Motivation and Emotion (Chapter 16) Lecture Outline : Theories of motivation Homeostasis and equilibrium Hunger and eating disorders [167]

History of Motivation b A motive is a want or a need that causes us to act In what direction is action? How is it initiated? Intensity? Persistence?In what direction is action? How is it initiated? Intensity? Persistence? b Instincts are inherited, stereotypical, species specific responses Animal examples, but hard to apply to humansAnimal examples, but hard to apply to humans b Drive theory: We act to reduce intrinsic drives, e.g., eat, safety, shelter, sleep, sex

Level of Arousal Efficiency of Performance Deep sleep Wake up Increasing alertness, interest Optimal level Increasing emotional disturbance, anxiety Cannot function Arousal and Performance: Yerkes-Dodson Law

Level of Arousal Efficiency of Performance Arousal and Performance: Varies by task difficulty Difficult task Easy task

Current theories b Arousal theory: Intermediate levels of arousal maximize performance Too low, boredom Too high, tension, fearToo low, boredom Too high, tension, fear b Opponent-Process theory: Stimulation moves us above an emotional baseline, which we return to, but habituate over time b Homeostatic-Regulation theory: Negative feedback loops to maintain equilibrium Eg., want pizza, eat pizza, stop eatingEg., want pizza, eat pizza, stop eating

Model of addiction: Maintaining homeostasis Neutral Begin Drug End Drug After many After few Positive Negative

Please respond to this picture

Is anyone here hungry? b Stomach contractions when 60-90% empty b Ventromedial hypothalamus (VMH) tells us to stop eating lesion in VMH causes hyperphagia in rats lesion in VMH causes hyperphagia in rats b Lateral hypothalamus (LH) tells us to eat Lesionin LH causes starvation and deathLesionin LH causes starvation and death b Glucostatic and lipostatic monitoring by brain to maintain set-point of body weight

Social images of body type

Disorders of eating b Obesity 20% over weight for a given height and weight20% over weight for a given height and weight Dieting leads to eating relapse, poorDieting leads to eating relapse, poor Obese individuals may eat due to external and not internal cuesObese individuals may eat due to external and not internal cues b Anorexia nervosa Loss of weight or failure to gain weightLoss of weight or failure to gain weight Ddistorted body image, amenorrheaDdistorted body image, amenorrhea b Bulemia: Binge and purge cycle

Bulemia: Binge and purge cycle Bingeing. Secretive eating, evidenced by missing food. Preoccupation with food and/or weight or avoidance of situations where food is present. Self-disparagement when too much has been eaten. Purging at least twice a week for a minimum of 3 months. Self-induced vomiting, but also other types Laxative, enema or diuretics abuse, fasting, diet pills. Rigid and harsh exercise regimes. Fear of being fat, regardless of weight. Feeling out of control, other acting out or sexualized behavior.