Reliability assessment of temporal discounting measures in virtual reality environments

Abstract

In recent years the emergence of high-performance virtual reality (VR) technology has opened up new possibilities for the examination of context effects in psychological studies. The opportunity to create ecologically valid stimulation in a highly controlled lab environment is especially relevant for studies of psychiatric disorders, where it can be problematic to confront participants with certain stimuli in real life. However, before VR can be confidently applied widely it is important to establish that commonly used behavioral tasks generate reliable data within a VR surrounding. One field of research that could benefit greatly from VR-applications are studies assessing the reactivity to addiction related cues (cue-reactivity) in participants suffering from gambling disorder. Here we tested the reliability of a commonly used temporal discounting task in a novel VR set-up designed for the concurrent assessment of behavioral and psychophysiological cue-reactivity in gambling disorder. On 2 days, thirty-four healthy non-gambling participants explored two rich and navigable VR-environments (neutral: café vs. gambling-related: casino and sports-betting facility), while their electrodermal activity was measured using remote sensors. In addition, participants completed the temporal discounting task implemented in each VR environment. On a third day, participants performed the task in a standard lab testing context. We then used comprehensive computational modeling using both standard softmax and drift diffusion model (DDM) choice rules to assess the reliability of discounting model parameters assessed in VR. Test–retest reliability estimates were good to excellent for the discount rate log(k), whereas they were poor to moderate for additional DDM parameters. Differences in model parameters between standard lab testing and VR, reflecting reactivity to the different environments, were mostly numerically small and of inconclusive directionality. Finally, while exposure to VR generally increased tonic skin conductance, this effect was not modulated by the neutral versus gambling-related VR-environment. Taken together this proof-of-concept study in non-gambling participants demonstrates that temporal discounting measures obtained in VR are reliable, suggesting that VR is a promising tool for applications in computational psychiatry, including studies on cue-reactivity in addiction.

Increased temporal discounting and reduced model-based control in problem gambling are not substantially modulated by exposure to virtual gambling environments

“…Model comparison revealed that the DDM S (DDM including a sigmoidal drift rate modulation) accounted for the data best (Table 4), replicating previous findings [39,46,48,51] . Further analyses focused on the DDM S .…”

“…comparing F5 vs. S1) in either group for any physiological measure. Instead, in both groups, the tonic skin conductance level (SCL) increased substantially upon VR immersion in both groups (effect size r between .66 and .81 in both groups and both sessions) and remained elevated until the end of the experiment, an effect we have observed previously in non-gambling controls [39] . No corresponding effects were observed for heart rate or the number of spontaneous skin conductance responses.…”

“…There was also strong evidence that this decrease was significantly more pronounced than in gambling group (comparison of the group level posteriors of the s k parameter). The fact that non-gambling control participants tended to discount rewards less steeply in the VR gambling session is of potential interest, but it is important to note that in a previous study employing the same VR design [39] we observed the reverse effect in a group of non-gambling controls. In that study, controls if anything showed reduced temporal discounting in the VR neutral session.…”

“…Conversely, lab studies yield control over confounding variables but lack ecological validity. We recently proposed a virtual reality (VR) approach that combines ecological validity with the advantages of a highly controlled lab environment [39–41] . VR allows the concurrent measurement of physiological, subjective, and behavioral cue-reactivity in an ecologically valid virtual environment.…”

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

“…Alterations in TD are associated with a range of psychiatric conditions and problematic behaviors, including addiction, substance abuse and attention-deficit hyperactivity disorder (Amlung et al, 2019; Bickel et al, 2019; Jackson & McKillop, 2016; Wiehler & Peters, 2015). TD exhibits stability over weeks ( r = .91; Simpson & Vuchinich, 2000), months ( r = .77-.80; Arfer & Luhmann, 2017) and even one year ( r = .71; Kirby, 2009), and across different testing environments (Bruder et al, 2021; Odum, 2011). Temporal discounting is therefore regarded as a trait-like characteristic (Smith & Hantula, 2008).…”