Mousekilling,intermale fighting,and conditioned emotional response in rats

Several possible relationships between two forms of aggression in rats were studied. First, mouse killing and spontaneous intermale fighting were found to be correlated. Rats which attacked other rats were those most likely to kill mice. To determine whether aggressive and nonaggressive rats were also differentially responsive to other situations involving emotional arousal, but not aggression, mouse-killers and nonkillers were compared in a conditioned emotional response (CER) situation. Mouse-killers showed greater suppression to the conditioned stimulus (CS) and to the situational cues of the apparatus. Therefore, a common arousal mechanism may underlie a number of diverse agonistic responses. Nevertheless, extensive mouse-killing experience did not increase the tendency of rats to fight with either adult males or juvenile males.     

Behavioral ephemera,difficult discriminations,and behavioral stability

Every species possesses abilities for successfully interacting with its environment. These result from phylogeny. In the laboratory, one may arrange artificial conditions that thwart an organism's abilities. The result may be a “phenomenon.” With sufficient training, however, the phenomenon may prove to be ephemeral, as the organism's basic abilities reassert themselves. Pigeons respond extremely well to differences and nondifferences in rate of obtaining food. This ability may be thwarted in a variety of ways, but the results tend to be ephemeral. An example is an experiment that pitted pigeons' preference for unimpeded responding against their ability to respond to food rate. In a concurrent-chains procedure, the terminal links were identical variable-interval schedules, but in one terminal link, every response produced a timeout. The duration of the timeout varied, and preference varied with it, but the relation vanished with training, in keeping with the equality of food rate across the 2 terminal links. Some other examples of “phenomena” that tend to disappear with sufficient training and sufficient variation in experimental parameters are behavioral contrast, conditioned reinforcement, resistance to extinction, and suboptimal choice. These “phenomena” depend on pigeons' failing to make difficult discriminations. They appear to be behavioral ephemera.