Smells like inhibition: The effects of olfactory and visual alcohol cues on inhibitory control

Does the smell of alcohol make it harder to resist? The impact of olfactory cues on inhibitory control and attentional bias

BACKGROUND

It is well known that, owing to associative processing, olfactory cues can impact memory, emotion and behaviour. Research also points to a link between the smells of particular substances and craving. Yet, to date, little research has investigated how smell may impact other cognitive processes that are known to drive alcohol consumption.

AIM

To assess how exposure to alcohol-related (vodka) relative to neutral (citrus) olfactory cues impacts inhibitory control and attentional bias.

METHOD

Participants took part in a go/no-go (Study 1) and Stroop task (Study 2) while wearing masks that were pre-treated with vodka or citrus oil of equivalent intensity. STUDY 1 RESULTS: Response error rates were higher in participants in the alcohol-related (versus neutral) olfactory condition, with no interaction between olfactory and visual cue. STUDY 2 RESULTS: Responses to alcohol-related versus neutral words were similar, while performance appeared significantly impaired among participants wearing alcohol (relative to citrus) infused masks. Conclusion The smell of alcohol may impair signal detection performance on the go/no-go and Stroop task. As inhibitory control and attentional processes are known to be associated with decisions to drink or exercise restraint, these results may have implications for our understanding of alcohol consumption and for tailoring interventions.

Intoxication without anticipation: Disentangling pharmacological from expected effects of alcohol

BACKGROUND

The pharmacological effects of alcohol on executive function, craving and subsequent alcohol-seeking have been well documented. Yet, insufficient methodological controls within existing alcohol administration paradigms have meant that the relative importance of alcohol's pharmacological and anticipatory effects remains in need of further elucidation.

AIM

The objective of this study is to disentangle alcohol's pharmacological effects from its anticipatory effects on alcohol-related cognitions and subsequent consumption.

METHODS

Inhibitory control, attentional bias and craving were assessed pre- and post-consumption in 100 participants who were randomly allocated to one of four beverage conditions in a two by two design: (1) alcohol aware (alcohol with participant knowledge (pharmacological/anticipation effects)), (2) alcohol blind (alcohol without participant knowledge; in a novel grain alcohol masking condition (pharmacological/no anticipation effects)), (3) placebo (no alcohol but participants were deceived (anticipation/non-pharmacological effects)) and (4) pure control (no alcohol with participant knowledge (no anticipation/non-pharmacological effects)).

RESULTS

Findings suggest that the pharmacological effects of alcohol result in greater inhibitory control impairments compared with anticipated effects. Anticipatory but not the pharmacological effects of alcohol were found to increase attentional bias. Both pharmacology and anticipation resulted in increased craving, though higher levels of craving were observed due to alcohol's pharmacology. Furthermore, alcohol pharmacology resulted in heightened ad libitum consumption; however, anticipation did not. Changes in craving partially mediated the relationship between initial intoxication and subsequent drinking, while inhibitory control impairments did not.

CONCLUSIONS

Successive alcohol consumption appears driven primarily by the pharmacological effects of alcohol which are exerted via changes in craving.

The Effects of Placebo and Moderate Dose Alcohol on Attentional Bias, Inhibitory Control and Subjective Craving

AIMS

Previous research indicates that acute alcohol intoxication and placebo can inhibit people's control over consumption behaviour and heighten attentional bias (AB) towards alcohol-related stimuli and craving. We designed a study to disentangle anticipated from pharmacological effects of alcohol in order to gain a clearer view of their relative contributions to alcohol consumption.

METHODS

In a within-participants design (moderate alcohol dose, placebo and control), and over a minimum 2-week period, participants completed a battery of questionnaires and cognitive tasks, followed by a bogus taste task to measure ad libitum consumption.

RESULTS

Both alcohol preload and placebo resulted in cognitive and psychological changes, including impaired inhibitory control, heightened AB and craving. However, ad libitum consumption only increased following alcohol and not placebo. Furthermore, inhibitory control impairments did not mediate the relationship between initial intoxication and ad libitum consumption, and findings indicate that increases in craving may mediate this association.

CONCLUSION

Psychological processes such as craving may be more important in driving consummatory behaviour relative to transient changes in cognitive processes, such as inhibitory control.

Cigarette-specific disgust aroused by smoking warning images strengthens smokers' inhibitory control under smoking-related background in Go/NoGo task

RATIONALE

Reduced inhibitory control is more pronounced during substance-related cue exposure among addicts. However, it is inconclusive whether smokers' inhibitory control would be impaired by smoking-related background. Furthermore, few studies explored whether the cigarette-specific disgust aroused by smoking warning images would alleviate the negative effect of smoking-related cues on smokers' inhibitory control.

OBJECTIVE

Experiment 1 investigated the effect of smoking-related background on inhibitory control in cigarette smokers with a modified Go/NoGo task and experiment 2 explored whether cigarette-specific disgust aroused by smoking warning images would alleviate the negative effect of smoking-related background on smokers' inhibitory control.

METHOD

Sixty-two male participants (32 smokers and 30 non-smokers) were recruited in experiment 1 and 51 male smokers were recruited in experiment 2.

RESULTS

Experiment 1 found that compared to neutral background, smokers made more commission errors (i.e., executing a response to a no-go target) under smoking-related background, indicating that smoking-related background has a negative effect on smokers' inhibitory control. Experiment 2 found that after experiencing cigarette-specific disgust, smokers made fewer commission errors at post-mood induction than pre-mood induction, indicating that cigarette-specific disgust aroused by smoking warning images alleviates the negative effect of smoking-related background on smokers' inhibitory control.

CONCLUSIONS

These results suggest that the negative effect of smoking-related cues on smokers' inhibitory control would be alleviated by cigarette-specific disgust aroused by smoking warning images, which emphasizes the important role of cigarette-specific disgust in strengthening smokers' inhibitory control towards smoking-related cues.

Task-irrelevant odours affect both response inhibition and response readiness in fast-paced Go/No-Go task: the case of valence

Whether emotional stimuli influence both response readiness and inhibition is highly controversial. Visual emotional stimuli appear to interfere with both under certain conditions (e.g., task relevance). Whether the effect is generalisable to salient yet task-irrelevant stimuli, such as odours, remains elusive. We tested the effect of orthonasally-presented pleasant (orange) and unpleasant odours (trimethyloxazole and hexenol) and clean air as a control on response inhibition. In emotional Go/No-Go paradigms, we manipulated the intertrial interval and ratios of Go/No-Go trials to account for motor (Experiment 1, N = 31) and cognitive (Experiment 2, N = 29) response inhibition processes. In Experiment 1, participants had greater difficulty in withholding and produced more accurate and faster Go responses under the pleasant vs. the control condition. Faster Go responses were also evident in the unpleasant vs. the control condition. In Experiment 2, neither pleasant nor unpleasant odours modulated action withholding, but both elicited more accurate and faster Go responses as compared to the control condition. Pleasant odours significantly impair action withholding (as compared to the control condition), indicating that more inhibitory resources are required to elicit successful inhibition in the presence of positive emotional information. This modulation was revealed for the motor aspect of response inhibition (fast-paced design with lower Go/No-Go trial ratio) rather than for attentional interference processes. Response readiness is critically impacted by the emotional nature of the odour (but not by its valence). Our findings highlight that the valence of task-irrelevant odour stimuli is a factor significantly influencing response inhibition.

Alcohol-related attentional bias in a gaze contingency task: Comparing appetitive and non-appetitive cues

BACKGROUND

Non-problem drinkers attend automatically to alcohol-related cues compared to non-alcohol related cues on tests of inhibitory control. Moreover, attentional bias for alcohol-related cues varies between problem and non-problem drinkers.

AIM

To examine attentional bias towards alcoholic and non-alcoholic appetitive cues between problem and non-problem drinkers.

METHOD

Forty-one university students (9 male, 32 female; Mage = 21.50) completed an eye-tracking gaze contingency paradigm, measuring the number of times participants looked at peripherally and centrally located stimuli (break frequency) when instructed to maintain focus on a target object. Stimuli consisted of appetitive alcohol-related (e.g., wine), appetitive non-alcohol-related (e.g., cola) and non-appetitive (e.g., fabric softener) stimuli. Participants were split using the Alcohol Use Disorders Identification Test (AUDIT) into non-problem (M AUDIT = 3.86) and problematic drinkers (M AUDIT = 11.59).

RESULTS

Problematic drinkers had higher break frequencies towards peripheral appetitive stimuli than towards non-appetitive stimuli, while break frequency was equivalent between appetitive cues presented centrally (alcohol and non-alcohol-related). In contrast, there were no differences in break frequency across stimuli type or cue presentation location (central or peripheral) for non-problem drinkers.

CONCLUSION

In contrast to non-problem drinkers, people displaying more problematic consumption practices may find it more difficult to inhibit eye movements towards appetitive stimuli, particularly when in peripheral vision. This may suggest that attentional biases, as measured in terms of overt eye movements, in problem drinkers may be most powerful when the alcoholic and appetitive stimuli are not directly in field of view. An uncertainty reduction process in the allocation of attention to appetitive cues may help explain the patterns of results observed.

Decision-making and inhibitory control after smoking-related priming in nicotine dependent smokers and never-smokers

Impaired decision-making and inhibitory control are important characteristics of nicotine dependence (ND). We aimed to test 1) the effects of smoking-related priming cues on subsequent decision-making and inhibitory control in ND and 2) how these priming effects are related to valence ratings, nicotine deprivation and craving. A sample of 27 smokers with ND according to DSM-IV and a control group of 33 never-smokers performed an intertemporal choice task and a go/no-go task. Before each trial of the tasks, a priming cue appeared that was either smoking-related or neutral. Valence ratings, nicotine deprivation and craving were assessed with self-reports. After smoking-related compared to neutral primes, the ND group exhibited increased delay discounting (β = 0.07, 95% confidence-interval (CI): 0.01-0.14) and shorter go reaction times (β = -0.13, CI: -0.32 to -0.01) compared to the never-smoker group. The speed-up in go trials after smoking-related compared to neutral cues was significantly related to more pleasant valence ratings (β = 0.07, CI:0.01-0.13), a longer time since last cigarette (β = -0.17, CI:-0.30 to -0.03), and increased craving (β = -0.19, CI: -0.33 to -0.06) within the ND group. We found evidence for small group effects indicating that individuals with ND compared to never-smokers decide more dysfunctional and react faster after smoking-related compared to neutral cues. Faster reactions after smoking-related cues within the ND group, especially in states of increased nicotine deprivation and craving, without more errors could be explained by an increased attentional focus. Cue-induced alterations in decision-making and inhibitory control in ND highly depend on the temporal sequence of cue presentation.

The effect of alcohol cue exposure and acute intoxication on inhibitory control processes and ad libitum alcohol consumption

RATIONALE

Alcohol intoxication and alcohol cue exposure impair 'reactive' inhibitory control and increase motivation to drink. However, inhibitory control is a multi-component process that also comprises signal detection and proactive control. It is unknown whether intoxication and cue exposure selectively influence these subprocesses in heavy drinkers.

OBJECTIVES

In two pre-registered studies, we investigated whether exposure to alcohol-related cues (study 1) and alcohol priming (study 2) impair each of these subprocesses of inhibitory control and increase motivation to drink.

METHODS

In study 1, 64 heavy drinkers completed a modified stop-signal task in an alcohol context (with embedded alcohol cues) and a neutral context (with embedded neutral cues) followed by a subjective measure of craving and a bogus taste test to measure ad libitum alcohol consumption. In study 2, 36 heavy drinkers consumed an alcoholic beverage (0.6 g/kg body weight), an alcohol-placebo beverage, and water on a within-subjects basis, followed by the modified stop-signal task and a bogus taste test.

RESULTS

In study 1, alcohol cue exposure did not impair inhibitory control subprocesses. Reactive control was unexpectedly better following alcohol cue exposure (compared to neutral cue exposure). However, craving and ad libitum consumption increased as expected. In study 2, reactive control was significantly impaired following the alcohol and control primes, relative to the placebo, but there was no effect on proactive slowing or signal detection. As expected, intoxication increased motivation to drink and ad libitum consumption (compared to placebo and control).

CONCLUSIONS

Alcohol intoxication and cue exposure increase motivation to drink in the absence of impairments in subcomponents of inhibitory control.

Perfect for a Gin and Tonic: How Context Drives Consumption Within a Modified Bogus Taste Test

Aim

To implement a modified bogus taste test (BTT) and to examine the interactive effects of environmental and social contexts on levels of 'alcohol' consumption.

Method

University students (Study 1 n = 38, Study 2 n = 80), recruited via opportunity sampling, completed a modified BTT under the pretence of assessing garnish preference for gin and tonic. All participants were tested alone or as part of an existing friendship group. In Study 1 participants were in a laboratory setting but were exposed to different contextual cues (alcohol-related or neutral) by way of posters displayed on the walls. In Study 2, participants assessed the drinks in either a pub or a library setting.

Results

In Study 1 participants tested in a group consumed significantly more when exposed to pub-related stimuli in contrast to those who were exposed to library-related stimuli. Participants who were alone and exposed to library-related cues consumed significantly more than those in a group and exposed to these cues. In Study 2, as in Study 1, participants tested in a group condition consumed significantly more of what they believed to be alcohol when in the pub compared to those who were tested in the library. Higher group consumption was also evident in the library condition, although the size of this difference was not as large as in the pub testing condition.

Conclusion

In the absence of any pharmacological effects of alcohol, social and environmental context have an interactive impact on shaping consumption.

Generalised inhibitory impairment to appetitive cues: From alcoholic to non-alcoholic visual stimuli

BACKGROUND

Prior research demonstrates that individuals who consume alcohol show diminished inhibitory control towards alcohol-related cues. However, such research contrasts predominantly alcoholic appetitive cues with non-alcoholic, non-appetitive cues (e.g., stationary items). As such, it is not clear whether it is specifically the alcoholic nature of the cues that influences impairments in inhibitory control or whether more general appetitive processes are at play.

AIMS

The current study examined the hitherto untested assertion that the disinhibiting effects of alcohol-related stimuli might generalise to other appetitive liquid stimuli, but not to non-appetitive liquid stimuli.

METHOD

Fifty-nine participants (Mage=21.63, SD=5.85) completed a modified version of the Stop Signal Task, which exposed them to visual stimuli of three types of liquids: Alcoholic appetitive (e.g., wine), non-alcoholic appetitive (e.g., water) and non-appetitive (e.g., washing-up liquid).

RESULTS

Consistent with predictions, Stop-signal reaction time was significantly longer for appetitive (alcoholic, non-alcoholic) compared to non-appetitive stimuli. Participants were also faster and less error-prone when responding to appetitive relative to non-appetitive stimuli on go-trials. There were no apparent differences in stop signal reaction times between alcoholic and non-alcoholic appetitive products.

CONCLUSIONS

These findings suggest that decreases in inhibitory control in response to alcohol-related cues might generalise to other appetitive liquids, possibly due to evaluative conditioning. Implications for existing research methodologies include the use of appetitive control conditions and the diversification of cues within tests of alcohol-related inhibitory control.

The influence of groups and alcohol consumption on individual risk-taking

BACKGROUND

Research addressing the influence of alcohol and groups on risky behaviour has yielded contradictory findings regarding the extent to which intoxicated groups exaggerate or minimise risk-taking. Previous work has examined the effect of intoxication on risk-taking focusing on collective group decision-making, and to date the influence of alcohol consumption and groups on individual risk-taking has yet to be explored experimentally. The current study therefore examined the impact of intoxication and groups on individual risk-taking.

METHODS

In a mixed design, 99 social drinkers (62 female) attended an experimental session individually (N=48) or in groups of three (N=51). Individuals completed the study in isolation while groups were tested in the same room. Participants completed two behavioural measures of risk-taking: Balloon Analogue Risk Task (BART) and Stoplight Task (SLT), both before and following consumption of an alcoholic (0.6g/kg males, 0.5g/kg females) or a placebo beverage.

RESULTS

Those who participated in groups took significantly more risks in both tasks than those in isolation. Alcohol did not increase risk-taking on either risk-taking tasks. However, those who consumed placebo were significantly less risky on the SLT, compared to baseline. No interactions were found between context and beverage on risk-taking.

CONCLUSION

The findings do not support a combined effect of alcohol and groups on individual risk-taking. Rather, results indicate that risk-taking behaviour is influenced by peer presence regardless of alcohol consumption. Targeting the influence of groups (above those of alcohol) may hold promise for reducing risk-taking behaviours in drinking environments.

Elevated alcohol consumption following alcohol cue exposure is partially mediated by reduced inhibitory control and increased craving

RATIONALE

Exposure to alcohol-related cues leads to increased alcohol consumption, and this may be partially attributable to momentarily impaired impulse control.

OBJECTIVES

We investigated if exposure to alcohol cues would impair inhibitory control and if the extent of this impairment would partially mediate the effect of alcohol cues on subsequent voluntary alcohol consumption.

METHODS

We recruited 81 heavy drinkers (50 female) who completed baseline measures of inhibitory control (stop-signal task) and subjective craving before random allocation to an alcohol cue exposure or control group. The alcohol cue exposure group then completed a second stop-signal task (with embedded alcohol cues) with concurrent exposure to olfactory alcohol cues, in an alcohol context. The control group completed a second stop-signal task (with embedded water cues), accompanied by exposure to water cues, in a neutral context. Then, subjective craving and ad libitum alcohol consumption were measured in all participants.

RESULTS

Inhibitory control worsened (compared to baseline) to a greater extent in the alcohol cue exposure group compared to the control group. Craving and ad libitum alcohol consumption were elevated in the alcohol cue exposure group compared to the control group, although the group difference in alcohol consumption fell short of statistical significance. In support of our hypotheses, multiple mediation analyses demonstrated that elevated ad libitum alcohol consumption following alcohol cue exposure was partially mediated by both impaired inhibitory control and increased craving.

CONCLUSIONS

These findings suggest that state fluctuations in inhibitory control are a potential mechanism through which alcohol cues increase drinking behaviour.