Motivation - Motivation - Motive why behavior occurs -...

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Motivation - Motive – why behavior occurs - Motivation is the energizing force or impetus that causes an organism to act. As such, motivational constructs can e called upon to explain the following patterns of behavior: o Initiation (Activation) o Persistence o Cessation o Vigor (Intensity) - Motivation does not explain what we do, but rather WHY we do something. - Motivational forces are sometimes referred to as drives or needs. The Origin of Motivational Forces – Primary and Secondary Motives - Primary Motives o Physiological need states. o Arise when our physiological equilibrium (homeostasis) is disrupted. o Homeostatic drives come about when we are deprived of one or more of the commodities necessary for life. Hunger, Thirst, Respiration, Pain, Sleep - Secondary Motives o Learned or acquired drives which become instilled as the result of experience. Fear, Wealth, Social Acceptance, Achievement What is Hunger? - Local Theory of Hunger o Walter B. Cannon o Hunger is located in the stomach. Originates from contractions of the stomach walls into the void of an empty stomach. o Evidence Against the Local Theory Two nerve connections between stomach and brain Vagus Nerve (Motor nerve for stomach muscles) o Brain tells the stomach when to contract. o Severing the nerve permanently ends the stomach’s contractions, but the subject still becomes hungry and eats normally. Splanchnic Nerve (Sensory nerve) o Severing the Splanchnic eliminates sensations from the stomach, subjects still normal. Surgical Removal of the stomach. Subjects still feel hunger, only do not eat quite as much at one time. Blood Transfusions Transfusion of “Hungry Blood” into well-fed subjects causes them to eat (weak effects).
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Transfusion of “Satiated Blood” into starving subjects causes them to fast (strong effects). The Central Theory of Hunger - Hunger is a property of the central nervous system (the brain). - Good evidence of an important role being played by areas in the hypothalamus, specifically the Lateral Hypothalamus (LH) and the Ventromedial Hypothalamus (VMH). Hypothalamic Mechanisms of Hunger Lesion Stimulation Lateral Hypothalamus (Hunger Center) Aphagia and Adipsia (Never becomes hungry or thirsty again) Eventually Recovers (Very Very Slowly) Stimulus-bound Eating Ventromedial Hypothalamus (Satiety Center) Hyperphagia (Larger meals and more rapid eating rate) Stimulus-bound Fasting Obesity in the Human Being - Stanley Schachter has drawn some interesting parallels in the hunger and feeding patterns of overweight people and VMH-lesioned rats
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Motivation - Motivation - Motive why behavior occurs -...

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