P320: Motivation 11 Nov. 2008 Stress & Arousal Ferguson Ch. 3 By the end of this lecture, you should be able to address the following: Describe Selye?s view of the stress response as being a homeostatic process. What are the stages of the ?General Adaptation Syndrome? ? describe the changes that occur. Explain a number of the ways in which it is thought a person can ?buffer? herself/himself against stress. Describe Hull?s view of drive as being a homeostatic response to a state of deprivation. Define Hull?s Drive Equation, and describe the Perin (1942) study that illustrates drive theory. What are some of the major criticisms of Hull?s drive theory? Describe the Yerkes-Dodson Law. What does this tell you in general about levels of arousal and performance? 1. The Stress Response Stress (Selye 1973) non-specific response of the body to any demand made upon it Body is forced away from optimal conditions Stress response adaptive change to return body to optimal state Earlier in semester: flowchart of mechanisms triggered by a stressor What if stressor is not dealt with? What if it persists over long periods of time? Argued that all living organisms follow a General Adaptation Syndrome General way to do that is with a ?level of responding? either negative or positive He argued that you almost always see the same response to a long period of stress Corticoid activity and general resistance to stress Long-term changes in stress response ( Three stages Alarm Reaction- How the body deals with stressors, immediate negative response (lowered resistance to stress) at the end you see that the corticoid activity is beginning to drop to normal levels Stage Resistance- when back to baseline levels of stress hormones, but your body has changed, and you are a little more resistant to stress, physiologically your body is back to an optimal state Stage of Exhaustion- physiologically, psychologically, behaviorally, your body is giving up, it can?t continue to fight any longer and your resistance to stress plummets (ex. natural disaster, war zone that you can?t leave) Long-term stress with many negative impacts ?Buffers? from stress? There are a number of things that you can do to ?buffer? yourself from stress Social Support- being able to talk about things helps deal with problems Relaxation and Meditation Exercise- a lot of evidence that it strengthens an individual psychologically Optimism and Humor- going to see funny movies can help Knowledge- knowing what your body is going through during hard times Classical conditioning- can influence reactions to stress and shape how people respond to stress in beneficial ways Homeostasis- body at some optimal level- if deviation from that level, body ?works? to get back to optimum Major view in thinking about sleep, eating, drinking, and sensory seeking Role in Drive Theory- key approach in early motivational psychology 2. Hull?s Drive Theory Clark Hull- early to mid 1900s experimental psychologist, influenced by Darwin, and other early behaviorists Learning as major means of adaptation Looking for mathematical laws of behavior Bringing psychology into natural sciences (biology, chemistry) Basic idea: Hunger increases over time-----deprivation increases As you increase the period of someone to not have food, make it more like that they are going to seek out, find, and eat food, therefore the deprivation is the drive for the behavior One general change in individual that can produce stress is deprivation How to explain behavioral changes resulting from changes in state of deprivation? Clark Hull ? Drive Theory Motivated behavior in response to changing body needs that were acted upon by finding those items in environment that would reduce the drive Learning is your body doing something to get rid of that state of deprivation (tries to problem solve) Data from Perin, 1942, Journal of Experimental Psychology 30: 93-113 Trained a bunch of different groups of rats to press a bar to get a food reward They all learn that if they press a bar they get the reward He then puts then in a state of extinction, when they press the bar they do not get a reward It turns out what matters is ?what was its history? prior to going into the extinction phase One group he deprived for 3 hours- respond somewhat, what mattered was their history of learning (# of reinforcements), the longer they had experience the more likely they were to press the bar during the extinction phase A second set of groups went in with 22 hours of food deprivation, really hungry, very motivated to find food Found the same general response How to explain these data? Clark Hull (mid 20th Century psychologist) ? math laws of behavioral causation Hull?s Drive Equation E = H x D Energy= Habit X Deprivation E (energy)= persistence of bar pressing H (habit)= what was learned through reinforcement (experience of the animal) D (drive)= extent of deprivation View of behavior regulating homeostasis (what made his theory different) Motivation the engine driving behavior How well does it hold up? Initially pretty well Increase H or D, E increased If H or D= 0, E tended to be 0 Criticisms of Drive Theory There are too many exceptions to the rule If D- 0, sometimes see E > 0 One example is in non human behavior in a lot of species, young animals can be packed with food and yet if the stimuli arrive the young is going to beg Different motivated behavioral systems can conflict with one another Animals can go days on end with no food to defend their territory There is no generalized drive Over-reliance on strict behaviorist view of learning, lots of evidence that methodlogical approach constrains learning Optimal level of arousal at zero implied ?baseline?---drive= 0 and energy= 0 Intermediate levels of arousal often optimal for learning and performance 3. Optimal Arousal Plot level of arousal on one side and performance on the other, the optimal arousal argument is that you should see a bell curve Hebb 1950s- argued the lowest level of arousal is when you are asleep, so you aren?t going to be producing performance all that well to the extreme of highly tense, chances are the performance isn?t going to be that great BUT Intermediate levels of arousal often optimal Example: lesion preoptic area of rat, greatly decrease sexual behavior, preoptic nucleus Found that if you give the rat slight shock or tail pinch, may court and mate with female (because it has been arouse) Yerkes-Dodson Law Intermediate levels of arousal are where you get the highest levels of learning a particular tasks Tends to hold for more complex tasks Most studies support idea of ?optimal arousal? -- Sensory deprivation and pattern deprivation studies -- Arousal as a goal in athletes and performers = Arousal as a goal = a ?tool? for goal-directed behavior PAGE PAGE 3
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