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Motivation. Motivation is the energizing force or impetus that causes an organism to act. As such, motivational constructs can be called upon to explain the following patterns of behavior: Initiation (Activation) Persistence Cessation Vigor (Intensity). Electrical Activity of the Neuron.
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Motivation • Motivation is the energizing force or impetus that causes an organism to act. As such, motivational constructs can be called upon to explain the following patterns of behavior: • Initiation (Activation) • Persistence • Cessation • Vigor (Intensity) Electrical Activity of the Neuron
Motivation • Motivation is the energizing force or impetus that causes an organism to act. As such, motivational constructs can be called upon to explain the following patterns of behavior: • Initiation (Activation) • Persistence • Cessation • Vigor (Intensity) Electrical Activity of the Neuron Motivation does not explain what we do, but rather, why we do something Motivational forces are sometimes referred to as drives or need states.
The Origin of Motivational Forces Primary Motives – Physiological need states. Arise when our physiological equilibrium (homeostatis) is disrupted. 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 – Learned or acquired drives which become instilled as the result of experience. Fear, Wealth, Social Acceptance, Achievement Electrical Activity of the Neuron
What is Hunger? How do you feel? I feel hungry. Point to the spot.
The Local Theory of Hunger Evidence Against Severing the Vagus nerve permanently puts an end to stomach contractions. But subject still becomes hungry and eats normally Vagus Nerve (Motor)
The Local Theory of Hunger Evidence Against Splanchnic Nerve (Sensory) Vagus Nerve (Motor) Severing the Splanchnic eliminates sensations from the stomach. Subjects still normal.
The Local Theory of Hunger Evidence Against • Severing of the Vagus Nerve • Surgical removal of the stomach • Transfusions of “Hungry Blood” cause eating in well-fed rats. [Effect is weak] Transfusions of “Satiated Blood” causes starving animal to fast. [Effect is strong]
The Central Theory of Hunger According to this view, hunger is a property of the central nervous system (i.e., the brain) There is 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) Vetromedial Hypothalamus (Satiety Center)
Obesity in the Human Being Stanley Schachter has drawn some interesting parallels in the hunger and feeding patters of overweight people and VMH-lesioned rats Locus of Control Normal Body Weight People – have an internal locus of control. Their hunger and feeding is regulated by internal physiological processes. Obese People – have an external locus of control. Their hunger and eating is controlled by the environment (surroundings, social circumstance, appearance, smell, and taste of food). Internal physiological state is “irrelevant” for the obese person.
Experimental Evidence Consistent with Schachter’s Theory Several of Schachter’s experiments make use of a procedural technique called “deception”. Deception is when psychologists intentionally mislead or fail to inform subjects concerning the true purpose of the investigation. This is done to insure the naturalness of the subject’s behavior.
Experimental Evidence Consistent with Schachter’s Theory BODY WEIGHT NORMAL OBESE Empty Physiological Condition (Subjects had either been without food for six hours or had just finished a big meal) Full DV = How much food would subjects eat during the taste test (#crackers)
Experimental Evidence Consistent with Schachter’s Theory Effects of Visibility of Food – compared food intake of normal vs obese subjects in response to variation of an external factor (sight of food) BODY WEIGHT NORMAL OBESE One Sandwich Empty ) PORTION SIZE Three Sandwiches Full DV = # Sandwiches Consumed
Experimental Evidence Consistent with Schachter’s Theory Effects of the Taste of Food – compared food intake of normal vs obese subjects in response to variation of an external factor (taste of food) BODY WEIGHT NORMAL OBESE Good Taste Empty ) Taste of the Milk Shake Bad Taste Full DV = # Fl Oz of the milkshake Consumed
Experimental Evidence Consistent with Schachter’s Theory Effects of Time of Day Cues – compared food intake of normal vs obese subjects in response to variation of an external factor (apparent time of day indicated on a wall clock). Subjects were told to take ½ hour lunch break whenever they felt like eating. BODY WEIGHT NORMAL OBESE Real Clock Empty Apparent Time of Day (Wall Clock) ) Fast Clock Full DV = Actual Time of Day when subject broke for lunch
Experimental Evidence Consistent with Schachter’s Theory Effects of Effort Required to Obtain or Eat Food – compared likelihood to eat of normal vs obese subjects in response to variation of an external factor (difficulty of eating available food). Subjects were given a task to perform and told they could snack while they worked if desired. BODY WEIGHT NORMAL OBESE Shelled Nuts Empty Snack Bowl Contained ) Nuts in Shells Full DV = % of subjects who consumed the nuts
What is Thirst? Local Theory of Thirst – Thirst is a dryness of the mouth and throat Normal Drinking Dog Mouth Throat GUT
What is Thirst? Local Theory of Thirst – Thirst is a dryness of the mouth and throat Fistulated Dog
What is Thirst? Local Theory of Thirst – Thirst is a dryness of the mouth and throat Fistulated Dog Sham Drinking
What is Thirst? Local Theory of Thirst – Thirst is a dryness of the mouth and throat Fistulated Dog Stomach Load
What is Thirst? Local Theory of Thirst – Thirst is a dryness of the mouth and throat Central Theory of Thirst – Hypothalamic Control over thirst and drinking based upon water volume of the blood
The Appetitive-Aversive Classification Appetitive Motives – elicit approach e.g., hunger, thirst, sex Aversive Motives – elicit withdrawal or avoidance e.g., pain, fear, frustration Conflict – state that exists when two incompatible motivations compete for expression Four principal types of conflict
Approach-Approach Conflict Vicarious Trial and Error Short Resolution Times
Approach-Avoidance Conflict Interpretation of the interplay of motivational forces in the approach-avoidance conflict was provided by an experiment conducted by Judson Brown. His subjects were hungry rats who were rewarded with food for going to a goal box at the end of a straight-alley. The rats were outfitted with a harness attached to a strain gauge that measured the amount of force the rat was exerting at different distances from the goal.
Approach-Avoidance Conflict Other rats were placed in the goal box at the start of a trial and then received an electric shock there. Of course, these subjects ran out of and away from the goal box. Brown measured the strength of the force the rat exerted against the gauge as it withdrew from the goal area.
The Extrinsic - Intrinsic Classification Extrinsically-Motivated Behaviors - Produce or Remove an Incentive E.G., hunger R food fear R removes fearful stimulus Intrinsically-Motivated Behaviors - accomplish no end other than the response itself
Intrinsic Motivation Contact Comfort – studied in rhesus monkeys by Harry Harlow What is it that causes us to form an attachment to our mothers? (mother love) Is the mother a secondary stimulus (originally neutral) that becomes attractive because of its close association with primary incentives (food)? During ordinary upbringing there’s no way tell because food always occurs in association with the mother. Harlow’s research sought to separate out the connection of the mother and food from other qualities the mother might have.
The Surrogate Mother Experiments Infant rhesus monkeys were separated from their real mother shortly after birth. They were then raised in isolation from other monkeys in the presence of the two surrogate mothers depicted here. According to the experimental design, only one of the mothers was the source of food. A nursing bottle was embedded into the chest of either the “cloth mother” or the “wire mother”
Curiosity The Butler Box – Enclosure that isolated the monkey subject away from the outside world. Inside the box there was a plentiful supply of favored-food and fresh water. The biological needs of the monkey were satisfied. Yet, monkeys would learn a new instrumental response to open a window and get a brief view of the outside world.
Curiosity The Butler Box – Enclosure that isolated the monkey subject away from the outside world. Inside the box there was a plentiful supply of favored-food and fresh water. The biological needs of the monkey were satisfied. Yet, monkeys would learn a new instrumental response to open a window and get a brief view of the outside world. Rate of responding was dependent upon the extent of visual interest was provided by the view.
Achievement Motivation • the motivational tendency aroused in situations that involve competition with a standard of excellence (success vs failure) • Measurement of the need to achieve (nAch) • Thematic Apperception Test (TAT) – personality assessment test, subject is shown an intentionally ambiguous picture and is asked to write a brief story about what was happening in the picture
Achievement Motivation • the motivational tendency aroused in situations that involve competition with a standard of excellence (success vs failure) • Measurement of the need to achieve (nAch) • Thematic Apperception Test (TAT) – personality assessment test, subject is shown an intentionally ambiguous picture and is asked to write a brief story about what was happening in the picture • Scoring for nAch - does the story contain themes involving competition where winning, doing well, or being better at something than others occurs (success themes)? Also look for themes containing unique accomplishments or attainment of goals which require long-term commitment of effort.