PROCTOR: An on-line student evaluation and monitoring system for use with PSI format courses

PROCTOR, an on-line interactive system for student evaluation and monitoring in courses employing the PSI format, is described. This system involves a tester module that assumes many of the routine managerial duties traditionally assigned to the student proctor, such as quiz administration and scoring, performance feedback, and complete record keeping. Also, PROCTOR includes a multipurpose editor that allows an instructor to enter, examine, or modify any information in the disk files accessed by the tester. Factors related to the implementation and use of this system are considered, and its advantages for management, quality control, and staffing in PSI courses are discussed.     

The detection of anisochrony in monaural and interaural sound sequences

Nakao and Axelrod (1976) and van Noorden (1975) showed that the threshold for discriminating an anisochronous duple rhythm (a series of clicks with a temporal offset on every other one) from an isochronous rhythm (no offset) is poorer when the clicks are presented alternately to the two ears than when they are presented to the same ears. Van Noorden reported that the difference between the thresholds in the alternating and nonalternating conditions varied with the tempo of the sequence. Nakao and Axelrod found invariance of this threshold difference with sequence speed. According to our quantification of temporal processing of interaural sequences, the latter result should be expected. We carried out five psychophysical experiments to establish interaural and monaural discrimination between isochronous and anisochronous rhythms. Across experiments, base time intervals of 60–720 msec were spanned. The main result was that we replicated the poorer discrimination for interaural sequences. This deterioration in discrimination was the same for all sequence speeds. It was also the case that the thresholds were almost constant up to a sound repetition rate of about 3 per second, but increased linearly with slower rates. This result supports evidence in the literature that temporal processing of sequences faster than about 3–4 sounds per second differs from temporal processing of slower sequences.     

Recognition of faces in the presence of two-dimensional sinusoidal masks

The spatial frequencies most relied upon by subjects in a recall task for face recognition were found to lie in the midfrequency range. A linear systems analysis model cannot account for these masking data in terms of retinocortical processing limitations alone. In order to account for the greater disruption of the face recognition task by masks in the range of 2.2 cycles/deg, the existence of unequal filtering of spatial frequency components must be recognized. This unequal filtering may occur either during memory deposition or retrieval of the input stimulus in the recall task or at any time in between.     

Simple statistical methods for scalogram analysis

Simple statistical methods are developed to test whether coefficients of reproducibility, of homogeneity, or of consistency differ significantly from what can be expected if responses to different items are statistically independent. Simple methods are also developed for estimating the variance of coefficients of reproducibility when it is not assumed that responses to different items are independent. These estimates are used to test whether a coefficient differs significantly from any prescribed value, and also to obtain confidence intervals for these coefficients. The rationale for the measurement of reproducibility is also discussed.This research was carried out at the Statistical Research Center, University of Chicago, under sponsorship of the Statistics Branch, Office of Naval Research, and of the Social Science Research Committee, University of Chicago. Reproduction in whole or in part is permitted for any purpose of the United States Government. The author is indebted to Jacob Gewirtz for some very helpful comments.This paper is dedicated to Professor Jacob Marschak on the occasion of his sixtieth birthday, July 23, 1958.     

A proposed index of the conformity of one sociometric measurement to another

An index is proposed to measure the extent of agreement of the data of a sociometric test with another test made at an earlier time or on another test criterion. The index is used to define an index of concordancebetween the two tests. It is shown how the index may be used for either individuals or groups. Tests of the hypothesis that agreement is random are given for all cases and applied to an example.Work done under the sponsorship of the Office of Naval Research.     

Reduction of the “psychological refractory period”

The usual increase in reaction time which occurs when a reaction stimulus is preceded by one irrelevant stimulus was-reduced 30% by preceding the latter with a second irrelevant stimulus at certain critical intervals between stimuli. The interaction between the irrelevant stimuli, as measured by reaction time, has a different time course than the interaction implicit in tlte “psychological refractory period”.     

Variable Names and Constant Names in Wittgenstein's Tractatus

In this paper, I argue that the Tractatus classifies names into constant names and variable names. A variable name, via the application of the existential quantifier against the background of picturing, picks out and denotes an unspecified object from the range of objects of the form shown by the relevant variable. A constant name labels an object picked out from a scope of the existential quantifier. I also refute two types of attempts to argue that the Tractarian relation between a name and its meaning is not realist, and to explain why it is more reasonable to hold that it is.