to the rationale, theoretical basis and design of the experiments. Programmed the experiments, collected and analysed the data as part of PhD project. Wrote up the experiments. Peter M. Jones: Co-contributer to the rationale, theoretical basis and design of the experiments. Consulted on analysis and write up as PhD supervisor. Chris J. Mitchell: Co-contributer to the rationale, theoretical basis and design of the experiments. Consulted on analysis and write up as co-author. Andy J. Wills: Consulted on analysis and write up as PhD supervisor.3 AbstractThree experiments were conducted to investigate a possible role for certainty in human causal learning. In these experiments, human participants were initially trained with a set of cues, each of which was followed by the presence or absence of an outcome. In a subsequent training stage, two of these cues were trained in a causal compound, and the change in associative strength for each of the cues was compared, using a procedure based on Rescorla (2001). In each experiment, the cues differed in both their causal certainty (on the part of participants) and size of their prediction error (with respect to the outcome). The cue with the larger prediction error was always the cue with the more certain causal status. According to established prediction error models (Bush & Mosteller, 1951;Rescorla & Wagner, 1972;Rescorla, 2001), a larger prediction error should result in a greater updating of associative strength. However, the opposite was observed, as participants always learned more about the cue with the smaller prediction error. A plausible explanation is that participants engaged in a form of theory protection, in which they were resistant to updating their existing beliefs about cues with a certain causal status. Instead, participants appeared to attribute outcomes to cues with a comparatively uncertain causal status, in an apparent violation of prediction error. The potential role of attentional processes (Mackintosh, 1975;Pearce & Hall, 1980) in explaining these results is also discussed.

Loot boxes (LBs) are video game-related purchases with a chance-based outcome. Due to similarities with gambling, they have come under increasing scrutiny from media, academics and policymakers alike. Initial evidence suggested that LB engagement might be associated with both problem gambling (PG) and problem video gaming (PVG). We therefore conducted a systematic review of the evidence for associations between LB purchasing, PG and PVG. For LB/PG, 12 of 13 publications reported a positive relationship, with a moderately sized mean effect of r = .27. For LB/PVG, the mean effect was r = .40, although this finding was drawn from only six surveys in total. For PG/PVG, the mean effect was r = .21, with only 11 of 20 studies reporting significant effects. While further evidence is required to determine the direction of causality, the strength of relationships suggests that policy action on LBs may have benefits for harm minimisation.

Introduction Loot boxes are purchasable randomised reward mechanisms in video games. Due to structural and psychological similarities with gambling, there are fears that loot box purchasing may be associated with problematic gambling. Whilst monthly expenditure is typically modest (i.e. < $20), the distribution is highly skewed, with a small number of high-level spenders, sometimes referred to as "whales". It is not known what proportion of industry profits are derived from such players, and whether they are typically wealthy individuals and/or problem gamblers. Methods We used structured literature searches to identify surveys of gamers with open-access loot box data. The resulting datasets were aggregated, and correlations between loot box expenditure, problem gambling and earnings investigated using Spearman's rho correlations. Results The combined open-access data comprised 7,767 loot box purchasers (5,933 with self-report earnings). Secondary analysis of this self-report data confirmed that disproportionate revenue appears to be generated from high-level spenders: the top 5 % of spenders (> $100/month) represent half of loot box revenue. Previously reported correlations between problem gambling and loot box expenditure were confirmed, with an aggregate correlation of ρ = .34, p < .001. In contrast, there was no significant correlation between loot box spend and earnings ρ = .02, p = .10. Conclusion Our secondary analysis suggests that games developers (unwittingly or not) are disproportionately profiting from moderate and high-risk gamblers, rather than high earning customers. Such patterns of spending mirror those observed with gambling revenues, and have implications for harm minimisation and ongoing policy debates around loot boxes.

In 2 spatial navigation experiments, human participants were asked to find a hidden goal (a WiFi signal) that was located in 1 of the right-angled corners of a kite-shaped (Experiment 1) or a cross-shaped (Experiment 2) virtual environment. Goal location was defined solely with respect to the geometry of the environment. Following this training, in a test conducted in extinction, participants were placed onto the outside of the same environments and asked to locate the WiFi signal. The results of both experiments revealed that participants spent more time searching in regions on the outside of the environments that were closest to where the WiFi signal was located during training. These results are difficult to explain in terms of analyses of spatial navigation and reorientation that emphasize the role of local representational encoding or view matching. Instead, we suggest that these results are better understood in terms of a global representation of the shape of the environment.

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Background and Aims: Loot boxes are purchasable randomised rewards in video games that share structural and psychological similarities with gambling. Systematic review evidence has established reproducible associations between loot box purchasing and both problem gambling and problem video gaming. We aimed to measure the association between loot box engagement and socioeconomic correlates. Design:The study was a cross-sectional online survey using the recruitment platform, Prolific.

Excessive engagement with (increasingly prevalent) loot boxes within games has consistently been linked with disordered gambling and/or gaming. The importance of recognising and managing potential risks associated with loot box involvement means understanding contributing factors is a pressing research priority. Given that motivations for gaming and gambling have been informative in understanding risky engagement with those behaviours, this qualitative study investigated motivations for buying loot boxes, through in-depth interviews with 28 gamers from across the UK. A reflexive thematic analysis categorised reasons for buying into seven “themes”; opening experience; value of box contents; game-related elements; social influences; emotive/impulsive influences; fear of missing out; triggers/facilitators. These themes are described in detail and discussed in relation to the existing literature and motivation theories. This study contributes to understanding ways in which digital items within loot boxes can be highly valued by purchasers, informing the debate around parallels with gambling. Findings that certain motivations were disproportionately endorsed by participants with symptoms of problematic gambling has potential implications for policy and warrants further study.

Co-contributer to the rationale, theoretical basis and design of the experiments. Programmed the experiments, collected and analysed the data as part of PhD project. Wrote up the experiments. Peter M. Jones: Co-contributer to the rationale, theoretical basis and design of the experiments.Contributed to analysis and write up as PhD supervisor.Chris J. Mitchell: Co-contributer to the rationale, theoretical basis and design of the experiments.