Lead researcher Dr. Akaysha Tang, an expert in the Psychology Department at the University of New Mexico, joined forces with researchers from Rockefeller University to examine whether rats that experienced greater novelty by spending three minutes a day away from their familiar home environment during infancy had a greater ability to compete against other rats for exclusive access to chocolate reward, compared to their siblings that stayed in the home environment during infancy.
Reporting their findings in the open-access journal PLoS ONE, the researchers said that novelty-exposed rats were able to "beat out" their competitors more often than their home-staying siblings.
The researchers also found that across repeated sessions of competition, novelty-exposed rats decreased their release of stress hormones into the bloodstream, suggesting that they adapted faster to the stressful situation.
The findings were made among rats that were 24 months of age, considered old age for a rat.
The differences in early experience were induced by approximately 60 minutes of cumulative differential treatment carried out during the first three weeks of life.
The researchers say that these facts go to suggest that very brief exposures to a novel environment during infancy can have a life-long influence on social competitive ability and the stress response.
Dr. Tang and her colleagues also observed whether the differences between siblings depended on the care received from their mothers during infancy.
They measured how much mother rats licked and groomed their pups after the novelty exposure procedure, and how consistently they provided care from day to day.
The researchers found that the mother rats that delivered more care to their pups on average were inconsistent in their amount of care from day to day.
It suggested that the novelty-exposed rats with the most adaptive stress responses had mothers that gave highly consistent but lesser amounts of care, said the researchers.
Based on their observations, the researchers came to the conclusion that the consistency of maternal care may be more important than the amount of maternal care and that other sources of influences like environmental novelty can play an important role in shaping a child's development.