Mechanisms of Motivation Chapter 6 Motivation and Incentives Motivation the collection of factors responsible for the initiation direction and maintenance of behavior Motivational state or drive an internal condition which can change over time that orients an individual to a specific set of goals e g hunger thirst sex curiosity Incentives goals or reinforcers in the external environment e g good grades food a mate Drives Homeostasis the constancy of internal conditions that the body must actively maintain Drives may be an upset in homeostasis inducing behavior to correct the imbalance Animals do behave in accordance with their tissue needs e g increasing or decreasing caloric intake drive for salt However homeostasis cannot explain all drives Types of Drives Regulatory drives helps preserve homeostasis e g hunger thirst oxygen Nonregulatory drives serve other purposes e g sex achievement Drives as States of the Brain Central state theory of drives different drives correspond to neural activity in different sets of neurons in the brain Central drive system set of neurons in which activity constitutes a drive Drives as States of the Brain The hub of many central drive systems lies in the hypothalamus Hunger Drive Two areas of the hypothalamus the lateral and ventromedial areas play a central role in the hunger drive Hunger Drive Other stimuli that act on the brain to increase or decrease hunger include satiety signals from the stomach signals indicating the amount of food molecules in the blood leptin a hormone indicating the amount of fat in the body the appetizer effect Reward Pathways in the Brain Medial forebrain bundle runs from the midbrain through the lateral area of the hypothalamus into the nucleus accumbens in the basal ganglia neurons in this tract secrete dopamine animals will self stimulate this pathway euphoria producing drugs affect the level of dopamine in this tract evolved to promote survival and reproduction Reward Mechanisms Three Components of Reward Liking subjective feeling of pleasure or satisfaction E g praise pay good food exploration etc Occurs after a reward is received Wanting desire to obtain a reward Measured by the effort expended to reach a goal Occurs before a reward is received Reinforcement the effect a reward has in promoting learning Reward Mechanisms Separating Liking from Wanting Medial forebrain bundle MFB and nucleus accumbens NA become active in situations where an individual receives a reward Dopamine is released by neurons in the MFB that terminate in the NA which appears to be related to the wanting component but not the liking component In rats dopamine is released into the NA before and not after receiving a reward Drugs that block the effect of dopamine in the NA are related to declines Endogenous morphine like substances Endorphines are related to the liking in seeking out food component In humans drugs that decrease the effectiveness of endorphins are related to a decrease in perceived enjoyment of food and other rewards Effects of Culture and Habits on Body Weight Settling point cluster of genetic and environmental factors that cause a person s weight to settle within a given range Weight can be affected by factors like diet exercise and daily habits e g stairs instead of elevator Biological Rhythms Circadian Rhythms cycles about every 24 hours Example sleep wake cycle Ultradian Rhythms cycles more than once per day Example stages of sleep within 8 hours changes in alertness and body temperature Infradian Rhythms cycles less than once per day Example nesting in birds human female menstrual cycle Sleep Measure sleep with the EEG Stages of sleep Types of waves Dreams Why Do We Sleep Preservation and protection theory Body restoration theory Brain maintenance theory Function of dreams Theories of Motivation Need to account for why people seek states of disequilibrium E g thrill seeking curiosity entertainment etc etc etc Homeostatic mechanisms can t explain the desire to achieve affiliation with and attachment to others gain power altruistic behavior etc etc etc Additional Theories of Motivation Arousal Theory Organisms are motivated to achieve and maintain an optimum level of arousal Some arousal is necessary High arousal is helpful on easy tasks As level of arousal increases quality of performance decreases with task difficulty Too much arousal is harmful Additional Theories of Motivation Self determination Theory Deci and Ryan 1985 Humans are motivated to maintain an optimum level of arousal Humans have a basic need for competence and self determination Thus situations in which a person feels optimally aroused and competent promotes intrinsic motivation Intrinsic Motivation motivation from within where one seeks internal rewards that are informative and internally satisfying rather than controlling Extrinsic Motivation motivation from without where one seeks external rewards for the value of the reward per se rather than for the internal reward of the behavior itself Additional Theories of Motivation Self efficacy Theory Albert Bandura Self efficacy the belief in one s confidence in one s ability to successfully achieve a desired goal Behavior is motivated by the expectancy that one can accomplish a given task High self efficacy tends to increase effort and thus a higher level of motivation resulting in a higher likelihood of success Low self efficacy tends to decrease effort and thus a lower level of motivation resulting in a lower likelihood of success Additional Theories of Motivation Expectancy Value Theory Behavior is motivated by An expectancy that a goal is achievable The subjective value of the goal The greater the belief that a goal is attainable and the higher incentive value of the goal the greater the motivation Expectancy and Value are multiplicative not additive Additional Theories of Motivation Attribution Theory An individual s causal attribution i e explanation of an outcome determines subsequent motivation to engage in future behavior Bernard Weiner s attributional theory of motivation Three types of causes people use to explain events Locus Internal versus External Stability Stable versus Unstable Controllability Controllable versus Uncontrollable Additional Theories of Motivation Attribution Theory Example You ve just failed an important exam What will you do next According to Weiner s theory it depends on how you explain why you failed Additional Theories of Motivation Control Theory Carver and Scheier 1998