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Biomedical subjects

A H Baker

Publications and source records attributed to A H Baker.

14 recordsLinked to original sources

Lateral imbalance of the visual field affects conjugate lateral eye movement: an experimental demonstration.

Baker (1989) reported a serendipitous observation: When subjects were seated closer to the left than to the right wall of the room, conjugate lateral eye movement (CLEM) following a question involving shared eye gaze was predominantly toward the right. This study sought to verify this observation. In the asymmetrical condition, half the subjects sat next to the right wall and the other half sat next to the left wall. In the symmetrical condition, each subject was seated equidistantly from the right and left walls. More CLEM was found in asymmetrical conditions in the direction toward the center of the wall the subject faced, a finding consistent with the earlier formulations and findings of the sensory-tonic theory of perception.

Adult

The relationship of undershooting (anticipation) error in space localization to spatial dimension and spatial category width.

In this study I explored whether the degree of anticipation/habituation (undershooting/overshooting) varies with the dimension to be localized, when the method of adjustment is used in space localization. In this study, undershooting occurred for both the vertical (Group 1) and the horizontal (Group 2) dimensions, but was significant only for verticality. The magnitude of undershooting observed for verticality was significantly greater than that for horizontality. A secondary issue regarding the possible relationship between spatial category width and undershooting/overshooting was examined. It was hypothesized that greater degree of spatial category width would be associated with greater undershooting. The opposite was found: Spatial category width was negatively related to undershooting. Finally, within each group, very high consistency of magnitude of spatial category width was observed (rs greater than .90), despite the fact that spatial category width showed shrinkage over the course of the study.

Cognition

Kinesthetic aftereffect and augmenting/reducing: a two-session procedure, and hence identification of stimulus-governed subjects, is contraindicated.

A few of the recent researchers of kinesthetic aftereffect (KAE) as an index of augmenting/reducing have continued to employ a two-session procedure. Findings that have accrued in the past decade indicate (a) The first administration of KAE is a reliable (internally consistent) and valid index of augmenting-reducing; (b) there are carry-over effects from the first to the second administration that bias the second session's preinduction scores; (c) KAE scores from sessions after the first do not relate to first-session scores (low retest reliability) and do not measure augmenting/reducing; and (d) unless special procedures are undertaken to avoid using the biased second- (or later-) session preinduction scores, a KAE procedure involving more than one session is contraindicated. When we reached a similar conclusion earlier (Baker et al., 1974), Petrie (1974) disagreed, arguing that a two-session procedure was needed to identify and eliminate an atypical subgroup, the "stimulus governed." The case for determining which subjects are stimulus-governed is assessed and found wanting. Except in special circumstances, a one-session KAE procedure, in which all preinduction trials precede the first exposure to aftereffect induction, is indicated.

Adult

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.

Humans

Menstrual cycle affects kinesthetic aftereffect, an index of personality and perceptual style.

Research suggests that kinesthetic aftereffect (KAE) scores reflect status on a postulated stimulus intensity modulation (SIM) mechanism that damps down subjective stimulus intensity for some (reducing) and increases it for others (augmenting). Such a mechanism would help account for empirically observed individual differences in such behaviors as pain tolerance, sensory deprivation reactivity, and stimulation seeking. It was hypothesized and confirmed in three adult female samples that KAE varies curvilinearly over the menstrual cycle: Greater KAE reduction occurs at the cycle's beginning and end. Neither tiredness, oral contraception, medication, attention, nor social expectations can explain this finding. Of the behaviors studied in the KAE literature, only five are also encompassed by the menstrual cycle literature. Four of these (antisocial behavior, acute schizophrenic episodes, accidents, and activity level) show similar curvilinearity over the cycle. We hypothesize that cyclical variation in the SIM mechanism mediates the curvilinear pattern observed for both these four behaviors and KAE.

Adult

The accuracy of the simultaneous binaural bithermal test in the diagnosis of acoustic neuroma.

Forty-three patients with a surgically confirmed unilateral acoustic neuroma were studied preoperatively with both alternate and simultaneous binaural bithermal caloric tests using horizontal lead electronystagmography. Twenty-four patients had a significant reduced vestibular response on the side of the tumor utilizing the alternate binaural bithermal calorization of Fitzgerald-Hallpike. The addition of the simultaneous binaural bithermal stimulus improved the diagnostic accuracy of caloric testing from 56% to 86%. The simultaneous test was of particular accuracy in diagnosing the inferior vestibular nerve neuroma. The simultaneous stimulus, which adds only six and one-half minutes to overall testing time, is felt to be a valuable adjunct to the alternate test of Fitzgerald-Hallpike.

Adult

Kinesthetic aftereffect and personality: a case study of issues involved in construct validation.

Kinesthetic Aftereffect (KAE), once a promising personality index, has been abandoned by many investigators because of poor retest reliability and intermittent validity. In challenging this current consensus, we argue that (a) first-session KAE is valid; (b) poor retest reliability simply reflects later-session bias; (c) hence, multisession studies should not be used to assess validity without taking this bias into account. Those recent studies which failed to support KAE validity were each multisession in design. If our bias contention is correct, these studies should be ignored, and the claim of intermittent validity is thus rebutted. Reanalysis of the most recent major multisession, nonsupportive validity study indicates (a) Session 1 validity, (b) later-session bias, and (c) later-session valdiity when multisession scores are combined to avoid bias. Thus, KAE validly measures personality.

Humans

The frequency of suicide attempts: a retrospective approach applied to college students.

Suicide attempt rates are usually reported as an annual statistic. However, annual rates may underestimate the cumulative prevalence of attempters since they ignore people whose attempts occurred in years other than the one examined. The authors studied the prevalence of suicide attempters over several years through data gathered from retrospective reports of college students. They found that 15% of the total sample studied (N=293) reported having attempted suicide at one time. This unexpectedly high rate suggests that suicidal behavior is a serious problem among college students and underlines the need for further retrospective studies of the prevalence of suicide attempters.

Female