Judgments Of Position Research Articles

Ascending spinal axons that signal the position of the hindlimbs under static conditions: location and receptor input.

Psychophysical experiments have shown that signals from slowly adapting subcutaneous receptors are used to sense limb position under static conditions (i.e., when the joints are stationary). The ascending collaterals of the slowly adapting primary sensory neurons supplying the deep tissues of the hindlimb do not project to the brain via the fasciculus gracilis. In experiments on cats, we have found a population of axons in the lateral fasciculus that signal the position of the ipsilateral hindlimb with a slowly adapting discharge. In the lower thoracic cord these fibers lie between the spinocervical tract and the ventral roots. Although plentiful in the lower thoracic cord, they are sparse or absent below L3. In addition, a few position signaling axons with crossed input were found in the ventral part of the lateral white matter and in the ventral columns. Since the clinical evidence suggests that the spinal pathway for position sense is uncrossed, we propose that information used for conscious judgments of limb position when the joints are stationary initially ascends via the dorsal columns and then relays to the lateral fasciculus on the same side. These slowly adapting signals also may be used to judge limb position when the joints are moving. To determine whether this slowly adapting discharge originates from muscle or joint receptors, the tendons crossing the ankle joint were exposed but left in continuity and then pulled on while the joint was stationary. In this way individual lateral fascicular axons that signaled ankle flexion, extension, abduction or adduction could be shown to receive a strong excitatory input from muscle receptors. After the muscle tendons crossing the ankle joint were cut, tract fibers signaling ankle flexion, extension, abduction or adduction could no longer be found in this portion of the spinal white matter. Axons signaling clockwise or counterclockwise twist of the ankle were reduced in number but a few were still present. These results suggest that muscle receptors provide the predominant signal used to sense ankle flexion, extension, abduction and adduction and that receptors in articular tissues may signal ankle twist.

Evaluative meaning and temporal coding

Previous research has demonstrated that evaluative meaning is related to recall accuracy; pleasant items are recalled more accurately than less pleasant items. The present experiment was conducted to determine whether evaluative meaning was also related to temporal coding accuracy. Subjects saw three separate homogeneous lists, one pleasant, one neutral, and one unpleasant. The results demonstrated that: (1) pleasant words were recalled more accurately than neutral or unpleasant words, (2) evaluative meaning had no influence on the accuracy of temporal position judgments, and (3) evaluative meaning had no influence on subjects’ confidence in their temporal position judgments.

Perceptual Isolation and Position Judgment

Prior findings showed that perceptual isolation of one item in a low similarity list facilitated total-list learning of order. A reconstruction procedure in which a spatial framework was provided during test trials, was used in those studies. In order to extend the generality of those findings, a position judgment procedure was used in the present experiments; subjects estimated ordinal position of each item following each of six study trials in which the 12 CVC items were displayed in a fixed sequence. That to-be-learned sequence was defined temporally in Experiment 1, which failed to corroborate prior findings, but was presented simultaneously and spatially in Experiment 2, which did. Interpretation focused on conditions necessary for finding homologous effects for supplied anchors and isolating stimuli, suggesting that absolute judgment can be regarded as a special case of serial learning, and vice versa, and on circumstances allowing utilization of an isolating stimulus as an organizational device.

Britain's place in the world

There is no better known judgement of Britain's post-war international position than Dean Acheson's view that: “Britain has lost an Empire and has not yet found a role”. Acheson's words have echoed and reechoed through the corridors of Whitehall because they seem so true, capturing not only the uncertainty about Britain's role but the decline in her international status. The judgement has attracted the attention of scholars as well as officials and politicians, as was demonstrated in a recent number of this journal when Christopher Hill wrote about “Britain's Elusive Role in World Politics”. Hill warned against the dangers of seeing foreign policy making in terms of “role”, arguing that it suppressed contradictions in the interests of a predominant image, and encouraged the illusion that a state could plough a lone furrow in pursuit of its particular interests. “Unfortunately”, he argued, “the quest for a unique role, like the pursuit of the Holy Grail, is a fatal distraction to politicians with responsibility”, and later he warned of “role” degenerating into “the medium of limp metaphor and rhetoric”.

Durational cues to phrase boundaries: foot lengthening versus phrase‐final lengthening

The prosodic importance of the foot or interstress interval is assessed by experiments in which subjects are asked to judge the phrase structure of sentences such as “Pat or Antonia and Dave will help.” In such sentences a syntactic boundary may occur in the middle rather than at the end of a foot. Lengthening the whole foot produced identical perceptual results to lengthening the phrase‐final vowel and subsequent pause by the same total amount. However, simply lengthening that part of the foot that occured after the phrase boundary was not as effective at influencing listeners' judgments as was lengthening only the phrase‐final vowel (and pause). Both the interstress interval and the duration of syllables within the foot influence listeners' judgments of phrase boundary position.

Major axes of stimulus figures do not account for dot displacements

Wenderoth's (1978) comments on my paper (Hartley, 1978) contain a serious oversight that taints the interpretation offered. Briefly, I showed observers dots placed within a square or an incom­ plete square on a piece of paper. They were asked to reproduce the position of the dot on a second, blank piece of paper. Glossing over details, the find­ ing was that the reproduced position was displaced from the veridical position toward the location of the surrounding lines. There was no displacement toward axes of bilateral symmetry, that is, major axes. In a task requiring that a rod be set to the gravita­ tional vertical, Beh and Wenderoth (1972), Beh, Wenderoth, and Purcell (1971), and Wenderoth (1973) had found that settings were displaced toward real lines of a surrounding figure or toward its axes of symmetry, whichever was nearer the rod. This would compensate for an illusory displacement away from the axes, termed a direct or repulsion effect. I noted that the dot displacements I observed did not agree with the results of the rod-setting experi­ ments. Wenderoth challenges this, asserting that the observed displacements of dot positions are in perfect agreement with the rod-setting results. Wenderoth's argument runs as follows: The observers position the dot closer to the real lines because its apparent position has been displaced away from the axis of symmetry. His argument is sufficient to explain the displacements of dots that were 4 em from the nearest real line and 2 em from the axis of symmetry. The argument founders, however, since extension of the rod-setting results would predict that dots placed 2 cm from the real line and 4 em from the axis of symmetry would be displaced away from the real line and toward the axis of symmetry (a direct effect of the real line). Instead, the reproductions were toward the real line. Thus, the results for dot positioning do not, as I stated correctly, agree with those for rod-setting. On the pretext of pointing out findings that I over­ looked in interpreting my results, Wenderoth then presents an extended recapitulation of two articles that became available after the submission of my paper (Wenderoth, 1977; Wenderoth & Beh, 1977). Wenderoth provides a convenient summary of these important works, including one that may not be familiar to readers in the United States (Wenderoth, 1977). Although the discussion of these works is presented as a critique of my paper, it is encouraging to note that the conclusions Wenderoth draws from the research they report agree closely with those I offered. First, it is clear that the major-axis hypoth­ esis-the notion that displacements can be described as a function of the relation between the test stimu­ lus and the axes of symmetry of the inducing figure­ is inadequate as a descriptive model. The results from my three-sided square and Wenderoth and Beh's (1977) incomplete squares establish this. Thus, no explanatory version of the model need be developed. Second, explanatory models based on lateral inhibi­ tion between lines of the inducing figure (or perhaps on spatial frequency analysis) seem to be attractive alternatives. My hypothesis that loci of neural inter­ actions may account for the nonveridical perceptions is quite similar to the lateral inhibition model offered by Wenderoth and Beh (1977) (also see O'Toole & Wenderoth, 1977). Both are loose, informal models that suggest the outlines of an adequate theory. Finally, Wenderoth argues that dot-position methods do not necessarily bear on any theory of orientation judgments. The theories in question are not theories of orientation judgments, but rather theories of the effects of stimulus figures on nearby perceptual space. There is no a priori reason to suppose that either judgments of dot position or judgments of orientation would not provide an adequate test of theoretical predictions. In fact, dot judgments may provide sensitive probes of the microstructure of illusions, as Wenderoth's recent research on the Poggendorf illusion demonstrates (Wenderoth, Beh, & White, 1978; Wenderoth, White, & Beh, 1978). In summary, the results I reported previously cannot be explained away as being in perfect agree­ ment with the major-axis hypothesis. Moreover, taken together with results reported by Wenderoth and Beh (1977), they provide converging evidence for the inadequacy of the hypothesis that certain non­ veridical perceptions are related in any simple way to the axes of bilateral symmetry of surrounding figures.

Oculomotor Factors In Visual Perceptual Response Efficiency

The preprogramming of saccadic eye movements is examined by studying the pattern of oculomotor sequences while scanning a visual display. The effects of interference employing a backward masking paradigm on the oculomotor response as well as on position judgment and stimulus identification are examined. Data indicate that the motor programming of an ocular saccade is linked to the perceptual analysis of target position and cannot be set in motion with an impairment in perceptual localization.

Coding left and right.

The present study compared the processing of direction for up and down arrows and for left and right arrows in visual displays. Experiment 1 demonstrated that it is more difficult to deal with left and right than with up and down when the two directions must be discriminated but not when they must simply be oriented to. Experiments 2 and 3 showed that telling left from right is harder regardless of whether the responses are manual or verbal. Experiment 4 showed that left-right discriminations take longer than up-down discriminations for judgments of position as well as direction. In Experiment 5 it was found that position information can intrude on direction judgments both within a dimension (e.g., a left arrow to the left of fixation is judged faster than a left arrow to the right of fixation) and across dimensions (e.g., judging vertically positioned left and right arrows is more difficult than judging horizontally positioned left and right arrows). There was indirect evidence in these experiments that although the spatial codes for up and down are symmetrical, the codes for left and right may be less so; this in turn could account for the greater difficulty of discriminating left from right.

Perceptual Localization, Feature Identification and Ocular Motor Factors in Scanning a Visual Display

The preprogramming of saccadic eye movements is examined by studying the pattern of ocular-motor sequences while scanning a visual display. The effects of interference employing a backward masking paradigm on the ocular-motor response as well as on position judgment and stimulus identification are examined. Data indicates that the motor programming of an ocular saccade is linked to the perceptual analysis of target position and cannot be set in motion with an impairment in perceptual localization.

An evaluation of measures used in studying temporal codes for words within a list

Experiment I evaluated three response measures which have been used in the study of temporal codes for memories. The three measures were judgments of recency, position, and lag. Earlier studies had suggested that subjects could make valid position judgments without being able to make valid lag judgments. This finding was confirmed; although the subjects learned a great deal about temporal ordering when asked to use lag judgments, the lag judgments per se were very poorly related to true lag. Transfer from lag judgments to recency judgments and from position judgments to recency judgments was essentially 100%. Transfer from recency judgments and lag judgments to position judgments was partial. It appeared that recency judgments can be mediated with little knowledge of the absolute position in the study list held by one or both of the items in the recency test pairs. Experiment II demonstrated that, under certain circumstances, lag judgments could be valid. The results raised the possibility that when lag judgments are not valid the magnitude of the lag judgments may be influenced by certain contrast effects. The data also suggested that serial learning can be directly implicated in recency judgments, hence, in temporal coding.

Judging pictorial and linguistic aspects of space

A test is made of the notion that Stroop-like interference and facilitation effects arise from two different sources, one pictorial and the other linguistic. It was hypothesized that when irrelevant information is pictorial, it interferes with a pictorial code used in the processing of the relevant information; when it is linguistic, it interferes with a linguistic code. The experiment required subjects to respond to (1) the meaning of a spatial word, t2) its absolute position, or (3) its relative position, while attempting to ignore the two irrelevant dimensions of the display. It was found that word meaning and absolute position information affected the speed of relative position judgments in an additive manner. No other Stroop-like effects were found. The results supported the hypothesis under test. It was concluded that the existence of different kinds of Stroop effect must be accommodated by current models of the phenomenon.

Perception of clicks in music

Subjects were asked to judge the position of a click which occurred during a short piece of music. Clicks were on average judged to be later than their actual position for a slow tune, but almost no bias in the judgement of click position was found for a fast tune. The click and the music were presented through headphones to different ears, and the clicks were judged to be significantly later if they arrived at the right ear rather than the left. There was also a significant tendency for clicks to be attracted to phrase boundaries in the music. These last two results are similar to those from experiments with a click during speech, but the late judgements of a click in music contrasts with the tendency for early judgements of a click in speech.

Cardiac deceleration as an indicator of correct performance.

A within-subjects experiment involving 10 subjects was performed to examine the relationship between the accuracy of judgment of position and cardiac deceleration. The results supported the hypothesis that accurate (correct) performance is accompanied by greater cardiac deceleration than inaccurate performance for those subjects (9 out of 10) who exhibited cardiac deceleration to stimulus onset. The data indicated, however, that the relationship varied with time. Part of this variability appears related to the initial exploratory behavior in which subjects engaged and later reported during the post-experiment interview.

Field dependency and perceptual cues in perception of two trapezoid illusions.

40 males and 40 females rated as field-independent or field-dependent on the Group Embedded-figures Test were tested on two dynamic trapezoid illusions and made position judgments of static trapezoidal targets. Field-independent subjects reported more illusory experiences on the perception of rotation of an oscillating target than the perception of oscillation of a rotating target. The opposite was true for field-dependent subjects. Position judgments were related to the latter illusion but not the former. There was strong evidence of a differential use of perceptual cues for the two dependent groups.

Uterine perforation in connection with vacuum aspiration for legal abortion.

ABSTRACTThe incidence of uterine perforation complicating vacuum aspiration for legal termination of first trimester pregnancy varies widely. Nineteen cases of perforation (0.64%) occurred 1967–1974 at the Department of Obstetrics and Gynecology, Karolinska Sjukhuset, Sweden. These cases were analysed and compared with 71 other reported uterine perforations. The dilator, suction curette and uterine sound were about equally the instrument responsible for perforation. The dilatation of the cervix is a critical point of the operation. In 22% the lesion was observed in the cervix‐isthmus. If this procedure could be replaced by administration of prostaglandins the number of perforations might be reduced. Correct judgement of uterine position and size immediately prior to operation appears to be of utmost importance.

Interaural time vs. interaural intensity in a lateralization paradigm

In a two-interval lateralization procedure, observers judged whether a stimulus presented with an interaural intensive difference was right or left in lateral space of the same stimulus presented with only an interaural temporal difference. The stimuli were pure tones of 500 and 1,000 Hz and 1,000-Hz low-pass noise. All stimuli were presented at both 65 and 55 dB SPL. For each of several values of interaural time (ranging from 0 to 1,000 microsec across all stimuli), a function was determined which related proportion of “right” relative position judgments to the value of the interaural intensive difference. The intercepts of these functions indicated that a progressively smaller amount of interaural intensive difference was required for the two stimuli to occupy a similar lateral location as the interaural temporal difference was increased. The slopes of the function suggested that the images associated with larger values of the interaural temporal differences are less distinct and blend together more than the images associated with small values of the temporal difference. Thus, the procedure provided a means for comparing the lateral location of images produced by interaural differences of time and intensity.

Teachers' Predictions of the Social Position and Speaking Competence of Stuttering Students

Teachers' predictions of their students' judgments of the social position and speaking competence of stuttering boys in their classes were compared with the judgments made by the children. Teachers' predictions did not differ significantly from the children’s actual judgments, regardless of the grade level (third or sixth) or stuttering severity (mild or moderate and severe) of the stuttering boys. Reasons for unfavorable judgments by the children were usually similar to those mentioned by the teachers in their predictions. Several implications of these results for school personnel are discussed.

Three Processes Which Occur during Adaptation to Transformation of the Visual Field

Changes in visually guided responses, including spatial judgments of object or limb position, which result from optical transformation of visual input are usually referred to as adaptation. The purpose of this paper is to show that the response changes observed in adaptation can be conceptualized as resulting from at least three distinct components—behavioral compensation, sensory adaptation, and visual shift. Data from a series of experiments show the nature of the interaction of behavioral compensation and sensory adaptation. Implications of this latter finding for intermanual transfer are discussed.

On oculomotor programming and perception

During the period of latency (200 msec) of the response to a visual stimulus, and before oculomotor output occurs, a preparatory state of the oculomotor system develops. If a second stimulus is delivered during this latency period, the plasticity of the motor commands ( i.e., possibility of deviating the response toward the new target) appears to become progressively reduced when the interval between stimuli increases. The plasticity also depends on the spatial relations between the initial and the replacing target: a saccade may be shortened and/or reoriented into another direction, but is never lengthened. Concerning the relationship between motor and perceptual responses initiated, several competitive hypotheses can be proposed. On the one hand, the oculomotor triggering may proceed through lower (subcortical?) paths, perceptual responses requiring a cortical elaboration. On the other hand, the same information processing can produce the motor as well the perceptual localization responses. A backward masking paradigm is used as a method for selectively disturbing the most elaborate or time-consuming response processes, thereby enabling the different, usually associated outputs, to be separated. Brief exposure of a small target (a letter) in some part of the peripheral visual field is followed, after a variable delay (10–250 msec), by a large masking pattern: when the delay is short, the perception of the target can thus be prevented. Experimental data show that, in various conditions, backward masking occurs both for adjusted ocular saccadic responses and for overt judgments of target position. However, these two (motor and perceptual) localization tasks are more resistant to the masking effect than target identification, which is hindered for longer delays.

Contextual associations and memory for serial position.

Three experiments used a combination list-discrimination and positionjudgment task to investigate the role of contextual factors in incidental memory for serial position. In Experiment I, two temporally denned lists were presented; in Experiments II and III, there were four and three lists, respectively. Following presentation of the lists, 5s made judgments of the list membership and within-list position of test words. Judgment frequencies revealed: (a) a temporal factor, affecting list identification and producing strong primacy and recency effects; and (b) an effect of position, when more than two lists were used, such that a word assigned to an incorrect list still tended to be placed in the correct within-list position. When the retention interval was lengthened the effects of primacy and within-list position were unaffected, while the effect of recency was reduced. An interpretatio n is offered which assumes judgments of serial position are based on contextual associations.