“Impossible figures” and interpretations of polyhedral figures

The concept “impossible figure” is analyzed by formalizing the interpretations of a polyhedral figure by an observer, and defining several types of inconsistency in such interpretations. Tests for these inconsistencies are developed using simple graph theory, and a sufficient condition is established for the feasibility of an interpretation. Finally, techniques are derived for the automatic construction of usual or unusual multibar figures.     

Pavlovian conditioned stimulus effects upon instrumental choice behavior are reinforcer specific

In a transfer-of-control experiment with rats, Pavlovian CSs were tested for the specificity of their effects. The instrumental behavior consisted of a discriminative, conditional two-lever choice task in which qualitatively different appetitive reinforcers were contingent upon the two correct choices. In a Pavlovian phase, subjects experienced conditioning to establish either a CS⁺ or CS^? for one reinforcer or a CS⁺ or CS^? for the other reinforcer. Finally, in a test, these CSs were presented when there was the opportunity to make choice responses. The CS⁺s evoked choices of the lever which had eventuated in the reinforcer that had served as the Pavlovian US, while the CS^?s showed only a slight tendency to evoke the other choice responses. When the CSs were compounded with the original S^Ds, the CS⁺s had little effect upon the vigor of responding while the CS^?s reduced the vigor of responding to the S^D for the reinforcer that was the same as the US used in establishing the CS^?. The results are discussed in terms of associative mediational theory and the reinforcer specificity of Pavlovian conditioned excitation and inhibition.     

Towards a new philosophy of education: Extending the conversational metaphor for thinking

Recently, feminists like Jane Roland-Martin, Elizabeth Young-Bruehl, and others have advocated a conversational metaphor for thinking and rationality, and our image of the rational person. Elizabeth Young-Bruehl refers to thinking as a constant interconnecting of representations of experiences and an extension of how we hear ourselves and others. There are numerous disadvantages to thinking about thinking as a conversation.We think there are difficulties in accepting the current formulation of the conversational metaphor without question. First, there is danger that we will lose important dialectical connections like that between the self and society. Second, the conversational metaphor alone cannot fully express the way conversations are constructed. We will want to take up the notion of narrative as a metaphor for thinking advocated by Susan Bordo, Alasdair MacIntyre, Jerome Bruner, and others, including Mary Belenky and her colleagues.Eventually, we want to champion narrative and the dramatic narrative of culture as a metaphor for thinking that involves such expressions as sights, insights, silences, as well as sounds, moments of mood and poetic moments. The dramatic narrative provides the structural possibilities needed to criticize certain kinds of conversations, in order to talk about the relations of public and private, self and society and most importantly, about the drama of our lives within and without.The dramatic narrative for thinking helps dispel the dangerous dualisms of mind and body that not even conversation or narration alone can banish, and allows us to frame questions about education that do not require us to separate mind from body. The dramatic narrative metaphor for thinking lets us show who we are, act out what we think, and reconstruct rationality to reflect what many women, and some men, do.     

Repetition,cuing, and state-dependent memory

Two experiments examined the effects of several types of repetition on state-dependent memory for conceptually categorized words. In both experiments, compatibility between pharmacological states at encoding and at retrieval facilitated the uncued recall of nonrepeated categories but had no appreciable effect on the recall of words within recalled categories. In both experiments, compatibility between encoding/retrieval states failed to facilitate the uncued recall of repeated categories li.e., categories whose names and/or exemplars were presented at least twice, in a constant or variable order, and with substantial spacing between successive presentations). And again, in both experiments, the level of uncued recall was higher for repeated than for nonrepeated categories, irrespective of the compatibility or incompatibility of encoding/retrieval states. These findings, together with other relevant observations reported in the literature, suggest that repetition in general, and repetition of category names in particular, influences recall in much the same ways as does explicit cuing with category names: It enhances the accessibility of higher order units, as reflected in uncued category recall, and it diminishes to the extent to which access to these units is state dependent.     

Affective and cognitive mediators of reactions to spatial invasions

At a crosswalk on a busy street, a confederate, sketching a drawing or not, stood close or far from a pedestrian for 10 sec before the street light indicated “Walk.” In the first study, pedestrians were given the opportunity to subsequently help this confederate or another accomplice by calling attention to a dropped pen. In the second study, crossing speeds were timed and pedestrians were asked to record their mood and reactions to “another pedestrian,” who happened to be the confederate. These studies tested and found evidence for both cognitive and arousal explanations of reactions to spatial invasions. Cognitive and attributional theories imply that characteristics of the invader are important mediators of reactions to the invasion. The close nonartist was judged to be more inappropriate, produced faster escape speeds, and was helped less than the close artist or the far confederates. Arousal explanations imply that any invasion produces a generalized reaction which would be unrelated to characteristics of the invader. The other accomplice was helped less when the subject had been invaded and this reduction in helping was unaffected by the artist manipulation. These findings suggest a general arousal response to any invasion with a subsequent reliance on cognitive interpretations.