When Stimulation is Too Much of a Good Thing

The seminal studies of Spitz and colleagues established the importance of stimulation in infancy by nurturing caretakers (e.g., Psychoanal Study Child 1945; 1:53); its absence led to developmental failure and high infection rates. But in our current, multi-tasked, overstimulated household environments, might too much stimulation be deleterious to infants? These researchers tested the effects of various environmental inputs on microvascular development in infant mice, starting at postnatal day 15.

Overstimulation — 10 hours of repetitive noise for 5 days, 10 hours of whisker stimulation for 8 days, or 2.25 hours on a treadmill for 5 days — was associated with a 70% decrease in new vascular branching and an 80% decrease in growth of branch len…