Olivia M. Maynard

Episodic Memory and Appetite Regulation in Humans

Psychological and neurobiological evidence implicates hippocampal-dependent memory processes in the control of hunger and food intake. In humans, these have been revealed in the hyperphagia that is associated with amnesia. However, it remains unclear whether ‘memory for recent eating’ plays a significant role in neurologically intact humans. In this study we isolated the extent to which memory for a recently consumed meal influences hunger and fullness over a three-hour period. Before lunch, half of our volunteers were shown 300 ml of soup and half were shown 500 ml. Orthogonal to this, half consumed 300 ml and half consumed 500 ml. This process yielded four separate groups (25 volunteers in each). Independent manipulation of the ‘actual’ and ‘perceived’ soup portion was achieved using a computer-controlled peristaltic pump. This was designed to either refill or draw soup from a soup bowl in a covert manner. Immediately after lunch, self-reported hunger was influenced by the actual and not the perceived amount of soup consumed. However, two and three hours after meal termination this pattern was reversed - hunger was predicted by the perceived amount and not the actual amount. Participants who thought they had consumed the larger 500-ml portion reported significantly less hunger. This was also associated with an increase in the ‘expected satiation’ of the soup 24-hours later. For the first time, this manipulation exposes the independent and important contribution of memory processes to satiety. Opportunities exist to capitalise on this finding to reduce energy intake in humans.

Visual attention to health warnings on plain tobacco packaging in adolescent smokers and non-smokers.

AIMS Previous research with adults indicates that plain packaging increases visual attention to health warnings in adult non-smokers and weekly smokers, but not daily smokers. The present research extends this study to adolescents aged 14-19 years. DESIGN Mixed-model experimental design, with smoking status as a between-subjects factor and pack type (branded or plain pack) and eye gaze location (health warning or branding) as within-subjects factors. SETTING Three secondary schools in Bristol, UK. PARTICIPANTS A convenience sample of adolescents comprising never-smokers (n = 26), experimenters (n = 34), weekly smokers (n = 13) and daily smokers (n = 14). MEASUREMENTS Number of eye movements to health warnings and branding on plain and branded packs. FINDINGS Analysis of variance, irrespective of smoking status revealed more eye movements to health warnings than branding on plain packs, but an equal number of eye movements to both regions on branded packs (P = 0.033). This was observed among experimenters (P < 0.001) and weekly smokers (P = 0.047), but not among never-smokers or daily smokers. CONCLUSION Among experimenters and weekly smokers, plain packaging increases visual attention to health warnings and away from branding. Daily smokers, even relatively early in their smoking careers, seem to avoid the health warnings on cigarette packs. Adolescent never-smokers attend the health warnings preferentially on both types of packs, a finding which may reflect their decision not to smoke.

Avoidance of cigarette pack health warnings among regular cigarette smokers

BACKGROUND Previous research with adults and adolescents indicates that plain cigarette packs increase visual attention to health warnings among non-smokers and non-regular smokers, but not among regular smokers. This may be because regular smokers: (1) are familiar with the health warnings, (2) preferentially attend to branding, or (3) actively avoid health warnings. We sought to distinguish between these explanations using eye-tracking technology. METHOD A convenience sample of 30 adult dependent smokers participated in an eye-tracking study. Participants viewed branded, plain and blank packs of cigarettes with familiar and unfamiliar health warnings. The number of fixations to health warnings and branding on the different pack types were recorded. RESULTS Analysis of variance indicated that regular smokers were biased towards fixating the branding rather than the health warning on all three pack types. This bias was smaller, but still evident, for blank packs, where smokers preferentially attended the blank region over the health warnings. Time-course analysis showed that for branded and plain packs, attention was preferentially directed to the branding location for the entire 10s of the stimulus presentation, while for blank packs this occurred for the last 8s of the stimulus presentation. Familiarity with health warnings had no effect on eye gaze location. CONCLUSION Smokers actively avoid cigarette pack health warnings, and this remains the case even in the absence of salient branding information. Smokers may have learned to divert their attention away from cigarette pack health warnings. These findings have implications for cigarette packaging and health warning policy.

Plain cigarette packs do not exert Pavlovian to instrumental transfer of control over tobacco-seeking

Aims To gain insight into the potential impact of plain tobacco packaging policy, two experiments were undertaken to test whether ‘prototype’ plain compared with branded UK cigarette pack stimuli would differentially elicit instrumental tobacco-seeking in a nominal Pavlovian to instrumental transfer (PIT) procedure. Design, Setting and Participants Two experiments were undertaken at the University of Bristol UK, with a convenience sample of adult smokers (experiment 1, n = 23, experiment 2, n = 121). Measurement In both experiments, smokers were trained on a concurrent choice procedure in which two responses earned points for cigarettes and chocolate, respectively, before images of branded and plain packs were tested for capacity to elicit the tobacco-seeking response in extinction. The primary outcome was percentage choice of the tobacco- over the chocolate-seeking response in plain pack, branded pack and no-stimulus conditions. Findings Both experiments found that branded packs primed a greater percentage of tobacco-seeking (overall mean = 62%) than plain packs (overall mean = 53%) and the no-stimulus condition (overall mean = 52%; Ps ≤ 0.01, ŋp2s ≥ 0.16), and that there was no difference in percentage tobacco-seeking between plain packs and the no-stimulus condition (Ps ≥ 0.17, ŋp2s ≤ 0.04). Plain tobacco packs showed an overall 9% reduction in the priming of a tobacco choice response compared to branded tobacco packs. Conclusions Plain packaging may reduce smoking in current smokers by degrading cue-elicited tobacco-seeking.

Neural mechanisms underlying visual attention to health warnings on branded and plain cigarette packs

Abstract Aims To (1) test if activation in brain regions related to reward (nucleus accumbens) and emotion (amygdala) differ when branded and plain packs of cigarettes are viewed, (2) test whether these activation patterns differ by smoking status and (3) examine whether activation patterns differ as a function of visual attention to health warning labels on cigarette packs. Design Cross‐sectional observational study combining functional magnetic resonance imaging (fMRI) with eye‐tracking. Non‐smokers, weekly smokers and daily smokers performed a memory task on branded and plain cigarette packs with pictorial health warnings presented in an event‐related design. Setting Clinical Research and Imaging Centre, University of Bristol, UK. Participants Non‐smokers, weekly smokers and daily smokers (n = 72) were tested. After exclusions, data from 19 non‐smokers, 19 weekly smokers and 20 daily smokers were analysed. Measurements Brain activity was assessed in whole brain analyses and in pre‐specified masked analyses in the amygdala and nucleus accumbens. On‐line eye‐tracking during scanning recorded visual attention to health warnings. Findings There was no evidence for a main effect of pack type or smoking status in either the nucleus accumbens or amygdala, and this was unchanged when taking account of visual attention to health warnings. However, there was evidence for an interaction, such that we observed increased activation in the right amygdala when viewing branded as compared with plain packs among weekly smokers (P = 0.003). When taking into account visual attention to health warnings, we observed higher levels of activation in the visual cortex in response to plain packaging compared with branded packaging of cigarettes (P = 0.020). Conclusions Based on functional magnetic resonance imaging and eye‐tracking data, health warnings appear to be more salient on ‘plain’ cigarette packs than branded packs.

Neural correlates of cigarette health warning avoidance among smokers

Highlights • Smokers implicitly and explicitly avoid cigarette health warnings.• Smokers and non-smokers lectroencephalography (EEG) responses to cigarette health warnings were compared.• Smokers show no difference in early perceptual processing (P1, vMMN and P3).• Smokers show reduced later cognitive responses (Late Positive Potential).• Smokers show reduced sensitivity to cigarette health warnings emotional content

Plain packaging of cigarettes and smoking behavior: study protocol for a randomized controlled study

BackgroundPrevious research on the effects of plain packaging has largely relied on self-report measures. Here we describe the protocol of a randomized controlled trial investigating the effect of the plain packaging of cigarettes on smoking behavior in a real-world setting.Methods/DesignIn a parallel group randomization design, 128 daily cigarette smokers (50% male, 50% female) will attend an initial screening session and be assigned plain or branded packs of cigarettes to smoke for a full day. Plain packs will be those currently used in Australia where plain packaging has been introduced, while branded packs will be those currently used in the United Kingdom. Our primary study outcomes will be smoking behavior (self-reported number of cigarettes smoked and volume of smoke inhaled per cigarette as measured using a smoking topography device). Secondary outcomes measured pre- and post-intervention will be smoking urges, motivation to quit smoking, and perceived taste of the cigarettes. Secondary outcomes measured post-intervention only will be experience of smoking from the cigarette pack, overall experience of smoking, attributes of the cigarette pack, perceptions of the on-packet health warnings, behavior changes, views on plain packaging, and the rewarding value of smoking. Sex differences will be explored for all analyses.DiscussionThis study is novel in its approach to assessing the impact of plain packaging on actual smoking behavior. This research will help inform policymakers about the effectiveness of plain packaging as a tobacco control measure.Trial registrationCurrent Controlled Trials ISRCTN52982308 (registered 27 June 2013).

Are waterpipe users tobacco-dependent?

Jawad and colleagues (1) argue that waterpipe tobacco smoking has the potential to become the next public health priority, as the global prevalence of waterpipe smoking is increasing, especially among younger users. They note that, across a number of geographical regions, users typically lack knowledge about the health risks of waterpipe tobacco smoking. A number of misbeliefs appear to be common, such as that the water in the waterpipe bowl acts as a filter for harmful chemicals, that waterpipe tobacco has fewer toxic chemicals than cigarettes, and that the aromatic flavour and smell of waterpipe tobacco (something that is regulated for cigarettes in many countries) implies safety. Although these misbeliefs are worrying, there is also a lack of reliable evidence on the health effects of waterpipe tobacco smoking. There have been relatively few studies investigating the effect of waterpipe tobacco smoking on health, and those that have been conducted are typically of limited quality. Similarly, research on the relative level of toxicant exposure resulting from waterpipe tobacco smoking (compared with cigarette smoking) is misleading, due to the differing patterns of use between the two. In many groups, particularly those where it is a recent phenomenon, waterpipe is often infrequent and more social in nature. It may therefore not be associated with the same pattern of dependence seen in regular, habitual cigarette smokers.

No Impact of Calorie or Unit Information on Ad Libitum Alcohol Consumption

Abstract Aims To investigate the impact of unit and calorie information on drinking behaviour in an ad libitum taste test paradigm. Methods In this experimental human laboratory study, participants were randomized to one of four conditions, balanced by gender, using a 2 (unit information: present vs. absent) × 2 (calorie information: present vs. absent) between-subjects design. The percentage of beer consumed during the taste test was the primary outcome measure. Results Among this largely undergraduate student population, we found no evidence that either unit or calorie information impacted alcohol consumption in an ad libitum taste test. A manipulation check indicated that few of the participants receiving either unit and/or calorie information could accurately recall the number of units and/or calories in the beverages provided to them, indicating low levels of engagement with this information. Analysis of qualitative reactions to calorie and unit labelling indicated possible negative unintended consequences of calorie and unit information, including using unit information to facilitate consumption of higher strength beverages, and calorie information to reduce food consumption prior to a drinking episode. Conclusion We find no evidence to support an effect of unit or calorie information, a public-health initiative supported by the alcohol industry, on drinking behaviour. It is possible that compulsory unit and calorie labelling, at least in the numeric format used here, would have no effect on alcohol intake and may even have some negative unintended consequences among certain populations.

Effect of glass markings on drinking rate in social alcohol drinkers

Abstract Background: The main aim of these studies was to explore the influence of volume information on glassware on the time taken to consume an alcoholic beverage. Methods: In Study 1, male and female social alcohol consumers (n = 159) were randomised to drink 12 fl oz of either low or standard strength lager, from either a curved glass marked with yellow tape at the midpoint or an unmarked curved glass, in a between-subjects design. In Study 2, male and female social alcohol consumers (n = 160) were randomised to drink 12 fl oz of standard strength lager from either a curved glass marked with ¼, ½ and ¾ volume points or an unmarked curved glass, in a between-subjects design. The primary outcome measure for both studies was total drinking time of an alcoholic beverage. Results: In Study 1, after removing outliers, total drinking time was slower from the glass with midpoint volume marking [mean drinking times (min): 9.98 (marked) vs. 9.55 (unmarked), mean difference = 0.42, 95% CI: −0.90, 1.44]. In Study 2, after removing outliers, total drinking time was slower from the glass with multiple volume marks [mean drinking times: 10.34 (marked) vs. 9.11 (unmarked), mean difference = 1.24, 95% CI: −0.11, 2.59]. However, in both studies confidence intervals were wide and also consistent with faster consumption from marked glasses. Conclusion: Consumption of an alcoholic beverage may be slower when served in glasses with volume information. Replication in larger studies is warranted.