Relative to females, male rats are more willing to forego obtaining sucrose reward in order to prevent harm to their cage mate

Rationale Empathy, or the ability to perceive, share, and act upon the emotions of another, is a crucial social skill and is dysfunctional in autism and schizophrenia. While the complexities of human empathy are difficult to model in rodents, behavioral paradigms utilizing rats which study decision-making in social contexts may provide a translational framework for assessing biological, pharmacotherapeutic, and environmental interventions. Objectives Modify and expand upon the three-session rat harm aversion task, which measures the willingness of rats to cease pressing a lever that earns them sucrose reward but delivers a shock to their cage mate. We sought to test the sustainability of harm aversion across seven sessions in male and female rats. Methods Same-sex pair-housed rats were assigned as either the observer, which had access to the lever, or the demonstrator, which would receive shocks. After training the observer to press the lever to receive sucrose pellets, the demonstrator was placed into an adjacent chamber at which point lever responses would also deliver a shock. If the observer did not press the lever, no shock and no sucrose was delivered. Results A sex difference in harm aversion was observed with female rats having significantly higher response rates and decreased response latencies across the seven test sessions, thus delivering more shocks and obtaining more sucrose, relative to males. Conclusions These data demonstrate that male rats sustain harm aversion to a greater extent relative to females.