A new study from the psychology department of the University of Gothenburg in Sweden sought to discover whether alcohol consumption really does lessen your ability to observe and remember. There's already an interesting theory about this--it's called alcoholic myopia theory, and it posits that when under the influence of alcohol, people actually pay more attention to environmental cues judged to be salient, and less attention to environmental cues that aren't salient.
But the findings actually contradicted this theory. Three groups of testers were chosen, and given either plain orange juice, orange juice with enough vodka to reach a 0.04 percent blood alcohol concentration, or orange juice with enough vodka to reach a 0.07 percent blood alcohol level (the latter being just under the legal driving limit in the US and UK, which means these are not really drunk people--just tipsy). Then each group was shown a short video, from a witness's perspective, of a kidnapping at a bus station.
After a week, the participants were brought back and asked to look at an eight-person lineup in which, randomly, the kidnapper from the video may or may not be. The participants were then asked if the kidnapper was in the lineup, and if so, to identify him.
Interestingly, the participants with the highest blood alcohol level actually scored higher than either of the other two groups (though not significantly). That said, none of the scores were particularly good; even the best group was only slightly better than chance. Still, it's a really interesting study. Read more about it here.
Sooo the important thing to take away from this is that eye witness testimony is unreliable and probably shouldn't be used for convictions?...
Detective fiction for years has harped on the unreliability of eyewitnesses. Probably it's a theme based on real world experiences.
As for alcohol, this experiment might be missing some things.
1. The testers were shown a video and presumably told that they should be observing it. In real life they might not have paid much attention.
2. Sorry, tipsy is just that. It's a good standard for impaired driving etc -- mainly due to an unnoticed loss of motor skills. Probably still reasonably coherent.
Hick... Offic...er.r. I saw everything.
First there was this Bright Light.
And wind was blowing about
A strange quiet was around me.
Then the lights begin to dim and I could see the ship.
It was saucer like and had many blinking lights.
A presure gasp happen, then the door open.
Then Officer, I saw it. I really did!
I saw that alien come out of the ship!
He must of stood 8 foot tall. WoW, he was a bigg'n.
He had a ray gun too and pointed at me.
I was trying to talk to the guy, then
he blast me with his ray gun.
Then everything went black and out was out,
until you showed up.
Yea, officer, I saws everything,.... hick....