William G. Chase

Perception in chess

Abstract This paper develops a technique for isolating and studying the perceptual structures that chess players perceive. Three chess players of varying strength — from master to novice — were confronted with two tasks: (1) A perception task, where the player reproduces a chess position in plain view, and (2) de Groots (1965) short-term recall task, where the player reproduces a chess position after viewing it for 5 sec. The successive glances at the position in the perceptual task and long pauses in the memory task were used to segment the structures in the reconstruction protocol. The size and nature of these structures were then analyzed as a function of chess skill.

Skill in Chess

As genetics needs its model organisms, its Drosophila and Neurospora, so psychology needs standard task environments around which knowledge and understanding can cumulate. Chess has proved to be an excellent model environment for this purpose. About a decade ago in the pages of this journal, one of us, with Allen Newell, described the progress that had been made up to that time in using information-processing models and the techniques of computer simulation to explain human problem-solving processes. (Simon et al, 1964). A part of our article was devoted to a theory of the processes that expert chess players use in discovering checkmating combinations (Simon et al, 1962), a theory that was subsequently developed further, embodied in a running computer program, mater, and subjected to additional empirical testing. (Baylor et al, 1966).

Skill and Working Memory

Publisher Summary This chapter focuses on the important role of retrieval structures as working memory states. The working memory has at least the following components: (1) short-term memory, which provides direct and virtually immediate access to very recent or attended knowledge states; (2) intermediate-term memory, the task-specific retrieval structure in long-term memory, which provides direct and relatively fast access to knowledge states; and (3) context, which contains structures for controlling the flow of processing within the current task and provides relatively fast and direct access to knowledge structures relevant to the current task and context. The auditory and visual–spatial buffers are important components of working memory.

Spatial Representations of Taxi Drivers

The issue that guides the present research programme concerns the representation of large-scale environments, environments that are too large to be perceived from a single vantage point. In particular, this paper is concerned with the effects of experience on the representation of a large urban environment, and how experience is manipulated by the use of expert and novice taxi drivers.

Perceptual coding strategies in the formation and verification of descriptions.

Three experiments were carried out to study the “picture coding” process implicit both in making up descriptions of pictures and in verifying descriptions against pictures. In the first experiment, Ss were asked simply to describe pictures of one object above another; some pictures were symmetrical vertically and some were not. In the other two experiments, other Ss were timed as they judged whether sentences likeStar isn’t below line were true or false of such pictures. According to the results, Ss comply to three ordered “preference” rules in describing the two objects, rules that are conditional on characteristics of the picture and demands of the task. Furthermore, Ss in the verification task comply to the same three rules when they view and encode the picturebefore they read the sentence to be verified, but to only one of the rules when they view the pictureafter they read the sentence. The results also reconfirm two recently proposed models for the process of verifying sentences against pictures.

Parallel processing in item recognition

It is shown that in Sternberg’s item recognition task Ss need not make a judgment of the absolute size or color of the test item before comparing it with memory. However, Ss do use size or color information, when possible, to reduce long reaction times for large memory loads. The results suggest that Ss are able to scan memory for form in parallel with testing for gross stimulus features, like size or color. This finding has important implications for sequential two-stage theories of attention.

The equivalence of target and nontarget processing in visual search

A comparison of a forced-choice visual search task with an item recognition task did not support Neisser’s (1967) hypothesis of a preattentive stage that processes targets and nontargets differentially. In the forced-choice condition, Ss indicated which of two items in a visual display was a target; in item recognition, Ss determined whether or not the single item in the visual display was a target. The size of the memorized set of possible targets was varied from one to six items for both tasks. Latencies increased linearly with memory set size in both conditions; the slopes for forced choice and item recognition were 41.8 and 27.9 msec per item, respectively. The ratio of 1.38 between the two slopes was well fit by Sternberg’s (1967) item recognition model, which predicts a ratio of 1.50.

Individual Differences in Memory Span

One series of experiments examined the correlation between memory span and the speed of symbol manipulation in short-term memory, and another experiment analyzed the effects of extended practice on memory span. In the first study, most of the estimates of processing speed did not correlate with memory span, and it was concluded that short-term memory capacity is not determined by the speed of symbol manipulation in short term memory. In the second study, memory span greatly increased with extended practice, but this increase was due to the acquisition of a mnemonic system. Short-term memory capacity was unaffected by practice.

Maps and Navigation: Introduction

Most researchers suggest that peoples’ internal representations of their environment have many map-like properties. As a person moves about in the environment, invariant properties of the environment are preserved in the mental map, such as the relative location of objects with respect to each other, while the location of the person in the mental map is continually updated. A mental map has important “emergent properties”, such as triangualation. If the locations of A relative to B and B relative to C are both known, then the location of A relative to C can be derived. Mental maps can be used to derive new spatial information, such as what something looks like from a different perspective. Mental maps can be used to plan movements, such as what route to take to a destination, what direction to turn at a choice point, where landmarks are located, and so on. Many researchers have even argued that maps have evolved as the most “natural” way to represent spatial information because they are compatible with the way people think. In other words, maps supposedly correspond to the abstract, symbolic and schematic spatial representations of the human mind.