Is vision metric? Comment on Lappin and Love (1992)

In a recent paper, Lappin and Love (1992) showed that depth judgments, based on planar motion of a stimulus, are remarkably precise. This led them to the conclusion that perception of planar motion allows acquiring metric information about visual space. We show, however, that Lappin and Love’s stimuli contained 2-D cues in the frontal plane that could subserve the subjecfs judgments.     

The suppressing effect of chlorpromazine treatment on alimentary-social differentiation in amygdala dogs

Experiments were performed on dogs with bilateral electrolytic damage of dorso-medial amygdala. Before the operation dogs were trained in alimentary-social reward differentiation. It consisted in conditioning of instrumental responses of either right or left foreleg to two different tones respectively. Chlorpromazine was injected intramuscularly in 1,5 mg/kg dose during four consecutive days, beginning at third to fifth week after the operation. Amygdala damage produced significant deterioration of the instrumental performance both reinforced by food and by social-sensory rewards. Chlorpromazine produced further dramatic decrease of performance of both responses. It was concluded that chlorpromazine exerts a suppressing effect on motivated behavior reinforced by positive rewards in amygdala dogs. As the effect of chlorpromazine and medial amygdalar damage are summated it may be suggested that the deficit of medial amygdala neurons impairs similar neurochemical mechanisms, (probably dopaminergic and α-adrenergic transmission) as does chlorpromazine.     

Can relativism be reconciled with realism and causalism?

This paper deals with two fundamental assumptions of the Strong programme in the sociology of knowledge and the theoretical (im) possibility of their co‐existence with the general relativist tendency of this programme. The first assumption is the realist thesis introduced into the Strong programme through the materialist presupposition that sense experience is reliable and humans are able to learn about the regularities of the non‐social world in order to survive. The second assumption is the causal principle. Arguments developed in this paper lead to the conclusion that neither realism nor causalism can be reconciled with relativism. In both cases inconsistency is brought about by a tension between scientific perspective and relativism, between an external approach aiming at objective, universal, and causal explanation of what is studied, on the one hand, and the internal, relativist and reflexive, hermeneutical understanding of the human, on the other hand. The belief that the sociology of knowledge can be at the same time scientific, like the natural sciences, and relativist, like certain philosophies but not the natural sciences, is not sufficiently justified in the Strong programme.     

On linear classifications under varying choice probabilities

The paper deals with certain problems connected with the assumption that choice probabilities p_s(x, y) depend on the subject s. A set of postulates is given, which implies the existence of sequences of “classification standards”, i.e., sequences {z_j} such that whenever we have 0 < p_s0(x, z_i) < 1 for some s₀ and i, then p_s(z_i+k, x) = p_s(x, z_i?k) = 1 for all s, and k ≥ 1. Elements of any such sequence {z_j} can serve as boundaries between successive categories of classification based on the following rule: Assign x to jth category if you feel it is “to the right” of z_j and “to the left” of z_j+1. Under the condition stated above this rule is unambiguous, and the resulting classification has the property that every element is assigned to one of the two neighboring categories, regardless who performs the classification.Next, the postulates are enriched so as to imply the existence of “tightest” among such sequences {z_j}, hence leading to a classification with largest number of categories.