Chapter 12.doc

Learned Helplessness: • a response to exposure to an inescapable aversive stimulus, characterized by reduced ability to learn a solvable avoidance task; thought to play a role in the development of some psychological disturbances • organisms can learn that they have no control over their destiny Maier and Seligmen(1976) • Experiments demonstrating that animals can learn that behaviour doesn’t affect environmental events • Dog placed in apparatus where it received electric shocks that could not be avoided, then placed the dog in an apparatus where electric shock was preceded by warning (shock could be avoided by stepping over barrier to other side) • Dogs in control group learned to avoid the shock, but if dog previously received inescapable shocks it failed to learnlearned to be helpless • Implications: when people have experiences leading to helplessness lowered expectation that trying will lead to success • Learned helplessness has characteristics of personality traitpeople with history of learned helplessness will stop trying in other aspects of life Eating • Need to eat shaped evolutionary development of our species Causes of hunger Physiological factors body needs nourishment • Canon and Washburn(1912) o hunger results from empty stomach, thirst from dry mouth (spit and rumble theory), but people without stomachs still feel hunger • Depletion of nutrients is more likely cause glucose and fatty acids • Short-term reservoirin liver and muscles • When glucose is eaten, some is used for fuel, and rest is converted to glycogen and stored in liver • glycogen: an insoluble carbohydrate that can be synthesized from glucose or converted to it, used to store nutrients • long-term reservoir consists of adipose (fat) tissue, under skin and in abdomen • when glycogen level is low, body goes to long-term supply (during prolonged fast) • glucose feeds the brain • Mayer(1955) o Glucostatic hypothesis: hunger is caused by low level/availability of glucose, condition monitored by specialized sensory neurons(glucostats) o Led to discovery of 2 detectors in the livermeausure glucose and fatty acids o This detector system only occurs when blood is severely depleted of nutrients Social and Cultural Factors • 3 meals a day eating pattern not only biological, but also by habit • Hunger can w