If you've ever walked down a dark alley and seen a stranger approach, then you probably know that automatic vigilance -- a signal from your brain making you more alert. And even if you consider yourself unprejudiced, you may have also noticed that this response is more prevalent when you encounter people of races other than yours. It can be chalked up partly as caution around the unknown -- the fact that we are generally less familiar with other races than we are with our own -- but it is still discouraging for race relations. Some new research, however, has shown that we may have more control over our race-based vigilance reaction than previously thought.