Investigating Latencies In Acoustic Selection by Hyla chrysoscelis in the Presence of Informational Masking

Abstract

In this project, I investigated the effect of informational masking on the ability of female frogs (Hyla chrysoscelis) to make a choice regarding a potential mate. Informational masking refers to interference of noise in the brain, having the potential to hinder the frog’s ability to recognize conspecific calls. I used the R program to analyze data from a series of tests performed on actively mating treefrogs this summer. Specifically, I investigated how the latency, or the time taken for the frog to make a choice, varied as a result of informational masking. In late May and June, females were collected and placed one at a time in a soundproof chamber. Two forms of discrimination tests were carried out, one where the signals differed in pulse rate, and one where they differed in pulse number. For each type of test, there were trials involving a quiet background, trials involving a control masker, and trials involving the informational masker. Given background knowledge about this species of frog, it was predicted that informational masking would result in the greatest latency. Following the same logic, it was expected that the control masker would have an intermediate latency, and the quiet condition would have the smallest latency. Results were not entirely conclusive for any tests, both when incorrect choices were included and when they were filtered out. According to the pulse rate findings, there was a slight trend for greater latency in the presence of maskers. However, there was little difference between the effect of the Control Masker and the Informational Masker. There was little difference between the graphs produced from all latencies and the graphs produced only from correct choice latencies. Pulse number graphs did not produce a trend. Overall, it was determined that latency may not be a good marker for observing the effects of informational masking.