Estimation of true score and error variance for tests under various equivalence assumptions

Maximum-likelihood estimators of true score variance and error variance for mental tests are derived for six different models of equivalent measurements. Statistical properties of the estimators are examined. Main emphasis is placed upon essentially-equivalent measurements. A statistical criterion for this type of measurement is given. The solution of the comparatively simple maximum-likelihood equations is effected by means of a rapid Newton-Raphson procedure. Two different initial estimators are considered and their relative merits in terms of second moments evaluated. Four numerical examples are appended by way of illustration.Paper read at the Mathematical Psychology Meeting, August 28, 1968, at Stanford, Calfornia.This research was supported in part by the National Institute of Child Health and Human Development, Research Grant 1 P01 HD01762.     

INTENTIONAL COMMUNICATION IN THE TREE DRAWING TEST

K onttinen , R. & K arila , A. Intentional communication in the tree drawing test. Scand. J. Psychol ., 1969, 10 , 129–136—One way in which relationships between drawing variables and personality traits may be conceived is by interpreting the drawing as intentional communication. Some implications of this proposition were tested. Five formal variables of tree drawings were studied: angularity, size, form level, shading, and pressure. Only angularity can unambiguously be given a communication interpretation; but the other variables, too, may perhaps be used for intentional communication.     

Testing significance of differences between two chi-squares

This paper presents a way to test the difference between twoX ²'s. The test requires evaluating the difference with respect to theT _m (x) Bessel function. Included is a table of the 5 percent and 1 percent points for the Bessel function with degrees of freedom up to 100.This investigation was supported by National Science Foundation Grant Number GE 9846.     

Book reviews

Animal Discrimination Learning. Edited by R. M. Gilbert and N. S. Sutherland. London: Academic Press. 1969. Pp. xvi + 501. 1358.

Luce, R. D. and Tukey, J. W. (1964). Simultaneous conjoint measurement: a new type of fundamental measurement. J. math. Psychol. I, 1-27.

Discrimination Learning. By D. A. Riley. Boston: Allyn and Bacon Inc. 1968. Pp. 172. Paperback 21s.

Annual Review of Psychology. Vol. 20. Palo Alto: Annual Reviews Inc. 1969. Pp. ix + 544. $9.00.

Cutaneous Sensation. By David Sinclair. London: Oxford University Press. 1967. Pp. xii + 306. 63s.

Modelling of Thinking and the Mind.. By N. M. Amosov. Translated by L. Finegold. New York: Spartan Books. London: Macmillan. 11967. Pp. xiii + 192.

The Mind of Mnemonist. By A. R. Luria. London: Jonathan Cape. 1969. Pp. xi + 160. 25s.

Determinants of Infant Behaviour IV. Edited by B. M. Foss. London: Methuen. 1969. Pp. 303. £3 10s.

Brain and Behaviour. Volumes 1-4. Edited by Karl Pribram. Harmondsworth: Penguin Books Ltd. 1969. Pp. 496 +573 + 523 + 524. 12s. 6d. per volume.     

Prior stimulation and the perception of causality

An attempt was made to discover whether, in conditions similar to those of Michotte, the number of causal responses given by subjects was influenced by stimulation during the period just before the main experiment. Time-intervals between the arrival of object A and the departure of object B were systematically varied within the range 60 to 390 msec. Those who had earlier been exposed to shorter time-intervals (60 to 210 msec.) gave fewer causal responses than those who had been exposed to longer ones (150 to 300 msec. and 240 to 390 msec.). A possible explanation is offered in terms of the modification of existing “schemata.”     

Comparison of Life Styles of Honors,Non-Honors Women

This study compares the after-college life styles of participants in a college honors program with a control group of women who were not college honors students in order to determine the effects of a college honors program on life roles after college. The 81 participants of this study represent 93 percent of women who participated as college freshmen and during their ensuing college years in a study to determine the effects of an honors program on students while still in college. The results of the current study—the first contact with the women since they left college—illustrates the differences between the present life roles of these two groups of women in the areas of family involvement, careers, education, and community participation. The results show significant differences between honors and non-honors subjects in career-orientation and in commitment to their field of study and to the university at which they studied.     

Effects of uncertain warning signals on reaction time

Three experiments were conducted in an attempt to assess the effectiveness of a warning signal in reducing reaction time when (1) the signal to respond (danger signal) follows the warning signal with a probability less than 1.0, and (2) the interval between warning and danger signals (W-D interval) is variable. The required response was the depression of a foot pedal, as in automobile braking. It was determined that probabilistic warning information could be effective if observers made use of the W-D interval to prepare to make the response required by the danger signal. It was noted, however, that observers differed considerably in their tendency to do this. A model was proposed for describing different response strategies.     

Frequency discrimination near masked threshold

Frequency DLs (Δf) at 1000 Hz were obtained in quiet and under masking conditions similar to those used in pitch-shift experiments, narrow-band noise at levels of 60, 80, and 100 dB SPL and tones at 15 dB SL or less. The Δfs were obtained by means of a tracking task in which the S controlled the input voltage to a frequency modulator. Characteristic improvement was seen when Δf was plotted as a function of sensation level. However, noise level itself was a significant factor, with more intense noise resulting in larger Δfs for tones of equal sensation level re masked threshold. This departure from previous findings is attributed to the signal and noise levels used, although the possibility exists that it is due to the use of modulated tones.     

On the rate of stimulus occlusion during intermittent retinal stimulation

The CFF was determined with three sectored disks, each of which corresponded to one of the three rings in a Helmholtz disk. The fusion frequency is identical for all three rings of a Helmholtz disk but with the three sectored disks it was found that the rate of stimulus occlusion is a major factor in determining the CFF. It was tentatively concluded that the effect was not a consequence of different stimulus wave-forms. The phenomenon appears to have been reported late in the last century.