Actualism,ontological commitment,and possible world semantics

Actualism is the doctrine that the only things there are, that have being in any sense, are the things that actually exist. In particular, actualism eschews possibilism, the doctrine that there are merely possible objects. It is widely held that one cannot both be an actualist and at the same time take possible world semantics seriously — that is, take it as the basis for a genuine theory of truth for modal languages, or look to it for insight into the modal structure of reality. For possible world semantics, it is supposed, commits one to possibilism. In this paper I take issue with this view. To the contrary, I argue that one can take possible world semantics seriously and yet remain in full compliance with actualist scruples.     

Neuroticism,coping and change in MCMI-II clinical syndromes: test of a mediator model

The aim of the study was to examine prospectively whether coping mediated the relation between Neuroticism and change in different clinical mental syndromes. Assessments were conducted with 154 former psychiatric outpatients six and seven years after their initial contact with an outpatient clinic. Dispositional coping mediated the relation between Neuroticism and change in four of the nine clinical scales of the Millon Clinical Multiaxial Inventory (MCMI-II) (Millon, 1987). High Neuroticism led to coping strategies of disengagement and the venting of emotions and to a lack of problem-focused coping, which in turn translated into a relative increase on the MCMI-II scales. The mediator model of coping was found to apply to the MCMI-II scales "somatoform disorder’, ‘dysthymia’, ‘alcohol dependence’ and ‘thought disorder’. Results are discussed under the perspective of an integration of the positions of the transactional theory of stress and personality psychology. .     

The Fundamental Theorem of World Theory

The fundamental principle of the theory of possible worlds is that a proposition p is possible if and only if there is a possible world at which p is true. In this paper we present a valid derivation of this principle from a more general theory in which possible worlds are defined rather than taken as primitive. The general theory uses a primitive modality and axiomatizes abstract objects, properties, and propositions. We then show that this general theory has very small models and hence that its ontological commitments—and, therefore, those of the fundamental principle of world theory—are minimal.     

An efficient computerized testing method for the capuchin monkey (<Emphasis Type="Italic">Cebus apella</Emphasis>): Adaptation of the LRC-CTS to a socially housed nonhuman primate species

Even with advances in automated testing techniques, the capuchin monkey (Cebus apella) can be a difficult species to test in the laboratory, given its social/behavioral tendencies and typical activity pattern. Laboratories that maintain social colonies of capuchin monkeys are able to separate and test individuals, but the process can be very effortful and time consuming, and the resulting data can be modest in quantity. The present article describes procedures and apparatuses that were used to train a colony of computer-naive capuchin monkeys to quickly and reliably isolate themselves from group members and interact with a computerized test system in order to produce a large volume of data. Several elements that were important in motivating the monkeys to participate are discussed.     

Navigating two-dimensional mazes: chimpanzees (Pan troglodytes) and capuchins (Cebus apella sp.) profit from experience differently

We examined whether navigation is impacted by experience in two species of nonhuman primates. Five chimpanzees (Pan troglodytes) and seven capuchin monkeys (Cebus apella) navigated a cursor, using a joystick, through two-dimensional mazes presented on a computer monitor. Subjects completed 192 mazes, each one time. Each maze contained one to five choices, and in up to three of these choices, the correct path required moving the cursor away from the Euclidean direction toward the goal. Some subjects completed these mazes in a random order (Random group); others in a fixed order by ascending number of choices and ascending number of turns away from goal (Ordered group). Chimpanzees in both groups performed equivalently, demonstrated fewer errors and a higher rate of self-correcting errors with increasing experience at solving the mazes, and made significantly fewer errors than capuchin monkeys. Capuchins were more sensitive to the mode of presentation than chimpanzees; monkeys in the Ordered group made fewer errors than monkeys in the Random group. However, capuchins’ performance across testing changed little, and they remained particularly susceptible to making errors when the correct path required moving away from the goal. Thus, these two species responded differently to the same spatial challenges and same learning contexts. The findings indicate that chimpanzees have a strong advantage in this task compared to capuchins, no matter how the task is presented. We suggest that differences between the species in the dynamic organization of attention and motor processes contribute to their differences in performance on this task, and predict similar differences in other tasks requiring, as this one does, sustained attention to a dynamic visual display and self-produced movements variably towards and away from a goal.     

In defense of the possibilism–actualism distinction

Philosophical Studies - In Modal Logic as Metaphysics, Timothy Williamson claims that the possibilism–actualism (P–A) distinction is badly muddled. In its place, he introduces a...     

Spatial memory and monitoring of hidden items through spatial displacements by chimpanzees (Pan troglodytes)

This study examined chimpanzee (Pan troglodytes) short-term memory for food location in near space. In Experiments 1 and 2, either 1 or 2 items (chocolate pieces) were hidden in an array of 3 or 5 containers that either remained stationary or were rotated 180 degrees or 360 degrees. When the array remained stationary, the chimpanzees remembered both item locations. When arrays were rotated, however, chimpanzees found only 1 item. In Experiment 3, 2 items were hidden in an array of 7 cups. Both items were found at levels significantly better than chance. Ninety percent of errors were made after the 1st item was found, and errors reflected memory failure rather than a failure of inhibitory control.