Aggressive displays form a communication "threat code" that is more or less constant over individuals within each species. This code is thought to reflect the mood or motivational state of the animal. However, whether or not an individual - should - accurately reveal its mood or intentions to others is a matter of theoretical controversy. Game theory suggests that an individual should maximize its success in winning encounters and might bluff or "lie" as to its intentions. Studies of the development of aggression also suggest that, while the form of the actions may be inherited, individuals must learn how best to employ these actions. If threat behaviors are not a mere telegraphing of intentions, they likely reflect the experience of the individual and consequences of having performed a display in the past. Dr. Losey will study the degree to which experience serves to shape the threat code of the individual. Displays that result in winning an encounter may come to be favored over those that meet with less success. Dr. Losey will work at the University of Leiden to take advantage of their expertise in the quantitative analysis of behavior and their facilities and extensive experience with the three-spined stickleback, a species of small fish. Dr. Losey will vary the experience of individual males of this species by varying the stimuli received as a consequence of performing particular aggressive displays. Individuals exposed to different stimulus treatments should change their use of the displays, perhaps in intensity, threshold, sequencing, etc. Stimuli to be presented will include such relevant natural consequences of the behavior as "removal of opponent" or "attack by opponent," such less- relevant natural consequences as "exposure to gravid female" or "exposure to large predator," and a less natural but more traditional experimental consequence, electric shock. The effects of experience will be tested by recording the responses to both restrained and unrestrained male intruders into the territory of the test males.
