Stress studies frequently utilize physical stressors to establish animal models of stress.In the majority of cases,these models are not consistent with human circumstances.The present study simulated a social isolation plus resident intruder stress model in the rat.The rats were subjected to daily social isolation and resident intruder stress for 2 weeks.Behaviors were then tested.Rats subjected to social stress exhibited different aggressive behavior styles;some rats had greater scores on composite aggression behaviors,as well as locomotor and exploratory activity,but lower scores on latency than others.The high-aggressive group exhibited predominantly anger-out,while the low-aggressive group exhibited anger-in.Results suggest that social isolation plus resident intruder may serve as an appropriate model for anger-in and anger-out emotion modeling in the rat.