Some effects of alcohol and eye movements on cross-race face learning

The influence of acute alcohol intoxication and hair visibility on delayed face recall

Many witnesses are intoxicated at crime scenes, yet little is known of their ability to accurately describe perpetrators to police. We therefore explored the impact of alcohol on delayed verbal face recall across two experiments. Participants were administered an alcoholic or non-alcoholic beverage prior to viewing either one or two unfamiliar female faces, which they described from memory the following day while in a sober state. Each to-be-remembered model had long hair worn either loose (i.e., visible), or tied behind the head (i.e., concealed). Testing the hypothesis that alcohol narrows the focus of attention to the external (hairstyle) region of faces, we expected intoxicated participants to have poorer memory of internal face features (eyes, nose, mouth) than sober controls for stimulus faces with visibly long hair. Results revealed poorer recall accuracy for internal face details following alcohol consumption (Exp. 2), but the effect was uninfluenced by hairstyle. Findings are therefore consistent with the more general view that alcohol is associated with a bias to the external (hairstyle) region of faces during face learning, irrespective of hair visibility.

Impaired face symmetry detection under alcohol, but no 'beer goggles' effect

BACKGROUND

The 'beer goggles' phenomenon describes sexual attraction to individuals when alcohol intoxicated whom we would not desire when sober. One possible explanation of the effect is that alcohol impairs the detection of facial asymmetry, thus lowering the drinker's threshold for physical attraction.

AIMS

We therefore tested the hypotheses that higher breath alcohol drinkers would award more generous ratings of attractiveness to asymmetrical faces, and be poorer at discriminating bilateral facial asymmetry than less intoxicated counterparts.

METHODS

Ninety-nine male and female bar patrons rated 18 individual faces for attractiveness and symmetry. Each type of rating was given twice, once per face with an enhanced asymmetry and once again for each face in its natural form. Participants then judged which of two same-face versions (one normal, the other perfectly symmetrised) was more attractive and, in the final task, more symmetrical.

RESULTS

Alcohol had no influence on attractiveness judgements but higher blood alcohol concentrations were associated with higher symmetry ratings. Furthermore, as predicted, heavily intoxicated individuals were less able to distinguish natural from perfectly symmetrised face versions than more sober drinkers.

CONCLUSIONS

Findings therefore suggest alcohol impairs face asymmetry detection, but it seems that this perceptual distortion does not contribute to the 'beer goggles' phenomenon.

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.

Effects of alcohol and task difficulty on visual tracking and inattentional blindness

RATIONALE

Inattentional blindness (IB) describes the failure to notice salient but unexpected stimuli in one's focal visual field. It typically occurs while performing a demanding task (e.g. tracking and counting basketball passes), which consumes attentional resources. Alcohol intoxication is also known to reduce attentional resources, thereby potentially increasing IB and disrupting task performance.

OBJECTIVES

To test the extent to which acute alcohol and task difficulty disrupt counting performance and increase the rate of IB across two experimental tasks.

METHODS

To test the effects of alcohol consumption and task difficulty on IB, we used the Simons and Chabris (Percept 28:1059-1074, 1999) and Simons (2010) "gorilla in our midst" basketball clip in experiment 1 and abstract but analogous stimuli presented in a computerised alternative to that task in experiment 2.

RESULTS

IB was associated with increased (counting) task difficulty but not alcohol consumption. However, counting accuracy was impaired by both alcohol and increased task difficulty, with the largest detriment being for alcohol participants who noticed the salient but unexpected stimulus.

CONCLUSION

The absence of alcohol effects on IB in both experiments was unexpected and warrants further investigation in a field vs lab study comparison and in combination with baseline cognitive measures to test for alcohol expectancy and task compensation effects.

Acute Alcohol Intake Affects Internal Additive Noise and the Perceptual Template in Visual Perception

A reduction in visual performance is among the serious consequences of acute alcohol intake. Contrast sensitivity (CS) is a fundamental feature of visual function. Here, we investigated the negative effect of a moderate dose of alcohol on CS across a wide range of spatial frequencies and with multiple levels of external noise and clarified the corresponding mechanisms in the context of a perceptual template model (PTM). To avoid the effect of alcohol washout, a quick contrast sensitivity function (qCSF) method was used to assess the visual performance of subjects before and 30 min after a moderate dose of alcohol intake. We found that (1) CS was significantly disrupted by acute alcohol intake; (2) alcohol-induced CS loss was dependent on spatial frequency and external noise; and (3) increased internal additive noise and an impaired perceptual template accounted for alcohol-induced CS loss. These results help us better understand the negative effect of alcohol consumption and provide guidance for driver safety studies.

Does Cross-Race Contact Improve Cross-Race Face Perception? A Meta-Analysis of the Cross-Race Deficit and Contact

Contact with racial outgroups is thought to reduce the cross-race recognition deficit (CRD), the tendency for people to recognize same-race (i.e., ingroup) faces more accurately than cross-race (i.e., outgroup) faces. In 2001, Meissner and Brigham conducted a meta-analysis in which they examined this question and found a meta-analytic effect of r = -.13. We conduct a new meta-analysis based on 20 years of additional data to update the estimate of this relationship and examine theoretical and methodological moderators of the effect. We find a meta-analytic effect of r = -.15. In line with theoretical predictions, we find some evidence that the magnitude of this relationship is stronger when contact occurs during childhood rather than adulthood. We find no evidence that the relationship differs for measures of holistic/configural processing compared with normal processing. Finally, we find that the magnitude of the relationship depends on the operationalization of contact and that it is strongest when contact is manipulated. We consider recommendations for further research on this topic.

Visuoperceptive Impairments in Severe Alcohol Use Disorder: A Critical Review of Behavioral Studies

The present literature review is aimed at offering a comprehensive and critical view of behavioral data collected during the past seventy years concerning visuoperception in severe alcohol use disorders (AUD). To pave the way for a renewal of research and clinical approaches in this very little understood field, this paper (1) provides a critical review of previous behavioral studies exploring visuoperceptive processing in severe AUD, (2) identifies the alcohol-related parameters and demographic factors that influence the deficits, and (3) addresses the limitations of this literature and their implications for current clinical strategies. By doing so, this review highlights the presence of visuoperceptive deficits but also shows how the lack of in-depth studies exploring the visual system in this clinical population results in the current absence of integration of these deficits in the dominant models of vision. Given the predominance of vision in everyday life, we stress the need to better delineate the extent, the specificity, and the actual implications of the deficits for severe AUD.

Influence of Alcohol and Cognitive Capacity on Visual Number Judgements

We used an enumeration task to address the question of whether acute alcohol intoxication reduces cognitive or perceptual capacity. To control for individual differences in cognitive resources, we took a sober record of each participant's working memory capacity (WMC). Alcohol was expected to impair enumeration performance, either for the automatic parallel counting of small stimulus sets indicating a perceptual impairment, or the controlled counting or estimating of larger sets indicating a cognitive impairment. Enumeration showed an overall decline in accuracy following a vodka beverage and the deficit was negligible for small sets, which is inconsistent with a loss of perceptual capacity. Having a higher WMC facilitated the enumeration of larger sets and the correlation between WMC and accuracy was stronger in the alcohol condition suggesting that low-WMC participants were more impaired by the beverage. Our findings therefore suggest that alcohol diminished cognitive rather than perceptual capacity.

Alcohol myopia and the distracting effects of hair in face recognition

BACKGROUND

According to alcohol myopia theory, alcohol reduces cognitive resources and restricts the drinker's attention to only the more prominent aspects of a visual scene. As human hairstyles are often salient and serve as important facial recognition cues, we consider whether alcohol restricts attention to this region of faces upon initial viewing.

AIMS

Participants with higher breath alcohol concentrations just prior to encoding a series of unfamiliar faces were expected to be poorer than more sober counterparts at recognising the internal but not external features of those faces at test.

METHODS

Drinkers in a nearby bar (n=76) were breathalysed and then shown a sequence of 21 full face photos. After a filled five-minute retention interval they completed a facial recognition task requiring them to identify the full, internal or external region of each of these among a sequence of 21 previously unseen (part or whole) faces.

RESULTS

As predicted, higher breath concentrations were associated with poorer discrimination of internal but not external face regions.

CONCLUSIONS

Our findings suggest that alcohol restricts unfamiliar face encoding by narrowing the scope of attention to the exterior region of unfamiliar faces. This has important implications for drunk eyewitness accuracy, though further investigation is needed to see if the effect is mediated by gender, hair length and face feature distinctiveness.

Gaze entropy measures detect alcohol-induced driver impairment

Driving under the influence of alcohol is an ongoing cause of road traffic accidents. The biphasic nature of alcohol effects on subjective experience appears to contribute to the prevalence of drink-driving, as people perceive the declining phase of the BAC curve as recovery from intoxication and are more willing to drive despite significant impairments in objectively measured functions. The present study investigates whether alcohol-induced changes in gaze behaviour can be detected during engagement in a simulated driving task. In a repeated-measures and placebo-controlled design, this study examines the biphasic influence of moderate alcohol intake (0.6 g/kg) on measures of gaze behaviour and simulated driving performance. Twenty-two healthy young adults completed three driving sessions (baseline, ascending and descending) under two conditions (placebo, alcohol) while their eye movements were simultaneously recorded. The results revealed that gaze behaviour as measured by gaze transition entropy (GTE) and stationary gaze entropy (SGE) and driving performance measured by the standard deviation of lateral position (SDLP) of the vehicle, were significantly affected by alcohol across the ascending and descending sessions. The alcohol-induced reduction in GTE with an increase in SGE is discussed as alcohol's impact on top-down modulation of gaze resulting in more dispersed and erratic pattern of visual scanning. The observed changes in gaze behaviour also mediated the influence of alcohol upon driving performance. These results have significant implications for the development of driver monitoring systems that can detect alcohol-induced impairment.

Alcohol increases inattentional blindness when cognitive resources are not consumed by ongoing task demands

RATIONALE

Inattentional blindness (IB) is the inability to detect a salient yet unexpected task irrelevant stimulus in one's visual field when attention is engaged in an ongoing primary task. The present study is the first to examine the impact of both task difficulty and alcohol consumption on IB and primary task performance.

OBJECTIVES

On the basis of alcohol myopia theory, the combined effects of increased task difficulty and alcohol intoxication were predicted to impair task performance and restrict the focus of attention on to task-relevant stimuli. We therefore expected increases in breath alcohol concentration to be associated with poorer primary task performance and higher rates of IB, with these relationships being stronger under hard than easy task conditions.

METHODS

This hypothesis was tested in a field study where alcohol drinkers in a local bar were randomly assigned to perform a dynamic IB task with an easy or hard visual tracking and counting task at its core (Simons and Chabris in Perception 28:1059-1074, 1999).

RESULTS

Increasing the difficulty of the primary task reduced task accuracy but, surprisingly, had no impact on the rate of IB. Higher levels of alcohol intoxication were, however, associated with poorer task performance and an increased rate of IB, but only under easy primary task conditions.

CONCLUSIONS

Results are consistent with alcohol myopia theory. Alcohol intoxication depletes attentional resources, thus reducing the drinker's awareness of salient stimuli that are irrelevant to some ongoing primary task. We conclude that this effect was not observed for our hard task because it is more resource intensive, so leaves no spare attentional capacity for alcohol to deplete.

Do intoxicated witnesses produce poor facial composite images?

RATIONALE

The effect of alcohol intoxication on witness memory and performance has been the subject of research for some time, however, whether intoxication affects facial composite construction has not been investigated.

OBJECTIVES

Intoxication was predicted to adversely affect facial composite construction.

METHODS

Thirty-two participants were allocated to one of four beverage conditions consisting of factorial combinations of alcohol or placebo at face encoding, and later construction. Participants viewed a video of a target person and constructed a composite of this target the following day. The resulting images were presented as a full face composite, or a part face consisting of either internal or external facial features to a second sample of participants who provided likeness ratings as a measure of facial composite quality.

RESULTS

Intoxication at face encoding had a detrimental impact on the quality of facial composites produced the following day, suggesting that alcohol impaired the encoding of the target faces. The common finding that external compared to internal features are more accurately represented was demonstrated, even following alcohol at encoding. This finding was moderated by alcohol and target face gender such that alcohol at face encoding resulted in reduced likeness of external features for male composite faces only.

CONCLUSIONS

Moderate alcohol intoxication impairs the quality of facial composites, adding to existing literature demonstrating little effect of alcohol on line-up studies. The impact of intoxication on face perception mechanisms, and the apparent narrowing of processing to external face areas such as hair, is discussed in the context of alcohol myopia theory.

Testing Alcohol Myopia Theory: Examining the Effects of Alcohol Intoxication on Simultaneous Central and Peripheral Attention

The effect of alcohol intoxication on central and peripheral attention was examined as a test of Alcohol Myopia Theory (AMT). Previous research has supported AMT in the context of visual attention, but few studies have examined the effects of alcohol intoxication on central and peripheral attention. The study followed a 2 (alcohol treatment) × 2 (array size) × 2 (task type) mixed design. Forty-one participants (placebo or intoxicated) viewed an array of four or six colored circles, while simultaneously counting the flashes of a centrally presented fixation cross. Participants were instructed to prioritize flash counting accuracy. The subsequently presented colored probe matched the cued peripheral stimulus on 50% of trials. Flash counting and probe identification accuracy were recorded. There was a significant main effect of alcohol treatment on accuracy scores, as well as an alcohol treatment by task type interaction. Accuracy scores for the central flash counting task did not differ between treatment groups, but scores for peripheral probe identification were lower in the alcohol group. As predicted by AMT, alcohol impairment was greater for peripheral probe detection than for the central and prioritized flash counting task. The findings support the notion that alcohol intoxication narrows attentional focus to the central aspects of a task.

When alcohol narrows the field of focal attention

The aim of this study was to measure the extent to which alcohol intoxication restricts the scope of attention in the visual field. A group of intoxicated ( n = 31; mean BAC ≈ .08%) and placebo control ( n = 31; mean BAC ≈ .00%) participants were required to correctly identify visual probes while performing two verbal categorization tasks: one designed to widen the scope of visual attention on to each stimulus word, the other to narrow attention on to the central letter of each word. Response times to surprise probes interpolated between categorization trials were measured and these catch trials could appear in any of the stimulus word letter positions. As predicted by alcohol myopia theory (AMT), which assumes that the drug narrows focal attention, intoxicated participants made slower responses than the sober controls to probes displayed in non-central letter positions, although right-field probe reaction times (RTs) were slower than those for left-field targets. This response asymmetry and the wider theoretical implications of these findings are discussed.