The use of latent class models for assessing prerequisite relations and transference among traits

This paper presents a strategy for pairwise assessment which may be used to evaluate the nature of both prerequisite and transference relations existing among a set of traits. This strategy is appropriate for use both within a confirmatory context, in which an attempt is made to establish the validity of some specified set of relations among traits, as well as within an exploratory context, in which a search is made for unconjectured prerequisite and transference relations existing between pairs of traits. Both uses of this strategy are based on a variety of latent class models which are representative of various possible relational states existing between pairs of traits. Thus, the nature of trait relations may be investigated through the use of statistical assessments of both absolute and relative fit attained by these models. An application is presented to exemplify how this strategy may be used within the exploratory context.The author is obliged to Clifford Clogg, C. Mitchell, Dayton, and William Schafer for helpful comments made regarding a previous draft of this paper as well as to Mary Papageorgiou who provided access to the data which was considered in this study.     

Making and correcting errors during sentence comprehension: Eye movements in the analysis of structurally ambiguous sentences

Eye movements were recorded as subjects read sentences containing temporary structural ambiguities. In accord with the garden-path theory of sentence comprehension, shorter reading times were found for sentences conforming to certain independently motivated parsing strategies (late closure and minimal attachment) than for comparable sentences which violate these strategies. Further, longer fixation durations were associated with the very first fixation in the region of the sentence which disambiguated the sentence, suggesting that the human sentence-parsing mechanism operates in a rather systematic fashion, immediately computing the structural consequences of fixated material for the analysis of preceding material. The pattern of regressive eye movements did not conform to the view that the parsing mechanism automatically returns to the beginning of the sentence to revise an incorrect analysis of linguistic material nor did it support the view that the parsing mechanism systematically backtracks through the sentence until the source of the erroneous analysis is located. Rather, the pattern of regressions indicated that the parsing mechanism typically engages in selective reanalysis, exploiting whatever information it has available about the type of error it has committed to guide its reanalysis attempts. Finally, it is emphasized that an understanding of the parser's revision procedures is essential to an explanation of why certain linguistic structures cannot be successfully parsed by humans.     

Deviation from hierarchical structure in recall: Is there an “optimal” structure?

Past research has suggested that proportionally more superordinate than sub-ordinate propositions are recalled from expository texts, following a hierarchical analysis of the text structure. Since free recall has typically followed this hierarchical pattern, several researchers have assumed that the related memory structures are isomorphic to the text structure. However, few of these studies have examined how individual differences and text structure interact to affect free recall. In two experiments, the assumption of hierarchical patterns of children's recall of expository text was tested. In Experiment 1, high- and average-ability fourth graders (9 years old) were asked to read and recall a passage. Experiment 2 was a replication and extension of Experiment 1. In this experiment, fourth and sixth graders (9 and 11 years old) read and recalled a different passage. The combined results of both experiments support the notion that there is probably no one optimal hierarchical structure for storage and retrieval of expository text.     

QUANTUM PHYSICS AND FREEDOM IN A WHITEHEADIAN PERSPECTIVE

This paper attempts to demonstrate the critical significance of early advances in quantum physics for Alfred North Whiteheads development of the categories of his metaphysics and to illustrate the capacity of his system to serve as a bridge between the sciences and the humanities by relating specific Whiteheadian categories to concrete microphysical behavior with special reference to the notion of freedom.     

Information flow in the brain: Computer requirements (A tutorial)

This paper covers mathematical, statistical, and experimental design considerations needed to design a computer system for EEG data acquisition, spectrum, and cross-spectrum analyses. A tutorial approach is used in which no formal proofs are offered. Conclusions are stated simply and in summary fashion, without justifying arguments. References to formal works are given. Conclusions about system design are discussed. Frequently encountered design issues are mentioned with various alternatives.     

Recognition models evaluated: A commentary on Keren and Baggen

In a recent paper (1981), Keren and Baggen proposed two new models for alphanumeric confusion data, based on Tversky’s (1977) feature model of similarity, and compared them with Luce’s (1963) biased choice model. On the basis of their data, they concluded that, although the choice model fit slightly better, their models were to be preferred on grounds of parsimony and interpretability. It is shown here that both of these models are special cases of the Luce model, so that the general Luce model will necessarily fit better. This leads to considerable reinterpretation of Keren and Baggen’s conclusions. Finally, better methods of estimating parameters and evaluating goodness-of-fit are suggested, taking advantage of this relation between the models.     

Direct and continuous measurement of relational learning in human pavlovian conditioning

Three experiments were conducted employing a continuous measure of conditional stimulus/unconditional stimulus (CS/US) contingencies as perceived by the subject (i.e., subjective contingency or SC). It is argued that direct measurement of relational learning, as indexed by SC, can lead to a better understanding of Pavlovian conditioning processes. The first two experiments applied this approach to a methodologic controversy, raising the debate from a procedure-based argument to testing what the subject actually learns about CS/US relationships. While the issue was not resolved, testable hypotheses for future research were generated from the data. The third experiment contrasted the contingency stimulus-stimulus (S-S) account of Pavlovian conditioning with an earlier stimulus-response (S-R) continguity-reinforcement account. In this experiment, both SC and skin resistance were measured. Evidence for the existence of both cognitive-propositional and response-learning processes in conditioning was obtained.     

Power functions of loudness magnitude estimations and auditory brainstem evoked responses

The correspondence between subjective and neural response to change in acoustic intensity was considered by deriving power functions from subjective loudness estimations and from the amplitude and latency of auditory brainstem evoked response components (BER). Thirty-six subjects provided loudness magnitude estimations of 2-sec trains of positive polarity click stimuli, 20/sec, at intensity levels ranging from 55 to 90 dB in 5-dB steps. The loudness power function yielded an exponent of .48. With longer trains of the same click stimuli, the exponents of BER latency measures ranged from -.14 for wave I to -.03 for later waves. The exponents of BER amplitude-intensity functions ranged from .40 to .19. Although these exponents tended to be larger than exponents previously reported, they were all lower than the exponent derived from the subjective loudness estimates, and a clear correspondence between the exponents of the loudness and BER component intensity functions was not found.