Weaver et al (2004)

researcher

Weaver et al 2004

AIM

investigate whether environment affects behaviour, in this case stress levels.

SAMPLING

two groups of rats

Weaver et al. investigated the stress levels of rat offspring with calmer and more nurturing mothers, compared to the stress levels of rat offspring with more anxious, less attentive mothers.

METHOD

- The stress levels of the rats were measured by placing each rat in a confined tube for 20 minutes and then recording the amount of corticosterone, a stress hormone, was in the rat after the confined tube.

- conducted another experiment: The second study was focused on the nurture of the rat offspring, examining whether rats with more nurturing and calmer mothers had lower corticosterone.

The first group was made up of rats that received less attention from the mothers, but were now receiving vigorous licking and grooming from other rats.

the second group was made up of rats who received vigorous licking and grooming from their mothers, but were now receiving less attention.

RESULTS

1st Experiment: found that rats with calmer and more maternal mothers had lower stress levels than the rats with more anxious mothers that showed less attention to their offspring.

2nd Experiment: that not only can inheritance of genes affect behaviour. The environment can have an impact on genes and gene expression.

Rats who were neglected showed higher cortiscerone levels, linked to stress

CONCLUSION

that not only can inheritance of genes affect behaviour. The environment can have an impact on genes and gene expression.

Glucocorticoid receptor genes were methylated in offspring of neglectful mothers, resulting in the pups being less resilient to stress

Genes

Sections of DNA that code for the production of a particular protein

Epigenetics

The study of how genes are switched off or on due to gene regulation. One example of an epigenetic mechanism is that of methylation, with methylation decreasing expression of a certain gene.