While positive emotion can be conceptualized broadly as a response to the potential for reward, the environment offers different kinds of rewards, and these are best approached in somewhat different ways. A functional approach to positive emotion differentiation distinguishes among several different types of rewards with strong implications for adaptive fitness and posits the existence of "discrete" positive emotions that promote an adaptive response to each reward. A taxonomy of eight positive emotions, dubbed the "PANACEAS" taxonomy based on an acronym of the first letter of each of the eight constructs, is presented as an example of this approach. Positive emotion constructs defined through functional analyses are useful for guiding empirical research, especially for identifying prototypical eliciting stimuli, and generating hypotheses about the implications of different positive emotions for a variety of outcomes. Research findings are reviewed that support the importance of positive emotion differentiation in understanding the effects of positive emotions on cognition, physiology, and behavior. Advantages of the functional approach are discussed, as well as implications of the approach for evaluating major theories of the structure of emotion. Positive Emotion Differentiation: A Functional ApproachImagine that you are in each the following situations: waiting eagerly for a cool drink you just ordered on a hot afternoon; stretching out on your couch after a long day and a satisfying dinner; holding your new baby niece or nephew in your arms; making eye contact with a sexy person you just met at a party; having a loved one care for and comfort you when you're sick; laughing at a joke told by a colleague; and gazing at the view from a high ridge on a mountain. Each of these situations is pleasant. Each offers potential for reward. Yet the nature of the reward varies considerably from situation to situation, and you take advantage of that reward by somewhat different means. While there is undoubtedly overlap in the emotions felt in each of these situations, there are important differences as well.For the most part, theories of positive emotion have not emphasized the possibility that different positive emotions might have qualitatively distinct implications for cognition, physiological responding, motivation, and behavior, or offered a strong basis for hypotheses about differential effects. A functional approach to positive emotion differentiation helps to address this gap. Analyses of the adaptive functions of "discrete" negative emotion states have long been used to guide research on emotional responding (e.g., Lazarus, 1991), producing a rich body of empirical work. In this paper, we discuss the advantages of using functional analysis to define discrete positive emotion constructs as well; present a taxonomy of eight positive emotions, labeled with the acronym "PANACEAS", that serves as an example of the functional approach; and offer several examples of research guided by the PANACEAS model and simi...

Directional asymmetry (DA), the consistent difference between a pair of morphological structures in which the same side is always larger than the other, presents an evolutionary mystery. Although many paired traits show DA, genetic variation for DA has not been unambiguously demonstrated. Artificial selection is a powerful technique for uncovering selectable genetic variation; we review and critique the limited number of previous studies that have been performed to select on DA and present the results of a novel artificial selection experiment on the DA of posterior crossvein location in Drosophila wings. Fifteen generations of selection in two genetically distinct lines were performed and none of the lines showed a significant response to selection. Our results therefore support and reconfirm previous findings; despite apparent natural variation and evolution of DA in nature, DA remains a paradoxical trait that does not respond to artificial selection.

Otologic cases are dwindling in numbers, jeopardizing the clinical training of our residents. A survey was performed to determine the magnitude of the problem facing our training programs. Seventy-three of 79 questionnaires distributed were returned. Results of the survey indicate that facial nerve decompression, exostosis repair, and stapedectomy were, on the average, infrequently performed by residents. Training for these seldom-performed procedures consists of temporal bone laboratory experience, close operative supervision, and the use of private patients for resident training. The majority (84%) of respondents did not feel that fellowship training was required to perform otologic surgery on graduation or that it should be required for obtaining hospital privileges in seldom-performed cases. Approximately three quarters (76%) of the program directors consider the training of seldom-performed procedures to be a moderate-to-serious problem facing otologic training today.

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