Animal Research and Hormones

Question 1

Meaney et al (1998)

Answer 1

Aim: Determine the effect of stress hormones on memory

Procedure:
2 groups. One treatment group were newborn rats, taken away from their mothers, that were brushed for 15 minutes a day to simulate the grooming of the mother rate for a few weeks. These rats would have low levels of stress hormones. A control group of rats that were also taken away from their mothers but not groomed. These rats would have high levels of stress hormones. Then, once the rats were two years old, they would be put into a pool of milky water to find a platform.

Results:
Rats who were not groomed were found to have accelerated hippocampal neuron loss and cognitive impairments in aging. Furthermore, it took them much longer than the groomed rats to find the platform, often taking circuitous routes.

Findings:
Extra stroking may have activated genes responsible for regulating stress responses (epigenetics) leading to a longer and healthier life.

Question 2

Newcomer et al (1999)

Answer 2

Aim: Investigate whether high levels of the stress hormone cortisol interferes with verbal declarative memory.

Procedure: Double blind experiments in which participants were given one of 3 tablets. Condition 1 had a high level of cortisol tablet. Condition 2 had a low level of cortisol tablet. Condition 3 had a placebo tablet. All participants were asked to listen to and recall a paragraph of prose. Every day they would be given a different piece of prose. Firstly, participants were tested before taking any cortisol, the finding was that there was no significant difference between groups (eliminates individual differences).

Results:
High cortisol levels impaired performance in the memory task since the participants who received the highest level of cortisol also showed the worst performance in declarative memory.

Question 4

1 pro 2 cons of Meaney

Answer 4

• Results were in line with Newcomers’ study (increasing external validity)
• Artificial reducing ecological validity
• Ethical concerns because they had to kill the rats to measure hippocampal volume

Question 5

2 pros, 2 cons of Newcomer

Answer 5

• Study was experimental, clear cause and effect relationship increasing internal validity
• Baseline test was done to eliminate the possible confounding variable of individual differences
• Ethical considerations since they ingested cortisol but this was overcome with informed consent
• Memorizing a piece of prose may not be the best way to authentically test memory (lower ecological validity)