Eye tracking applied to tobacco smoking: current directions and future perspectives

Over the years the general awareness of the health costs associated with tobacco smoking has motivated scientists to apply the measurement of eye movements to this form of addiction. On one hand they have investigated whether smokers attend and look preferentially at smoking related scenes and objects. In parallel, on the other hand eye tracking has been used to test how smokers and nonsmokers interact with the different types of health warning that policymakers have mandated in tobacco advertisements and packages. Here we provide an overview of the main findings from the different lines of research, such as the evidence related to the attentional bias for smoking cues in smokers and the evidence that graphic warning labels and plain packages measurably increase the salience of the warning labels. We point to some open questions, such as the conditions that determine whether heavy smokers exhibit a tendency to actively avoid looking at graphic warning labels. Finally we argue that the research applied to gaze exploration of warning labels would benefit from a more widespread use of the more naturalistic testing conditions (e.g. mobile eye tracking or virtual reality) that have been introduced to study the smokers’ attentional bias for tobacco-related objects when freely exploring the surrounding environment.  

EXAMINING THE BEHAVIORAL MECHANISM OF COCAINE CUE ATTENTIONAL BIAS

Heightened attentional bias towards cocaine-related stimuli relative to neutral stimuli is a characteristic observed in cocaine-use disorders. Response time is an indirect measure of attention and research has failed to consistently demonstrate evidence of clinical relevance. Eye tracking presents a novel tool for directly measuring attentional allocation. The aim of this dissertation was to assess the sensitivity, reliability, and specificity of attentional bias through fixation and response time during the visual probe task. In the visual probe task, substance-related and matched neutral images were presented side-by-side on a computer screen. Eye-tracking technology measured time spent fixating on each image. A probe then replaced one image and time to respond was measured. Attentional bias was defined as the difference between neutral and substance-related images for fixation time and response time. A programmatic series of experiments was conducted using the visual probe task to demonstrate the sensitivity, reliability, and specificity of attentional bias as measured by fixation time during the visual probe task. Cocaine users displayed a robust and reliable cocaine cue attentional bias as measured by fixation time. Non-cocaine-using controls did not display a cocaine cue attentional bias. Fixation time was specific to substance use history. Individuals dependent on both cocaine and alcohol displayed an attentional bias to both substances, whereas individuals dependent on cocaine only displayed an attentional bias towards cocaine, but not alcohol. Fixation time also correlated with craving and deprivation. Cigarette cue attentional bias correlated positively with self-reported cigarette craving. Response time was a less sensitive measure of attentional bias, displayed low reliability, and did not correlate with substance use severity. Unlike response time, eye tracking applied to the visual probe task is a sensitive, reliable, and specific measure of attentional bias in cocaine users. Importantly, fixation time during the visual probe task is sensitive to clinically relevant differences in substance abuse. This outcome is consistent with incentive motivational hypotheses, proposing that reward-paired cues obtain incentive salience. These findings provide future directions for attentional bias research, such as applying eye tracking to treatment-related outcomes

Mu Suppression as an Indicator of Activation of the Perceptual-Motor System by Smoking-Related Cues in Smokers

The goal of the current study was to determine whether activation of the mirror neuron system, as measured by mu rhythm desynchronization, varied as a function of image content in smokers compared with nonsmokers. EEG activity was recorded while participants passively viewed images depicting smoking-related and nonsmoking-related stimuli. In half of the images, cues were depicted alone (inactive), while for the remaining images, cues were depicted with humans interacting with them (active). For the nonsmoking stimuli, smokers and nonsmokers showed greater mu suppression to the active cues compared to the inactive cues. However, for the smoking-related stimuli, smokers showed greater perception-action coupling for the active cues as reflected in their enhanced mu suppression, compared to nonsmokers. The results of the current study support the involvement of the perceptual-motor system in the activation of motivated drug use behaviors

Testing a frequency of exposure hypothesis in attentional bias for alcohol-related stimuli amongst social drinkers

Aims To examine whether a group of social drinkers showed longer response latencies to alcohol-related stimuli than neutral stimuli and to test whether exposure to 1) an alcohol-related environment and 2) consumption related cues influenced the interference from alcohol-related stimuli. Methods A 2 × 2 × 2 × 5 factorial design with Exposure Group (high, low) and Consumption Group (high, low) as between-participant factors and Word Type (alcohol, neutral) and Block (1–5) as within-participant factors was used. Forty-three undergraduate university students, 21 assigned to a high exposure group and 22 to a low exposure group, took part in the experiment. Exposure Group was defined according to whether or not participants currently worked in a bar or pub. Consumption Group was defined according to a median split on a quantity–frequency measure derived from two questions of the Alcohol Use Disorders Identification Test (AUDIT) questionnaire. A modified computerised Stroop colour naming test was used to measure response latencies. Results Exposure and consumption factors interacted to produce greater interference from alcohol-related stimuli. In particular, the low consumption group showed interference from alcohol-related stimuli only in the high exposure condition. Exposure did not affect the magnitude of interference in the high consumption group. Conclusions Attentional bias is dependent upon exposure to distinct types of alcohol-related cues

The clinical relevance of attentional bias in substance use disorders

Individuals with substance use disorders typically show an attentional bias for substance-related cues: Those cues are able to grab and hold the attention, in preference to other cues in the environment. We discuss the theoretical context for this work before reviewing the measurement of attentional bias, and its relationship to motivational state and relapse to substance use after a period of abstinence. Finally, we discuss the implications of this research for the treatment of substance use disorders. We conclude that attentional bias is associated with subjective craving, and that moment-by-moment fluctuations in attentional bias may precede relapse to substance use. The evidence regarding the predictive relationship between attentional bias assessed in treatment contexts and subsequent relapse is inconsistent. Furthermore, there is currently insufficient evidence to endorse attentional bias modification as a treatment for substance use disorders. Clinical implications and suggestions for future research are highlighted

Dopamine, urges to smoke, and the relative salience of drug versus non-drug reward

When addicted individuals are exposed to drug-related stimuli, dopamine release is thought to mediate incentive salience attribution, increasing attentional bias, craving and drug seeking. It is unclear whether dopamine acts specifically on drug cues versus other rewards, and if these effects correspond with craving and other forms of cognitive bias. Here, we administered the dopamine D 2 /D 3 agonist pramipexole (0.5 mg) to 16 tobacco smokers in a double-blind placebo-controlled crossover design. Visual fixations on smoking and money images were recorded alongside smoking urges and fluency tasks. Pramipexole attenuated a marked bias in initial orienting towards smoking relative to money but did not alter a maintained attentional bias towards smoking. Pramipexole decreased urges to smoke retrospectively after the task but not on a state scale. Fewer smoking words were generated after pramipexole but phonological and semantic fluency were preserved. Although these treatment effects did not correlate with each other, changes in initial orienting towards smoking and money were inversely related to baseline scores. In conclusion, pramipexole can reduce the salience of an addictive drug compared with other rewards and elicit corresponding changes in smoking urges and cognitive bias. These reward-specific and baseline-dependent effects support an ‘inverted-U’ shaped profile of dopamine in addiction

Attentional Bias in Moderate and Heavy College Drinkers: An Eye-tracking Study

Behavioral economic research regarding alcohol use aims to understand how substance use becomes favored over other rewarding non-substance activities (Meshesha, Dennhardt, & Murphy, 2014). The present study investigated attentional bias as an objective index of the relative valuation of substance-related rewards versus substance-free rewards among college students categorized as either heavy or moderate drinkers. The primary goal of this study was to assess the relative valuation of alcohol-related and alcohol-free rewards using multiple behavioral methods, such as attentional bias for alcohol measured via eye-tracking device, subjective ratings of the pleasantness of alcohol-related and alcohol-free stimuli, and measurement of recent activit participation and enjoyment realted to alcohol-related versus alcohol-free activities. The current study tested the hypothesis that various relative reinforcing value indices are associated with each other, and with traditional measures of alochol severity (e.g., drinking quantity and frequency, alcohol-related problems, and DSM-5 alcohol use disorder symptoms). A Pearson product-moment correlation coefficient revealed no statistically significant relationships between the attentional bias indices and the other relative reinforcing value indices or the traditional measures of alcohol severity. However, a statistically significant negative correlation between craving and fixation on social, non-alcohol appetitive stimuli was found. Additionally, a repeated measures ANOVA indicated that there was no statistically significant relationship between drinking level and attentional bias for alcohol-related stimuli

Relapse to smoking during unaided cessation: Clinical, cognitive, and motivational predictors

Rationale: Neurobiological models of addiction suggest that abnormalities of brain reward circuitry distort salience attribution and inhibitory control processes, which in turn contribute to high relapse rates. Objectives: To determine whether impairments of salience attribution and inhibitory control predict relapse in a pharmacologically unaided attempt at smoking cessation. Methods: 141 smokers were assessed on indices of nicotine consumption / dependence (e.g. the FTND, cigarettes per day, salivary cotinine), and three trait impulsivity measures. After overnight abstinence they completed experimental tests of cue reactivity, attentional bias to smoking cues, response to financial reward, motor impulsiveness, and response inhibition (antisaccades). They then started a quit attempt with follow-up after 7 days, 1 month, and 3 months; abstinence was verified via salivary cotinine levels ≤ 20ng/ml. Results: Relapse rates at each point were 52.5%, 64% and 76.3%. The strongest predictor was pre-cessation salivary cotinine; other smoking / dependence indices did not explain additional outcome variance and neither did trait impulsivity. All experimental indices except responsivity to financial reward significantly predicted one week outcome. Salivary cotinine, attentional bias to smoking cues and antisaccade errors explained unique as well as shared variance. At one and three months, salivary cotinine, motor impulsiveness and cue reactivity were all individually predictive; the effects of salivary cotinine and motor impulsiveness were additive. Conclusions: These data provide some support for the involvement of abnormal cognitive and motivational processes in sustaining smoking dependence and suggest that they might be a focus of interventions, especially in the early stages of cessation. Dawkins L, Powell JH, Pickering AD, Powell JF, and West RJ (2009) Addiction 104, 850-

The Relationship Between Electronic Nicotine Delivery System Use and Alcohol Consumption: A Neurocognitive and Behavioral Investigation

Indiana University-Purdue University Indianapolis (IUPUI)Increasing research shows that the use of electronic nicotine delivery systems (ENDS) is associated with higher rates and quantity of alcohol consumption; however, no research to date experimentally examines the relationship between ENDS use and alcohol use. The present study uses a two-session within-subjects design to examine 1) the relationship between ENDS use prime and attentional bias for alcohol related cues and 2) the relationship between ENDS use and laboratory ad libitum alcohol consumption. A total of N = 31 (mean age = 28.71, SD = 11.17; 45.2% women; 54.8% White/Caucasian) healthy users of ENDS who endorsed liking beer completed the present study, which included 1) a dot-probe and eye-tracking task that assessed attentional bias (reaction time, initial orientation, and delayed disengagement) to alcohol images following ENDS prime or no prime and 2) an ad libitum beer consumption task that assessed mL of beer consumed by the participants when concurrent use of ENDS was allowed or not allowed. All analyses controlled for age, race, and gender. Results of repeated measure ANCOVA’s indicate that attentional bias for alcohol does not differ between the ENDS prime or control conditions (F’s 0.01 to 0.12, ηp2’s 0.001 to 0.01). There is a large interactive effect of self-reported days of concurrent use of ENDS and alcohol over the last 14 days (ηp2’s 0.35 to 0.85), small to medium effects of alcohol craving preceding eye-tracking (ηp2’s 0.02 to 0.09), and small to medium effects of ENDS craving preceding eye-tracking (ηp2’s 0.06 to 0.13), all of which show increases in attentional bias following the ENDS prime; however, these results were limited by data quality issues that preclude strong support of these effects. Results of repeated measure ANCOVA’s demonstrate that amount of beer consumed does not differ by ENDS condition, F (4, 26) = 0.03, p = .86, ηp2 = 0.001. Results of a hierarchical linear regression show that amount of ENDS weight change (g) is not significantly related to mL of beer consumed in the ENDS session (b = -86.48, t = -0.90, p = 0.38, ∆R2 = 0.03). Results of linear mixed modeling testing the effect of ENDS puffs on alcohol sips temporally across the ad lib task show puffs are significantly related to sips (estimate = 0.23, SE = 0.07, p = .002) and number ENDS puffs account for some variability in slope of participant sips across participants. Results of repeated measure ANCOVA’s do not demonstrate significant interactions between mL of beer consumed by session and concurrent self-reported ENDS use over the past two weeks (ηp2 = 0.45), alcohol craving, or ENDS craving (ηp2’s = 0.002). Overall, results indicate that increased frequency of ENDS use is related to an increased frequency of beer consumption in real time. Since ENDS is related to alcohol use in time and place, individuals at risk for alcohol use problems should take care in their ENDS use. This study suggests that research should more fully measure and compare event-level and meta-level data on ENDS and alcohol use and that patterns based in the cigarette literature may not always generalize to ENDS