Before I discuss the dissertation, a thank you to Karin and Floris for their time and hospitality for meeting the collegues of military performance psychology. Their patience in answering all the (same) questions about heart rate, HRV, freezing, realism in training, and so on, is greatly appreciated. Special thanks for giving Ashley the opportunity to play the game with a superb HRV. What stands out from these conversations and my podcast with Karin is the entirely different perspective on ‘freeze’ as a positive mechanism. Also, the perspective on realism – it depends on what you want to train, in this case, the management of physical arousal – and still achieve effectiveness and transfer. Realism is not a singular concept; it can be task realism or physiological realism. A few more quotes, and then onto the summary of the dissertation (unfortunately, I couldn’t attend).
Quotes from the thesis I like
About freezing
“However, when threat is still at distance or it is not entirely clear yet what action to take, parallel activation of the cholinergically-driven parasympathetic system puts a break on the cardiac and motor system and causes us to freeze.
Freezing is characterized by upregulation of both sympathetic and parasympathetic arousal, but dominance in the parasympathetic system results in a net bradycardia (heart-rate deceleration, hypoventilation and motor inhibition that is so typical for freezing; Hagenaars et al., 2014; Roelofs, 2017; Roelofs & Dayan, 2022).
Important for the present thesis, parasympathetic dominance not only results in heart rate (HR) deceleration and hypoventilation, it also results in an increased heart rate variability (HRV). This occurs potentially via vagally mediated mechanisms, including respiratory sinus arrythmia, which results in the acceleration of the HR during inhalation, and deceleration during exhalation (Hirsch & Bishop, 1981; Shaffer et al., 2014; Yasuma & Hayano, 2004).
Interestingly, the increased parasympathetic activity seen during the state of freezing is fundamental to preparing the body for optimal action (Gladwin et al., 2016). The reduced heart rate is linked to gathering information for improved decision-making (Klaassen et al., 2021), among others by enhancing perception (de Voogd et al., 2022; Lojowska et al., 2015; Rösler & Gamer, 2019).
Once we have made the decision, we see parasympathetic withdrawal and the already alerted sympathetic branch of the autonomic nervous system enables fast acting, notably with temporary increases in strength (Jerath et al., 2006). These defensive cascades can happen largely automatically, and adequate tuning may be essential for optimal coping with threat (Fragkaki et al., 2017; Niermann et al., 2019; Roelofs et al., 2023).
The increased sympathetic activity in the active fight-or-flight-state can be of
paramount importance for survival when fast action has to be generated. However, when it is associated with reduced parasympathetic activity, a decrease in HRV can take place, which has been linked to impaired decision-making capacities (Forte et al., 2022; Ramírez et al., 2015). Indeed, high HRV is suggested to be a proxy of ventromedial prefrontal cortex mediated activities that guide flexible control over behavior (Thayer et al., 2012).”
About realism
“We suggest that less realistic game-based elements can often prove more effective in homing in on the core causal units necessary for generalizability claims.”
Summary of the dissertation
This thesis delves into the utilization of a virtual reality (VR) game-based biofeedback training to assist police officers in mastering control over their psychophysiological stress responses. The ultimate goal is to enhance their decision-making capabilities and resilience in high-stress scenarios.
Chapters 1 and 2 establish the theoretical groundwork for this innovative training by delineating the constraints and drawbacks associated with the use of VR and biofeedback in scientific and training contexts. Despite the numerous promises and expectations surrounding VR biofeedback, fulfilling them poses challenges, including the complexities of developing realistic VR scenarios and interpreting data when subjects have freedom of movement. Consequently, this thesis advocates for the adoption of simpler, game-like environments for effective stress management training for police officers.
Chapter 3 addresses the technical challenges and solutions related to creating efficient physiological markers for real-time biofeedback, particularly in managing stress during activities such as participant movement and players’ perception of controllability.
In Chapter 4, the initial proof-of-concept study explores the impact of training a small group of nine police trainers over multiple days using the VR game. The study aims to chronicle the development of in-game breathing training effects over a one-month period, comprising ten training sessions. The results illustrate the feasibility and potential of biofeedback training in an active context. Insights and discoveries from this exploratory study inform the design of the subsequent large-scale multi-day randomized control trial in Chapter 5, involving 109 police trainers from various centers in the Netherlands. This trial demonstrates the efficacy of training Heart Rate Variability (HRV) in a condensed and fast-paced schedule, as well as the transfer of the acquired skill to a new police-relevant task outside VR. Additionally, the study indicates an increased physiological awareness among participants throughout the training, along with a high level of engagement and willingness to embrace the training.
The thesis concludes by highlighting the effectiveness of the VR environment in training HRV control skills that can be applied to real-life situations outside of VR. It also introduces a study design capable of exploring causal relationships within a training intervention. Ultimately, this study serves as a foundation for further research and suggests the integration of VR biofeedback training into the curriculum for police students and other first responders.
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THE HEART ON DUTY Training police officers in action using a biofeedback virtual-reality game Proefschrift ter verkrijging van de graad van doctor aan de Radboud Universiteit Nijmegen op gezag van de rector magnificus prof. dr. J.M. Sanders, volgens besluit van het college voor promoties in het openbaar te verdedigen op maandag 22 januari 2024
Further reading and watching