Aging persons' estimates of vehicular motion.

Estimated arrival times of moving autos were examined in relation to viewer age, gender, motion trajectory, and velocity. Direct push-button judgments were compared with verbal estimates derived from velocity and distance, which were based on assumptions that perceivers compute arrival time from perceived distance and velocity. Exp 1 showed that direct estimates of younger Ss were most accurate. Older women made the shortest (highly cautious) estimates of when cars would arrive. Verbal estimates were much lower than direct estimates, with little correlation between them. Exp 2 extended target distances and velocities of targets, with the results replicating the main findings of Exp 1. Judgment accuracy increased with target velocity, and verbal estimates were again poorer estimates of arrival time than direct ones, with different patterns of findings. Using verbal estimates to approximate judgments in traffic situations appears questionable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing auditory distance perception using perceptually directed action

Three experiments investigated auditory distance perception under natural listening conditions in a large open field. Targets varied in egocentric distance from 3 to 16 m. By presenting visual targets at these same locations on other trials, we were able to compare visual and auditory distance perception under similar circumstances. In some experimental conditions, observers made verbal reports of target distance. In others, observers viewed or listened to the target and then, without further perceptual information about the target, attempted to face the target, walk directly to it, or walk along a two-segment indirect path to it. The primary results were these. First, the verbal and walking responses were largely concordant, with the walking responses exhibiting less between-observer variability. Second, different motoric responses provided consistent estimates of the perceived target locations and, therefore, of the initially perceived distances. Third, under circumstances for which visual targets were perceived more or less correctly in distance using the more precise walking response, auditory targets were generally perceived with considerable systematic error. In particular, the perceived locations of the auditory targets varied only about half as much in distance as did the physical targets; in addition, there was a tendency to underestimate target distance, except for the closest targets.     

Effect of distance information and range on two indices of visually perceived distance

Subjects made verbal reports of the perceived distance of near visual targets and indicated their distances by pointing at them with an unseen hand. The targets were presented under three stimulus conditions: monocular, binocular, and multicue. Two ranges of target distance were studied in separate experiments: 11-39 cm and 21-33 cm. When reciprocals of both response distance and target distance were plotted, all functions were approximately linear. The verbal and manual responses (distance indices) differed greatly, but were found to be related by a constant transform. The range of target distances had no effect on either index. The standard deviation of the manual response was about half that of the verbal response. Stimulus condition had a large effect, with the multicue condition producing the greatest change in indicated distance. and the monocular condition the least. The results are discussed with reference to the definition of perceived distance, and hypothesis concerning the integration of distance information.     

Binocular distance perception: Egocentric distance tasks.

Tested an extension of the present author's (1978; see also PA, Vol 64:11699) theory of binocular distance perception, which has been shown to give a good account of performance in relative distance tasks. In 2 experiments, 5 18–36 yr olds indicated perceived egocentric distance of targets (perceived distance from him/herself) by means of a verbal report or manual pointing response. In Exp I, the distance to 2 targets was varied while maintaining a constant disparity between them. In Exp II, 1 target was held fixed while the distance to a 2nd target was varied. In each case, Ss indicated the perceived distance of each target. Manual and verbal responses agreed with each other to within a linear transform. Both sets of data are consistent with the theory and indicate that reference parallax is a weighted average of target parallaxes. The systematic inaccuracy of binocular distance perception is attributed to the misperception of egocentric distance to the configuration. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal learning and memory in children with fetal alcohol syndrome

Children with fetal alcohol syndrome (FAS) were administered the California Verbal Learning Test-Children's Version, a word list learning task that assesses immediate and delayed recall and recognition memory. When compared with matched control children, the children with FAS had difficulty learning and recalling the words after a delay period and tended to make an increased number of intrusion and perseverative errors. In addition, they had difficulty discriminating target words from distracter words and made more false-positive errors on recognition testing. Some of these deficits persisted even when mental age was controlled. The results suggest that children with FAS have profound verbal learning and memory deficits, and that some of these deficits cannot be accounted for even when mental age is considered. Furthermore, the results are consistent with deficits in encoding verbal information and impairment in response inhibition capabilities.     

The Developmental Roots of the Speed-Accuracy Trade-Off.

The speed of adult reaching movements is lawfully related to the distance of the reach and the size of the target. The authors had 7-, 9-, and 11-month-old infants reach for small and large targets to investigate a possible relation between the emergence of this speed-accuracy trade-off and the improvements in infants' ability to pick up tiny objects. By 7 months of age, infants slowed down their reaches for smaller objects. The authors concluded that it was not the ability to use a precision grip that facilitated the speed-accuracy trade-off but rather the other way around. The slowing down toward the end of the movement might set the conditions for the development of fine distal control of the hand. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal and nonverbal fluency in patients with probable Alzheimer's disease.

Verbal fluency (semantic category naming and letter fluency) and nonverbal fluency (semantic category drawing and design fluency) were measured in mildly and moderately demented patients with probable dementia of the Alzheimer type (pDAT), and related to age at onset, disease duration, and disease severity. Group and individual patient analyses revealed impairments within verbal and nonverbal modalities that were most severe on semantic category fluency tasks. Detailed assessments of errors emphasized the role of compromised semantic memory in pDAT patients' impaired fluency, regardless of the modality of response. Fluency performance was related to dementia severity but not to age of onset or disease duration. It is concluded that deficits on measures of fluency in pDAT are due in large part to semantic memory impairments and that fluency may be useful for following disease progression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term memory for reaching to visual targets: psychophysical evidence for body-centered reference frames

Pointing to a remembered visual target involves the transformation of visual information into an appropriate motor output, with a passage through short-term memory storage. In an attempt to identify the reference frames used to represent the target position during the memory period, we measured errors in pointing to remembered three-dimensional (3D) targets. Subjects pointed after a fixed delay to remembered targets distributed within a 22 mm radius volume. Conditions varied in terms of lighting (dim light or total darkness), delay duration (0.5, 5.0, and 8.0 sec), effector hand (left or right), and workspace location. Pointing errors were quantified by 3D constant and variable errors and by a novel measure of local distortion in the mapping from target to endpoint positions. The orientation of variable errors differed significantly between light and dark conditions. Increasing the memory delay in darkness evoked a reorientation of variable errors, whereas in the light, the viewer-centered variability changed only in magnitude. Local distortion measurements revealed an anisotropic contraction of endpoint positions toward an "average" response along an axis that points between the eyes and the effector arm. This local contraction was present in both lighting conditions. The magnitude of the contraction remained constant for the two memory delays in the light but increased significantly for the longer delays in darkness. These data argue for the separate storage of distance and direction information within short-term memory, in a reference frame tied to the eyes and the effector arm.     

Children's spatial knowledge of their school campus.

72 4th-, 6th-, and 8th-grade boys were tested with different methodologies for deriving measures of their knowledge of interlandmark distances and directions on their school campus. Results show that age group differences were not large and appeared comparable for most measures. However, other results indicated that measures derived from direction vs distance information were independent. First, the accuracy with which Ss made distance and direction estimates varied across specific combinations of reference sites and targets; this pattern of differential accuracy was quite different for distance vs direction estimates. Second, correlations among the dependent measures indicated that Ss who were accurate at direction estimates were not necessarily accurate for distance estimates. It is emphasized that measures derived from Ss' estimates of direction information were not comparable with measures derived from their estimates of distance information. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Grade Level and Task Difficulty in Learning by Discovery and Verbal Reception Methods.

The present study compared the acquisition, retention, and transfer performance of subjects taught by the verbal reception and discovery methods. First-, third-, and sixth-grade subjects acquired a simple or complex conceptual rule by either the verbal reception or discovery method. The results indicated that discovery subjects took significantly longer than verbal reception subjects to reach the original learning criterion. Verbal reception subjects generally demonstrated performance which was superior to discovery subjects on all measures of retention and transfer. The level of task difficulty interacted with the method of instruction so that increases in task difficulty led to an increase in the differential effectiveness of the two teaching methods. Differences in experience with the two instructional methods was proposed as one of the variables contributing to the above results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus–target compatibility for reaching movements.

Reaction time, movement time, and initial direction of reaching movements toward a target in left or right hemispace were measured. In Experiment 1, the target of movement and hand had to be selected; movements toward the imperative stimulus were initiated faster than movements toward the alternate target, and ipsilateral reaches were initiated faster than contralateral reaches. In Experiment 2, the difference between ipsilateral and contralateral reaches disappeared when no selection of the hand had to occur. In Experiment 3, no target had to be selected, and only a stimulus-hand compatibility effect appeared. The results reveal different compatibility effects (stimulus-target, stimulus-hand, target-hand), implying that participants exploit different correspondences, depending on the degrees of freedom of the action. The notion of compatibility effects relating to movement targets offers a new perspective on the negative Simon effect and it questions the general concept of response codes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time estimation abilities in mild cognitive impairment and Alzheimer's disease.

Accurate time estimation abilities are assumed to play an important role in efficient performance of many daily activities. The authors investigated the role of episodic memory impairment in temporal perception using a prospective verbal time estimation paradigm. Verbal time estimations were made for filled intervals both within (i.e., 30 s) intervals. The verbal time estimates of both older adult groups, however, deviated more significantly from true time when compared with younger adult controls. In Experiment 2, 17 individuals with Alzheimer's disease (AD) demonstrated greater error and variability in their time estimates, but no disproportionate differences emerged between short- and long-duration estimates when compared with age-matched controls. The findings did not support a noteworthy role for episodic memory impairment in temporal perception but rather elucidated a significant effect of normal aging, as well as a detrimental effect of AD on temporal perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Primed numbers: Exploring the modularity of numerical representations with masked and unmasked semantic priming.

In Experiment 1, participants classified a 1st number (prime) as smaller or larger than 5 and then performed the same task again on a 2nd number (target). In Experiment 2, participants classified a target number as smaller or larger than 5, while unknown to them a masked number was displayed for 66 ms prior to the target. Primes and targets appeared in Arabic notation, in verbal notation, or as random dot patterns. Two forms of priming were analyzed: quantity priming (a decrease in response times with the numerical distance between prime and target) and response priming (faster responses when the prime and target were on the same side of 5 than when they were not). Response priming transferred across notations, whereas quantity priming generally did not. Under conditions of speeded processing, the internal representation of numerical quantities seems to dissociate into multiple notation-specific subsystems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaching to ipsilateral or contralateral targets: within-hemisphere visuomotor processing cannot explain hemispatial differences in motor control

Aiming movements made to visual targets on the same side of the body as the reaching hand typically show advantages as compared to aiming movements made to targets on the opposite side of the body midline in the contralateral visual field. These advantages for ipsilateral reaches include shorter reaction time, higher peak velocity, shorter duration and greater endpoint accuracy. It is commonly hypothesized that such advantages are related to the efficiency of intrahemispheric processing, since, for example, a left-sided target would be initially processed in the visual cortex of the right hemisphere and that same hemisphere controls the motor output to the left hand. We tested this hypothesis by examining the kinematics of aiming movements made by 26 right-handed subjects to visual targets briefly presented in either the left or the right visual field. In one block of trials, the subjects aimed their finger directly towards the target; in the other block, subjects were required to aim their movement to the mirror symmetrical position on the opposite side of the fixation light from the target. For the three kinematic measures in which hemispatial differences were obtained (peak velocity, duration and percentage of movement time spent in deceleration), the advantages were related to the side to which the motor response was directed and not to the side where the target was presented. In addition, these effects tended to be larger in the right hand than in the left, particularly for the percentage of the movement time spent in deceleration. The results are interpreted in terms of models of biomechanical constraints on contralateral movements, which are independent of the hemispace of target presentation.     

Relationship of reading achievement to verbal processing abilities.

Examined the relationship between reading achievement and ability to process verbal information in 67 achieving and 67 nonachieving readers drawn from 4th-grade classes. Verbal processing abilities were evaluated with 10 instruments, which included measures of memory span, associative learning, semantic association, automatic word processing, and time taken to name pictures, read words, and recode (pronounce) pseudowords. Achieving readers performed better on all measures except automatic word processing. Factor analysis yielded 3 factors, labeled Verbal Coding Speed, Memory Span, and Verbal Operations. Reading comprehension had high loadings on the 1st and 3rd factors but had a low loading on Memory Span. Results suggest that 1 primary component of the reading achievement of 4th-grade children is the ability to perform operations or manipulations on verbal material. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning to reach: A mathematical model.

Presents a mathematical model of the development of reaching that assumes that the major problem facing infants is their lack of lower level motor control and that infants learn to adjust their reaching strategies as a consequence of their previous experience and to match their current level of control. The model hypothesizes that infant reaches are a series of submovements, with the goal being to get the hand to the target in the face of errors in executed submovements. To relate actual infant reaches to this model, reaching data were decomposed into submovements, using a polynomial fitting algorithm that assumed minimum-jerk submovements. The model makes quantitative predictions about the course of development that are supported by existing results. The validity of the model's underlying assumptions was assessed by comparing the directional variability of the submovements with the variability assumed in the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validity of the Kaufman Brief Intelligence Test.

The Kaufman Brief Intelligence Test (K-BIT) is a motor-free screening measure of intelligence that yields Verbal, Nonverbal, and Composite IQ estimates. To determine its concurrent validity, the K-BIT and the Wechsler Adult Intelligence Scale—Revised (WAIS—R) were administered as part of a neuropsychological examination to 200 clinical patients (aged 16–74 yrs). Correlations between the Verbal, Nonverbal, and Composite scales of the 2 measures were .83, .77, and .88, respectively. WAIS—R and K-BIT scores were also similar across age and educational levels, although mean K-BIT scores tended to be approximately 5 points higher than their WAIS—R counterparts. Differences between the 2 measures could not be attributed to psychomotor speed, expressive language, or manual dexterity. The K-BIT appears to be a promising screening measure of verbal, nonverbal, and general intellectual ability for use when time constraints preclude use of a longer measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional characteristics of auditory temporal—spatial short-term memory: Evidence from serial order errors.

The functional characteristics of auditory temporal-spatial short-term memory were explored in 8 experiments in which the to-be-remembered stimuli were sequences of bursts of white noise presented in spatial locations separated in azimuth. Primacy and recency effects were observed in all experiments. A 10-s delay impaired recall for primacy and middle list items but not recency. This effect was shown not to depend on the response modality or on the incidence of omissions or repetitions. Verbal and nonverbal secondary tasks did not affect memory for auditory spatial sounds. Temporal errors rather than spatial errors predominated, suggesting that participants were engaged in a process of maintaining order. This pattern of results may reflect characteristics that serial recall has in common with verbal and spatial recall, but some are unique to the representation of memory for temporal-spatial auditory events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' predictive reaching for moving objects in the dark.

Infants were presented with a moving object under 2 lighting conditions to investigate the role of vision in early reaching. The motion of the target object also allowed for an analysis of the infants' ability to use a predictive style of reaching. Infants were tested twice, at 5 and 7.5 months of age, with a moving object in the light and the same object painted with luminescent paint in the dark. Infants successfully contacted the glowing object on about half of their attempts at both ages, although 7.5 month-olds reached more often. Infants also took into account the motion of the target object by aiming their reaches ahead of the object and by reaching with their contralateral hand. These results suggest that proprioceptive feedback and sight of the target allow for successful reaching with limited visual information, even in relatively complex reaching tasks. The infants' success also demonstrates their ability to adapt their movements and reaching strategy to the speed and trajectory of the target object in order to reach predictively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tool Use Affects Perceived Distance, But Only When You Intend to Use It.

Recent research demonstrates neurologic and behavioral differences in people's responses to the space that is within and beyond reach. The present studies demonstrated a perceptual difference as well. Reachability was manipulated by having participants reach with and without a tool. Across 2 conditions, in which participants either held a tool or not, targets were presented at the same distances. Perceived distances to targets within reach holding the tool were compressed compared with targets that were beyond reach without it. These results suggest that reachability serves as a metric for perception. The 3rd experiment found that reachability only influenced perceived distance when the perceiver intended to reach. These experiments suggest that the authors perceive the environment in terms of our intentions and abilities to act within it. (PsycINFO Database Record (c) 2011 APA, all rights reserved)