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Chapter 13

ch.13 detailed textbook notes


Department
Psychology
Course Code
PSYA02H3
Professor
John Bassili
Chapter
13

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Chapter 13 - Motivation and Emotion
Human behaviour is inconsistent
Reasons for inconsistent behaviour are aspects of motivation (latin word meaning “to move”)
In common use, motivation refers to driving force that moves us to a particular action
Motivation is a general term for a group of phenomena that affect the nature, the strength and the
persistence of the behaviour
Motivation includes two type of phenomena
1. Stimuli that have become associated with pleasant or unpleasant events motivate approach or avoidance
behaviours
2. Being deprived of a particular reinforcer increases an organism’s preference for a particular behaviour
The nature of motivation and its relation to reinforcement
Physiological aspects of motivation - external stimuli and internal changes that affect a person’s behaviour
Our behaviour is motivated by situations that we tend to approach or to avoid; situations that are important
to us
Situations also evoke behaviours that other people can recognize (facial expressions, changes in posture,
alterations in tone of voice)
They also affect how we feel - situations that motivate our behaviour also provoke emotions
What is Motivation?
We are motivated to perform a behaviour to gain (or avoid losing) a reinforcer or to avoid (or escape from)
a punisher
Ex. Of reinforcer and punisher - food and pain; smiles and frowns
Biological needs
Biological needs can be very potent motivators
We all need air, food, water, various vitamins and minerals, and protection from extremes in temperature
Complex organisms have physiological mechanisms that detect deficits or imbalances associated with
these needs and related regulatory behaviours that bring physiological conditions back to normal
Ex. Eating, drinking, shivering
Homeostasis - the process of detection and correction, which maintains physiological systems at their
optimum value; “stable state”
Regulatory system has four essential features:
1. system variable - characteristic to be regulated
2. set point - optimum value of the system variable
3. Detector - monitors the value of the system variable
4. correctional mechanism - restores the system variable to the set point
Ex. System variable = temperature of room; detector = thermostat; correctional mechanism = coils of
heater; set point = preset temperature
Negative feedback - a process whereby the effect produced by an action serves the diminish or terminate
that action; regulatory systems are characterized by negative feedback loops
Drive reduction hypothesis - theory that stated that biological needs, caused by deprivation of the
necessities of life, are unpleasant
Hunger serves as a drive, energizing an organism’s behaviour
The act of eating reduces hunger, and this drive reduction is reinforcing
Not all drives are based on homeostasis; ex. Drive associated with sexual behaviour
Drive reduction hypothesis has been disfavoured because:
1. Drive is almost impossible to measure and to prove that it exists
2. If we examine our own behaviour, we find that many events we experience as reinforcing, are also
exciting, or drive increasing
Ex. A rollercoaster ride doesn’t decrease drive
The experiences we really want to repeat (the ones we find reinforcing) are those that increase, not
decrease our level of arousal
Physiology of Reinforcement

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Neural circuits stimulated by electricity are also responsible for motivating effects of natural reinforcers
like food, water, or sexual contact, and of drugs like alcohol and heroin
Electrical stimulation of the brain is reinforcing because it activates the same system that is activated by
natural reinforces and by drugs that people commonly abuse
Normal function of this system is to strengthen the connections between the neurons that detect the
discriminative stimulus and the neurons that produce the operant response
All reinforcing stimuli appear to trigger the release of dopamine in the brain
Optimum-Level Theory
Optimum-level hypothesis of reinforcement and punishment - when an individuals arousal level is too
high, less stimulation is reinforcing; when it is too low, more stimulation is desired - we seek an
optimum level of arousal
Two kinds of exploration related to arousal:
1. diversive exploration - response to under stimulation (boredom) that increases the diversity of the
stimuli the organism tries to come in contact with
2. specific exploration - response to over stimulation (usually because of a specific need, such as lack of
food or water) that leads to the needed item, thereby decreasing the organism’s drive level
Perseverance
The tendency to continue to perform a behaviour even when it is not being reinforced
Understanding the effects of reinforcement helps explain why some people persevere and others do not
Effects of intermittent reinforcement
When an organism’s behaviour is no longer reinforced, the behaviour eventually ceases/extinguishes
If the behaviour was previously reinforced only intermittently, the behaviour persists for a long time
Intermittent reinforcement leads to perseverance, even when the behaviour is no longer reinforced
A person’s previous experience with various schedules of reinforcement probably affects how long and
how hard the person will work between occasions of reinforcement
Effects of Unnecessary Reinforcement
Need for extrinsic rewards (those that originate outside oneself) to encourage and maintain a behaviour
because of the lack of intrinsic rewards (those that originate inside oneself) for doing so
Theorists have hypothesized that offering and giving extrinsic rewards to people who are already
motivated by intrinsic rewards may undermine their intrinsic motivation
General idea behind this over justification hypothesis is that the superfluous application of extrinsic
rewards to behaviour that is intrinsically motivated creates a shift to extrinsic motivation; net result is
loss of intrinsic motivation
over justification hypothesis predicts that after a shift from intrinsic to extrinsic motivation occurs, and the
extrinsic rewards disappear, a person will show what amounts to a loss of interest and perseverance in
the rewarded activity
Extrinsic rewards that are understood by their recipients to convey information about competent
performance, and therefore that function as praise, and that are not offered coercively, may increase
intrinsic motivation
Learned Helplessness
Organisms can learn that they are powerless to affect their own destinies
Learned helplessness involves learning that an aversive event cannot be avoided or escaped
Ex. Dogs getting shocks - some learn to avoid it when they get a warning sign, but those who got shocked
either way just sat there helpless as they received the shocks
When people have experiences that lead to learned helplessness, they become depressed and their
motivational level decreases
Read interim summary p. 422
Eating
Motivation to eat is aroused when there is a deficit in the bodys supply of stored nutrients
Satisfied by a meal that replenishes this supply
What causes a person to start eating and what brings the meal to an end?
Hunger is determined by a variety of conditions

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Physiological factors
Do physiological factors determine when we eat?
Cannon’s “spit and rumble theory”:
Hunger results from an empty stomach - walls rub together producing hunger pangs
Thirst produced by a dry mouth because of decreased flow of saliva due to lack of fluids in the body
Removing a stomach still causes hunger pangs - people who had oesophagus connected to intestine said
they still felt hunger pangs and satiety that they had before their stomachs were removed
Depletion of the body’s store of nutrients is a more likely cause of hunger
Primary fuels for cells of body are glucose and fatty acids
Digestive tract is sometimes empty so there has to be a reservoir that stores nutrients to keep the cells of
the body nourished when the gut is empty - there are two reservoirs:
1. Short term reservoir that stores carbohydrates - brain primarily lives off of carbohydrates
2. Long term reservoir that stores fats - keeps us alive during a long fast; rest of body lives on fatty acids
Mayers Glucostatic hypothesis of hunger - hunger occurs when the level of glucose in the blood
becomes low, presumably after the glycogen in the bodys short-term reservoir has been used up
glucostats - glucose-sensitive neurons that detect decrease in blood sugar
There are two different types of nutrient detectors in the liver which measure the blood level of glucose
and fatty acids
They both send information to the brain and neural circuits there can stimulate hunger - extreme cases of
deprivation of food
What else initiates eating?
Cultural and social factors
Regular pattern of eating is partially determined by habit
Hunger can wax and wane according to a learned schedule
We learn when to eat and what to eat
What we accept as food depends on our culture and location
Tastes shaped by habits acquired early in life
Immediate environment affects our hunger
We’re more likely to feel hungry and to consume more food in the presence of companions who are doing
the same
What stops a meal?
The primary cause of hunger is not an empty stomach, but the primary cause of satiety (the cessation of
hunger caused by eating) seems to be a full stomach
Stomach contains detectors that inform the brain about the chemical nature of its contents as well as the
quantity
Eating should stop soon if the food is nutritious and continue for a longer time when it is not
Ex. Rats got milk and salt injected into their stomachs - milk rats ate less than salt rats 30 minutes later
Detectors that measure amount and nutritive value of food in stomach contribute only to short-term control
of eating (termination of a single meal)
Liver is important
Obesity is caused by an inability of the OB gene in fat cells to produce leptin, which inhibits hunger
Leptin is an anti-obesity hormone
The level of leptin (produced by fat cells) in the blood is correlated with obesity
Obesity
Some people don’t control their eating habits and become too fat or too thin
Obesity is BMI of 30 or more
Psychological variables in causes of obesity - low impulse control, inability to delay gratification,
maladaptive eating styles (eating too fast) - no empirical support for this
Unhappiness and depression are effects not causes of obesity
Dieting behaviour makes problem worse
Partial explanations for obesity:
Habit - early life formations of ideas about how much food constitutes a meal; amount of physical activity
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