Personality is a product of nurture, and not nature, according to new research, at least in the case of some birds.
Researchers from the University of Exeter and the University of Hamburg in Germany carefully studied the behavior of young zebra finches (Taeniopygia guttata) and their foster parents. What they found was that the behavior of the adult birds raising the young was more influential on the young birds than their genetics. The physical size of the young, however, was inherited from their birth parents.
"This is one of the first experiments to show that behavior can be non-genetically transmitted from parents to offspring. Our study shows that in zebra finches, personality traits can be transmitted from one generation to another through behavior, not just genetics," Nick Royle, a senior author of the study, said. Royle is a senior lecturer in Behavioral Ecology at the University of Exeter.
Royle and his team began the study by placing several birds in a new environment and recording how often they visited different locations. From this, they were able to categorize the avians into two groups - shy ones that mainly stayed in one location, and those they deemed outgoing, who visited a greater number of new locations.
Birds were paired off according to personality type and allowed to breed. Then, the 150 eggs were switched, just before hatching, with birds exhibiting the opposite personality traits. The behavior of the young birds was then examined. Birds preferentially took on the behaviors of the birds that raised them, not their birth parents. No other factor, including the number of other young in the nest with them influenced their behavior to any degree.
Consistent behavioral differences are found throughout the animal kingdom, and can greatly influence the young of a species. Studies of this type measuring the effects of nature vs. nurture in animals has only been completed for a handful of species. These new findings in birds may or may not translate to behavior in other species, including human beings.
"Although this study considers personality inheritance in zebra finches, it raises questions about the inheritance of personality in other species, including humans. Do adopted children inherit the personality characteristics of their birth parents or their adoptive parents? Is the environment more important than genetic inheritance in the development of personality?" Royle said.
Research leading to this finding was funded by the European Social Fund and the National Environment Research Council.
The new findings of the effects of nurture over nature in the birds was published in the journal Biology Letters.