做夢的時候，我們常會夢見白天見到的事情，夢醒后還能回憶起夢里的畫面。但是盲人什么也看不到，他們的夢境有畫面嗎？還是想象出來的？

    A recent column pointed out that some Americans, mostly those raised in the age before color television, dream only in black and white. But that observation raised another question — whether people who don’t see images during the day might see them when they shut their eyes at night.

    For people with normal vision, dreaming is intensely visual. The dream state typically involves vivid scenes and imagery, much of it drawing upon our daytime experiences and concerns (whether conscious or not). Auditory stimulation plays a small role, and the other senses, like taste and smell, are virtually absent.

    But studies led by a psychologist at the University of Hartford show that for the blind, depending on when in life they lost their sense of sight, the reverse seems to be true. People born without the ability to see report no visual imagery in their dreams, but they do experience a heightening of taste, touch and smell. They also report a higher percentage of dreams that involve mishaps related to traveling or transportation, perhaps reflecting one of their biggest daytime concerns: safely finding their way around.

    Although individual experiences vary, researchers say people who go blind before age 5 rarely experience visual imagery in their dreams. But those who lose their vision after age 5 often continue to see in their dreams, though the frequency and clarity diminish over time.