Expertise effects in memory recall: comment on Vicente and Wang (1998).

K. J. Vicente and J. H. Wang (1998) proposed a "constraint attunement hypothesis" to explain the large effects of domain expertise on memory recall observed in a number of task domains. They claimed to have found serious defects in alternative explanations of these effects, which their theory overcomes. Reexamination of the evidence shows that their theory is not novel but has been anticipated by those they criticized and that other current published theories of the phenomena do not have the defects that Vicente and Wang attributed to them. Vicente and Wang's views reflect underlying differences about (a) emphasis on performance versus process in psychology and (b) how theories and empirical knowledge interact and progress with the development of a science.

Expert chess memory: revisiting the chunking hypothesis.

After reviewing the relevant theory on chess expertise, this paper re-examines experimentally the finding of Chase and Simon (1973a) that the differences in ability of chess players at different skill levels to copy and to recall positions are attributable to the experts' storage of thousands of chunks (patterned clusters of pieces) in long-term memory. Despite important differences in the experimental apparatus, the data of the present experiments regarding latencies and chess relations between successively placed pieces are highly correlated with those of Chase and Simon. We conclude that the two-second inter-chunk interval used to define chunk boundaries is robust, and that chunks have psychological reality. We discuss the possible reasons why Masters in our new study used substantially larger chunks than the Master of the 1973 study, and extend the chunking theory to take account of the evidence for large retrieval structures (templates) in long-term memory.

Templates in chess memory: a mechanism for recalling several boards.

This paper addresses empirically and theoretically a question derived from the chunking theory of memory (Chase & Simon, 1973a, 1973b): To what extent is skilled chess memory limited by the size of short-term memory (about seven chunks)? This question is addressed first with an experiment where subjects, ranking from class A players to grandmasters, are asked to recall up to five positions presented during 5 s each. Results show a decline of percentage of recall with additional boards, but also show that expert players recall more pieces than is predicted by the chunking theory in its original form. A second experiment shows that longer latencies between the presentation of boards facilitate recall. In a third experiment, a Chessmaster gradually increases the number of boards he can reproduce with higher than 70% average accuracy to nine, replacing as many as 160 pieces correctly. To account for the results of these experiments, a revision of the Chase-Simon theory is proposed. It is suggested that chess players, like experts in other recall tasks, use long-term memory retrieval structures (Chase & Ericsson, 1982) or templates in addition to chunks in short-term memory to store information rapidly.

Recall of random and distorted chess positions: implications for the theory of expertise.

This paper explores the question, important to the theory of expert performance, of the nature and number of chunks that chess experts hold in memory. It examines how memory contents determine players' abilities to reconstruct (1) positions from games, (2) positions distorted in various ways, and (3) random positions. Comparison of a computer simulation with a human experiment supports the usual estimate that chess Masters store some 50,000 chunks in memory. The observed impairment of recall when positions are modified by mirror image reflection implies that each chunk represents a specific pattern of pieces in specific location. A good account of the results of the experiments is given by the template theory proposed by Gobet and Simon (in press) as an extension of Chase and Simon's (1973b) initial chunking proposal, and in agreement with other recent proposals for modification of the chunking theory (Richman, Staszewski, & Simon, 1995) as applied to various recall tasks.

Cue recognition and cue elaboration in learning from examples.

This paper describes the processes used by students to learn from worked-out examples and by working through problems. Evidence is derived from protocols of students learning secondary school mathematics and physics. The students acquired knowledge from the examples in the form of productions (condition-->action): first discovering conditions under which the actions are appropriate and then elaborating the conditions to enhance efficiency. Students devoted most of their attention to the condition side of the productions. Subsequently, they generalized the productions for broader application and acquired specialized productions for special problem classes.

Recall of rapidly presented random chess positions is a function of skill.

A widely cited result asserts that experts' superiority over novices in recalling meaningful material from their domain of expertise vanishes when they are confronted with random material. A review of recent chess experiments in which random positions served as control material (presentation time between 3 and 10 sec) shows, however, that strong players generally maintain some superiority over weak players even with random positions, although the relative difference between skill levels is much smaller than with game positions. The implications of this finding for expertise in chess are discussed and the question of the recall of random material in other domains is raised.

Simulation of expert memory using EPAM IV.

EPAM is a theory of the processes of human perception and memory, first programmed for a computer by E. A. Feigenbaum in 1959, that has shown an excellent fit to experimental data from a wide variety of psychological tasks. Over the years, it has been progressively extended to new domains without essential change in its central mechanisms. This article examines EPAM IV, a version extended to account for expert memory, especially the work in recent years by Chase and Ericsson (1981, 1982) and Staszewski (1988a, 1988b, 1990). EPAM IV has also been adapted to deal with numerous other short-term and long-term memory tasks, which will be reported elsewhere. The main modifications of EPAM that are relevant to the serial recall task examined in this article are a schema in long-term memory (called a retrieval structure) created by the expert's learning and the addition of an associative search process in long-term memory. These new components operate in close interaction with the other EPAM structures to match the observed behavior. EPAM IV reproduces all of the phenomena explained previously by EPAM III and in addition gives an accurate detailed account of the performance (studied by Staszewski) of an expert recalling long sequences of digits. The theory substantially revises, improves, and extends Chase and Simon's earlier "chunking" explanation of expert memory.

A mechanism for social selection and successful altruism.

Within the framework of neo-Darwinism, with its focus on fitness, it has been hard to account for altruism behavior that reduces the fitness of the altruist but increases average fitness in society. Many population biologists argue that, except for altruism to close relatives, human behavior that appears to be altruistic amounts to reciprocal altruism, behavior undertaken with an expectation of reciprocation, hence incurring no net cost to fitness. Herein is proposed a simple and robust mechanism, based on human docility and bounded rationality that can account for the evolutionary success of genuinely altruistic behavior. Because docility-receptivity to social influence-contributes greatly to fitness in the human species, it will be positively selected. As a consequence, society can impose a "tax" on the gross benefits gained by individuals from docility by inducing docile individuals to engage in altruistic behaviors. Limits on rationality in the face of environmental complexity prevent the individual from avoiding this "tax." An upper bound is imposed on altruism by the condition that there must remain a net fitness advantage for docile behavior after the cost to the individual of altruism has been deducted.

Studying scientific discovery by computer simulation.

BACON is a computer program that simulates some of the important processes of scientific discovery. When provided with data about temperatures before and after two substances are brought into contact, the program infers the concept of specific heat and arrives at Black's law of temperature equilibrium. Comparison of BACON's discovery methods with historical records of Black's work casts light on the relation between data-driven and theory-driven discovery.

The rural-urban population balance again.

"This paper explores further the economics of the rural-urban population balance, using the method of comparative statics. It confirms the results obtained by Artle and his colleagues, using the method of excess demand analysis, thus demonstrating that the two methods of analysis are equivalent in this context. In analysing the effects of non-neutral technological change upon urbanization, it is essential to distinguish between the total elasticity of demand for manufactured products, and the income and (compensated) price elasticities, respectively. The empirical plausibility is questioned of assuming that total demand for the aggregate of manufactured goods is elastic."