Effects of acute alcohol consumption on processing of perceptual cues of emotional expression

A systematic review of the acute effects of alcohol on emotion recognition of facial expressions

Alcohol has been linked to both positive (e.g., sociability) and negative (e.g., aggression) social outcomes, and researchers have proposed that alcohol-induced changes in emotion recognition may partially explain these effects. Here, we systematically review alcohol administration studies to clarify the acute effects of alcohol on emotion recognition. We also investigate various moderator variables (i.e., sex, study quality, study design, alcohol dosage, emotion recognition task and outcome measure). PsycINFO, PubMed and Google Scholar were searched following a pre-registered PROSPERO protocol (CRD42021225392) and PRISMA methodology. Analyses focused on differences in emotion recognition between participants consuming alcoholic and/or non-alcoholic (i.e., placebo or no-alcohol control) beverages. Nineteen unique samples (N = 1271 participants) were derived from 17 articles (two articles included two studies, each conducted on a unique sample). Data were extracted for sample characteristics, alcohol administration methods and emotion recognition tasks and outcomes. All studies compared an alcoholic beverage to a placebo beverage and used tasks that asked participants to identify emotions from images or videos of facial expressions. Otherwise, methodologies varied substantially across studies, including the alcohol dosage(s) tested, the specific emotion recognition task(s) used and the outcome variable(s) assessed. No consistent effects of alcohol on emotion recognition emerged for any emotion. None of the moderator variables affected the findings, except for some indication that alcohol may affect males' emotion recognition abilities more so than females. Alcohol does not appear to consistently affect positive or negative emotion recognition of facial expressions, at least with the tasks currently used in the field.

The acute effects of alcohol on social cognition: A systematic review of experimental studies

RATIONALE

Alcohol effects on social cognition have been studied by measuring facial emotion recognition, empathy, Theory of Mind (ToM) and other forms of information processing.

OBJECTIVES

Using the PRISMA guidelines, we reviewed experimental studies that examined acute effects of alcohol on social cognition.

METHODS

Scopus, PsycInfo, PubMed, and Embase were searched between July 2020 - January 2023. The PICO strategy was used for identifying participants, interventions, comparators, and outcomes. Participants (N = 2330) were adult social alcohol users. Interventions consisted of acute alcohol administration. Comparators included placebo or the lowest alcohol dose. Outcome variables were grouped into three themes: facial processing, empathy and ToM, and perceptions of inappropriate sexual behavior.

RESULTS

A total of 32 studies were reviewed. Studies measuring facial processing (67%) often found no effects of alcohol on the recognition of specific emotions, facilitated emotion recognition at lower doses and worsened emotion recognition at higher doses. In studies measuring empathy or ToM (24%), lower doses were more likely to lead to improvements while higher doses were generally impairing. Within the third group of studies (9%), moderate to high alcohol doses made it more difficult to perceive sexual aggression accurately.

CONCLUSIONS

Lower alcohol doses might sometimes help facilitate social cognition, but most data were in line with the idea that alcohol tends to worsen social cognition, particularly at higher doses. Future studies might focus on examining other moderators of the effects of alcohol on social cognition, particularly interpersonal characteristics such as trait emotional empathy, and participant and target gender.

The dosing procedure that "makes the poison": Comparing the effects of single versus cumulative alcohol administration methods on emotion recognition

BACKGROUND

Most people often consume alcohol cumulatively and gradually. Yet almost scientific knowledge about alcohol's acute effects on cognition, behavior, and affect stems from laboratory studies that employ a single beverage administration procedure.

OBJECTIVE

This study tests the hypothesis that alcohol's acute effects depend on both methods of administration and alcohol blood level. We introduce a new laboratory procedure for studying cumulative alcohol drinking and examine alcohol's effects on emotion recognition as a function of both alcohol administration method and alcohol blood level.

METHODS

Participants were recruited for one of two studies. One study employed a between-subject design using a single alcoholic dose. Participants were randomly assigned to drink either placebo (0.00%), low (0.03%), moderate (0.06%), or high (0.09%) alcohol levels. The second study employed a within-subject design using a cumulative alcoholic administration method, in which each participant drank four drinks (placebo, followed by three alcoholic drinks). Both groups reached similar breath alcohol concentrations. In both studies, participants attended a single study session, in which emotion recognition was examined following alcohol administration.

RESULTS

Single alcoholic beverage administration method caused greater impairment in emotion recognition ability, specifically for anger, happiness, and fear, as compared with cumulative administration method, even though breath alcohol levels were similar in both conditions.

CONCLUSIONS

This paper presents questions concerning the internal validity of previous laboratory studies that use a single beverage administration procedure. Insights into the effects of alcohol on behavior, as well as regarding our knowledge about models of addiction are presented.

Does alcohol affect emotional face processing via interoceptive pathways?

BACKGROUND

Our brain uses interoceptive signals from the body to shape how we perceive emotions in others; however, whether interoceptive signals can be manipulated to alter emotional perceptions is unknown. Alcohol has acute effects both on emotional processing and on the physiological substrates supporting interoception. In this registered report, we examine whether alcohol administration triggers physiological changes that alter interoceptive signals and manipulate emotional face processing. Such knowledge will broaden understanding of the mechanisms by which alcohol affects emotional face processing.

METHODS

Participants (n = 36) will be administered an alcohol or placebo beverage. Cardiovascular physiology will be recorded before and after administration. Participants will complete two behavioral tasks in which they view emotional faces presented in synchrony with different phases of the cardiac cycle (i.e., systole, diastole). This manipulation creates an index of how interoceptive signals amplify emotional face processing.

HYPOTHESES

We hypothesize that, compared to placebo, alcohol administration will disrupt the cardiac amplification of emotional face processing. We further explore whether this disruption depends on the nature and magnitude of changes in cardiovascular physiology after alcohol administration.

Gender moderates the association between acute alcohol intoxication and facial emotion recognition in a naturalistic field study setting

BACKGROUND

Alcohol intoxication is associated with significant negative social consequences. Social information processing theory provides a framework for understanding how the accurate decoding and interpretation of social cues are critical for effective social responding. Acute intoxication has the potential to disrupt facial emotion recognition. If alcohol impairs the processing and interpretation of emotional cues, then the resultant behavioral responses may be less effective. The current study tested the association between alcohol intoxication and facial emotion recognition in a naturalistic field study of intoxicated participants.

METHODS

114 participants (59.4% men; M_age  = 24.2 years) who had been consuming alcohol were recruited in the downtown area of a mid-size town surrounded by several drinking establishments in the mid-southern United States. Participants were shown images depicting 5 facial displays of emotions (happy, sad, anger, disgust, and no emotion) portrayed by 1 male and 1 female actor per emotion and breath alcohol concentration (BrAC) was measured by the field breathalyzer test (M = 0.078%, SD = 0.052).

RESULTS

BrAC was significantly negatively associated with emotion recognition accuracy when controlling for average alcohol use, B = -.35, t = -2.08, p < 0.05, F(3, 110) = 5.28, p < 0.01, R²  = 0.13. A significant BrAC × gender interaction was revealed, B = -0.39, t = -2.07, p = 0.04, ΔR²  = 0.033, p = 0.04, such that men (but not women) displayed a significant negative association between BrAC and emotion recognition accuracy.

CONCLUSIONS

Acute intoxication was associated with impaired facial emotion recognition, particularly for men, in a field study context. Findings support and extend some previous experimental laboratory-based research and suggest that intoxication can impair the decoding stage of social information processing.

Effects of acute alcohol consumption on emotion recognition in social alcohol drinkers

BACKGROUND

Research suggests that acute alcohol consumption alters recognition of emotional expressions. Extending this work, we investigated the effects of alcohol on recognition of six primary expressions of emotion.

METHODS

We conducted two studies using a 2 × 6 experimental design with a between-subjects factor of drink (alcohol, placebo) and a within-subjects factor of emotion (anger, disgust, sadness, surprise, happiness, fear). Study one ( n = 110) was followed by a direct replication study ( n = 192). Participants completed a six alternative forced choice emotion recognition task following consumption of 0.4 g/kg alcohol or placebo. Dependent variables were recognition accuracy (i.e. hits) and false alarms.

RESULTS

There was no clear evidence of differences in recognition accuracy between groups ( ps > .58). In study one, there were more false alarms for anger in the alcohol compared to placebo group ( n = 52 and 56, respectively; t(94.6) = 2.26, p = .024, d = .44) and fewer false alarms for happiness ( t(106) = -2.42, p = .017, d = -.47). However, no clear evidence for these effects was found in study two (alcohol group n = 96, placebo group n = 93, ps > .22). When the data were combined we observed weak evidence of an effect of alcohol on false alarms of anger ( t(295) = 2.25, p = .025, d = .26).

CONCLUSIONS

These studies find weak support for biased anger perception following acute alcohol consumption in social consumers, which could have implications for alcohol-related aggression. Future research should investigate the robustness of this effect, particularly in individuals high in trait aggression.

A moderate dose of alcohol selectively reduces empathic accuracy

RATIONALE

Drinking alcohol is associated with various interpersonal effects, including effects on cognitive empathy. Empathic accuracy (EA) is a form of cognitive empathy concerned with perceivers' accuracy in inferring a target's thoughts and feelings. The effects of alcohol on EA have not previously been studied.

OBJECTIVES

We examined the effect of a moderate alcohol dose on EA in social drinkers.

METHODS

Fifty-four men with varying levels of hazardous drinking according to the Alcohol Use Disorders Identification Test (AUDIT) participated in a randomized, double-blind, between-group study. The alcohol group received 0.56 g/kg alcohol in a vodka and tonic-mixed drink. The placebo group received tonic, with 4 ml of vodka sprayed on top. All participants performed an EA task that involved watching 16 videos of people narrating positive and negative emotional autobiographical events and continuously rating how targets felt while narrating.

RESULTS

There were no significant main effects of beverage condition on the EA task. There was an effect of the condition by AUDIT interaction for EA on the positive videos. Post-hoc simple contrasts revealed that in participants with lower AUDIT scores, the alcohol condition had lower EA for positive videos than the placebo condition. No significant main effect for condition occurred in the participants with higher AUDIT scores.

CONCLUSIONS

The effect of condition in participants with lower AUDIT scores indicates alcohol selectively reduced EA in individuals low on hazardous drinking. This suggests either alcohol-induced impairments of EA for positive events or a positivity bias in men at low risk for alcohol dependency.

Alcohol acutely enhances decoding of positive emotions and emotional concern for positive stimuli and facilitates the viewing of sexual images

RATIONALE

Social cognition influences social interactions. Alcohol reportedly facilitates social interactions. However, the acute effects of alcohol on social cognition are relatively poorly studied.

METHODS

We investigated the effects of alcoholic or non-alcoholic beer on emotion recognition, empathy, and sexual arousal using the dynamic face emotion recognition task (FERT), Multifaceted Empathy Test (MET), and Sexual Arousal Task (SAT) in a double-blind, random-order, cross-over study in 60 healthy social drinkers. We also assessed subjective effects using visual analog scales (VASs), blood alcohol concentrations, and plasma oxytocin levels.

RESULTS

Alcohol increased VAS ratings of stimulated, happy, talkative, open, and want to be with others. The subjective effects of alcohol were greater in participants with higher trait inhibitedness. Alcohol facilitated the recognition of happy faces on the FERT and enhanced emotional empathy for positive stimuli on the MET, particularly in participants with low trait empathy. Pictures of explicit sexual content were rated as less pleasant than neutral pictures after non-alcoholic beer but not after alcoholic beer. Explicit sexual pictures were rated as more pleasant after alcoholic beer compared with non-alcoholic beer, particularly in women. Alcohol did not alter the levels of circulating oxytocin.

CONCLUSIONS

Alcohol biased emotion recognition toward better decoding of positive emotions and increased emotional concern for positive stimuli. No support was found for a modulatory role of oxytocin. Alcohol also facilitated the viewing of sexual images, consistent with disinhibition, but it did not actually enhance sexual arousal. These effects of alcohol on social cognition likely enhance sociability.

TRIAL REGISTRATION

www.clinicaltrials.gov/ct2/show/NCT02318823.

Drug effects on responses to emotional facial expressions: recent findings

Many psychoactive drugs increase social behavior and enhance social interactions, which may, in turn, increase their attractiveness to users. Although the psychological mechanisms by which drugs affect social behavior are not fully understood, there is some evidence that drugs alter the perception of emotions in others. Drugs can affect the ability to detect, attend to, and respond to emotional facial expressions, which in turn may influence their use in social settings. Either increased reactivity to positive expressions or decreased response to negative expressions may facilitate social interaction. This article reviews evidence that psychoactive drugs alter the processing of emotional facial expressions using subjective, behavioral, and physiological measures. The findings lay the groundwork for better understanding how drugs alter social processing and social behavior more generally.

Selective effects of acute alcohol intake on the prospective and retrospective components of a prospective-memory task with emotional targets

RATIONALE

Prospective memory involves remembering to do something in the future and has a prospective component (remembering that something must be done) and a retrospective component (remembering what must be done and when it must be done). Initial studies reported an impairment in prospective-memory performance due to acute alcohol consumption. Retrospective-memory studies demonstrated that alcohol effects vary depending on the emotionality of the information that needs to be learned.

OBJECTIVES

The aim of the present study was to investigate possible differential effects of a mild acute alcohol dose (0.4 g/kg) on the prospective and retrospective components of prospective memory depending on cue valence.

METHOD

Seventy-five participants were allocated to an alcohol or placebo group and performed a prospective-memory task in which prospective-memory cue valence was manipulated (negative, neutral, positive). The multinomial model of event-based prospective memory (Smith and Bayen 2004) was used to measure alcohol and valence effects on the two prospective-memory components separately.

RESULTS

Overall, no main effect of alcohol or valence on prospective-memory performance occurred. However, model-based analyses demonstrated a significantly higher retrospective component for positive compared with negative cues in the placebo group. In the alcohol group, the prospective component was weaker for negative than for neutral cues and the retrospective component was stronger for positive than for neutral cues. Group comparisons showed that the alcohol group had a significantly lower prospective component for negative cues and a lower retrospective component for neutral cues.

CONCLUSION

This is the first study to demonstrate selective alcohol effects on prospective-memory components depending on prospective-memory cue valence.

Gender effects in alcohol dependence: an fMRI pilot study examining affective processing

BACKGROUND

Alcohol dependence (AD) has global effects on brain structure and function, including frontolimbic regions regulating affective processing. Preliminary evidence suggests alcohol blunts limbic response to negative affective stimuli and increases activation to positive affective stimuli. Subtle gender differences are also evident during affective processing.

METHODS

Fourteen abstinent AD individuals (8 F, 6 M) and 14 healthy controls (9 F, 5 M), ages 23 to 60, were included in this facial affective processing functional magnetic resonance imaging pilot study. Whole-brain linear regression analyses were performed, and follow-up analyses examined whether AD status significantly predicted depressive symptoms and/or coping.

RESULTS

Fearful Condition-The AD group demonstrated reduced activation in the right medial frontal gyrus, compared with controls. Gender moderated the effects of AD in bilateral inferior frontal gyri. Happy Condition-AD individuals had increased activation in the right thalamus. Gender moderated the effects of AD in the left caudate, right middle frontal gyrus, left paracentral lobule, and right lingual gyrus. Interactive AD and gender effects for fearful and happy faces were such that AD men activated more than control men, but AD women activated less than control women. Enhanced coping was associated with greater activation in right medial frontal gyrus during fearful condition in AD individuals.

CONCLUSIONS

Abnormal affective processing in AD may be a marker of alcoholism risk or a consequence of chronic alcoholism. Subtle gender differences were observed, and gender moderated the effects of AD on neural substrates of affective processing. AD individuals with enhanced coping had brain activation patterns more similar to controls. Results help elucidate the effects of alcohol, gender, and their interaction on affective processing.

The effects of alcohol on the recognition of facial expressions and microexpressions of emotion: enhanced recognition of disgust and contempt

OBJECTIVE

The study compared alcohol's effects on the recognition of briefly displayed facial expressions of emotion (so-called microexpressions) with expressions presented for a longer period.

METHOD

Using a repeated-measures design, we tested 18 participants three times (counterbalanced), after (i) a placebo drink, (ii) a low-to-moderate dose of alcohol (0.17 g/kg women; 0.20 g/kg men) and (iii) a moderate-to-high dose of alcohol (0.52 g/kg women; 0.60 g/kg men). On each session, participants were presented with stimuli representing six emotions (happiness, sadness, anger, fear, disgust and contempt) overlaid on a generic avatar in a six-alternative forced-choice paradigm. A neutral expression (1 s) preceded and followed a target expression presented for 200 ms (microexpressions) or 400 ms. Participants mouse clicked the correct answer.

RESULTS

The recognition of disgust was significantly better after the high dose of alcohol than after the low dose or placebo drinks at both durations of stimulus presentation. A similar profile of effects was found for the recognition of contempt. There were no effects on response latencies.

CONCLUSION

Alcohol can increase sensitivity to expressions of disgust and contempt. Such effects are not dependent on stimulus duration up to 400 ms and may reflect contextual modulation of alcohol's effects on emotion recognition.

[Executive function and behavior in university drinkers]

OBJECTIVES

Establish the profile of executive function and behavior in fifty consumers of alcohol are located in a high-risk level according to the Alcohol Use Disorders Identification Test (AUDIT) and which belong to different universities in the city of Bogota.

MATERIAL AND METHODS

Was used analytical transverse design, and were taken as study variables executive function (inhibition, monitoring, sequencing, planning, cognitive flexibility, working memory, attentional control, categorization and concept formation) and executive behavior (decision making, impulse control, emotional feedback, empathy and theory of mind).

RESULTS AND CONCLUTIONS

Results showed that there is a greater number of cognitive domains of executive function involved in contrast to those of executive behavior. Such is for inhibition, sequencing, attention control (processing speed), categorization, cognitive flexibility, self monitoring and planning.

Effects of acute alcohol consumption and processing of emotion in faces: Implications for understanding alcohol-related aggression

The negative consequences of chronic alcohol abuse are well known, but heavy episodic consumption ("binge drinking") is also associated with significant personal and societal harms. Aggressive tendencies are increased after alcohol but the mechanisms underlying these changes are not fully understood. While effects on behavioural control are likely to be important, other effects may be involved given the widespread action of alcohol. Altered processing of social signals is associated with changes in social behaviours, including aggression, but until recently there has been little research investigating the effects of acute alcohol consumption on these outcomes. Recent work investigating the effects of acute alcohol on emotional face processing has suggested reduced sensitivity to submissive signals (sad faces) and increased perceptual bias towards provocative signals (angry faces) after alcohol consumption, which may play a role in alcohol-related aggression. Here we discuss a putative mechanism that may explain how alcohol consumption influences emotional processing and subsequent aggressive responding, via disruption of orbitofrontal cortex (OFC)-amygdala connectivity. While the importance of emotional processing on social behaviours is well established, research into acute alcohol consumption and emotional processing is still in its infancy. Further research is needed and we outline a research agenda to address gaps in the literature.

Effects of lowering the minimum alcohol purchasing age on weekend assaults resulting in hospitalization in New Zealand

OBJECTIVES

We estimated the effects on assault rates of lowering the minimum alcohol purchasing age in New Zealand from 20 to 18 years. We hypothesized that the law change would increase assaults among young people aged 18 to 19 years (the target group) and those aged 15 to 17 years via illegal sales or alcohol supplied by older friends or family members.

METHODS

Using Poisson regression, we examined weekend assaults resulting in hospitalization from 1995 to 2011. Outcomes were assessed separately by gender among young people aged 15 to 17 years and those aged 18 to 19 years, with those aged 20 and 21 years included as a control group.

RESULTS

Relative to young men aged 20 to 21 years, assaults increased significantly among young men aged 18 to 19 years between 1995 and 1999 (the period before the law change), as well as the postchange periods 2003 to 2007 (incidence rate ratio [IRR] = 1.21; 95% confidence interval [CI] = 1.05, 1.39) and 2008 to 2011 (IRR = 1.20; 95% CI = 1.05, 1.37). Among boys aged 15 to 17 years, assaults increased during the postchange periods 1999 to 2003 (IRR = 1.28; 95% CI = 1.10, 1.49) and 2004 to 2007 (IRR = 1.25; 95% CI = 1.08, 1.45). There were no statistically significant effects among girls and young women.

CONCLUSIONS

Lowering the minimum alcohol purchasing age increased weekend assaults resulting in hospitalization among young males 15 to 19 years of age.

Alcohol use, drinking consequences, and sensitivity to social cues among college women

College students who drink vary in the extent to which they experience drinking consequences, prompting a need to identify factors that differentiate higher-risk drinkers from others. The present study investigated whether difficulty in processing subtle social information is related to negative drinking consequences experienced within the past year. Specifically, poor ability to detect subtle non-verbal sarcasm cues was predicted to contribute to drinking consequences. Participants were 39 women, aged 18 to 27 (M=22), who were enrolled in a public, four-year university. Participants completed a video measure of ability to detect sarcastic comments. After controlling for (high school drinking consequences, maximum drinks in the past 3 months, age), poorer performance in the Simple Sarcasm condition (which provided no cues to others' intentions) explained an additional 10.8% of the variance in recent drinking consequences (ΔF (1, 34)=6.15, p=.018). When predicting risky/hazardous alcohol use consequences (e.g., driving intoxicated, fights, unplanned/unprotected sex), Simple Sarcasm again improved prediction by explaining an additional 8.6% of the variance (ΔF (1, 34)=4.75, p=.036). Sarcasm conditions that provided additional cues to others' meanings were unrelated to alcohol consequences. Findings are discussed within the context of neurological (orbito-frontal-subcortical) pathways that are common to social information and alcohol reinforcement processes.

Processing of facial affect in social drinkers: a dose-response study of alcohol using dynamic emotion expressions

RATIONALE

Studies of affect recognition can inform our understanding of the interpersonal effects of alcohol and help develop a more complete neuropsychological profile of this drug.

OBJECTIVES

The objective of the study was to examine affect recognition in social drinkers using a novel dynamic affect-recognition task, sampling performance across a range of evolutionarily significant target emotions and neutral expressions.

METHODS

Participants received 0, 0.4 or 0.8 g/kg alcohol in a double-blind, independent groups design. Relatively naturalistic changes in facial expression-from neutral (mouth open) to increasing intensities of target emotions, as well as neutral (mouth closed)-were simulated using computer-generated dynamic morphs. Accuracy and reaction time were measured and a two-high-threshold model applied to hits and false-alarm data to determine sensitivity and response bias.

RESULTS

While there was no effect on the principal emotion expressions (happiness, sadness, fear, anger and disgust), compared to those receiving 0.8 g/kg of alcohol and placebo, participants administered with 0.4 g/kg alcohol tended to show an enhanced response bias to neutral expressions. Exploration of this effect suggested an accompanying tendency to misattribute neutrality to sad expressions following the 0.4-g/kg dose.

CONCLUSIONS

The 0.4-g/kg alcohol-but not 0.8 g/kg-produced a limited and specific modification in affect recognition evidenced by a neutral response bias and possibly an accompanying tendency to misclassify sad expressions as neutral. In light of previous findings on involuntary negative memory following the 0.4-g/kg dose, we suggest that moderate-but not high-doses of alcohol have a special relevance to emotional processing in social drinkers.

Amphetamine as a social drug: effects of d-amphetamine on social processing and behavior

RATIONALE

Drug users often report using drugs to enhance social situations, and empirical studies support the idea that drugs increase both social behavior and the value of social interactions. One way that drugs may affect social behavior is by altering social processing, for example by decreasing perceptions of negative emotion in others.

OBJECTIVES

We examined effects of d-amphetamine on processing of emotional facial expressions and on the social behavior of talking. We predicted amphetamine would enhance attention, identification, and responsivity to positive expressions, and that this in turn would predict increased talkativeness.

METHODS

Over three sessions, 36 healthy normal adults received placebo, 10, and 20 mg d-amphetamine under counterbalanced double-blind conditions. At each session, we measured processing of happy, fearful, sad, and angry expressions using an attentional visual probe task, a dynamic emotion identification task, and measures of facial muscle activity. We also measured talking.

RESULTS

Amphetamine decreased the threshold for identifying all emotions, increased negative facial responses to sad expressions, and increased talkativeness. Contrary to our hypotheses, amphetamine did not alter attention to, identification of, or facial responses to positive emotions specifically. Interestingly, the drug decreased the threshold to identify all emotions, and this effect was uniquely related to increased talkativeness, even after controlling for overall sensitivity to amphetamine.

CONCLUSIONS

The results suggest that amphetamine may encourage sociability by increasing sensitivity to subtle emotional expressions. These findings suggest novel social mechanisms that may contribute to the rewarding effects of amphetamine.

Effects of acute alcohol consumption on the perception of eye gaze direction

Alcohol consumption is associated with increases in aggressive behaviour, but the mechanisms underlying this relationship are poorly understood. One mechanism by which alcohol consumption may influence behaviour is via alterations in the processing of social cues such as gaze. We investigated the effects of acute alcohol consumption on the perception of gaze, using a task in which participants determined whether a stimulus face was looking towards or away from them. Gaze direction varied across trials, allowing calculation of a threshold at which participants considered gaze to switch from direct to averted. Target faces varied in both sex and attractiveness. Thirty social drinkers attended three randomized experimental sessions. At each session, participants consumed 0.0, 0.2 or 0.4 g/kg alcohol, and completed the gaze perception task. A significant three-way interaction involving target sex, participant sex and alcohol dose indicated that alcohol increased the cone of gaze for females viewing male targets (i.e. females were biased towards making a direct gaze judgement), but decreased the cone of gaze for males viewing male targets. Our data indicate that alcohol consumption influences gaze perception, but that these effects vary across sex of both stimulus and rater. These effects may have important implications for alcohol-related violence.

Alcohol affects the emotional modulation of cognitive control: an event-related brain potential study

OBJECTIVE

The present study aimed to determine whether alcohol affects the emotional modulation of cognitive control and its underlying neural mechanisms, which is pivotal to an understanding of the socially maladaptive behaviors frequently seen in alcohol-intoxicated individuals.

METHOD

Event-related potentials (ERPs) were recorded in male participants receiving either a moderate dose of alcohol (0.65 g/kg alcohol; n = 32) or a non-alcoholic placebo beverage (n = 32) while performing an emotional Go/No-Go task that required response execution (Go trials) to pictures of a "target" emotional facial expression (angry, happy, neutral) and response inhibition (No-Go trials) to a different "non-target" expression.

RESULTS

Overall, N200 and P300 amplitudes were more enhanced during No-Go than Go trials. Interestingly, alcohol-intoxicated individuals displayed larger No-Go N200 amplitudes across all emotional conditions than controls, accompanied by decreased task performance (i.e., more errors), particularly in response to angry faces. P300 amplitude in the alcohol group was significantly reduced for both Go and No-Go trials, but only following angry and happy emotional expressions.

CONCLUSIONS

These results suggest that alcohol-intoxicated individuals need to effortfully activate more cognitive resources during the early inhibition process in order to regulate a response than controls. Moreover, alcohol affected the emotional modulation of both response inhibition and execution in the later stages of cognitive control. Alcohol dampened emotional responsiveness, which may restrict the availability of attentional resources for cognitive control. Yet, these findings may underlie the lack of control in alcohol-intoxicated individuals when faced with emotionally or socially challenging situations.

A meta-analysis of alcohol toxicology study findings among homicide victims

AIM

To synthesize the results of alcohol toxicology reports for homicide victims and examine variations in these results across person and setting characteristics.

METHODS

We meta-analyzed 61 independent studies from 57 published manuscripts which met the study inclusion criteria and reported alcohol toxicology test results for homicide victims. A total of 71, 031 toxicology test results, derived from 78, 265 homicide victims across 13 countries (most from the United States), were examined.

RESULTS

On average, 48% of homicide victims tested positive for alcohol and 33% (using the 0.08 threshold) or 35% (using the 0.10 threshold) were determined to be intoxicated. The proportion of homicide victims testing positive for alcohol appeared to be decreasing over time. Further, the proportion testing positive increased with age is higher for female than for male victims, and differs by race. Finally, the overall estimates were relatively stable across study sites.

CONCLUSION

Alcohol toxicology test results remain an important method for measuring the success of efforts to manage the consequences of alcohol. However, future toxicology studies should focus upon collecting information on evidence processing time, establishing measurement standards for reporting data and ensuring that subgroup estimates are included for purposes of cross-site comparisons.

Examining and Understanding the Joint Role of Caffeine and Alcohol in Facilitating Violent Offending and Victimization

The study draws attention to the importance of considering and controlling for caffeine and the interactive effects between caffeine and alcohol when investigating aggressive and violent behavior. Various pathways between caffeine and alcohol consumption and aggression and violence are examined. Given recent changes in preferences and availability of caffeine and energy drinks among licit and illicit substance users, this study argues for the importance of focusing research attention on the role of caffeine, particularly when combined with alcohol, in facilitating violent outcomes. Evidence suggests that both caffeine and alcohol are linked to aggression and violence and that both substances should be considered within the context of our efforts to manage the negative consequences of drugs. Caffeine, via energy drink consumption, may contribute to violent offending and victimization in a variety of ways. Evidence suggests that caffeine/energy drink consumption is popular among a subculture of toxic jock users, may motivate and facilitate increased alcohol consumption particularly in late night-time economies, and can potentially contribute to disrupted decision-making. Recent increases in caffeinated-product availability, marketing, and consumption necessitate focused research and policy attention. Many of these products are consumed with alcohol and/or in late evening settings by individuals that are already at increased risk for violent offending and victimization.

Effects of alcohol consumption and alcohol expectancy on the categorisation of perceptual cues of emotional expression

RATIONALE

Evidence that alcohol leads to increased aggressive behaviour is equivocal and confounded by evidence that such effects may operate indirectly via expectancy. One mechanism by which alcohol consumption may increase aggressive behaviour is via alterations in the processing of emotional facial cues.

OBJECTIVES

We investigated whether acute alcohol consumption or the expectancy of consuming alcohol (or both) induces differences in the categorisation of ambiguous emotional expressions. We also explored differences between male and female participants, using male and female facial cues of emotional expression.

METHODS

Following consumption of a drink, participants completed a categorisation task in which they had to identify the emotional expression of a facial stimulus. Stimuli were morphed facial images ranging between unambiguously angry and happy expressions (condition 1) or between unambiguously angry and disgusted expressions (condition 2). Participants (N = 96) were randomised to receive an alcoholic or non-alcoholic drink and to be told that they would receive an alcoholic or non-alcoholic drink.

RESULTS

Significant effects of alcohol were obtained in the angry-disgusted task condition, but only when the target facial stimulus was male. Participants tended to categorise male disgusted faces as angry after alcohol, but not after placebo.

CONCLUSIONS

Our data indicate that alcohol consumption may increase the likelihood of an ambiguous but negative facial expression being judged as angry. However, these effects were only observed for male faces and therefore may have been influenced by the greater expectation of aggression in males compared to females. Implications for alcohol-associated aggressive behaviour are discussed.