Can you trust a rat ? Using animal models to investigate the neural basis of trust-like behavior

The ability to form and maintain long-term trusting relationships with others arguably has enabled humans to develop high levels of cooperation within social groups. Trust, as operationalized in the economic trust game, varies greatly between individuals and under different contexts, probably reflecting contributions from different component processes. From a mechanistic point of view, progress has been made to delineate neural substrates and neurochemical pathways involved in trusting behavior. However, many questions regarding the exact neural implementation of trust remain unanswered. To make progress on these outstanding questions, it would be helpful to be able to turn to an animal model of trust, in which the full range of neurobiological manipulations and readout could be employed. The fundamental question therefore is: can trust be adequately modeled in laboratory animals, such as rodents? Here we present a breakdown of trusting behavior into its component processes such as social recognition, and reward contingency learning, and discuss which of these components could be translated to an animal experiment. We finally present a pilot experiment that indicates that rodents can learn reward probability contingencies that depend on social cues, and that this probability estimation bias persisted even when the actual outcome distributions between social partners was equated, suggesting a rudimentary capability for trust-like behavior in rodents.