Right-hemisphere interactions in picture-word processing

The processing of pictures was investigated in three experiments which eliminated the response effects involved in naming. When a categorization task was used, clear advantages in response latency and accuracy were observed for left visual-field (LVF) presentations. This was in contrast to previous investigations which have used a naming task and which have reported right visual-field (RVF) advantages. When a distracting word was added to the display, the pattern of influence also changed from that reported previously. The use of naming tasks has indicated predominantly left-hemisphere effects, with demonstrations of interactions between pictures and words in the RVF. With a categorization task in Experiment 2, however, the only effective words were those related in meaning to the picture, and only when they were projected to the right hemisphere. The third experiment confirmed the LVF advantage for picture processing with masked displays, but found no reliable asymmetry with unmasked presentations. The pattern of semantic facilitation was also confirmed with the masked displays, but when the mask was removed an inhibition effect replaced the facilitation effect. These effects are interpreted as indicating that picture recognition is localized within the right cerebral hemisphere. It is suggested that the facilitating effect of related words is restricted to the left hemisphere because it is an effect upon recognition processes, whereas the inhibition effect reflects response competition. It is also suggested that previous reports of left-hemisphere interference effects are due to effects of response competition in naming tasks.     

Learning to program in LISP

We have gathered protocols of subjects in their first 30 hours of learning LISP. The processes by which subjects write LISP functions to meet problem specifications has been modeled in a simulation program called GRAPES (Goal Restricted Production System). The GRAPES system embodies the goal-restricted architecture for production systems as specified in the ACT* theory (Anderson, 1983). We compare our simulation to human protocols on a number of problems. GRAPES simulates the top-down, depth-first flow of control exhibited by subjects and produces code very similar to subject code. Special attention is given to modeling student solutions by analogy, how students learn from doing, and how failures of working memory affect the course of problem-solving. Of major concern is the process by which GRAPES compiles operators in solving one problem to facilitate the solution of later problems.     

Eye-fixation patterns during reading confirm theories of language comprehension

Eye-movement patterns during reading are consistent with proposition-by-proposition models of speech comprehension. (1) Fixation times are least affected by word length at ends of clauses: this confirms the theory based on the study of speech comprehension that, at such points, attention is directed inward to text integration. (2) Fixation time for words at the end of clauses is longer for canonical sequences which conform to the pattern, “N-V-N = actor-action-object”; this confirms the view that complete semantic integration of such sequences is routinely delayed until their completion. A two-variable model based on principles of exhaustive visual search and speech comprehension accounts for 80% of the fixation durations in a sample paragraph from Just and Carpenter (1980) and Thibodeou, Just ond Carpenter (1982). This comprehension-based model compares favorably with their models constructed within a production-system framework. This result clarifies the relationship between reading and listening.     

Computing with connections in visual recognition of origami objects

This paper summarizes our initial foray in tackling Artificial Intelligence problems using a connectionist approach. The particular task chosen was the visual recognition of objects in the Origami world as defined by. The two major questions answered were how to construct a connectionist network to represent and recognize projected line drawings of Origami objects and what advantages such an approach would have. The structure of the resulting connectionist network can be described as a hierarchy of parameter or feature spaces with each node in each of the feature spaces representing a hypothesis about the possible existence of a specific geometric feature of an Origami object. The dynamic behavior of the network is a form of iterative refinement or relaxation whose major characteristic is to prefer more globally interesting interpretations of the input over locally pleasing ones. Examples from the implementation illustrate the system's ability to deal with forms of noise, occlusion and missing information. Other benefits are an inherently parallel approach to vision, limitation of explicit ordering of the search involved in matching model to instance and the elimination of backtracking due to the sharing of partial results as the search progresses. Extensions and problems are also discussed.     

Self-behavior focus of attention as a determinant of children's and adults' attributions to stories with negative outcomes

This study explored characteristics of attributions made to negative outcome stories by fourth-, sixth-, and eighth-graders as well as college students. All subjects read six stories representing three stories for each of two levels (self-focus and behavior-focus) of a within-subjects factor, Focus of Attention. Dependent measures included both spontaneous attributions and structured evaluations on the dimensions of causality, responsibility, blame, and deservingness. Analyses of the spontaneous attributions indicated that Self attributions were more frequently given than either Behavior or External attributions to both self- and behavior-focus stories. The experimental manipulation of internal focus produced matching attributions only in the self manipulation. Analyses of the structured evaluations indicated that subjects used Cause and Responsibility interchangeably but only eighth-graders and college students differentiated Cause/Responsibility from both Blame and Deservingness. Cause/Responsibility was also shown to have more salience in the behavior-than self-focus stories. It is suggested that a verbal focus on behavior has limited effects in producing defensive, self-distanced attributions but may heighten evaluations of Cause/Responsibility. In addition, behavior-focus seems to have little effect on the development of the psychologically more complex evaluations of blame and deservingness.