Cognitive Ecology – How the threat of predation influences information processing and decision making.
Open Access
- Author:
- Beri, Steven Robert
- Graduate Program:
- Ecology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- October 31, 2012
- Committee Members:
- Victoria Anne Braithwaite Read, Thesis Advisor/Co-Advisor
Paul Allen Bartell, Thesis Advisor/Co-Advisor
Tracy Lee Langkilde, Thesis Advisor/Co-Advisor - Keywords:
- Cognition
Brachyrhaphis episcopi
cognitive ecology
predation effects
speed accuracy trade-off
extinction response - Abstract:
- Predation is arguably one of the most important selective pressures in evolution. As a result, many prey species are likely to assess predation risk through information processing (i.e. learning), thus cognition can play a crucial role in survival. Cognition and an animal’s ability to process, store and retrieve information also affects to the way animals behave in other contexts. Experiments comparing the cognitive abilities of animals coming from populations exposed to contrasting ecological environments have provided insights into the factors that contribute to variation in learning and memory ability. To investigate this further, I selected natural populations of tropical freshwater fish, the Panamanian bishop (Brachyrhaphis episcopi) that are naturally exposed to contrasting levels of predation. The research presented in this thesis compares the spatial learning abilities and the memory duration of an associatively learned task in B. episcopi from these different populations. First, I compared spatial learning performance to determine whether fish varied in their ability to solve a maze task, and in the information that they paid attention to as they moved through the maze. Fish from high predation sites were quicker to make decisions about which route to take, but were also more apt to make mistakes. In contrast, fish from low predation areas made slower, more accurate decisions. The relative exposure to predators did not predict which kinds of spatial information the fish would use, but differences were found between rivers. My second experiment examined the ability of the fish to learn a conditioned response (associate a light cue with the delivery of a food reward) and then compared the rate of extinction of this learned association once the light cue no longer predicted the arrival of food. While fish with different experiences of predation showed no differences in the rate at which they formed the conditioned association between the light and the food, we did find that fish from low predation sites were quicker to show an extinction response compared to high predation conspecifics. Together, the results presented in this thesis indicate that ecological variables, specifically predation, play a substantial role in shaping learning, memory and other behavioral traits in fish.