Professor Frank Krueger brings together diverse theories to build a psychoneurobiological model for trust frameworks

To trust or not to trust: A psychoneurobiological framework


A trusting society is open, inclusive, and promotes both social and personal wellbeing. Understanding the interpersonal trust between any members of society, be it a belief, intention or behaviour, is of crucial importance to fields ranging from psychology and neuroscience to economics.


Professor Frank Krueger of George Mason University brings together economic exchange games, psychological systems, and neuroscience mechanisms (eg, brain circuits, hormones, genes) to build a ‘psychoneurobiological’ model of trust.

Read his original article:

Read more about the Social Cognition and Interaction: Functional Imaging (SCI:FI) Lab here.

Image credit: Giggsy25/Shutterstock



Hello, and welcome to ResearchPod. Thanks for joining us today.


In this episode, we’ll be looking at research by Frank Krueger, Professor of Systems Social Neuroscience at the School of Systems Biology at George Mason University in Fairfax, VA, USA.


As well as acting as Faculty Member of the Institute for Biohealth Innovation, and Core Member of the Center for Adaptive Systems of Brain-Body Interactions at George Mason University, Krueger is also Lab Chief of the Social Cognition and Interaction: Functional Imaging Lab, or the ‘SCI:FI Lab’. Trained as a psychologist, physicist, and neuroscientist, Krueger’s research combines social psychology, experimental economics, and social computational neuroscience to better understand psychological functions and the neurobiological mechanisms of social cognition and interactions.


With this transdisciplinary toolbox, his lab aims to further three lines of enquiry, with the overarching purpose of the findings’ translation into the treatment and prevention of social brain disorders:


1) the advancement of our understanding of the neuropsychological underpinnings of social beliefs such as morality, religion, and free will);


2) getting a grasp on the neural signatures of altruistic punishment of social norm violations; and


3) the investigation of the neural correlates of interpersonal trust in social dyads.


In the episode of the podcast, we’ll be finding out more about his most recent work on ‘interpersonal trust’.


Confucius famously told a disciple that a state without trust ‘cannot stand’. Trust is present in almost every social interaction we make as humans, both public and private; we trust that a pharmacist is handing us the medicine we need, we trust that an electrician is wiring our house correctly, we trust that our spouse will not engage in extramarital affairs. Throughout the COVID-19 pandemic we needed to trust that our governments were making the best decisions for our health and well-being, or we would not have followed the lock-down and vaccination guidance they were giving.

When trust is disrupted, this can have a severe effect on our mental health as well as the social and economic structures we rely on to live our everyday lives. A trusting society is open and inclusive, as well as being good for economic development and wellbeing. It also gives rise to uncertainty though, and this gives rise to deceptive human behaviours. One term to specifically describe confidence in another person, or between people, is ‘interpersonal trust’, and this is what Krueger is particularly interested in.


Study of interpersonal trust has spanned disciplines for many years. Economists, psychologists and, recently, neuroscientists have all investigated, hypothesised, and debated the topic. Definitions and theories from these different fields have remained isolated and unconnected though; for example, there remains debate in the literature as to whether trust is a belief, intention, or behaviour. Krueger argues that a coherent framework of trust will lead to a better understanding of the psychoneurobiological underpinning of trust, which could then be expanded from interpersonal trust to other types of trust, such as institutional and intercultural trust. In a recent paper, Krueger does just this; bringing together economic exchange games, psychological systems (ie, motivation, affect, cognition) and neuroscience mechanisms (eg, brain circuits, hormones, genes) to build a ‘psychoneurobiological’ model of trust.


Krueger’s framework of trust is arranged as a top-down triangle, beginning at the top with behaviour and ranging to genes at the bottom. The framework allows a pragmatic consideration of culture, nature, and nurture. At the behavioural level of the framework, Krueger considers a two-person trust game, measuring the predilection and dynamics of interpersonal trust behaviour. At the psychological level, psychometric tests and surveys allow evaluation of psychological systems such as motivation, affect and cognition, and their linked TRUST (Treachery, Reward, Uncertainty, Strategy and Trustworthiness) components.


At the next level, the neurofunctional level, neuroimaging methods (such as functional magnetic resonance imaging, or fMRI) are able to identify the domain-general large-scale brain networks that form the TRUST components shaping trust behaviour. The anticipation of reward (that is to say, their motivation, activating the brains reward network) contrasted with the risk of treachery (or the affect, in the brains salience network) creates uncertainty, which is associated with vulnerability of trusting another person.


To remove uncertainty, two types of bounded rationality can be employed, where the salience network acting as a switch engages either the central-executive network, also called directed cognition, or the default-mode network , also called internally directed cognition.


Trustors with extrinsic incentives (ie, self-regarding interest) adopt a context-based strategy employing the central-executive network (cognitive control) to reap personal benefits (ie, economic rationality), whereas trustors with intrinsic incentives (ie, other-regarding interest) evaluate the relationship-based trustworthiness engaging the default-mode network (social cognition) to contribute to the relationship’s success (ie, social rationality).


Following this, at the neurochemical level, pharmacological manipulations of neuropeptide hormones including oxytocin and steroid hormones like testosterone as well as neurotransmitters such as dopamine reveal the neural signalling pathway mechanisms invoked in trust behaviour.


Finally, at the neurogenetic level, twin and genetic studies look at individual variations in the human genome, such as the regions of DNA encoding the oxytocin receptor gene, explaining the mechanisms of genetic variation in producing different trust behaviours.


Krueger claims this framework will allow the identification of patterns in interpersonal trust in healthy people, which in turn will allow us to detect the roots of trust impairment, which is already recognised in the neuropathology of mental disorders.


The interdisciplinary approach that Krueger has employed in this instance to build his framework is, he thinks, critical to advancing research and understanding in the field of trust. With the same intention, Krueger has also recently edited a book, published by Cambridge University Press in 2021, which brings together a collection of work on ‘The Neurobiology of Trust’, exploring transdisciplinary methods in a seminal and exciting volume. Furthermore, Krueger has begun to put together the Transdisciplinary Research Union for the Study of Trust Initiative, abbreviated to TRUST for short.


This brings together researchers with different backgrounds to study trust under one common framework. Krueger is so convinced about the importance of transdisciplinary cooperation in this area that he has also begun to connect personally with other relevant research work and projects, including the recent delivery of a keynote lecture for the NeuroInformation Systems Society on ‘The Neurobiology of Trust: Benefits and Challenges for Neuro IS’.


Collaboration between researchers of different fields will, Krueger reasons, allow us to understand how interpersonal trust is encoded in our brains, and therefore why we trust, or indeed mistrust, others. This discovery could have a significant impact on the treatment and prevention of social disorders; getting to the bottom of the ‘how’ and ‘why’ of mistrust is essential to beginning this journey. Furthermore, Krueger’s transdisciplinary approach to interpersonal trust can also be applied to human-machine trust.


As the Specialty Chief Editor for the Frontiers journal Social Neuroergonomics, he recently published a Specialty Grand Challenge Article arguing that social neuroergonomics – devoted to the application of knowledge of the neurobiological underpinnings of social processes and behaviours to the design, engineering, and evaluation of human–machine systems – has the unique potential to advance our understanding of how humans engage in social interactions with technology (ranging from automated technical systems to autonomous robots) and to use these insights to foster more efficient and satisfying human–machine interactions, including human–machine trust. As Krueger puts it, ‘Eventually, understanding human–machine interactions will help us to understand ourselves better.’


However, to move forward with these important research questions, academics and scientists must reach outside of their silos; disciplines working autonomously cannot possibly make the same progress as those who share and learn across specialties and schools. In short, to advance our understanding of trust, we must trust in one another.


That’s all for this episode, thank you for listening. You can find links to Dr Kruegers work in the show notes for this episode, and be sure to stay subscribed to ResearchPod for more of the latest science. See you again soon.

Leave a Reply

Your email address will not be published.

Researchpod Let's Talk

Share This

Copy Link to Clipboard