2. Models Presented

ABSTRACT This chapter introduces the two theoretical models to be applied to qualitative and quantitative data in the case study of Dodge Morgan. We present the five-factor model (FFM) and the life-story model (LSM) separately, with attention to their differing origins, assumptions, and utilities. We briefly trace the development and resurgence of the factor-analytic FFM and delineate the extent of its current influence in the field of personality. We discuss individual factors and consider the ways in which the model can be expected to be useful as well as limited in application to the individual. We next present the genealogy of the narrative, constructivist LSM and describe its components; we also discuss its contrasting strengths and limitations.     

6. The Life Voyage

ABSTRACT Chapter 6 applies the five-factor model and the life-story model as complementary perspectives to the multiple data sources collected for the case study of Dodge Morgan. We integrate the two models to create a new level of analysis that captures differing aspects of experience. We develop a holistic personality analysis of Morgan, interpreting his childhood, young manhood, adventures in Alaska and on the boat Coaster, his return to the mainland and embrace of business and entrepreneurship, and his solo circumnavigation. We address questions of voyage outcomes with reference to the quantitative analyses of his voyage log; we consider not only the external journey but also his internal psychological issues and developmental tasks.     

Comparing Locomotion With Lever-press Travel In An Operant Simulation Of Foraging

An operant model of foraging was studied. Rats searched for food by pressing on the left lever, the patch, which provided one, two, or eight reinforcers before extinction (i.e., zero reinforcers). Obtaining each reinforcer lowered the probability of receiving another reinforcer, simulating patch depletion. Rats traveled to another patch by pressing the right lever, which restored reinforcer availability to the left lever. Travel requirement changed by varying the probability of reset for presses on the right lever; in one condition, additional locomotion was required. That is, rats ran 260 cm from the left to the right lever, made one response on the right lever, and ran back to a fresh patch on the left lever. Another condition added three hurdles to the 260-cm path. The lever-pressing and simple locomotion conditions generated equivalent travel times. Adding the hurdles produced longer times in patches than did the lever-pressing and simple locomotion requirements. The results contradict some models of optimal foraging but are in keeping with McNair's (1982) optimal giving-up time model and add to the growing body of evidence that different environments may produce different foraging strategies.     

Stochastic ordering using the latent trait and the sum score in polytomous IRT models

In a restricted class of item response theory (IRT) models for polytomous items the unweighted total score has monotone likelihood ratio (MLR) in the latent trait. MLR implies two stochastic ordering (SO) properties, denoted SOM and SOL, which are both weaker than MLR, but very useful for measurement with IRT models. Therefore, these SO properties are investigated for a broader class of IRT models for which the MLR property does not hold.In this study, first a taxonomy is given for nonparametric and parametric models for polytomous items based on the hierarchical relationship between the models. Next, it is investigated which models have the MLR property and which have the SO properties. It is shown that all models in the taxonomy possess the SOM property. However, counterexamples illustrate that many models do not, in general, possess the even more useful SOL property.Hemker's research was supported by the Netherlands Research Council, Grant 575-67-034. Junker's research was supported in part by the National Institutes of Health, Grant CA54852, and by the National Science Foundation, Grant DMS-94.04438.     

The Individuation of Actions

I argue against a view of the individuation of actions endorsed most notably by Hornsby and Davidson. This is the view that in, for example, Anscombe's case of the pumping man, we have a single action which can be described, variously, as a pumping, a poisoning and so on. I argue that, even in the area of the standard arguments against this view, such as that based on the logic of 'by' and the argument from temporal dimensions, the case against the Davidson-Hornsby view has not been made as strong as it ought to have been. I show how those standard arguments can be strengthened; and I argue that the principal considerations adduced in support of the view do not in fact lend it the support that they have been widely thought to lend it. I conclude that the view should be rejected.     

How Can Pictures be Propositions?

Wittgenstein's Picture Theory of language holds that one fact can represent another, and that propositions are pictures of states of affairs. What makes a fact into a picture of a given s tate of affairs are the correlations between picture elements and objects and the correlations between relations among picture elements and relations among objects. But a problem sometimes raised is that propositions can't be pictures, as pictures—unlike propositions—do not say anything. An interpretation (e.g. Anscombe's) holds that the above-mentioned correlations do make the picture into a proposition. But this neither handles the objection, nor is it Wittgenstein's view. Further, Wittgenstein's own account faces serious difficulties in addressing these issues, and the Anscombe-type interpretation obscures this fact.