Friday, November 5, 1999 Published at 11:05 GMT
Nurture puts one over nature
Caring mother rats produce confident offspring
Canadian scientists have done experiments which would suggest that a child's personality traits are influenced more by the parents' behaviour than by genes.
Michael Meaney and colleagues looked at how much attention mother rats paid to their pups.
They had noticed the pups whose mothers licked and groomed them relatively often and nursed them in a certain arched-back position became less fearful than pups with more "reserved" mothers.
Such personality differences could be inherited through the genes or could be acquired after birth. To find out the answer, the McGill team studied several generations of rats.
What is more, the pups own offspring exhibited more attentive maternal behaviour themselves.
Researchers tested a pup's fearfulness by timing how long it spent exploring or staying in one place within a controlled open-field area.
The McGill team conclude that it is the mother's behaviour in the early days of the pups' life that influences their personality.
"In humans, social, emotional, and economic contexts influence the quality of the relationship between parent and child and can show continuity across generations," they write in the journal Science.
"Our findings in rats may thus be relevant in understanding the importance of early intervention programmes in humans."