I've always been told that alcohol will reduce reaction times. There are lots of sources for this online. For example:

https://www.sciencedaily.com/releases/2010/10/101019162149.htm http://www.alcoholismrehab.org/research/alcohol-affects-reaction-time/ http://www.alcoholismrehab.org/research/alcohol-increases-errors-and-reaction-time-during-decision-making-new-study-shows/

And countless others. It seems pretty solid.

However, anecdotally, I've noticed a trend where my performance in activities that benefit from a low reaction time improve after I've had a few drinks (namely online FPS games). I decided to investigate further and setup a small experiment.

The Experiment

Every 20 minutes I would record my BAC level using a breathalyzer, take an online reaction time test (http://www.humanbenchmark.com/tests/reactiontime) five times, and consume 1oz of 80 proof alcohol.

For reference, I also consulted an online chart estimating BAC levels (http://bloodalcoholcalculator.org/bac-charts/ - I'm male and ~160 pounds)

The results I saw are completely contradictory to everything I've ever been told. Over the span of three hours, my reaction time did not increase. In fact, it decreased! Each point in the chart below is 20 minutes apart - and the estimated BAC level from the website. And the test consisted of 10 measurements (and I dropped the 2 lowest, 2 highest and averaged the remaining).

BAC Drops over time

The difference between ~270ms and ~230ms is pretty significant - according to the data collected by the Human Benchmark site I used in my experiment. At 270ms, my reaction time is right in the most common range. But as I drank, I ended up way ahead of the curve.

Faster reaction time

My question is - how can I explain this result? Everything I find online says alcohol increases reaction time. I've read studies and I can't disagree with them. It seems unlikely that I'm some rare abnormality though....so, what's the deal?

  • Great question! But I must ask: How much should we trust the data collection skills of someone who would have been obviously impaired within the first 90 minutes of his experiment?
    – Carey Gregory
    Mar 31, 2016 at 0:24
  • 1
    You realize practice and motivation decrease reaction time. This seems better suited at CogSci.SE.
    – StrongBad
    Apr 1, 2016 at 0:37
  • 1
    Your experiment does not include any control at all.
    – rumtscho
    Apr 1, 2016 at 15:10


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