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)
Electrical •Activity
of the Neuron
Persistence
• Cessation
• Vigor (Intensity)
The Motivation Sequence
The Motivation Sequence
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)
Electrical •Activity
of the Neuron
Persistence
• Cessation
• Vigor (Intensity)
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,
Sleep
Electrical
Activity
of the Pain,
Neuron
Secondary Motives – Learned or acquired drives which
become instilled as the result of experience.
Fear, Wealth, Social Acceptance, Achievement
What is Hunger?
How do you feel?
I feel hungry.
Point to the spot.
The Local Theory of Hunger
Evidence Against
Vagus
Nerve
(Motor)
Severing the
Vagus nerve
permanently
puts an end to
stomach
contractions.
But subject
still becomes
hungry and
eats normally
The Local Theory of Hunger
Evidence Against
Vagus
Nerve
(Motor)
Splanchnic
Nerve
(Sensory)
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 wellfed 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
Lateral Hypothalamus
(Hunger Center)
Vetromedial
Hypothalamus
(Satiety Center)
Lesion
Stimulation
Aphagia
(with Adipsia)
Stimulus-bound
Eating
Hyperphagia
Stimulus-bound
Fasting
The VMH Syndrome
The VMH Syndrome
The VMH Syndrome
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
One Sandwich
Empty
)
PORTION SIZE
Three Sandwiches
Full
OBESE
1.96
1.48
1.88
2.32
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
Good Taste
Empty
Taste of the )Milk
Shake
Bad Taste
Full
OBESE
10.6
13.9
6.4
2.6
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
Apparent Time of
)
Day (Wall Clock)
OBESE
Real Clock
Empty
Ate About the
Same Time
Ate Later
Fast Clock
Full
Ate About the
Same Time
Ate Earlier
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
Snack Bowl
)
Contained
NORMAL
OBESE
ShelledEmpty
Nuts
50%
95%
Nuts in Shells
Full
55%
5%
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
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.
Point of
Maximum
Conflict
Double Approach-Avoidance Conflict
The Extrinsic - Intrinsic Classification
Extrinsically-Motivated Behaviors - Produce or Remove an Incentive
E.G., hunger R
fear R
food
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”
The Surrogate Mother Experiments
The Surrogate Mother Experiments
The Surrogate Mother Experiments (Fearful Stimulus)
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.
Characteristics of a High nAch Person
•high nAch is chronic not situational
• high nAch person a moderate risk taker, sets realistic attainable goals
•feedback (concerning success of one's efforts) extremely important to high nAch
person
•most likely to be employed in business (entrepreneurial) occupations
•money important, not as an end, but rather as a means of achieving further
success and as a source of feedback
•not an extremely likeable person (nonempathetic, unlikely to make a good leader,
a loner)
•independent (even as children), resistant to social influence
•able to delay gratification to achieve long-term success
•"hope" rather than "fear" oriented
•have strong internal locus of control (skill not luck)
•show a strong Ziegarnik Effect
•more likely to pick an "expert" rather than a "friend" for work partner