Uned 4

Question 1

Types of validity

Answer 1

• Face Validity - whether a self-report measures looks like it measures what the researcher intended to measure.
• Content validity - content of the test represents the area of interest
• Concurrent validity - comparing current method with previously validated method
• Construct validity - assesses the extent that a test measures the target construct.
• Predictive validity - whether the scores predict what you would expect them to predict.

Question 2

Dealing with issues of validity

Answer 2

• If internal validity is low items on the questionnaire/interview need to be revised
• If external validity is an issue, sampling method may produce unrepresentative sample.

Question 3

Longitudinal studies

Answer 3

• research conducted over a long period of time to observe long-term effects
• Case studies e.g Bowlby, Forty-four Juvenile Thieves

Question 4

Cross-sectional studies

Answer 4

• One groupe of a young age are compared to another, older group at the same point in time, investigating influence of age on behaviour. (effect of time)
• Might look at behaviours of different professional groups (in different sections of society)

Question 5

Evaluate - Advantages of longitudinal studies

Answer 5

• Control for participant variables
• Often uses a repeated measures design = all variables are controlled

Question 6

Evaluate - Advantages of cross-sectional studies

Answer 6

• Relatively quick
• Can be conducted in less than a year.

Question 7

Evaluation - Disadvantages of longitudinal studies

Answer 7

• Attrition - some participants drop out, ones that drop out more likely to have particular characteristics (less motivated, unhappy),= biased sample, small sample
• Participants are likely to become aware of the research aims, their behaviour may be affected
• Take a long time to complete, difficult to finance

Question 8

Evaluation - Disadvantages of cross-sectional studies

Answer 8

• Differences between groups may be due to participant variables rather than the independent variable
• Cohort effects - people who share the same age share the same experiences

Question 9

Brain Scans - EEG

Answer 9

• 1950s, only methos for studying brain activity
• Electrodes placed on the scalp, electrical activity in different regions of the brain can be recorded.
• Dement and Kleitman - detect different stages of sleep

Question 10

CAT Scans

Answer 10

• Taking a series of x-rays and combining them to form a 2/3 dimensional picture.
• Dye is injected as a contrast material
• Patient placed in the CAT scan
• Johnstone et al - used CAT scans to show that brains of people with schizophrenia were different to normal brains

Question 11

Evaluate CAT Scans

Answer 11

Advantages
* useful for revealing abnormal structures in the brain (tumours, structural damage)
* Quality of images ar higher than traditional x-rays
Disadvantage
* They require more radiation than x-rays, more detailed it is more radiation exposure
* Only provide structural information

Question 12

MRI Scans

Answer 12

• Involve the use of a magnetic field that causes atoms of the brain to change their alignment and emit radio signals when the magnet is turned off
• Detector reads the signals and uses them to map the structure of the brain
• (fMRI) provides anatomical and functional information by taking repeated images of the brain in action
• Maguire et al - used MRI to demonstrate that taxi drivers have larger hippocampi, this area is important in spatial memories

Question 13

Evaluate - MRI Scans

Answer 13

Advantage
* give a more detailed image of soft tissue than CAT
* involve passing a strong magnetic field through patient rather than x-rays
* Best for when patient is to have the examination several times, doesn’t expose to radiation
Disadvantage
* Can take a long time
* Can be uncomfortable

Question 14

PET Scans

Answer 14

• Administering slightly radioactive glucose to the patient.
• Most active areas use glucose, radiation detectors can see radioactive areas, showing activity in the brain.
• Take 10-40 minutes
• Raine et al - used PET scans to compare brain activity in murderers and normal individuals. Found differences in prefrontal cortex, amygdala, regions associated with aggressive behaviour.

Question 15

Evaluate - PET Scans

Answer 15

Advantage
* Reveal chemical information that is not available with other imaging techniques
* Show the brain in action
Disadvantage
* Expensive technique, not easily available for research
* Can only be used a few times as patient has to be injected with a radioactive substance.
* Less precise

Question 16

Null Hypothesis

Answer 16

No relationship/difference/correlation between variables being studied

Question 17

Observed and critical values

Answer 17

• Observed - value you calculate
• Critical - find
  Degrees of freedom (number of participants)
  One tailed (directional hyp) or two-tailed (non-directional hyp)