PSYC 2800 Chapter Notes - Chapter 12: Taste, Posterior Pituitary, Olfactory Bulb Mitral Cell

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Chapter 12 April 10, 2012
What Causes Emotional and Motivated Behavior?
Knowing that the brain makes emotional experience real-more than mere metaphors of hurt or pain- how do we
incorporate our thoughts and reasons for behaving as we do?
Clearly, our subjective feelings and thoughts influence our actions. The cognitive interpretation of subjective feelings are
emotions- ANGER< FEAR< SADNESS< JEALOUSY< EMBARASSMENT< JOY but these feelings can operate outside our
immediate awareness as well.
We focus both on emotions and on the underlying reasons for motivation- behavior that seems purposeful and goal-
directed.
Motivated behaviors include both regulatory behaviors, such as eating, which are essential for survival, and non-
regulatory behaviors, such as curiosity, which are not required to meet the basic needs of an animal.
Review: Identifying the Causes of Behavior
Free will is not an adequate explanation of behavior because the nervous sytem can produce behaviors over which an
organism has neither choice nor control.
Researchers have investigated causes f behavior, including the apparent need of the brain to maintain at least a
minimum level of stimulation and the behavioral control exerted by the nervous system.
The earlier idea that internal, energizing drives build up and are released in behavior gave way to a more powerful
explanation: behavior results from the activity of hormonal and neural circuits inside the brain that control how we
think, act, and feel.
Is it free will?
Possible explanation: brain needs stimulation?
Sensory Deprivation
Subject is allowed only restricted sensory input
Low tolerance for deprivation and may even display hallucinations
Hebb and Heron (1950s)
After about 4 to 8 hours, subjects became quite distressed; few subjects lasted more than 24 hours
Brain has an inherent need for stimulation; one reason that we engage in behavior is to stimulate the
brain
Similar studies with rhesus monkeys
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Drives and Behavior
The cat’s seemingly unremarkable actions provide three clues to the causes of behavior:
1. The cat’s response to a particular stimulus I s not the same each time. Both the food and the toy mouse elicit
behavior on some occasions but not on others.
2. The strength of the cat’s behaviors varies. For instance, the mouse toy stimulates vigorous behavior at one time
and none at another.
3. The cat engages not only in behaviors that satisfy obvious biological needs (eating, drinking, sleeping) but also in
behaviors that are not so obviously necessary (playing, affection seeking, exploring).
The flush model also assumes separate stores of energy for different behaviors. For instance, cats have a drive to play, and they
have a drive to kill. Engaging in one of these behaviors does not reduce the energy stored for the other. That is presumably why a
cat may play with a mouse that it has caught for many minutes before finally killing it. The cat will pounce and attack the mouse
repeatedly until all its energy for play is used up, and only then will it proceed to the next drive-induced behavior, feeding.
The flush model can be applied to many different behaviors and makes some intuitive sense. We do seem to behave as if there
were energy reserves for various behaviors. Males of most mammalian species, for instance, typically enter a refractory period
subsequent to sexual intercourse when they no longer have interest in sex. Later, the interest or energy returns. It is as though a
pent-up sexual urge, once satisfied, vanishes for a time, awaiting a new energy buildup.
Drive
Hypothetical state of arousal that motivates an organism to engage in a particular behavior
Drive theories of motivation assume the brain is storing energy for behavior
Flush model:
Once a behavior is started, it will continue until all the energy in its reservoir is gone
There are separate stores of energy for different behaviors
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Later this proved wrong!!!
As psychologists and biologists began to ponder tha causes of behavior in the 1930s, they concluded that some sort of
internal energy must drive it. This internal energizing factor had many names, including instinct, but the name that stuck
was drives.
Neural circuit and Behavior
Behavioral change correlates with biological changes in hormones and cellular activity. Researchers studying the sexual
drive, for example, found that a man’s frequency of copulation correlates with his levels of androgens (male hormones).
Unusually high androgen levels are related to very high sexual interest, whereas abnormally low androgen levels are
linked to low sexual interest or perhaps no interest at all. The concept of sexual drive no longer seemed needed.
An electrode used to stimulate the brain cells activated by androgens can induce sexual behavior. Such brain stimulation
can produce amazing sexual activity in male rats, sometimes allowing 50 ejaculations over a couple of hours. Clearly,
neuronal activity is responsible for the behavior, not some hidden energy reservoir as drive theories presumed.
The idea of a neural basis for behavior has wide application. For instance, we can say that Roger had such a voracious
and indiscriminate appetite either because the brain circuits that initiated eating were excessively active or because the
circuits that terminated eating were inactive. Similarly, we can say that HEBB’s subjects were highly upset by sensory
deprivation because the neural circuits that respond to sensory inputs were forced to be abnormally underactive. So the
main reason why a particular thought, feeling, or action occurs lies in what is going on in brain circuits.
For example, cats must have a brain circuit that controls prey killing. Why does this prey-killing circuit become active
when a cta does not need food? One explanation is that, to secure survival, the activity of circuits such as the prey-
killing circuit have become rewarding sin some way- they make the cat “feel good”.
Conclude: neuronal activity responsible for behavior, not drives
Evolutionary Influences on Behavior
The evolutionary explanation hinges on the concept of innate releasing mechanisms (IRMS, activators for inborn,
adaptive responses that aid in an animal’s survival. IRM’s help an animal to successfully feed, reproduce, and escape
predators. The concept is best understood by analyzing its parts.
The term innate implies that the mechanisms have proved adaptive for the species and therefore have been maintained
in the genome. Innate releasing mechanisms are present from birth rather than acquired through experience. The term
releasing indicates that IRMs act as triggers on behaviors for which there are internal programs.
Evidence for a prewired motor program related to facial expressions also comes from the study of congenitally blind
children. These children spontaneously produce the very same facial expressions that sighted people do, even though
they have never seen them in others. IRMs such as these are prewired are not the brain, but they can be modified by
experience. Our cat Hunter’s stalking skills were not inherited fully developed at birth but rather matured functionally as
she grew older. The same is true of many human IRMs, such as those for responding to sexually arousing stimuli.
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