Large-Scale Web Scraping for Problem Gambling Research: A Case Study of COVID-19 Lockdown Effects in Germany.

The COVID-19 pandemic and the measures to prevent its spread have had a negative impact on substance use behaviour. It is likely that social distancing and lockdown measures have also altered gambling behaviour, for instance shifting from land-based to online gambling. We used large-scale web scraping to analyse posting behaviour on a major German online gambling forum, gathering a database of more than 200k posts. We examined the usage of different subforums, i.e. terrestrial, online gambling and problem gambling sections, and changes in posting behaviour related to the casino closures that were part of the nationwide restrictions in Germany in 2020. There was a marked increase in newly registered users during the first lockdown compared to the preceding weeks, an increase in the number of posts in the online gambling subforum and concurrent decrease in the terrestrial gambling subforum. Further, the number of short-latency replies was higher during the first lockdown compared to the preceding weeks. Many users who posted in both the online and terrestrial forum contributed at least once to the problem gambling subforum, implying that the topic of problem gambling is widely discussed. Our findings may indicate a shift from terrestrial to online gambling during lockdown, and mirror the general increase in screen time and usage of online platforms after the onset of the COVID-19 pandemic. The analyses help to identify lockdown-related effects on gambling behaviour. These potentially detrimental effects pose a special threat for individuals at risk and may require monitoring and special public health measures.

Pharmacological Enhancement of Dopamine Neurotransmission Does Not Affect Illusory Pattern Perception.

Psychotic symptoms and delusional beliefs have been linked to dopamine transmission in both healthy and clinical samples and are assumed to result at least in part from perceiving illusory patterns in noise. However, the existing literature on the role of dopamine in detecting patterns in noise is inconclusive. To address this issue, we assessed the effect of manipulating dopaminergic neurotransmission on illusory pattern perception in healthy individuals (n = 48, n = 19 female) in a double-blind placebo-controlled within-subjects design (see preregistration at https://osf.io/a4k9j/). We predicted individuals on versus off ʟ-DOPA to be more likely to perceive illusory patterns, specifically objects in images containing only noise. Using a signal detection model, however, we found no credible evidence that ʟ-DOPA compared with placebo increased false alarm rates. Further, ʟ-DOPA did not reliably modulate measures of accuracy, discrimination sensitivity, and response bias. In all cases, Bayesian statistics revealed strong evidence in favor of the null hypothesis. The task design followed previous work on illusory pattern perception and comprised a limited number of items per condition. The results therefore need to be interpreted with caution, as power was limited. Future studies should address illusory pattern perception using more items and take into account potential dose-dependent effects and differential effects in healthy versus clinical samples.

Erotic cue exposure increases physiological arousal, biases choices toward immediate rewards, and attenuates model-based reinforcement learning.

Computational psychiatry focuses on identifying core cognitive processes that appear altered across distinct psychiatric disorders. Temporal discounting of future rewards and model-based control during reinforcement learning have proven as two promising candidates. Despite its trait-like stability, temporal discounting may be at least partly under contextual control. Highly arousing cues were shown to increase discounting, although evidence to date remains somewhat mixed. Whether model-based reinforcement learning is similarly affected by arousing cues remains unclear. Here, we tested cue-reactivity effects (erotic pictures) on subsequent temporal discounting and model-based reinforcement learning in a within-subjects design in n = 39 healthy heterosexual male participants. Self-reported and physiological arousal (cardiac activity and pupil dilation) were assessed before and during cue exposure. Arousal was increased during exposure of erotic versus neutral cues both on the subjective and autonomic level. Erotic cue exposure increased discounting as reflected by more impatient choices. Hierarchical drift diffusion modeling (DDM) linked increased discounting to a shift in the starting point bias of evidence accumulation toward immediate options. Model-based control during reinforcement learning was reduced following erotic cues according to model-agnostic analysis. Notably, DDM linked this effect to attenuated forgetting rates of unchosen options, leaving the model-based control parameter unchanged. Our findings replicate previous work on cue-reactivity effects in temporal discounting and for the first time show similar effects in model-based reinforcement learning in a heterosexual male sample. This highlights how environmental cues can impact core human decision processes and reveal that comprehensive modeling approaches can yield novel insights in reward-based decision processes.

Trial-wise exposure to visual emotional cues increases physiological arousal but not temporal discounting.

Humans and many animals devalue future rewards as a function of time (temporal discounting). Increased discounting has been linked to various psychiatric conditions, including substance-use-disorders, behavioral addictions, and obesity. Despite its high intra-individual stability, temporal discounting is partly under contextual control. One prominent manipulation that has been linked to increases in discounting is the exposure to highly arousing appetitive cues. However, results from trial-wise cue exposure studies appear highly mixed, and changes in physiological arousal were not adequately controlled. Here we tested the effects of appetitive (erotic), aversive, and neutral visual cues on temporal discounting in 35 healthy male participants. The contribution of single-trial physiological arousal was assessed using comprehensive monitoring of autonomic activity (pupil size, heart rate, electrodermal activity). Physiological arousal was elevated following aversive and in particular erotic cues. In contrast to our pre-registered hypothesis, steepness of temporal discounting was not significantly affected by emotional cues of either valence. Aversive cues tended to increase decision noise. Computational modeling revealed that trial-wise arousal only accounted for minor variance over and above aversive and erotic condition effects, arguing against a general effect of physiological arousal on temporal discounting.