Biological Perspective

1. Biological Perspective Methodologies

2. Correlational Studies • Psychologists often investigate the relationship between brain and behavior by examining what happens after the brain is damaged. • They also study behavior changes after a brain injury. • These studies are correlational because changes in behavior are assumed to be related to brain damage.

3. Experiments • Experiments are often used to test the effectiveness of a particular drug. • Control Procedures used are: • Experimental group: receive the drug • Control group: receive no treatment • Placebo group: receive an inactive pill • Double Blind Procedure: neither the researcher nor the participants know which are the active and the inactive pills.

4. Invasive Procedures • Chemical Stimulation- to chemically stimulate the brain (microdialysis) by delivering or extracting neurotransmitters from a neural synapse and then studying how behavior is affected.

5. Electrical Stimulation – to electrically stimulate different regions of the brain to determine how the patient is affected. • ie: stimulation of the temporal lobes result in patients reporting specific memories. • Magnetic Stimulation- (Transcranial Magnetic Stimulation). A magnetic coil is held on the scalp & depending on strength of the current, brain areas can be made more or less active.

6. Lesions and Ablations • Lesion – when a part of the brain is either destroyed or its function disrupted. • Ablation– when a part of the brain is removed. • Experiments can be done to study behavior after lesions or ablations occur

7. Interviews and Tests: Non-Invasive Procedures • Neuropsychological assessment is also important to determine the effects of brain damage over time. • Tests can be administered again months or even years after the brain trauma to see if the person’s behavior has improved or worsened.

8. The two best known assessments measure intelligence and memory. • An intelligence test measures overall cognitive abilities. • It is made up of subtests that measure specific cognitive abilities. • Using a series of subtests, psychologists can measure different aspects of memory, pinpoint the memory problem and thus the area of the brain most likely affected.

9. Case Studies • Case studies are useful when there are very few examples of a particular type of damage. • One famous case study is that of Phineas Gage in the mid-19th Century. • Gage’s caseis “important for what it pointed to, rather than what we can learn in any detail about the relation between brain and behavior.

10. Strengths and Limitations of Invasive Procedures • Strengths • Brain lesions can tell us a lot about the function of the brain. • Limitations • Lesion procedures are difficult to perform • Surrounding tissue could also be damaged • It is difficult to know whether the lesioned site is directly responsible for a behavior – it could be one site of many that are responsible for a particular behavior

11. Limitations (continued) • Regions in the brain overlap and therefore so do functions. • There is rarely a one-to-one relationship between a brain region and a specific behavior.

12. Strengths and Limitations of Non-Invasive Procedures • Strengths • Neuropsychological testing can tell us a lot about brain function without any of the risks of invasive techniques. • Limitations • Intelligence tests can be culturally biased.

13. Ethical Considerations • There are limits to what researchers can do with human subjects. • There are pros and cons of animal research • Pros: use of animals has led to greater understanding of the brain and medical advances • Cons: not all findings in animal studies can necessarily be applied to humans