EXPLORING PSYCHOLOGY EIGHTH EDITION IN MODULES David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2011

Motivation

Basic Concepts and Hunger Module 25

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

Hunger The Physiology of Hunger The Psychology of Hunger CLOSE-UP: Eating Disorders Obesity and Weight Control CLOSE-UP: Waist Management

Motivation Motivation is a need or desire that energizes behavior and directs it towards a goal. Aron Ralston was motivated to cut his arm off in order to free himself from a rock that pinned him down. AP Photo/ Rocky Mountain News, Judy Walgren Aron Ralston

Motivational Concepts Four perspectives used to explain motivation include the following: Instinct Theory (replaced by the evolutionary perspective) Drive-Reduction Theory Arousal Theory Hierarchy of Needs

Instincts & Evolutionary Psychology Instincts are complex behaviors that have fixed patterns throughout different species and are not learned (Tinbergen, 1951). Preview Question 1: From what perspectives do psychologists view motivated behavior? Tony Brandenburg/ Bruce Coleman, Inc. © Ariel Skelley/ Masterfile Where the woman builds different kinds of houses the bird builds only one kind of nest.

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. The physiological aim of drive reduction is homeostasis – the maintenance of a balanced or constant internal state.

Incentive Where our needs push, incentives (positive or negative stimuli) pull us in reducing our drives. When there is both a need and incentive we are strongly driven. Therefore with each motive we can ask, ““How is it pushed by our inborn physiological needs and pulled by incentives in the environment?”

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.

A Hierarchy of Motives Abraham Maslow (1970) suggested that certain needs have priority over others, known as a hierarchy of needs.

The men became food-obsessed, preoccupied with their unfulfilled need. Hunger Ancel Keys (1950) studied the effects of semistarvation on male volunteers. The men became food-obsessed, preoccupied with their unfulfilled need. This illustrates how motives can hijack our consciousness. When we are hungry, thirsty, or fatigued little else seems to matter.

The Physiology of Hunger Stomach contractions (pangs) send signals to the brain making us aware of our hunger. Preview Question 2: What physiological factors produce hunger?

The Physiology of Hunger Tsang (1938) removed rat stomachs, connected the esophagus to the small intestines, and the rats still felt hungry (and ate food). If hunger pangs are not the only trigger, what else makes us hungry?

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.

Body Chemistry and the Brain 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.

Body Chemistry and the Brain The ventromedial hypothalamus (VMH) depresses hunger (stimulation). Destroy the VMH, and the animal eats excessively.

The hypothalamus monitors a number of hormones that The Appetite 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

Body Chemistry and the Brain Interaction of hormones and brain activity may help explain the body’s set point – a particular stable weight. Falling below normal weight signals this “weight thermostat” increasing hunger and decreasing activity. Heredity influences body type and set point and our bodies also regulate by controlling food input and energy output. Reducing energy expenditure drops basal metabolic rate – the rate of energy expenditure for maintaining basic body functions when the body is at rest

The Psychology of Hunger There is more to hunger than just our physiological state. Part of knowing when to eat is our memory of our last meal. As time passes we anticipate eating and become hungry again. Preview Question 3: What psychological and cultural factors influence hunger?

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

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

Eating Disorders Anorexia nervosa: A person (usually an adolescent female) diets and becomes significantly underweight, but still feels overweight. Bulimia nervosa: Episodes of overeating, usually high-calorie foods, followed by vomiting, using laxatives, fasting, or excessive exercise. Binge-eating disorder: Significant binge-eating episodes, followed by distress, disgust, or guilt, but without the compensatory purging, fasting, or excessive exercise

Eating Disorders What is behind the development of an eating disorder? Family: Families that put emphasis on weight or high achievement. Genetics: Eating disorders are more likely to occur in identical twins rather than fraternal twins. Environment: Cultures that idealize thinness and vilify “fattness”

Obesity and Weight Control Why do some people gain weight while eating the same amount as someone who does not? Is there weight-loss hope for the 66% of American who are overweight according to the CDC? Preview Question 4: What factors predispose some people to become and remain obese?

Obesity and Weight Control Our bodies have not yet caught up to our modern abundance of food. Obesity is a growing problem: More than 1 billion people worldwide are overweight (WHO, 2007) The U.S. adult obesity rate has more than doubled in the last 40 years Significant obesity increases the risk of diabetes, high blood pressure, heart disease, gallstones, arthritis, and certain types of cancer (Olshansky et al., 2005). In 2004 the U.S. Medicare system began recognizing obesity as an illness

Obesity Measured as Body Mass Index (BMI) The World Health Organization and many countries define obesity as a BMI of 30 or more (although muscular bodies may also have a high BMI).

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

Physiology of Obesity The immediate determinants of body fat are the size and number of fat cells. Once the number of fat cells increases—due to genetic predisposition, early childhood eating patterns, or adult overeating—it never decreases.

Set Point and Metabolism Once we become fat, we require less food to maintain our weight than we did to attain it. 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.

Genetic Influences Studies reveal a genetic influence on body weight: Adoptive siblings’ body weights are uncorrelated with one another or their adoptive parents. Rather, resembling those of their biological parents (Grilo & Pogue - Geile, 1991). Identical twins have similar weights, even when reared apart With an obese parent a boy is 3 times and a girl 6 times more likely to be obese Scientists have discovered genes that influence body weight

Environmental Influences on Obesity Environmental factors that affect obesity: Social influence Sleep loss Changing activity levels worldwide Changing food consumption patterns

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. Remember that permanent weight loss is difficult. Set realistic and moderate goals and lose weight gradually.

Waist Management Tips to lose weight Begin only if you are motivated Minimize exposure to tempting food cues Take steps to boost metabolism Eat healthy foods Don’t starve all day and eat at night Beware of the binge

Waist Management As life-styles have become more sedentary and TV watching has increased, so has the percentage of overweight people in Britain, North America, and elsewhere.