Weaver et al (2004)

• Weaver et al 2004 found similar results to Suderman et al 2014, in that gene expression can be affected by environmental events. involved in. They tested how corticosterone receptors are affected by maternal attention (corticosterone is responsible for stress responses)
• Weaver et al 2004 investigated stress responses of rat babies who received vigorous licking and grooming from their mothers in early infancy, comparing them to rats that hadn't received such attention. They measured the stress hormone corticosterone in each rat by placing the rat in a small tube for 20 minutes and measuring their reaction to being in a confined space
• Weaver et al 2004

  Results - Rats who received more attention from their mothers had lower levels of corticosterone than rats who didn't. This may be due to inheritance of temperament, in which calmer rats may have had calmer mothers and were hence able to engage in high attention maternal behavior. Just in case, they paired the offspring of anxious rats with calmer mothers who frequently licked their pups, and the offspring of calmer rats with anxious mothers. Reactivity to stress depended on adoptive mother behavior and not biological mother behavior
• Weaver et al 2004

  Conclusion/application - weaver et al 2004 is explained by gene expression, since the corticosterone receptor genes in the brain were methylated when mothers neglected their pups, which led them to become worse mothers and vice versa. Hence, acquired epigenetic modifications can be inherited and passed on to offspring, not just learned behavior
• Weaver et al 2004 was good because it provides strong support for the role of epigenetics in shaping behavior and gene expression. It has reasonable ecological validity as it examines the effects of natural variations (attentive, not attentive) in maternal care on offspring
• Weaver et al was limited mainly because it involves animal subjects, which not only raises the concern of the validity and generalizability of findings from mice to human nurturing behavior, but also ethical considerations.