EXAM 3: 11/25/14chapter 10: motivation and emotionmotivational theories and concepts -drive theories•Clark Hull - 1940s/50s, derived from Walter Cannon’s observations of homeostasis•homeostasis: a state of physiological equilibrium or stability-drive theories apply the concept of homeostasis to behavior•drive: an internal state of tension that motivates an organism to engage in activities that should reduce tensions-these unpleasant tensions are disruptions of the preferred equilibrium-when people experiences a drive, they’re motivated to pursue actions that will lead to drive reduction (hunger; internal discomfort = drive, motivates you to eat)•drive theories are unable to explain all motivation-homeostasis irrelevant to come human motives-motivation may exist without drive arousal (eat when you aren't hungry)-incentive theories•external stimuli regulate motivational states•incentive: an external goal that has the capacity to motivate behavior-some reduce drives while others do not•drive theories - internal states of tension push people in certain directions-source of motivation within the organism•incentive theories - external stimuli pull people in certain directions-source of motivation outside the organism-don’t operate according to the principle of homeostasis-stress environmental factors and downplay biological bases of motivation-evolutionary theories•human motives and those of other species are the products of natural selection (like anatomical characteristics)•explain motives (affiliation, achievement, dominance, aggression, sex drive) in terms of their adaptive value1EXAM 3: 11/25/14•evolutionary analyses of motivation are based on the premise that motives can best be understood in terms of the adaptive problems they solved for our hunter-gatherer ancestors•affiliation motive: need for belongingness-the range and diversity of human motives•humans display an enormous diversity of motives-most theories distinguish between biological motives (originate in bodily needs) and social motives (originate in social experiences)•K. B. Madsen - people have a limited humber of biological needs (10-15)-people all share the same biological motives; however, social motives may vary depending on experience•Henry Murray - most people have needs for achievement, autonomy, affiliation, dominance, exhibition, and order•our choices mainly reflect the motives of hunger, sex, and achievementmotives of hunger and eating -biological factors in the regulation of hunger•Walter Cannon and A. L. Washburn (1912) - there is an association between stomach contractions and the experience of hunger-Cannon theorized that stomach contractions cause hunger but he was wrong•if hunger can occur without a stomach, then stomach contractions can’t be the cause of hunger•brain regulation-the experience of hunger is controlled in the hypothalamus in the brain•hypothalamus is involved in the regulation of biological needs related to survival-studies in the 1940s and 50s showed that the lateral hypothalamus (LH) and the ventromedial nucleus of the hypothalamus (VMH) were the brain’s on-off switches for the control of hunger-today scientists believe that the arcuate nucleus and the paraventricular nucleus (2 other areas in the thalamus) play a larger role in the modulation of hunger•arcuate nucleus most important-contemporary theories focus more on neural circuits that pass through areas of the hypothalamus rather than anatomical centers in the brain2EXAM 3: 11/25/14•glucose and digestive regulation-glucose circulates in the blood; it is a simple sugar, important source of energy-most food we intake is converted into glucose-fluctuations in blood glucose seem to play a role in hunger•actions that decrease blood glucose levels can increase hunger"actions that increase glucose level can make people feel satiated-glucostatic theory: fluctuations in blood glucose levels are monitored in the brain, where they influence the experience of hunger •arcuate nucleus of the hypothalamus is sensitive to glucostatic fluctuations that contribute to the modulation of eating-the digestive system includes many other mechanisms that influence hunger•after you eat, cells in the stomach send signals to the brainstem that inhibit further eating•other nerves carry satiety messages that depend on how rich in nutrients the contents of the stomach are•hormonal regulation-hormonal regulation of hunger depends primarily on insulin, ghrelin, CCK, and leptin-insulin is secreted by the pancreas and must be present for cells to extract glucose from the blood•inadequate supply of insulin causes diabetes•insulin levels increase when people eat•insulin levels are sensitive to fluctuations in the body’s fat stores-ghrelin is released by the stomach when going too long without food•causes stomach contractions and promotes hunger•CCK is released by the upper intestine after food is consumed to deliver satisfying signals to the brain (reduced hunger)-leptin is produced by fat cells and released into the bloodstream•contributes to the long-term regulation of hunger and the modulations of numerous other bodily functions•higher levels of fat generate higher levels of leptin•leptin circulates throughout the bloodstream and provides the hypothalamus with info about the body’s fat stores3EXAM 3: 11/25/14•high leptin levels diminish hunger-these hormonal signals that influence hunger all converge in the hypothalamus, in the arcuate and paraventricular nuclei-environmental factors in the regulation of hunger•food availability and related cues-most research on hunger has been based on the assumption that hunger operates a drive system but some now emphasize the incentive value of food-organisms consume more good when it’s palatable, when more is available, where there is a greater variety, and when other people are around-humans and animals are motivated to eat by the anticipated pleasure of eating•palatability - the better food tastes, the more food is consumed•quantity available - people tend to consume what’s put in front of them; the more you’re served the more you eat•variety - increase consumption when a greater variety of food is available-sensory-specific satiety: as you eat a specific food, its incentive value dec.•presence of others - eat more when you eat with other people as opposed to eating alone; the more people present the more each
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