Chapter 3. Models of Abnormality. Models of Abnormality. In science, the perspectives used to explain phenomena are known as models or paradigms Each provides a set of assumptions and concepts that help us explain and interpret observations A school of thought
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Models of Abnormality
Four factors that are associated with this approach
1.Influence of germs
The brain is composed of ~ 100 billion nerve cells or neurons and thousands of billions of support cells or glia
Recent studies have focused on the role of NT in their impact on behavior
Acetylcholine - first known NT. it is involved with transmission to muscles.
Dopamine - regulates motor behavior, excess dopamine is thought to be a cause of schizophrenia. It is developed in the mid-brain above the pons.
Enkephalines - opiate receptors, affected by opium derivatives, may be able to produce natural highs. May be the source of runners high.
GABA - gamma-amino-butyric-acid, an inhibitory NT.
Histamines - allergic reactions
Norephinephrine - acts on autonomic nervous system to produce energizing responses.
Serotonin - transmissions within the brain, may play a role in depression.
Behavior genetics - examines influence of genes on behavior
• Genotype - a unique genetic code, a persons genetic makeup
• Phenotype - behavioral expression of the interaction of genotype and the environment. Often it is difficult to determine which is predominant --> nature vs. nurture controversy.
Twin studies are often used to study genetic/environment interactions
Two types of twins
• Monozygotic (MZ) - identical twins, develop from 1 fertilized egg. They have the exact same genotype. Do they have the same phenotype?
• Dizygotic (DZ) - fraternal twins, develop from 2 eggs fertilized by 2 different sperm. They have less than 50% of their genes in common.
Studies of Concordance - when twins develop the same disorder
Research studies use groups of MZ twins that are compared to DZ twins. If the concordance rate is higher in MZ (3:1) than in DZ twins, then it is likely their is a genetic connection for that disease.
If their is little concordance in the MZ twins it may be due to interaction with the environment or some other cause.
Recent studies of MZ twins have found
high concordance rates in
Measuring the brain
Other forms of brain study are needed to study brain function and structure.
• early methods - dissections
CT and MRI scans study brain structure.
Pet scans study brain function
CT (CAT) scan - computerized axial tomography, passes gamma-rays through cross-sections of the intact brain and measures radioactivity on the other side.
By locating differences in tissue density, tumors can be located.
MRI - Nuclear magnetic resonance imaging. More precise and detailed than CT.
Enclosed in a magnetic field, radio waves are used to locate abnormalities in tissue. Very accurate, excellent details. Can be used from different viewpoints to create different perspectives for different dimensional views.
PET - Positron Emission Tomography - (a measure of brain activity) observes brain activity by monitoring an injected radioactive tracer substance moving though blood vessels of the brain.
Studies have shown that schizophrenics have greater blood flow to the left hemisphere of the brain than the rt. hemi. The more severe the schiz. the greater the difference in left/right blood flow. One conclusion has been drawn, Schiz. is the result of left hemi. damage, greater blood flow is the bodies attempt to compensate.
Can limit rather than enhance our understanding
Evidence is incomplete or inconclusive
Treatments produce significant undesirable (negative) effects
Enjoys considerable respect in the field
Creates new therapies
Suggests new avenues of research
First hypothesis - became known as depth psychology
Two basic principles of this theory
I. Conflict causes anxiety
II. The mind works on 2 levels
1. Conscious mind, awareness, here and now
2. Unconscious mind, has 2 levels identifiable by the retrievability of memories
What evidence do we have that the unconscious exists?
Focus is on mental structures and instincts
Behavior is a product of 3 mental structures
First to recognize importance of psychological theories & treatment
Saw internal conflict as important source of psychological health and abnormality
First to apply theory and techniques systematically to treatment – monumental impact on the field
Unsupported ideas; difficult to research
Inaccessible to human subject (unconscious)
Operant conditioning - operant behavior is a voluntary, controllable behavior.
Thorndike’s (1874-1949) Law of Effect, the beginning of Operant Conditioning
Animals repeat certain behaviors when those behaviors are associated with positive consequences. Also, if the consequences were unpleasant the behaviors would be discouraged or reduced.
Principles of Operant conditioning
• Reinforcement - anything that increases the frequency or magnitude of the behavior is a reinforcer.
both positive and negative reinforcers increase the frequency of the desired behavior
- negative reinforcer, removes an aversive event.
• Punishment - either the removal of positive reinforcer, or the presentation of an aversive condition.
• Extinction - elimination of a behavior through non-reinforcement.
• Shaping - reinforcing successive behaviors towards a goal
Fear and Anxiety
Some symptoms can be treated by breaking the CS-CR bond.
Counter-conditioning - recognized early conditioning that has led to the symptoms. Negative stimulus is paired with a pleasant or neutral stimulus until the fear or anxiety is gone.
EG. Systematic desensitization
Flooding - exposure to the feared stimulus
Powerful force in the field
Rooted in empiricism
Phenomena can be observed and measured
Significant research support for behavioral therapies
Downplays role of cognition
New focus on self-efficacy, social cognition, and cognitive-behavioral theories
Explanations for symptoms using the behavioral model.
- Following the funeral of his grandfather, a 7 yr. old child becomes extremely fearful of riding in cars, especially black cars.
- A middle-aged women begins to feel nauseous and frequently vomits in the parking lot of the hospital when she arrive for her cancer chemotherapy.
- Heroin user overdoses and dies when they are injected with their typical fix, but without having prepared the drug themselves.
Very broad appeal
Clinically useful & effective
Focuses on a uniquely human process
Correlation between symptoms and maladaptive cognition
Therapies effective in treating several disorders
Adapt well to technology
Singular, narrow focus
Overemphasis on the present
Verification of cognition is difficult
Precise role is hard to determine
Emphasizes the individual
Taps into domains missing from other theories
Focuses on abstract issues
Difficult to research
Not much influence
Weakened by disapproval of scientific approach
Added greatly to the clinical understanding of abnormality
Increased awareness of labeling
Clinically successful when other treatments have failed
Research is difficult to interpret
Model unable to predict abnormality in specific individuals