendency to maintain a balanced or constant internal state -regulation of any aspect of body chemistry around a particular level Biological Equilibrium

12 Incentive Where our 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.

13 Yerkes-Dodson Law: 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. Harlow Primate Laboratory, University of Wisconsin Randy Faris/ Corbis

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15 The Arousal-Performance Relationship

16 Intrinsic and Extrinsic Motivation Intrinsic motivation –Motivation for a behavior is the behavior itself –Children playing is an example Extrinsic motivation –Behavior is performed in order to obtain a reward or to avoid punishment –A bonus program is an example

17 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. ( )

18 Hierarchy of Needs

19 Motivation and Hunger Hunger Overview  The Physiology of Hunger  The Psychology of Hunger  Obesity and Weight Control

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

21 The Physiology of Hunger Stomach contractions (pangs) send signals to the brain making us aware of our hunger.

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

24 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 Glucose Molecule

25 Body Chemistry & Leptin Fat cells in our body produce leptin Hypothalamus monitors these levels High levels of leptin signal the brain to reduce appetite or increase the rate at which fat is burned. Leptin deficiency can cause obesity

26 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. Lateral nucleus – Causes us to start eating and keep eating. (LATERAL) "Late night snack": LATEral is snacking [feeding] center.

27 Hypothalamic Centers The ventromedial hypothalamus (VMH) depresses hunger (stimulation). Destroy the VMH, and the animal eats excessively. Richard Howard Ventromedial nucleus - Causes us to stop eating and not be interested in food. (VomitMeal)

28 Hypothalamus & Hormones The hypothalamus monitors a number of hormones that are related to hunger. HormoneTissueResponse Orexin increaseHypothalamusIncreases hunger Ghrelin increaseStomachIncreases hunger Insulin increasePancreasIncreases hunger Leptin increaseFat cellsDecreases hunger PPY increaseDigestive tractDecreases hunger

29 Blood vessels supply the hypothalamus, enabling it to respond to our current blood chemistry as well as to incoming neural information about the body’s state. The hypothalamus controls eating and other body maintenance functions

30 Motivation-Hunger  Set Point  the point at which an individual’s “weight thermostat” is supposedly set  when the body falls below this weight, an increase in hunger and a lowered metabolic rate may act to restore the lost weight  Basal Metabolic Rate  body’s base rate of energy expenditure

31 The Hypothalamus and Hunger Adapted from Schwartz et al., Ana Bolic (fat girl) Cat Abolic (thin cat)

32 Basal Metabolic Rate The rate at which the body uses energy for vital functions while at rest What influences BMR…

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34 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).

35 Cognition/Unconscious and Hunger Think for a moment about why you eat food… You probably think you eat food because it tastes so good right? But, how big is the BOX? You decide how much to eat by how big the BOX is as much as how it tastes. If this is true is it a CONSCIOUS choice?

36 Taste Preference: Biology or Culture? We tend to avoid novel foods…this is probably adaptive. Richard Olsenius/ Black Star Victor Englebert

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38 Hot Cultures like Hot Spices Countries with hot climates use more bacteria- inhibiting spices in meat dishes.

39 Eating Disorders Anorexia Nervosa: A condition in which a person refuses to eat.

40 Eating Disorder: Bulimia Nervosa Intense fear of being fat. Characterized by binging episodes. Often followed by purging –Vomiting –Laxatives –Excessive exercise

41 Reasons for Eating Disorders 1.Sexual Abuse: Childhood sexual abuse does not cause eating disorders. 2.Family: Younger generations at greater risk when raised in families in which weight is an excessive concern. 3.Genetics: Twin studies show that eating disorders are more likely to occur in identical twins rather than fraternal twins. 4.Obsessive-compulsive disorder – need to control 5.Depression and low-self esteem

42 Obesity and Weight Control Fat is an ideal form of stored energy and is readily available. In times of famine, an overweight body was a sign of affluence.

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

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46 Body Image (Women) Western culture tends to place more emphasis on a thin body image in comparison to other cultures.

47 Factors Contributing to Being Overweight Highly palatable food—we eat because it tastes so good Supersize It—food portions are larger than necessary for health Cafeteria Diet Effect—more food and more variety leads us to eat more Snacking—does not cause us to eat less at dinner BMR—changes through the lifespan Sedentary lifestyles- we don’t move around much

48 Body Mass Index (BMI) Obesity in children increases their health risks…

49 Obesity and Mortality The death rate is high among very overweight men.

50 Social Effects of Obesity When women applicants were made to look overweight, subjects were less willing to hire them.

51 Social Contagion Obesity is contagious… If your friends are obese you are more likely to be obese. What about change… –If your friend gains a couple pounds you are more likely to gain a couple pounds. Your risk of infection… –If a friend becomes obese you are 57% more likely to become obese –Friend of a friend…20% more likely to gain weight too. (with friends of the same sex)

52 Physiology of Obesity Fat Cells: may divide, they may shrink but never disappear. Makes it easier to add fat in the future.

53 Set-Point Theory According to the set-point theory, there is a control system built into every person dictating how much fat he or she should carry – a kind of thermostat for body fat. We don’t know how to change the set- point yet…activity looks like the best bet.

54 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%. The obese defend their weight by conserving energy.

55 The Genetic Factor Identical twin studies reveal that body weight has a genetic basis. 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. Courtesy of John Soltis, The Rockefeller University, New York, NY

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

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

58 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.

59 EXPLORING PSYCHOLOGY (7th Edition in Modules) David Myers PowerPoint Slides Aneeq Ahmad Henderson State University, Bernstein, Lahey, and Amy Jones with Garber edits Worth Publishers, © 2008