Difficulty walking, blurred vision, slurred speech, slowed reaction times, impaired memory: how much and how often a person drinks; the age at which he or she first began drinking, and how long he or she has been drinking; the person’s age, level of education, gender, genetic background, and family history of alcoholism; whether he or she is at risk as a result of prenatal alcohol exposure; and his or her general health status. surveyed 772 college undergraduates about their experiences with blackouts and asked, “Have you ever awoken after a night of drinking not able to remember things that you did or places that you went?” Of the students who had ever consumed alcohol, 51 percent reported blacking out at some point in their lives, and 40 percent reported experiencing a blackout in the year before the survey.