A. Harvey Baker

How accurate are women's estimates of date of onset of next menses?

Abstract Because of individual differences in Occurrence of ovulation and patterns of hormonal secretions, one would usually prefer to measure locus in the menstrual cycle using physiological assessment procedures. But such methods are time consuming and costly. When exploring a new domain for possible relations to the menstrual cycle, it would be cost effective to use the simpler procedure of having each women verbally estimate date of onset of next menses. The accuracy of such estimates was studied in two college age samples. Estimated number of days until next onset correlated highly with actual number of days, as verified by follow-up (r = 0.90). As a group, women neither under- nor overestimated number of days. The precision with which these judgments were made was reasonably high. In sum, when a group of women are followed for one cycle, the average accuracy is very high, certainly high enough to support use of such verbal reports for certain scientific purposes.

Visual asymmetry biases assessment of conjugate lateral eye movement

This paper reports a serendipitous observation. Prior research led to the expectation that equal numbers of right-movers and left-movers would be found in a study aimed at exploring individual differences in conjugate lateral eye movement. Instead, most subjects were found to be right-movers (p <.001). Scrutiny of the study’s procedures revealed that the subjects had inadvertently been placed next to the left wall of the room. Apparently asymmetrical visual stimulation during the assessment of conjugate lateral eye movement can affect the right versus left directionality of such movement, an interpretation consistent with earlier formulations and findings of the sensory-tonic theory of perception.

Apparent arm length with active vs. passive touch

Two experiments tested the hypothesis that apparent length of the partially outstretched arm (1) shrinks when the fingertips of the passive hand are touched by an object and (2) increases when the fingertips of the hand touch an external, stationary object. Experiment 1 involved nominal judgments regarding which of two outstretched arms, each involved in a different type of contact, was longer. Experiment 2 used a single outstretched arm and involved interval scale measurements. Results, which supported the hypothesis, were interpreted as reflecting effects of the directionality of action (away from the person who is actively directed toward touching an object vs. toward the person who is passive and being touched) involved in the hand-object contact.

Kinesthetic aftereffect: one phenomenon or two?

Kinesthetic (figural) aftereffect (KAE) studies almost always involve an aftereffect-inducing stimulus (I) that is wider or narrower than the test stimulus (T). I ≠ T has been presumed to be a necessary condition for KAE’s occurrence. We contend that this, in part, reflects researchers’ failure to use an appropriate control condition (here, I = T): Effects due to size difference and effects due to induction per se have been confounded. In a new study, which explored the relationships of I > T and I < T relative to an I = T control condition, I < T did, but I > T surprisingly did not, differ from I = T. Two different KAE phenomena apparently exist: an aftereffect induction phenomenon and a contrast effect. There is also an effect for the I = T condition of decrease in width judgments.

Misinterpretation of Instructions in an Aftereffect Task

Some subjects in studies of kinesthetic aftereffect erroneously believe the task is to show the width of the aftereffect inducing rather than the standard stimulus. Although such subjects may be encountered rarely, the errors they make are very large. Precautionary steps are indicated.

Age changes in apparent arm length

To assess whether an earlier finding—viz., that overestimation of apparent head size was maximal in early childhood and decreased with increase in age (Wapner, 1959)—is generalizable to other body parts, the present study assessed age change in judged length of the outstretched arm with Ss ranging from 7 through 18 years. All age groups underestimated arm length, with the magnitude of underestimation decreasing with increase in age—a pattern opposite to that found for head size. Although the age changes observed for both judged head size and arm length can be described as reflecting an increase in accuracy, such a formulation in terms of accuracy cannot explain why young children maximally overestimate head size and maximally underestimate arm length. It is suggested that future research should explore the possibility that these observed differences reflect differential organization of the body schema at different levels of development.

Age Change in Kinesthetic Aftereffect in Young Adults

Prior research indicated that young adults show larger kinesthetic aftereffect than do the elderly. The present study explored whether, within a young adult sample, kinesthetic aftereffects vary with age. A significant correlation was observed between kinesthetic aftereffect scores and age for both males and females: Larger aftereffects were observed with increase in age. This finding confirms informal observations reported by Koehler and Dinnerstein (1947), the pioneer researchers into kinesthetic aftereffects.

Kinesthetic Aftereffects and Individual Differences in Carryover effects

Prior research has found that individual differences in long-lasting carryover effects occur in the kinesthetic aftereffect (KAE) task both when the aftereffect inducing block was wider (I greater than T) and narrower (I less than T) than the test block. The present study found that such individual differences in carryover effects also occur for a no-aftereffect-induction control condition, with a magnitude approximately equal to that found for the I greater than T and I less than KAE variants used here.Abstract Prior research has found that individual differences in long-lasting carryover effects occur in the kinesthetic aftereffect (KAE) task both when the after-effect inducing block was wider (I > T) and narrower (I T and I < T KAE variants used here.