When you drink you can't walk straight. You can't think straight either. Your body wanders along that straight line the police want you to walk. Your mind wanders from that straight line you intend to think.
I frequently go mind wandering. My mind can take a trip while I remain sitting at my desk. Sometimes I am reading a journal article and I realize I have no idea what I've been reading. I even keep scanning words and flipping pages, but my mind isn't there. I'm thinking about something else. Sometimes my mind takes a trip during a trip. I'm walking along and I discover that I've reached my destination. But my mind wandered and I don't seem to recall the entire trip.
Perhaps I'm just an absent minded professor, but I suspect we all experienced mind wandering. We've all tried to focus on one activity, but discovered out thoughts have meandered to something else - personal thoughts, feelings, fantasies, plans, and memories. Our minds have wandered to thoughts unrelated to the task.
A fascinating aspect of mind wandering is that it can take time before you become aware that your mind has wandered. Clearly we sometimes intentionally go wandering or daydreaming. We know that we are thinking about things unrelated to what we are supposed to be doing. Daydreaming can be quite useful during boring meetings.
But in other cases, you are unaware that you're off-task. Jonathan Schooler and his colleagues refer to this as a failure of meta-awareness. You are aware of what you are thinking but you are not meta-aware that these are off-task thoughts. Eventually you catch yourself. You realize you were zoning out. If you were reading, you flip back to the part you can remember reading.
In a study published in 2009, Sayette, Reichle, and Schooler studied how alcohol influences mind wandering - they titled the paper "Lost in the Sauce". They gave young men enough vodka to move their blood alcohol content to around .07% -- that's just below the legal driving limit in most places. They also had a nice placebo control group that thought they drank vodka because vodka was smeared around the edge of the glass. The participants then got to read War and Peace - not the whole book, but up to 34 pages for 30 minutes of reading time. Reading, particularly reading dense material, is the type of task that frequently causes mind wandering.
While reading War and Peace, the participants were supposed to press a computer key whenever they caught themselves zoning out, that is, mind wandering. In addition, they were probed every 2-4 minutes to check if they were mind wandering. Everyone caught themselves mind wandering occasionally. But the people who drank the vodka were twice as likely to let their minds wander without meta-awareness. On about 25% of the probes, the vodka drinkers reported that their minds had been wandering. Drinking impaired their ability to realize they were off-task.
I wonder if this explains some of those late night drunken conversations. When drinking, people may be more inclined to go mind wandering. But when their mind wanders, they are unaware that they are off-task. Then something they were thinking pops out of their mouths. Of course, the comment is unrelated to the ongoing conversation. Oh, I'm sorry. What were we talking about? My mind must have wandered.