ff ects of exposure to appetitive cues on inhibitory control : A meta-analytic investigation

https://doi.org/10.1016/j.appet. 2018.06. 024 Received 23 January 2018; Received in revised form 10 May 2018; Accepted 19 June 2018 ∗ Corresponding author. Department of Psychological Sciences, University of Liverpool, Bedford Street South, L69 7ZA. UK. E-mail address: ajj@liv.ac. uk (A. Jones). Appetite 128 (2018) 271–282 Available online 20 June 2018 0195-6663/ © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/). T one year (Nederkoorn, Houben, Hofmann, Roefs, & Jansen, 2010). Findings such as these are generally interpreted as indicating that inhibitory control is a stable trait characteristic that differs between individuals but remains fairly constant within individuals, which is why it reliably predicts between-subject variability in behaviour months or years later. However, more recent theoretical models have suggested that inhibitory control functions as a transient state which can fluctuate in response to environmental or internal ‘events’ (De Wit, 2009), and these short term impairments in inhibitory control may increase the immediate risk of temptation and subsequent (re) lapse. In a recent narrative review we (Jones, Christiansen, Nederkoorn, Houben, & Field, 2013a) suggested that individuals have a general stable capacity for inhibitory control, however this capacity can fluctuate (both improve and worsen) in response to environmental and internal events. Exposure to appetitive cues is one potential environmental event that may negatively influence inhibitory control, because those cues evoke automatic appetitive tendencies (Brockmeyer, Hahn, Reetz, Schmidt, & Friederich, 2015; Field, Kiernan, Eastwood, & Child, 2008; Kemps & Tiggemann, 2015; Kemps, Tiggemann, Martin, & Elliott, 2013), and these responses should conflict with inhibition of behaviour. Indeed, exposure to both alcohol (Czapla et al., 2015a,b) and food-related cues (Phelan et al., 2011) results in short-lived impairments in inhibitory control. Furthermore, these ‘cue-specific’ deficits in inhibition may predict greater variance in individual differences in health-related behaviours than general inhibition deficits (Houben, Nederkoorn, & Jansen, 2013; Petit, Kornreich, Noël, Verbanck, & Campanella, 2012), including ad-libitum food and alcohol consumption in the laboratory (Field & Jones, 2017; Price, Lee, & Higgs, 2016). However, as with many research questions that are studied intensively, there are some null or equivocal findings in the literature, in which cue-exposure has not impaired inhibitory control (Mainz et al., 2012; Nederkoorn, Baltus, Guerrieri, & Wiers, 2009). The aim of the present meta-analytic investigation was to quantify the extent to which exposure to appetitive-cues (alcohol and food-related pictures) causes transient impairments in the ability to inhibit behaviour, and to identify procedural variables or participant characteristics that may moderate this effect. Following initial scoping searches, we limited our investigation to alcohol and food-related cues because the vast majority of studies in the field were limited to these domains (however, the disinhibiting effects of smoking(Luijten, Littel, & Franken, 2011) and drug-related cues (Pike, Stoops, Fillmore, & Rush, 2013), have been investigated). We sought to identify potential moderators of the effects of appetitive cues on inhibitory control, including: drinking/weight status, the modality of cue-exposure (pictorial, lexical, olfactory), type of task used to measure inhibitory control, and to determine if cue-specific inhibitory deficits are associated with unhealthy behaviours or outcomes, such as alcohol consumption or BMI. We hypothesised that inhibitory control would be worse during or after exposure to appetitive cues compared to neutral cues, or the absence of cues. For our moderator analyses we predicted that this effect would be larger in heavier drinkers, individuals with alcohol use disorder and individuals with overweight/obesity because, theoretically, automatic appetitive responses to appetitive cues should be stronger in people who consume them more frequently (Volkow et al., 2013; Wiers et al., 2007). We had no a priori predictions regarding cue-modality, but we investigated this on the basis of findings from some individual studies which demonstrated differential effects of cues presented in different modalities on both inhibitory control and subjective craving (Boswell & Kober, 2016; Monk, Sunley, Qureshi, & Heim, 2016). Similarly, we examined the effects of different inhibitory control tasks as each have differing inhibitory pressures and may measure a different type of inhibitory control, e.g. action cancellation versus action inhibition (Eagle, Bari, & Robbins, 2008). However, we made no specific hypothesis as to which may be most affected by cue-exposure. 2. Methods 2.1. Information sources and search strategy We conducted scoping searches using three commonly used electronic databases (Scopus, PubMed and PsycInfo) in November and December 2015. We pre-registered our protocol and analysis strategy on Open Science Framework (https://osf.io/c9jf8/). Full searches were carried out in October 2017. Our literature search was guided by the Preferred Reporting Items for Systematic Review (PRISMA) guidelines. See supplementary materials for full search strategy and terms. Following identification of full text articles we conducted manual searches on reference lists, and identified further articles based on authors' knowledge. In total we identified 35 effect sizes for alcohol and 31 for food. 2.2. Eligibility criteria All studies had to meet the following criteria in order to be included in the meta-analysis; (i) include human participants aged 18+, (ii) include alcohol or food-related (appetitive) cue exposure, i.e. olfactory or visual cues, prior to or during an inhibitory control task, (iii) a control comparison, for example exposure to neutral cues during, or the absence of cue exposure (baseline) prior to or during, an inhibitory control task. Cue exposure involved food/alcohol and neutral images/ words that were embedded into an inhibitory control task (Houben et al., 2013; Jones et al., 2015), or the holding and sniffing of food/ alcohol prior to completing an inhibitory control task (Gauggel et al., 2010; Lattimore & Mead, 2015). 2.3. Outcome measure(s) Studies were required to have an outcome measure of inhibitory control during/following appetitive cue exposure, and either a measure of inhibitory control at baseline (prior to cue-exposure) or during exposure to non-appetitive (neutral) cues. Proposed measures of inhibitory control were cross-checked against previous literature and review papers to ensure that they were validated measures (e.g. Diamond, 2013). All authors agreed on the tasks for inclusion. 2.4. Data extraction and coding Three independent coders (JD, IK, NC) performed the searches and identified the relevant articles. After removal of duplicates, 4151 unique articles were identified. These articles were screened via title and abstract, which resulted in exclusion of 3819 articles with agreement from all coders. Data were extracted by the coders and cross-checked by the first author. In cases where insufficient data was available the authors were contacted to provide this data. If the authors did not respond to the data request and it was possible, we used Web Plot Digitizer (Version 3.10, Rohatgi, 2016) to estimate means and variances from figures presented in publications, as recommended (Jelicic Kadic, Vucic, Dosenovic, Sapunar, & Puljak, 2016; Vucic, Jelicic Kadic, & Puljak, 2015). To code moderator variables such as drinking and weight status we first examined if any participants were described in the article in a specific way (e.g. alcohol dependent, overweight). If no explicit claims were made we made group level inferences on alcohol use using established cut-offs for ‘heavy’ or ‘hazardous’ drinking via scores on the AUDIT (score > 8 indicative of hazardous drinking (see Saunders, Aasland, Babor, De La Fuente, & Grant, 1993) or estimates of units of alcohol consumed per week (> 14 units per week indicative of heavy drinking). For weight status we examined if group mean BMI> 25 kg/ 1 Note that these cut offs differ by country. Fourteen units per week is the UK A. Jones et al. Appetite 128 (2018) 271–282