Many decisions are associated with consequences that differ in temporal proximity and reward magnitude. Temporal discounting (TD), the tendency to favor smaller-but-sooner over larger-but-later rewards, is common in humans (Peters & Büchel, 2011) and many animals (Kalenscher & Pennartz, 2008). Alterations in TD are associated with a range of psychiatric conditions and problematic behaviors, including addiction, substance abuse and attention-deficit hyperactivity

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.

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.

Humans prefer smaller sooner over larger later rewards, a tendency denoted as temporal discounting. Discounting of future rewards is increased in multiple maladaptive behaviors and clinical conditions. Although temporal discounting is stable over time, it is partly under contextual control. Appetitive (erotic) cues might increase preferences for immediate rewards, although evidence to date remains mixed. Reward circuit activity was hypothesized to drive increases in temporal discounting following cue exposure, yet this was never tested directly. We examined erotic vs. neutral cue exposure effects on subsequent temporal discounting in a pre-registered within-subjects study in healthy male participants (n=38). Functional magnetic resonance imaging assessed neural cue-reactivity, value-computations and choice-related effects. We replicated previous findings of value-coding in ventromedial prefrontal cortices, striatum and cingulate cortex. Likewise, as hypothesized, lateral prefrontal cortex activity increased during delayed reward choices, potentially reflecting cognitive control. Erotic cue exposure was associated with increased activity in attention and reward circuits. Contrary to pre-registered hypotheses, temporal discounting was unaffected by cue-exposure, and cue responses in reward circuits did not reliably predict changes in behavior. Our results raise doubt on the hypothesis that upregulation of (dopaminergic) reward systems following erotic cue-exposure is sufficient to drive myopic approach behavior towards immediate rewards.

The COVID-19 pandemic and the measures to prevent its spread have had a negative impact on substance use behaviour and posed a special threat for individuals at risk. Problem gambling is a major public health concern, and it is likely that the lockdown and social distancing measures have altered gambling behaviour, for instance shifting from land-based to online gambling. In this study, 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 relative usage of different subforums, i.e. terrestrial, online gambling and problem gambling sections, posting frequency, 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 the number of newly registered users during the first lockdown compared to the weeks prior to the lockdown, which may reflect a shift from terrestrial to online gambling. Further, there was an increase in the number of posts in the online gambling subforum with a concurrent decrease in the number of posts in the terrestrial gambling subforum. An analysis of user types revealed that a substantial number of users who posted in both the online and terrestrial forum contributed at least once to the problem gambling subforum. This subforum contained the longest posts, which were on average twice as long as the average post. Modelling the relationship between reply frequency and latency between initial posts and replies showed that the number of short-latency replies (i.e. replies posted within seven hours after the initial post) was substantially higher during the first lockdown compared to the preceeding weeks.The increase during the first lockdown may reflect the general marked increase in screen time and/or usage of online platforms and media after the onset of the global COVID-19 pandemic. The analyses may help to identify lockdown-related effects on gambling behaviour. These potentially detrimental effects on mental health, including addiction and problem gambling, may require monitoring and special public health measures.