Signal detection theory predicts that costs associated with recognition errors, specifically failing to respond to relevant stimuli (missed detection) and responding to erroneous ones (false alarms), shape receiver permissiveness in animal communication systems. Fitness costs of missed detection and false alarms in response to sexual signals differ between the sexes, and are usually higher for females than males. This asymmetry in costs predicts that males should be more permissive than females in their responses to signals. In my dissertation I investigate the behavioral responses of male and female túngara frogs, Physalaemus pustulosus, to mating signals and sounds associated with such calls. Specifically I explore the following topics: i) responses of the sexes to call complexity, ii) perception of congeneric mating calls by males and females, iii) responses of males to the conspecific call compared to those of extant heterospecifics, iv) effect of sounds associated with increased predation risk in reproductive decisions, and v) effect of the task performed by each sex on signal permissiveness. My findings indicate that recognition errors are higher for males than females as predicted by the different costs associated with recognition errors for each sex. Males respond to a broader range of calls than females. Despite the differences, evolutionary history has left a footprint on the brain of both sexes. In addition, I found that females behaved more cautiously than males suggesting that the sexes balance the risk of predation and the cost of cautious mating strategies differently. In the mating system of túngara frog, as in many others, sexual signals elicit different tasks in the different sexes, female phonotaxis and male calling. Therefore, the sexual differences in decision making I found could be either sex-specific independent of task, or task-specific independent of sex. Here I show that sexual differences in receiver permissiveness are motivated by differences due to the typical reproductive tasks displayed by the sexes. / text

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Guidelines for using style to improve computer program comprehension have often been proposed without empirical testing. This thesis reports on the results of three controlled experiments that investigated ways program style may be used to aid comprehension of source code listings. Experiments 1 and 2 were conducted using advanced computer science students as subjects and short Pascal programs. Results showed that student programmers used meaningful identifier names as important sources of information during comprehension of short programs. A review of the literature showed the need for the thesis' proposed methodology for designing controlled experiments on program comprehension that produce results which generalize well to situations involving professional programmers working on real world tasks. This methodology was used to design Experiment 3. Text comprehension researchers have investigated the use of signaling, or the placement of non-content information, in a text in order to emphasize certain ideas and/or clarify the organization. Experiment 3 investigated the role of signaling in another domain, that of computer program source code listings. The experiment had professional programmers study a 913-line C program. Three types of signals were investigated: preview statements, headings, and typographic cueing. The major results were (a) meaningful module names served as headings in the source code listing and helped professional programmers understand and locate information in the program; (b) header comments, when written as preview statements, helped professional programmers understand and locate information in the program; (c) typographic cueing, designed to provide emphasis and segmentation cues, helped programmers understand the program; and (d) the effects of meaningful names, header comments, and typographic cueing were additive. No significant interactions of effects were observed. Based on these results, guidelines are proposed for ways programmers may use comments and module names in source code to act as signals that aid future readers. In addition, guidelines are suggested for adding typographic signaling to provide emphasis to the comments and names. / Graduation date: 1992

Dissertation (Ph.D.)--Auburn University, 2005. / Abstract. Includes bibliographic references.

Thesis (Ph. D.)--University of California, San Diego, 1997. / Vita. Includes bibliographical references (leaves 87-88).

Thesis (M.Sc.)--Victoria University of Wellington, 2009. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

The purpose of this investigation was to examine the supposition that chronic pain patients (CPPs) have altered pain perception. Two models were examined that led to opposing predictions as to how CPPs would respond to painful stimuli (i.e., the hypervigilance and adaptation-level models). Both predictions have been supported by past research but because of methodological variation and the type of pain disorder studied, it has remained unclear under what circumstances the predictions of these two models may be met. The responses of pain patients to painful stimuli have been found to vary for patients-with different clinical presentations (i.e. those with and without medically incongruent signs and symptoms). Therefore, the present investigation sought to compare the responses to radiant heat stimuli of sixty CPPs (thirty with and thirty without a medically incongruent pain presentation) to thirty age and sex matched normal control subjects (i.e., pain-tree individuals). Signal detection theory methodology was used in order to separately evaluate sensory sensitivity and the response bias to report sensations as painful. In addition, cognitive and affective factors were assessed in order to identity potential psychological correlates of altered pain perception. The results of this study indicated that the presence of a medically incongruent pain presentation distinguished patients on their subjective report of disability and to a lesser extent cognitive appraisal and affective distress regarding their pain condition. They did not differ in their responses to painful stimuli. In a post hoc analysis where CPPs were classified into 'organic' and 'functional’ diagnostic groups, significant differences in pain threshold and the response bias to report pain were found. Patients classified as 'organic' had significantly higher pain thresholds compared to normal control subjects and patients classified as 'functional'. Differences in pain threshold were primarily represented by the response' bias to report sensations as painful rather than sensory sensitivity to the stimuli. The 'functional' group had a slightly lower pain threshold than the normal control group but this difference was not significant. The results are discussed in light of the two models of pain perception. The two methods used to classify pain patients are discussed according to their orthogonal characteristics on sensory, cognitive, and affective components. / Arts, Faculty of / Psychology, Department of / Graduate

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