Effects of acute alcohol consumption and alcohol expectancy on processing of perceptual cues of emotional expression LC Craig Department of Experimental Psychology, University of Bristol, Bristol, UK. AS Attwood Department of Experimental Psychology, University of Bristol, Bristol, UK. CP Benton Department of Experimental Psychology, University of Bristol, Bristol, UK. IS Penton-Voak Department of Experimental Psychology, University of Bristol, Bristol, UK. MR Munafò Department of Experimental Psychology, University of Bristol, Bristol, UK. Abstract We recently demonstrated that alcohol elicits a difference between men and women in perceptual threshold for facial expressions of sadness. However, this study did not include a manipulation of alcohol expectancy. Therefore, we sought to determine whether these effects may be due to the expectation of having consumed alcohol. Male and female participants (n = 100) were randomised using a balanced-placebo design to receive either an alcoholic or a non-alcoholic drink and to be told that this was alcoholic or non-alcoholic. Participants completed a psychophysical task which presented male and female faces expressing angry, happy, and sad emotions. Analysis of threshold data indicated a significant two-way interaction of drink × target emotion, reflecting a higher threshold for the detection of sad facial expressions of emotion, compared with angry or happy expressions, in the alcohol condition compared with the placebo condition. We did not observe any evidence of sex differences in these effects. Our data indicate that alcohol modifies the perceptual threshold for facial expressions of sadness. Unlike our previous report, we did not observe evidence of sex differences in these effects. Most importantly, we did not observe any evidence that these effects were due to expectancy effects associated with alcohol consumption. Key words alcohol; balanced-placebo; emotional expression; expectancy; face processing Introduction There has been substantial recent concern regarding the effects of alcohol on aggressive behaviour and violent crime (Plant, 2004). In particular, arguments against the liberalisation of licensing laws and the greater availability of alcohol have included evidence that alcohol consumption increases levels of aggressive behaviour and leads to an increased risk of violence and violent behaviour (Hoaken and Stewart, 2003). To date, however, the evidence that alcohol directly leads to increased aggressive behaviour is equivocal (Bartholow and Heinz, 2006) and confounded by evidence that such effects may operate indi- rectly, at least partially, via expectancy effects: consumption of alcohol may lead to an increase in aggressive behaviour due to the expectation that this is a consequence of alcohol consump- tion (Quigley, Corbett, and Tedeschi, 2002). There is only limited evidence investigating direct links between alcohol consumption and aggressive behaviour. More importantly, even if one accepts that there is a causal link between alcohol consumption and aggression, the mechanisms (either direct or indirect) that may subserve this association remain largely unknown. This reduces the options available when attempting to educate adolescents and young adults regarding the possible consequences of alcohol consumption, and this also reduces the factual information available to policy makers regarding the effects of alcohol consumption. One possible mechanism by which acute alcohol consump- tion may lead to an increase in aggressive behaviour is via alterations in the expression and processing of emotional facial Original Papers Journal of Psychopharmacology 23(3) (2009) 258–265 © 2009 British Association for Psychopharmacology ISSN 0269-8811 SAGE Publications Ltd, Los Angeles, London, New Delhi and Singapore 10.1177/0269881108092126 Corresponding author: Marcus R. Munafò, PhD, Department of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol BS8 1TU, UK. Email: marcus.munafo@bristol.ac.uk at University of Bristol Library on May 5, 2015 jop.sagepub.com Downloaded from