Drunk Driving and Perception


            When Bernard Williams (1981) introduced the idea of Moral Luck, it led many to question the underpinnings of responsibility and culpability. The term describes how individuals often receive moral blame for circumstances that were evidently out of their control. Thomas Nagel (1979, p. 24) describes a situation in which a truck driver accidently runs over a child. In this scenario, Nagel suggests that the moral culpability of the driver doesn’t rest on him alone, but also on the presence of the child. The driver, even if culpable of some minor negligence on his part, would not have been viewed negatively in a scenario where no child is present. Therefore, the child is fully out of the driver’s moral control, and his culpability is based on luck.

Similarly, drunk driving fatalities fall into this gray moral area. Is drunk driving wrong? At first, we are inclined to say yes, despite not all drunk drivers ending up committing manslaughter. Many arrive back home moderately safe, thus the impairment caused by the alcohol alone is not enough to create a tragedy. A pedestrian (which the driver cannot account for) must be at the wrong place at the wrong time. According to the National Highway Traffic Safety Administration (2017), drunk drivers account for approximately 10,000 fatalities a year. In contrast, there are approximately 30,000 vehicular deaths a year. Therefore, drunk driving alone is not the sole contributor of accidents and fatalities, even when sober manslaughter is still very likely.

However, what if there is more than moral luck behind drunk driving fatalities? What if the act of drinking itself, alters our perceptions in such a way, that we are more prone to swerve towards the pedestrian, than away from them? For example, Tourette’s syndrome appears to have a higher likelihood of expressing inappropriate words in its verbal tics (Lanckerab & Cummings, 1999). Steven Pinker, speculates that these tics are more like urges—temptations induced by a faulty basal ganglia, which normally functions as the “packagers and inhibitors of behavior.” (2007, p. 335). If the act of losing inhibitions and self-control, can lead you to shout “Fire!” in a crowded airport, perhaps it is also able to cause behaviors you would otherwise not commit, such as swerving towards pedestrians.

It is not a secret that alcohol lowers your inhibitions—that is the main reason people drink, to “loosen up.” One negative consequence of this disinhibition is aggression. Everything from murder, kidnapping and robberies, and other violent crimes have occurred while under the influence of alcohol (Collins, 1980). Spousal abuse is also more likely to occur when alcohol is involved (Livingston, 2011). Lastly, alcohol also makes you more prone to risky behavior, such as unwanted and unprotected sex.

Based on this information, it seems probable that alcohol also affects our perceptions while driving, but in such a way that it disinhibits normal behaviors aimed to keep us and those around us safe. In other words, we will test the potential problem that alcohol makes one prone to swerve into pedestrians than away from them. Up until now research has mostly focused on reaction times, such as hitting the breaks at the appropriate times. Instead, we will measure what the participants attempt to do, rather than what they fail to do.


Participants. 50 Student volunteers from the psychology department at the University of Central Florida. Consent forms and IRB permission will be required, due to participants consuming alcohol during the experiment.

Experiment 1. In line with (Johansson, 1973) point-light walker experiment, we would like to gauge the sensitivity to biological movement, at various intoxication intervals. Given the ability of sober people to discern not only between people and animals using this method, but also whether someone is male or female, a runner, someone who is happy or sad, it is my belief that this ability should remain generally unhindered while inebriated. If visual cues while driving are leading drunk people to crash into pedestrians, their ability to see and recognize the pedestrian must remain fairly intact.

According to an analysis made by Zador (1991), at a BAC of around 0.02- 0.03%, accidents are 1.4 times more likely than while sober. The likelihood of a crash increases almost exponentially with each percentage increase: a BAC of 0.05-0.09% is 11.1 times more likely to get in an accident; At 0.10% to 0.14%, you are 48 times more likely, and at BACs of 0.15% or above, the likelihood of a crash rises to 380 times more likely than while sober. Based on this information, participants (which will consist of 50 individuals) will undergo the point-light experiment at roughly these intervals. Each participant will undergo 3 Trials. In Trial 1 they’ll participant with a BAC of .03%. In Trial 2 they’ll be legally impaired, at .08-.10% BAC, and lastly, they’ll try again with .15% BAC. There is no need for a trial while sober, since it will be identical to Johansson’s results.

Experiment 2. The same participants from Experiment 1 will participate in Experiment 2. During the second set of experiments we place people in front of a computer, or ideally, a Virtual Reality headset. A prerecorded driving simulation would have been filmed prior to the experiment. In the recording we’ll show a normal drive through a town or neighborhood, from the point of view of the driver. The video will be approximately 5-10 minutes in duration. During the recording we’ll show pedestrians walking casually on the sidewalk, or children, at specific intervals. We’ll also test other stimuli aimed to capture the attention of the driver. Some will be intriguing, such as a pink elephant, others will consist of things normally understood you are not supposed to hit with a car, such as cones.

Since this video will be prerecorded, it does not consist of a simulation, in which the participant is in control. The vehicle will not be able to be moved by the driver, though participants will not be told this. Instead participants will be given a wheel such as those used in video games. We will be measuring the degree and direction, no matter how slight, that they turn the wheel while thinking they are in control. The road in the recording will be mostly straight, and we’ll measure how what they do in the presence of the visual stimuli. We’ll also add moments where the car begins to diverge from the straight path into a pedestrian, to see how well the driver notices and attempts course-correct. We are not interested in reaction times, but intention. Measurements will be taken at the same BAC categories listed for Experiment 1. However, we will repeat this experiment while BAC is ascending as well as while it is descending due to the psychological differences experienced by people during the two events, and the likelihood that most drunk drivers, get into vehicles after they are finished drinking (Maisto, Galizio, & Connors, 2015).


            For Experiment 1 an independent samples t-test will be conducted on the results. We will analyze data in a similar fashion to Johansson, only given the BAC variable. For Experiment 2 a paired sample t-test will also be conducted on the results. We are not interested in any specific demographic variable, despite some research showing that young people are more likely to get into accidents while drunk, than adults. These findings are often due more to irrelevant circumstances, such as peer-pressure. Moreover, since we are conducting the trials twice in Experiment 2, both for ascending and descending BAC, an analysis of variance will also be conducted.


            Needless to say, if the research gives positive results, it will bring about a new level of understanding to the dangers of alcohol and driving. Current laws against drinking and driving are no different from those of texting and driving: they are both justified under the assumption that reaction time and attention are inhibited. However, if results indicate that alcohol “makes you do” things you normally wouldn’t, like swerve into a pedestrian, we would not only expect to see new legislature taking the results into account, but also a new wave of research aimed at understanding how perception, not just sensation, are affected by various drugs.


Collins, J. J. (1980). Alcohol use and criminal behavior: An empirical, theoretical, and methodological overview. New York: Guilford Press.

Johansson, G. (1973). Visual perception of biological motion and a model for its analysis. Perception & Psychophysics, 195-204.

Lanckerab, V. D., & Cummings, J. L. (1999). Expletives: Neurolinguistic and neurobehavioral perspectives on swearing. Brain Research Reviews, 83-104.

Livingston, M. (2011). A longitudinal analysis of alcohol outlet density and domestic violence. Addiction, 919-925.

Maisto, S. A., Galizio, M., & Connors, G. J. (2015). Drug use & abuse (ed. 7th). Canada: Cengage Learning.

Nagel, T. (1979). Moral Luck. Cambridge: Cambridge University Press.

National Highway Traffic Safety Administration. (2017, November 19). Drunk Driving. Retrieved from NHTSA: https://www.nhtsa.gov/risky-driving/drunk-driving

Pinker, S. (2007). The Stuff of Thought: Language as a Window into Human Nature. New York: Penguin Books.

Williams, B. (1981). Moral Luck. Cambridge: Cambridge University Press.

Zador, P. L. (1991). Alcohol-related relative risk of fatal driver injuries in relation to driver age and sex. Journal of Sudies on Alcohol, 52, 302-310.
















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