Changeover behavior and preference in concurrent schedules

Pigeons were trained on a multiple schedule of reinforcement in which separate concurrent schedules occurred in each of two components. Key pecking was reinforced with milo. During one component, a variable-interval 40-s schedule was concurrent with a variable-interval 20-s schedule; during the other component, a variable-interval 40-s schedule was concurrent with a variable-interval 80-s schedule. During probe tests, the stimuli correlated with the two variable-interval 40-s schedules were presented simultaneously to assess preference, measured by the relative response rates to the two stimuli. In Experiment 1, the concurrently available variable-interval 20-s schedule operated normally; that is, reinforcer availability was not signaled. Following this baseline training, relative response rate during the probes favored the variable-interval 40-s alternative that had been paired with the lower valued schedule (i.e., with the variable-interval 80-s schedule). In Experiment 2, a signal for reinforcer availability was added to the high-value alternative (i.e., to the variable-interval 20-s schedule), thus reducing the rate of key pecking maintained by that schedule but leaving the reinforcement rate unchanged. Following that baseline training, relative response rates during probes favored the variable-interval 40-s alternative that had been paired with the higher valued schedule. The reversal in the pattern of preference implies that the pattern of changeover behavior established during training, and not reinforcement rate, determined the preference patterns obtained on the probe tests.     

Electrodermal lability in anxiety disorders

Twenty-eight anxiety patients, aged below 50 years, were diagnosed according to DSM-III-R criteria (panic disorder with and without agoraphobia, generalised anxiety disorder, and anxiety disorder not otherwise specified). The patients were characterised by high levels of state and trait anxiety and neuroticism, compared with the controls. However, there were no differences between patients and controls in electrodermal habituation rate, non-specific activity, or skin resistance level. When the patients were divided into electrodermally labile and stable subjects, significant differences were found between patients and controls in both electrodermal activity and Eysenck's personality dimensions. The labile patients were more introverted and attained higher psychoticism scores than either the stable patients or controls. Duration of anxiety symptoms removed the difference found in extroversion, but not in any other variable. The results are discussed in relation to the utility of electrodermal measurements in validation of diagnostic entities. It is concluded, that from the psychophysiological point of view, anxiety disorders may be examined within a dimensional framework.     

Decompositions and biplots in three-way correspondence analysis

In this paper correspondence analysis for three-way contingency tables is presented using three-way generalisations of the singular value decomposition. It is shown that in combination with Lancaster's (1951) additive decomposition of interactions in three-way tables, a detailed analysis is possible of the deviations from independence. Finally, biplots are shown to produce powerful graphical representations of the results from three-way correspondence analyses. An example from child development is used to illustrate the theoretical developments.     

Contrary-to-duty obligations

We investigate under what conditions contrary-to-duty (CTD) structures lacking temporal and action elements can be given a coherent reading. We argue, contrary to some recent proposals, that CTD is not an instance of defeasible reasoning, and that methods of nonmonotonic logics are inadequate since they are unable to distinguish between defeasibility and violation of primary obligations. We propose a semantic framework based on the idea that primary and CTD obligations are obligations of different kinds: a CTD obligation pertains to, or pre-supposes, a certain context in which a primary obligation is already violated. This framework is presented initially as an extension of Standard Deontic Logic (SDL), a normal modal logic of type KD, and is illustrated by application to a series of examples. The concluding section is concerned with some resemblances between CTD and defeasible reasoning. We show first that the SDL-based framework contains a flaw and must be adjusted. A discussion of possible adjustments, including an alternative treatment in terms of a preference-based semantics, reveals difficulties that are reminiscent of problems in defeasible reasoning and intensional accounts of defeasible conditionals.     

General education,cultural diversity,and identity

The issue of this paper is cultural plurality as a problem for public, general education and for (personal) identity. In order to examine this question, one needs to be clear about the meaning of the concepts of general education, on the one hand, and cultural diversity on the other. In the first section, we will fix the meaning of these concepts. A conceptual distinction between cultural diversity and cultural pluralism will be introduced. In the second section, it will be argued that open pluralism can only be maintained if there is a basic common culture apart from the cultural diversity that pluralism affirms. Therefore, there is yet an indispensable role for general education in an open, pluralistic society. In the third section we will look at two metaphors that give an opposite significance to the relation between identity and diversity: the conversational metaphor and the food metaphor mishmash. The final section expands on the conversational metaphor by way of an exposition of Ricoeur's hermeneutics of the self. It supplies us with a promising concept of identity that is not in complete opposition to diversity.     

Is community necessary? Quasi-philosophical ruminations

In responding to and examining Mary Anne Raywid's (1989) adoption of community building as an aim for schools, I survey a number of types of communities, including recreational, intentional and language communities. In considering all these communities, I try to show both the power of communities in our personal lives and some idea of why we might be of two minds about promoting community as an ideal in the modern world and in schools in particular.     

Who is Afraid of Figure of Speech?

Aristotle's illustrations of the fallacy of Figure of Speech (or Form of Expression) are none too convincing. They are tied to Aristotle's theory of categories and to peculiarities of Greek grammar that fail to hold appeal for a contemporary readership. Yet, upon closer inspection, Figure of Speech shows many points of contact with views and problems that inhabit 20th-century analytical philosophy. In the paper, some Aristotelian examples will be analyzed to gain a better understanding of this fallacy. The case of the Third Man argument and some modern cases lend plausibility to the claim that Figure of Speech is of more interest as a type of fallacy than has generally been assumed. Finally, a case is made for the view that Figure of Speech, though listed among the fallacies dependent upon language, is not properly classified as a fallacy of ambiguity. More likely, it should be looked upon as a type of non sequitur. This has important consequences for the profile of dialogue associated with this fallacy.     

When More is Better than Less; Three Theories of Psychosis—Projection, Double Bind, and Possession

Three psychological theories of psychosis are described, each of which has standing in psychiatry. Defined by the terms projection, double bind, and possession, they initially appear to have little or nothing in common to explain psychosis, but converge at four points: (1) A high degree of anxiety precipitated by a dilemma or conflict perceived to be unsolvable by the person; (2) the anxiety triggers a shift from one thought or motive in the direction of its opposite, because the original was believed too antagonistic to the wishes of significant others; (3) the opposite, in order to remain opposite, requires that the original thought or motive be forgotten, (4) a singular means to produce and reinforce forgetting is the interposition of psychiatric symptoms. In psychiatry today treatment would fit more consistently with the three theories taken as a whole rather than any one, and a rationale for this viewpoint is elaborated.     

EFFECTS OF EXPLICIT TIMING ON MATHEMATICS PROBLEM COMPLETION RATES IN AFRICAN-AMERICAN THIRD-GRADE ELEMENTARY STUDENTS

A multiple baseline design was used to evaluate the effects of Van Houten and Thompson's (1976) explicit timing procedure on problem completion rates and accuracy levels in African-American third-grade students. During the explicit timing phase, students were told that they were being timed and were instructed to circle the last problem completed at each 1-min interval. Results showed that the explicit timing procedure increased problem completion rates. A decreasing trend in percentage of problems correct also occurred. Exploratory data analysis suggested that decreases in accuracy were not caused by the explicit timing procedure and did not occur in students who had attained high levels of preintervention accuracy. Discussion focuses on recommendations for educators who wish to use timing procedures to increase students' rates of accurate responding.