Measurement of Mood States Following Light Alcohol Consumption: Evidence from the Implicit Association Test

Abstract

As the problems of mood measurements during alcohol consumption of alcoholic beverages do not necessarily evoke interpretable physiological responses, explicit reports may be contaminated by various cognitive biases or expectations. The present study examined whether emotional responses induced by the consumption of beverages containing low concentrations of alcohol can be measured using the Implicit Association Test (IAT). The IAT can detect the estimates of internal proximity between bipolar target concepts (e.g., cheerfulness and fatigue). Participants (N = 30) received three IAT sessions, followed by drinking a beverage containing 0% (control), 1%, or 3% alcohol by volume, and three IATs (at 0, 30, and 60 min after the time of consumption). We also recorded the explicit responses regarding the extent of drunkenness. The analyses of variance with alcohol concentration and time reveal dissociation between implicit and explicit measures. The IAT scores under the alcohol conditions reflect a more cheerful mood state relative to the baseline test. This effect of enhanced cheerfulness was not observed under the non-alcohol control condition. These results demonstrate that the impact of the consumption of low-alcohol beverages on mood can be measured using the IAT.

Keywords: implicit association test; light alcohol consumption; measurement of mood state.

Figure 1

(Left) The sequence of events in one experimental session. The dark gray boxes represent administration of the Implicit Association Test (IAT) and the intoxication self-report. The light-gray box represents the time of consumption of the beverage. One IAT session (and one self-report pertaining to intoxication) took approximately 8 min (and 2 min) to complete. Two filler tasks were conducted during the inter-IAT periods (approximately 20 min) to avoid having participants fall asleep. (Right) Schematic representations of the IAT screen on the critical blocks (Blocks 4 and 7). Note that the category labels and target words in the display were shown in Japanese in the present study.

Figure 2

Mean reaction times of correct trials for each alcohol concentration (A: 0%, B: 1%, and C: 3%) and the two critical blocks (Blocks 4, self—cheerful/other—fatigue; and 7, self—fatigue/other—cheerful) as a function of time (baseline, 0, 30, and 60 min delay). Error bars show 95% confidence interval.

Figure 3

Boxplots for each of the alcohol concentrations (A: 0%, B: 1%, and C: 3%) show the median, first quartile, and third quartile of IAT scores as a function of time (baseline, 0, 30, and 60 min delay). Whiskers indicate scores to the 10th (downward) and 90th (upward) percentiles. The dot plots show outliers above (or below) the 90th (or 10th) percentile.