The researchers, led by Li-Hai Tan, used listening, naming and matching tasks to teach 19 adults artificial names of two shades of green and two shades of blue . The brain images of the participants showed that over five sessions administered in 3 days, a total training of one hour and 48 minutes, their brain gray matter volume increased in areas associated with color vision and perception. The training was designed to mimic the rapid and intense associations between words and objects that occur in early childhood verbal development .
Previous studies indicated that gray matter increases in adults but only after experiences that last weeks to years. However, the new work suggests that the intact human adult brain is structurally more plastic than previously thought .