Motivation

1. Motivation

3. Why did you choose St. FX?

4. Context and Sources of Motivation What distinguishes biological motives from social motives?

5. Functions of Motivation • Activates or energizes behaviour. • Directs behaviour. • Creates persistence in behaviour. • Strength determines activation and direction in face of competing motives.

6. Two Major Perspectives • Regulatory perspective • Motivation involves biological, internal states • Focused on underlying biology • Motivation is driven by homeostasis • Negative feedback model • System variable—room temperature • Set point—20 C degrees • Detector—thermometer • System regulator—thermostat • Biological negative feedback model • System variable—pulse, respiration, weight • Set point—normal pulse, respiration, weight • Detector—hypothalamus • System regulator—autonomic nervous system.

7. Two Major Perspectives • Purposive perspective • Behaviour has a purpose. • Social aspects of motivation • Based on goals (directed behaviour)

8. Terminology • Terms frequently used in discussion of motivated behaviour: • Needs—indicates a lack of something, now used for both biological and social motives. • Drives—the body state that is activated to meet a need. • Instincts—unlearned and automatic behaviour triggered by an external stimulus. Now talk of arousal. • Rewards—things that provide pleasure and thereby motivate us to earn them.

9. Regulatory Theories of Motivation • Instinct Theories • These argued that instincts are the basis for all behaviour. • Many, many instincts were identified (e.g., pleasure, curiosity, achievement, friendly, aggression) that could be combined to explain our motives for anything. • Problems • Don’t account for behavioural differences across cultures. • Do they really explain anything?

10. Regulatory Theories of Motivation • Drive Reduction Theories • Hunger, thirst, and sex were once considered drives, or activators of behaviour. • The organism is led to reduce that drive by behaviour that is reinforcing. • The drive produces discomfort that energizes the organism to action to reduce the drive and achieve equilibrium (homeostasis). • The reduction of the tension is reinforcing so we tend repeat the behaviour in a similar situation.

11. Regulatory Theories of Motivation • Drive Reduction Theories (cont’d) • Physiology of Reinforcement • More modern approach to understanding “drive reduction.” • Dopamine circuits in the brain are activated when we engage in reinforcing behaviour like eating or drinking, or in behaviour the permits these, such as barpressing or key pecking in research animals. • Seems to strengthen the link between the perceptual system that detects the stimulus and the motor system that directs the response. • Problems • Implies that all human behaviour is motivated to reduce tension, and we sometimes seek it out. Many reinforcing activities do not reduce the drive; instead we want more! • How do we measure drives, especially those like curiosity or excitement?

12. Regulatory Theories of Motivation • Optimal Level Theories • We seek an optimal level of arousal. • Sometimes seek to reduce stimulation, to avoid excitement and stimulation. • Stimulation too low, indulge in positively reinforced behaviour. Stimulation to high, indulge in negatively reinforced behaviour. • Also acknowledges that we may be motivated by external incentives. • Has the same problems of measuring drives and level of arousal.

13. Regulatory Theories of Motivation • Perseverance Views of Motivation • Clear indicator of motivation • Intermittent reinforcement? • Conditioned reinforcers? • Failure to persist—learned helplessness. • Studies with dogs. • Perhaps this accounts for depression.

14. Purposive Theories of Motivation • Need Based Theories (Humanistic Theories) • We are motivated to fill a deficiency, a need. • There clearly are biological deficiencies that we are motivated to fill, but it can also be argued there are psychological needs as well. • Psychological needs are social—need to be with other people, to have power, to achieve. • These theories consider that humans are motivated to fulfill themselves.

15. Purposive Theories of Motivation • Maslow’s Hierarchy of Needs • We are motivated to achieve personal fulfillment. • The ultimate goal isself-actualization, the achievement of personal goals and aspirations. • We have many classes of needs that can be ordered in a hierarchy. • We must achieve the lower order needs before we can move on to fulfill the later ones. • Maslow has been influential in education and business but difficult to test empirically. • For more about Maslow: http://www.ping.be/jvwit/Maslovmotivation.html

16. Purposive Theories of MotivationMaslow’s Hierarchy of Needs Currently unsatisfied but felt needs are motivators.

17. Sources of Motivation • These are the reinforcers that keep us striving toward our goals. • Extrinsic—do it for the reward or to avoid punishment • External rewards: praise, good grades, tokens, payment for services, etc. • Intrinsic—do it for its own sake • Internal pleasures: play, creativity, learning • May become less reinforcing if external rewards are given.

18. Eating as Motivated Behaviour • Physiological mechanisms: • What happens at the physiological level to motivate eating? • What motivates stopping of eating? • Psychological mechanisms • Social factors • External cues • Why do we overeat? • Obesity affects 1/3 of North Americans • Eating disorders • Anorexia • Bulimia

19. Eating as Motivated Behaviour • Early Theories • Link between hunger and stomach contractions. • Physiological mechanisms: • Role of the hypothalamus • Dual Centre Theory • Set-Point Theory • Role of the orbitofrontal cortex

21. Lateral Hyp

22. Role of the Hypothalamus • Ventromedial hypothalamus seems to be responsible for signaling when it is time to stop eating (satiety). • Lateral hypothalamus seems to signal when it is time to eat. • Both areas contain cells (glucostats) that are sensitive to blood sugar levels but act in different ways: • In the VMH glucostats respond to rising blood sugar levels • In the LH glucostats respond to dropping blood sugar levels.

23. Role of the HypothalamusDual Centre Theory • A decline in glucose activates the lateral hypothalamus (LH) • Activity within the LH gives rise to hunger • Hunger motivates the search for and consumption of food • Food is broken down to release glucose • Glucose activates the ventromedial hypothalamus (VMH) • Activation of the VMH causes a feeling of satiety • Satiety inhibited further feeding.

24. Dysphagic rat after lesion. Effect of lesions in the VMH on body weight and food intake. http://www.psy.plym.ac.uk/year3/psy337EatingNeuralFactors/PSY337EatingNeuralFactors.htm

25. Role of the HypothalamusSet-Point Hypothesis • Body weight seems to be regulated around a set-point, just as other bodily functions. • A hormone, leptin, is released from fat cells at the same rate that fat is being stored in those cells—the more fat storage, the more leptin in the blood stream. • Hypothalamus monitors levels of leptin and very slowly inhibits eating as levels increase and probably activates eating as the levels drop. • Thus, the hypothalamus seems to work to maintain that set point, some predetermined level of fat storage in the body. • Seems to regulate weight over the long term.

26. Role of the HypothalamusSet-Point Hypothesis • The number of fat cells in the body is determined, through genetics and eating experience, by the age of two. • What varies from then on the amount of fat stored in that set number of cells. • In animals deprived of food the metabolism slows and less food is required to maintain a given weight. • Weight gain occurs rapidly in these animals after deprivation—return to set-point.

27. Psychological Factors in Eating • Our emotional state affects our eating but affects different people in different ways (depression can lead to weight gain or weight loss). • Conditioning affects our eating habits—time of day, smell of food become triggers for eating. • These are learned cues that have been reinforced by our habits or experiences. • We learn what to eat and how much to eat.

28. Social Factors in Eating • Each culture has a view of what is an ideal appearance—a norm for weight. • Our present culture: • We value slimness and constantly see ideal shapes for a man or woman on TV and in magazines & movies. • We are very weight conscious and are preoccupied with eating, waistlines, and fat. • The conflict: • Our modern lifestyles have created a need for quick meals—leads to pre-prepared commercial food, high in fat and sugar.

29. Obesity • North American levels of obesity are the highest in history. What contributes to this? • The number of fat cells in the body, determined by both genetics and eating experience, is set by the age of two. • From then on, the only change is the amount of fat in those cells. • Those with more fat cells have greater storage capacity—gain weight more easily and are more likely to become obese.

30. Obesity • Animals who are hyperphagic and humans who are obese have some similar characteristics, empirically determined: • Lower sensitivity to internal body cues for eating and cessation of eating. • Greater sensitivity to external cues, such as time of day, food smells, appearance of food, presence of food and others who are eating. • Are less active, eat faster, and less willing to work hard for food.

31. Obesity • Why is it so hard to diet, and so hard to keep the weight off when successful? • Those who have become obese have more fat cells than normal weight individuals. If the set point says those cells have less than the ‘optimal’ amount of fat, the pressure to eat becomes strong. • It is harder for obese individuals to know when they are really hungry. • Obese individuals are very sensitive to external cues in a world that is full of pressure to eat. • Much of what we eat is high in fat and sugar because of the change in our life styles—more calories for the same volume of food.

32. Eating DisordersAnorexia and Bulimia

33. Eating DisordersAnorexia and Bulimia • Both are severe eating disorders characterized by an intense preoccupation with one’s weight. • More common in women. • Seems to have psychological roots: • Distorted body image—see themselves as overweight even when not. • Can lose huge amounts of weight and still see themselves as fat. • Typically occurs during adolescence, often triggered by family crisis or relationship breakup. • Can lead to death. • Treatment focuses on the psychological aspects with dietary management.

34. Eating DisordersAnorexia • Characterized by refusal to eat because of fear of becoming fat. • Can become preoccupied with exercise in order encourage weight loss.

35. Eating DisordersAnorexia • Physical results: • Extreme weight loss—not unusual to drop weight to 60 – 80 pounds. • Often unable to maintain bodily processes like body temperature and menstruation. • Electrolyte imbalance is common and can cause death. • Typical personality • High achievers and perfectionists. • Well-behaved

36. Eating DisordersBulimia • May occur alone, or with anorexia. • Characterized by bouts of uncontrolled eating (binges) followed by purging through self-induced vomiting or use of laxatives. • Physical results • Less likely to have extreme weight loss. • Damage to esophagus because of vomiting. • Electrolyte imbalance.