Biological Flashcards
Outline the use of experiments in the biological approach
Psychologists often use experiments to establish cause-and-effect relationships.
Researcher manipulates IV and records effect on DV, whilst ensuring all other potentially confounding variables are kept constant.
Participants are randomly allocated to conditions.
Draganski et al, 2004 (Brain and Behaviour: Neuroplasticity)
Aim?
Aim: Investigate whether structural changes would occur in the brain in response to practising a simple juggling routine.
Draganski et al, 2004 (Brain and Behaviour: Neuroplasticity)
Hypothesis?
Hypothesis: People who practised juggling for an extended period of time would develop structural changes in the brain.
Draganski et al, 2004 (Brain and Behaviour: Neuroplasticity)
Procedure?
Participants randomly allocated to one of two groups : Jugglers or non - jugglers (control).
Jugglers spent 3 months practising, followed by 3 months of no practise.
Participants had MRI scans recording brain structure on 3 occasions :
-Before experiment
- After 3 months
-After 6 months
The experiment used a mixed design, meaning research group compared to control group and also itself under different conditions.
Draganski et al, 2004 (Brain and Behaviour: Neuroplasticity)
Results ?
Before experiment: No difference in brain structure
3 months: jugglers had significantly more grey matter in the mid-temporal area of the cortex in both hemispheres - areas responsible for co-ordination of movement.
6 months: Differences decreased, but still more grey matter than before experiment.
Newcomer et al, 1999 (Hormones on human behaviour)
Aim?
Aim: Investigate whether stress can impair verbal declarative memory
Newcomer et al, 1999 (Hormones on human behaviour)
Hypothesis?
Higher Levels of Cortisol (IV) - the hormone secreted when we are stressed- would impair memory formation (DV).
Newcomer et al, 1999 (Hormones on human behaviour)
Procedure?
Participants randomly allocated to one of 3 conditions:
- High Dose (160 mg, major stress event)
-Low Dose ( minor surgical procedure)
-Placebo (thought was cortisol but wasn’t)
4 measures over 10 days of ptps. ability to recall prose passage.
Double Blind Trial; neither researcher nor ppts. aware of what dose had been ingested.
Newcomer et al, 1999 (Hormones on human behaviour)
Results?
- High dose group lowest recall ability
- Thus from manipulation of IV, can conclude that cortisol levels affected ppts. ability to form verbal declarative memories.
- Cortisol receptor sites on hippocampus.
Wedekind, 1995 (Genetics and behaviour)
Aim?
Investigate the effects MHC gene compatibility (IV) between individuals had on how attractive their scent (DV) was found to be.
Wedekind, 1995 (Genetics and behaviour)
Hypothesis?
MHC genes are responsible for our immune systems.
Inherited from both parents, and co-dominant, thus offspring acquires both immune systems.
- Wedekind hypothesised that “smell” is based on MHC profile and women should choose a partner who’s smell is distinct from their own to maximise their offspring’s immune efficacy.
Wedekind, 1995 (Genetics and behaviour)
Procedure?
Ppts. tested to establish MHC types.
Men asked to wear a cotton t-shirt for 2 nights and keep it in a plastic bag when not in use, asked to avoid smell changing activities and foods.
Starting from next day, Women first asked whether taking oral contraceptive as this affects smell preference.
Asked to rate 7 shirts for smell preference:
3 x similar MHC
3x distinct MHC
1x unworn, control t-shirt
Blind participant to prevent DC
2nd week menstrual cycle; smell more sensitive
Wedekind, 1995 (Genetics and behaviour)
Results?
Females preferred smell of distinct MHC types ( provided wasn’t taking oral contraceptive); would provide offspring with best immune system to increase chance of survival.
Outline ‘Informed Consent’ in the Biological Approach
Before experiment, researcher explains to participant: -Purpose and procedure of study -person's rights - right to withdraw and anonymity - Potential Effects of Participation In Bio Approach: -Animals can't consent -Mental Illness -Layman
Outline fMRI
- Allows researchers to see brain in real time
- magnetic field responds to change in levels of blood and flow of blood in response to neural activity.
- When neurons more active, use more O2, thus blood flow increases to active area.