Perceptual Categorization: Connectionist Modelling and Decision Rules

Although it is currently popular to model human associative learning using connectionist networks, the mechanism by which their output activations are converted to probabilities of response has received relatively little attention. Several possible models of this decision process are considered here, including a simple ratio rule, a simple difference rule, their exponential versions, and a winner-take-all network. Two categorization experiments that attempt to dissociate these models are reported. Analogues of the experiments were presented to a single-layer, feed-forward, delta-rule network. Only the exponential ratio rule and the winner-take-all architecture, acting on the networks' output activations that corresponded to responses available on test, were capable of fully predicting the mean response results. In addition, unlike the exponential ratio rule, the winner-take-all model has the potential to predict latencies. Further studies will be required to determine whether latencies produced under more stringent conditions conform to the model's predictions.     

Narrative and Metaphysical Ambition: On Being “in Christ”

This article addresses some of the confusion regarding the role of metaphysical claims in narrative theology. Proponents and critics of narrative theology alike wonder at the ambiguous place of metaphysical speech about God as an objective reality. This essay enters the conversation through the side door of soteriology. Rather than focusing on the relationship between narrative and metaphysics or narrative and analogy or narrative and first‐order theological claims, I examine what sort of metaphysical statements are required to make the Christian claim that human beings are “in Christ” intelligible as a soteriological reality. I argue that the Christian grammar itself assumes a Christology with a certain kind of metaphysical ambition without which Christianity lapses into incoherence. To make this case, I show that David Kelsey's “narrative identity” Christology in Eccentric Existence lacks the metaphysical statements necessary to uphold his conviction that human beings are “in Christ.” A comparison with T. F. Torrance and the Book of Hebrews reveals that when narrative circumvents metaphysical statements about the incarnate Son, soteriological claims lack coherence and the biblical narrative itself is distorted by a false metaphysic. Thus, metaphysical claims internal to the narrative of Jesus are necessary to tell the story of God faithfully. In this way, narrative is the expression of a theological metaphysics.     

Adaptation to displacing prisms in human infants.

This research reports a first attempt to study adaptation to laterally displacing prisms in human infants of ages six to ten months. Twenty infants were tested over four days under conditions similar to those used in adult adaptation studies. Evidence was found of vigorous adaptation when infants were exposed to base-right prisms under conditions of active exposure. Detailed consideration is given to the conditions and methods of studying adaptation in infants and implications for adult studies.