Effects of acute alcohol intoxication on visuospatial attention.

The aim of the present study was to examine the effects of acute alcohol intoxication on the spatial distribution of visual attention measured with simple reaction times (RTs) to targets presented over an extended region of the visual field. Control (n=10) and alcohol groups (n=14) were tested with the same protocol. Participants were tested in two different conditions; in Experiment I, participants were instructed to direct their visual attention to the centre, while in Experiment II they were asked to orient their attention covertly to both right and left, but not to the centre. Throughout participants were required to fixate a small cross in the centre of the computer screen. In the alcohol group, participants received an alcohol dose of 0.4 g/kg so as to produce a blood alcohol concentration (BAC) in the range of 0.08% during the experiments. The spatial distribution of RTs was analysed graphically with geostatistical methods and statistically through analysis of variance of particular regions of the visual field. Results showed that controls were able to direct their attention tightly towards the centre (Expt I) and also to divide attention (Expt II) to the right and left. Participants in the alcohol group fixed their attention more diffusely in the centre (Expt I) and were unable to disengage attention from the centre in Experiment II. We conclude that acute alcohol intoxication impairs the ability to dissociate attention from gaze.