The ad-libitum alcohol ‘taste test’: secondary analyses of potential confounds and construct validity

Abstract

RationaleMotivation to drink alcohol can be measured in the laboratory using an ad-libitum ‘taste test’, in which participants rate the taste of alcoholic drinks whilst their intake is covertly monitored. Little is known about the construct validity of this paradigm.ObjectiveThe objective of this study was to investigate variables that may compromise the validity of this paradigm and its construct validity.MethodsWe re-analysed data from 12 studies from our laboratory that incorporated an ad-libitum taste test. We considered time of day and participants’ awareness of the purpose of the taste test as potential confounding variables. We examined whether gender, typical alcohol consumption, subjective craving, scores on the Alcohol Use Disorders Identification Test and perceived pleasantness of the drinks predicted ad-libitum consumption (construct validity).ResultsWe included 762 participants (462 female). Participant awareness and time of day were not related to ad-libitum alcohol consumption. Males drank significantly more alcohol than females (p < 0.001), and individual differences in typical alcohol consumption (p = 0.04), craving (p < 0.001) and perceived pleasantness of the drinks (p = 0.04) were all significant predictors of ad-libitum consumption.ConclusionsWe found little evidence that time of day or participant awareness influenced alcohol consumption. The construct validity of the taste test was supported by relationships between ad-libitum consumption and typical alcohol consumption, craving and pleasantness ratings of the drinks. The ad-libitum taste test is a valid method for the assessment of alcohol intake in the laboratory.

Role Reversal: The Influence of Slot Machine Gambling on Subsequent Alcohol Consumption

“…We assessed awareness of the study hypothesis directly in Experiment 2. Approximately one third of participants guessed the true aims of the study upon completion, although this awareness did not predict alcohol consumption levels or desire to drink beer (also seen in previous experiments, see Jones et al, 2016). Thus, there is no positive evidence to link the ad libitum results in Experiment 1 to demand characteristics, although we recommend that future studies using the ad libitum procedure employ measures of awareness to assess demand characteristics.…”

“…That is to say, participants may have inferred our hypothesis that gambling would increase alcohol consumption and behave accordingly. Against this interpretation, consumption levels in both experiments were predicted by self-reported alcohol use outside of the laboratory (see also Jones et al 2016;Leeman et al 2009Leeman et al , 2013. We assessed awareness of the study hypothesis directly in Experiment 2.…”

“…Experiment 2 sought to corroborate Experiment 1 using an alternative 'taste test' procedure, in which the participant is asked to rate different beers under the pretext of market research (see Christiansen et al 2013;Jones et al 2016;Marlatt et al 1973). In this procedure, the tasting instruction obscures the true aim of measuring the volume of alcohol consumed, providing an unobtrusive measure.…”

“…In this procedure, the tasting instruction obscures the true aim of measuring the volume of alcohol consumed, providing an unobtrusive measure. The taste test procedure has established construct validity and consumption is not shaped by participants' awareness that their consumption is being monitored (Jones et al 2016). For this experiment, we also enhanced the salience of winning and losing by binarizing the bonus payment based on overall profit or loss.…”

“…The volume of beer was selected to ensure that all participants could consume the full quantity without exceeding the BAC threshold of 0.08%. Participants rated each cup for pleasant (unpleasant), flat (gassy), bitter (sweet), and tasteless (strong), and an overall liking rating, using 100 mm visual analogue scales (Jones et al, 2016). The Intention to Drink rating from Experiment 1 was replaced with two ratings, 'How thirsty are you right now?'…”