Behavioural measures and training interventions for food-related cognition, motivation and affect

The rise in overweight and obesity rates over the past decades can primarily be attributed to the over-consumption of unhealthy energy-dense foods. Understanding the determinants of eating behaviours is therefore paramount for helping individuals reduce their intake of unhealthy foods and make healthier choices. According to a dual-process framework of behaviour, individuals with lower inhibitory control may be more vulnerable to implicit influences on their actions, such as strong approach bias and automatic affective reactions towards cues in the environment. Automatic and controlled processes within this framework can be assessed using direct and indirect measures and there have been recent advancements in the development of behaviour change interventions, such as inhibitory control training (ICT). Chapter 1 of this thesis reviews the theory and methods surrounding cognitive control of eating behaviours. Chapter 2 reports an experiment on the effect of ICT on food evaluations, impulsive choices and automatic action tendencies. Although training had the expected effect on food choices, it did not reduce participants’ approach bias towards unhealthy foods. Chapter 3 describes a study which provided evidence for the feasibility and potential effectiveness of a novel ICT paradigm for reducing unhealthy food evaluations and cravings. The study presented in Chapter 4 investigates the methodological validity of the affective priming paradigm (APP) as an indirect measure of food liking in the context of healthy and unhealthy foods. The APP was found to be robust in two cohorts of participants (direct replication), but its predictive utility for food choice behaviour requires further investigation. Chapter 5 shows that ICT can reduce individuals’ food evaluations at both an explicit and implicit level (via the APP). In Chapter 6, these research findings are discussed in relation to theory and methods, together with general limitations and directions for future empirical and applied research

Response inhibition training and measures of explicit and implicit food valuation

The overvaluation of energy-dense foods is a key contributor to unhealthy eating behaviour, identifying it as a key target for therapeutic interventions. A growing literature has shown that by consistently associating specific food items with the inhibition of a motor response (i.e. stopping), the evaluations of these stimuli can be reduced after training. In this brief review, we focus on measures used to capture food valuation following such training interventions. Evidence for the food devaluation effect has primarily stemmed from studies that employ explicit measures such as ratings of food attractiveness or taste, and implicit measures, such as the implicit association test, which have yielded mixed findings. Although promising, our understanding of the utility of implicit measures in studies of eating behaviour is relatively sparse, and we offer recommendations for the use of explicit and implicit measures in future research

The past, present and future of Registered Reports

Registered Reports are a form of empirical publication in which study proposals are peer reviewed and pre-accepted before research is undertaken. By deciding which articles are published based on the question, theory and methods, Registered Reports offer a remedy for a range of reporting and publication biases. Here, we reflect on the history, progress and future prospects of the Registered Reports initiative and offer practical guidance for authors, reviewers and editors. We review early evidence that Registered Reports are working as intended, while at the same time acknowledging that they are not a universal solution for irreproducibility. We also consider how the policies and practices surrounding Registered Reports are changing, or must change in the future, to address limitations and adapt to new challenges. We conclude that Registered Reports are promoting reproducibility, transparency and self-correction across disciplines and may help reshape how society evaluates research and researchers

The affective priming paradigm as an indirect measure of food attitudes and related choice behaviour

In this Registered Report, we assessed the utility of the affective priming paradigm (APP) as an indirect measure of food attitudes and related choice behaviour in two separate cohorts. Participants undertook a speeded evaluative categorization task in which target words were preceded by food primes that differed in terms of affective congruence with the target, explicit liking (most liked or least liked), and healthiness (healthy or unhealthy). Non-food priming effects were tested as a manipulation check, and the relationship between food priming effects and impulsive choice behaviour was also investigated using a binary food choice task. As predicted, priming effects were observed for both healthy and unhealthy foods, but there was no difference in the magnitude of these effects. This may suggest that the paradigm is most sensitive to affective, but not cognitive, components of attitudes (i.e., healthiness), but alternative theoretical explanations and implications of this finding are discussed. Food and non-food priming effects were observed in both reaction time (RT) and error rate (ER) data, but contrary to expectations, we found no association between food RT priming effects and choice behaviour. All findings from confirmatory analyses regarding RT and ER priming effects, and the absence of the expected correlations between priming effects and impulsive food choices, were successfully replicated in the online cohort of participants. Overall, this study confirms the robustness of the APP as an indirect measure of food liking and raises questions about its applied value for research of eating behaviours

Beyond online participant crowdsourcing: The benefits and opportunities of big team addiction science

Participant crowdsourcing platforms (e.g., MTurk, Prolific) offer numerous advantages to addiction science, permitting access to hard-to-reach populations and enhancing the feasibility of complex experimental, longitudinal and intervention studies. Yet these are met with equal concerns about participant non-naivety, motivation, and careless responding, which if not considered can greatly compromise data quality. In this article, we discuss an alternative crowdsourcing avenue that overcomes these issues whilst presenting its own unique advantages – crowdsourcing researchers through big team science. First, we review several contemporary efforts within psychology (e.g., ManyLabs, Psychological Science Accelerator) and the benefits these would yield if they were more widely implemented in addiction science. We then outline our own consortium-based approach to empirical dissertations: a grassroots initiative that trains students in reproducible big team addiction science. In doing so, we discuss potential challenges and their remedies, as well as providing resources to help addiction researchers develop these initiatives. Through researcher crowdsourcing, together we can answer fundamental scientific questions about substance use and addiction, build a literature that is representative of a diverse population of researchers and participants, and ultimately achieve our goal of promoting better global health

The Restrain Food Database: validation of an open-source database of foods that should be eaten more or less as part of a healthy diet

Studies of food-related behaviours often involve measuring responses to pictorial stimuli of foods. Creating these can be burdensome, requiring a significant commitment of time, and with sharing of images for future research constrained by legal copyright restrictions. The Restrain Food Database is an open-source database of 626 images of foods that are categorized as those people could eat more or less of as part of a healthy diet. This paper describes the database and details how to navigate it using our purpose-built R Shiny tool and a pre-registered online validation of a sample of images. A total of 2150 participants provided appetitive ratings, perceptions of nutritional content and ratings of image quality for images from the database. We found support for differences between Food Category on appetitive ratings which were also moderated by state hunger ratings. Findings relating to individual differences in appetite ratings as well as differences between BMI weight categories are also reported. Our findings validate the food categorization in the Restrain Food Database and provide descriptive information for individual images within this investigation. This database should ease the burden of selecting and creating appropriate images for future studies

Post-publication critique at top-ranked journals across scientific disciplines: a cross-sectional assessment of policies and practice

Journals exert considerable control over letters, commentaries and online comments that criticize prior research (post-publication critique). We assessed policies (Study One) and practice (Study Two) related to post-publication critique at 15 top-ranked journals in each of 22 scientific disciplines (N = 330 journals). Two-hundred and seven (63%) journals accepted post-publication critique and often imposed limits on length (median 1000, interquartile range (IQR) 500–1200 words) and time-to-submit (median 12, IQR 4–26 weeks). The most restrictive limits were 175 words and two weeks; some policies imposed no limits. Of 2066 randomly sampled research articles published in 2018 by journals accepting post-publication critique, 39 (1.9%, 95% confidence interval [1.4, 2.6]) were linked to at least one post-publication critique (there were 58 post-publication critiques in total). Of the 58 post-publication critiques, 44 received an author reply, of which 41 asserted that original conclusions were unchanged. Clinical Medicine had the most active culture of post-publication critique: all journals accepted post-publication critique and published the most post-publication critique overall, but also imposed the strictest limits on length (median 400, IQR 400–550 words) and time-to-submit (median 4, IQR 4–6 weeks). Our findings suggest that top-ranked academic journals often pose serious barriers to the cultivation, documentation and dissemination of post-publication critique