Role of the inertia tensor in haptically perceiving where an object is grasped.

When an object is held and wielded, a time-invariant quantity of the wielding dynamics is the inertia tensor Iij. Examination of Iij as a function of different locations at which a cylindrical object is grasped revealed that the off-diagonal components of Iij, the products of inertia, related most systematically to grip position. In 3 experiments, Ss wielded an occluded rod held at an intermediate point along its length and reproduced, with the other hand, the felt grip position on a visible rod. In Exp 1, the wielded rods were homogeneous; in Exps 2 and 3, weights were added on either side of the grasp, with different manners of grasp contrasted in Exp 3. In all 3 experiments, perceived hand position was predicted by Iij. Discussion is focused on the role of Iij's eigenvalues in perceiving the magnitudes of objects and Iij's eigenvectors in perceiving hand–object relations (e.g., position of grasp). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Components of the location probability effect in visual search tasks.

In visual search tasks, targets are detected more rapidly when they appear in locations that commonly contain a target than when they appear in locations that rarely contain a target. Five experiments were conducted to investigate 2 specific properties of this location probability effect. In Exp I spatial location of a stimulus row was varied to determine whether high location probability facilitates target detection in a particular location in visual space or a particular relative position within the row. Both were facilitated to approximately the same extent. In Exp II an inducing target occurred with high probability in 1 of 4 display locations, and a test target occurred with equal probability in all 4 locations. Both targets were found more quickly in the high-probability location than in the other locations, but the advantage associated with targets in the high-probability location was larger for the inducing target than for the test target. In Exps III–V the correspondence between the components observed in Exps I and II was examined. The overall pattern of results was compatible with a model in which the location probability effect is produced partly by an attentional spotlight, which facilitates processing of any stimulus appearing in a particular location in visual space, and partly by a network of position-specific letter detectors, which facilitates detection of a particular letter in a particular relative position within a display. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring environments by hand or foot: Time-based heuristics for encoding distance in movement space.

In Experiment 1, blindfolded observers judged (a) the distance of pathways felt by hand and (b) the straight-line distance between pathway endpoints inferred from such exploration. In Experiment 2, blindfolded observers made corresponding estimates after traversing similar pathways on foot. Pathways were explored under three different speeds. Under both manipulatory and ambulatory exploration, there was substantial length distortion of inferred distance; the straight-line distance was increasingly overestimated with increases in the length of the explored pathway. With manipulatory exploration, slower movements increased length distortion, but duration effects proved secondary to effects of spatial extent. For ambulatory exploration, no duration effects were obtained. Observers used time-independent heuristics, that is, a footstep metric for estimating the pathway actually travelled and a spatial imaging strategy for estimating the inferred line between pathway endpoints. The studies establish length distortion as a general phenomenon in movement space and identify its major causes as spatial rather than temporal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Primacy of dimensions in color perception.

Used a procedure called selective/individual rotation to investigate the role of dimensions in the perception of color. Ss performed either selective-attention or divided-attention tasks to paired dimensions created from each of 3 orientations of axes in color space: 0°, 22.5°, and 45°. The authors evaluated a Euclidean hypothesis, namely, that speeded classification of interacting dimensions is invariant to rigid rotation of stimulus axes. All experiments obtained evidence against this Euclidean hypothesis. Exps 1–4 showed that selective attention was best at the orientation corresponding to saturation and brightness, suggesting primacy of these dimensions. The results were replicated with the pairs hue–saturation (Exp 7) and hue–brightness (Exp 8). The authors conclude that interacting dimensions can be primary and that dimensional primacy characterizes much of perceptual experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of age and processing stage on visual word recognition.

Used a lexical-decision task in 3 different experiments to examine whether age differences in word recognition were consistent across processing stage. In all experiments, word frequency and length were manipulated. In Exps 1 and 2, encoding difficulty was varied, and in Exp 3, response selection difficulty was varied. In all 3 experiments, there were no age differences for word frequency. However, in Exps 1 and 2, older adults showed a larger decrement for encoding. In Exp 3, age differences were larger when response selection load increased. These results suggest that age differences in word recognition occur because older adults exhibit primarily peripheral- rather than central-processing decrements. The implications of these data for generalized and localized slowing models are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial attention and the apprehension of spatial relations.

Seven experiments examined the role of spatial attention in apprehending spatial relations above, below, left, and right. In Exp 1, visual search was difficult when targets differed from distractors only in the spatial relation between their elements. Reaction time (RT) increased linearly with display size with a slope greater than 60 msec/item. In Exp 2, search was easy (the slope was flat) when targets differed from distractors in the identity of their elements. In Exps 3 and 4, target position was cued with a discrepant color, and performance was better when attention was pulled toward spatial-relation targets than away from them. Exps 5–7 generalized the results over different displays and extended practice. The results suggest that apprehending spatial relations requires spatial attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prominence of leading functors in function morpheme sequences as evidenced by letter detection.

Previous work indicated that the increased difficulty in detecting letters in function in comparison with content morphemes derives from the role of functors in supporting phrase structure. Presumably, letters disappear in the transition from structure to content. Here the effect was most powerful for leading functors in a sequence of function morphemes (e.g., "that" in "that from the"). This pattern was found for Hebrew function prefixes that can be appended as a sequence to a content word (e.g., SMHGN, meaning "that from the garden"; Exps 1 and 2) and also for sequences of Hebrew and English function words (Exps 3 and 4). This pattern of results did not hold, however, for THE, which maintained its strong disadvantage regardless of position. The results reflect the prominence of leading functors in organizing the local structural frames established in the early stages of text processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binocular vision and spatial perception on 4- and 5-month-old infants.

Conducted 4 experiments investigating the relation between the development of binocular vision and infant spatial perception. Exps I and II compared monocular depth perception in 39 4- and 5-mo-old infants. Results show that Ss in both age groups reached more consistently for the nearer of 2 objects under binocular viewing conditions than under monocular viewing conditions. Exps III and IV investigated whether the superiority of binocular depth perception in 89 4-mo-olds is related to the development of sensitivity to binocular disparity. In Exps I–II, under binocular viewing conditions, Ss who were identified as disparity-sensitive reached more consistently for the nearer object than did Ss who were identified as disparity-insensitive. The 2 group's performances did not differ under monocular viewing conditions. Results suggest that, binocularly, the disparity-sensitive Ss perceived the objects' distances more accurately than did the disparity-insensistive Ss. In Exps II–IV when Ss were habituated to an object, then presented with the same object and a novel object that differed only in size, disparity-sensitive Ss showed size constancy by recovering from habituation when viewing the novel object. Disparity-insensitive Ss did not show clear evidence of size constancy. Findings suggest that the development of sensitivity to binocular disparity is accompanied by a substantial increase in the accuracy of infant spatial perception. (64 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Repetition effects with categorizable stimulus and response sets.

The repetition effect refers to the finding that reaction times (RTs) are faster on trial n when the stimulus presented and/or the response required is the same as on trial n?–?1 than when it is different. Five experiments examined the importance of stimulus features and response features in obtaining the repetition effect. Exp 1 demonstrated a need for the stimuli to be categorically mapped to responses for a response repetition effect to be observed. Exps 2–5 showed that the repetition effect can be obtained across responding hands when spatial information (Exps 2 and 4) or finger information (Exps 2 and 5) is consistent across hands but not when these sources of information are eliminated (Exp 3). The results are in agreement with expectations developed from salient-features coding and with the inclusive links hypothesis proposed by H. Pashler and G. Baylis (1991). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Splitting visual space with attention.

The present study aimed at showing a spatial compatibility effect (and, by implication, a right–left subdivision of space) solely attributable to the orienting of attention. Five groups of 8 normal Ss were required to give right–left discriminative responses to stimuli presented within one of 6 empty boxes arranged in a horizontal row. Reaction times and errors were recorded. A right–left grouping of the boxes occurred regardless of whether Ss' fixation was kept at the intermediate position (Exp 1) or at one extremity (Exp 2) of the row. In Exps 3 and 4, Ss' attention was not aligned with a fixed position but was moved, through peripheral cues, from trial to trial and positioned between different pairs of adjacent boxes. Results showed that the display was again subdivided into 2 regions and that the reference point for the right–left subdivision was the focus of attention. In Exp 5, eye position was instrumentally monitored, and Ss' attention was directed by central cues. The results confirmed that the focusing of attention leads to a right–left partitioning of space. Directing attention to a position in space brings about a right–left perceptual organization that predominates over that provided by the other egocentric reference axes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of an irrelevant location dimension as a function of the relevant stimulus dimension.

The effect of an irrelevant location dimension on choice reactions to the relevant stimulus dimension was examined. Exp 1 used variations of the spatial Stroop task and the Simon task that differed in whether the relevant dimension (location name or color) was similar to the irrelevant location dimension. Congruity of the stimulus dimensions and stimulus–response (S–R) mapping had additive effects in the Simon task but overadditive effects in the Stroop task. Exps 2–4 showed that each pattern could be obtained for both tasks, suggesting that dimensional similarity is not crucial; overadditivity occurred only when stimulus identification was prolonged. Results can be interpreted in terms of the relative timing of activation for the relevant and irrelevant information, if it is assumed that the activation function for irrelevant location varies across different S–R mappings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of semantic priming on visual encoding of pictures.

We investigated the effects of semantic priming on initial encoding of briefly presented pictures of objects and scenes. Pictures in 4 experiments were presented for varying durations and were followed immediately by a mask. In Exps 1 and 2, pictures of simple objects were either preceded or not preceded by the object's category name (e.g., dog). In Exp 1 we measured immediate object identification; in Exp 2 we measured delayed old/new recognition in which targets and distractors were from the same categories. In Exp 3 naturalistic scenes were either preceded or not preceded by the scene's category name (e.g., supermarket). We measured delayed recognition in which targets and distractors were described by the same category names. In Exps 1–3, performance was better for primed than for unprimed pictures. Exp 4 was similar to Exp 2 in that we measured delayed recognition for simple objects. As in Exps 1–3, a prime that preceded the object improved subsequent memory performance for the object. However, a prime that followed the object did not affect subsequent performance. Together, these results imply that priming leads to more efficient information acquisition. We offer a picture-processing model that accounts for these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is retrievability grouping good for recall?

Most theories suppose that during unconstrained retrieval easy-to-retrieve items will be accessed before hard-to-retrieve items. Recent free-recall studies have supported a different access order, the cognitive triage pattern, in which hard-to-retrieve items are accessed first. The present experiments demonstrated that this pattern enhances total recall. In Exps 1–3, clustering type measures of goodness of triage (grouping output according to items' levels of retrievability) predicted total recall in children and adults. In Exps 4 and 5, goodness-of-triage measures predicted total recall when they were derived from on-line information about retrievability (error–success histories), but not when they were derived from normative information about retrievability (frequency and meaningfulness ratings). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Illusory correlation in the perception of groups: An extension of the distinctiveness-based account.

The prevailing explanation for illusory correlation in the stereotyping of groups is that distinctive information (minority groups' infrequent behaviors) is salient, receives enhanced encoding, and becomes highly accessible, thus biasing subsequent judgments. This distinctiveness-based explanation (DBE) depends on information distinctiveness at the time of its encoding. In the present study, 5 experiments were conducted, involving 417 undergraduates. Information distinctiveness at encoding was manipulated, while ultimate distinctiveness was kept constant. Exp 1, contrary to the DBE, found illusory correlations emerge regardless of distinctiveness at encoding. Exp 2 collected process data that showed that ultimately distinctive behaviors were highly accessible at the time of judgment even when they were not distinctive at encoding. Exps 3–5 ruled out an alternative account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of moderate intensity noise on the Bakan vigilance task.

Most studies of vigilance show noise effects only above 95 db SPL, but some suggest that tasks with possible involvement of subvocal speech may be more vulnerable. The present 4 experiments examined the effects of moderate intensity (85 db or lower) noise on visual versions of the Bakan vigilance task, which were given to a total of 64 20–56 yr old paid female Ss. Digit sequences were observed for particular target groupings of 3 odd (Exps I and II) or odd–even–odd (Exps III and IV) digits. All 4 experiments showed either a decrease in targets detected or a decrease in total responses (including false alarms). Exps III and IV used grouped presentation of stimuli to confirm whether the impairments were due to changed use of subvocal speech, but no support was found for any of the competing current suggestions on this point. The main implication is, therefore, that noise may produce impairment at levels lower than previously thought. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representation of order information: An analysis of grouping effects in short-term memory.

Exps I–IV tested the independence model, 2 hierarchical models, and the dependence model of matrix relationships with a probed recall procedure in which 91 undergraduates were presented with a grouped sequence of items and were then required to recall the position and group of 1 of the items. This technique provided information about how well Ss correctly recalled both the group and position, the group only, the position only, and neither the group nor the position of an item. Findings reveal that when the items in a group were letters, digits, or musical notes, the data conformed to a hierarchical structure. When the nonalphanumeric characters were used, a matrix structure emerged. Exps V–VII required 50 undergraduates to judge the dissimilarity of 2 sequences of grouped items, the 2nd of which (the variation) was a reordering of the 1st (the original). The variation was made by reordering the groups in the original, reordering positions within groups, or reordering both groups and positions. Results show that when the members of a group were able to be encoded as single verbal units, the data supported a hierarchical system. When this was not possible, a matrix system fitted the data best. It is concluded that there is no general code for representing the order of grouped sequences and that the results are more compatible with a theory that postulates a number of specific subsystems in short-term memory, each with its own format for preserving order, than one that assumes a generalized order code. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laterality and visual masking: Interhemispheric communication and the locus of perceptual asymmetries for words.

Exps I and II (with 16 17–32 yr old right handers) measured the critical interstimulus interval at which a word presented to the right or left field escaped a trailing noise or pattern mask. Perceptual asymmetries were absent in the noise mask condition. A right-field advantage of about 4 msec that did not vary with predictability of target location was found in the pattern mask condition. Exp III (8 Ss) showed that pattern masking leads to a right-field advantage even when accuracy is well below asymptote. Results suggest that hemispheric differences for word identification are either absent or inconsistent at early, peripheral stages of processing, but emerge strongly at higher-order central processing stages. The estimate of interhemispheric transmission times from these masking studies are on the order of 4 msec. (French abstract) (79 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representational aspects of word imageability and word frequency as assessed through word association.

Assessed the effects of word imageability and word frequency (WF) in word association (WA). Exps 1 and 2 employed the discrete WA task, whereas Exp 3 used the continued WA task. Data from Exps 1–3 showed that word imageability strongly determines responding in WA, whereas WF hardly affects it. Exp 4 (lexical decision) and 5 (word naming) explored the possibility that WF effects on the word-recognition stage in WA might have interfered with any effect of WF on the association-retrieval stage, a possibility that was not borne out by data. Exps 6–8 examined whether the absence of frequency effects on WA in Exps 1–3 might have been due to the fact that the WF classes had a restricted range. A new set of stimulus materials was constructed, with frequency classes further apart. Some small effects of this variable on WA were found. Results point out that the concept nodes for high-imageability words contain more information than those of low-imageability words and that relatively strong links depart fron the former type of nodes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of expertise in mathematical problem solving.

Investigated the distinctive strategies employed by expert and novice problem solvers (forward-chaining and means–ends, respectively) in 7 experiments using 14 mathematics graduates and 162 9–12 yr olds. Exp I studied the course of development of expertise using a subset of kinematics problems. Ss demonstrated the switch from a means–ends to a forward-chaining strategy. This was associated with the conventional concomitants of expertise such as a decrease in the number of moves required for solution. Ss appeared to categorize problems according to the order in which equations would be required. Exps II and III tested the hypothesis that the means–ends strategies used by novices retarded the acquisition of appropriate schemata. The use of nonspecific rather than specific goals was found to enhance the acquisition of expertise, the number of moves required for solution, and the number of equations written without substitutions. Exps IV and V, using geometry problems, duplicated the enhanced rate of strategy alteration found with reduced goal specificity. Results of Exps VI and VII indicated that reduced goal specificity also enhanced the rate at which problem solvers induced appropriate problem categories. It is concluded that in circumstances in which the primary reason for presenting problems is to assist problem solvers in acquiring knowledge concerning problem structure, the use of conventional problems solved by means–ends analysis may not be maximally efficient. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonvisual judgment of the crossability of path gaps.

The ability of persons to locomote without vision with the aid of a hand-held probe was investigated in 4 experiments focusing on the negotiation of gaps in a pathway. In Exp 1, Ss of extreme heights judged under sighted and blindfolded conditions whether gaps of different sizes could be crossed by walking. Crossability boundaries were lower for shorter Ss, but the height effect disappeared under normalization by leg length. Exps 2–4 altered mechanical aspects of the probe (length and mass distribution) in the nonvisual case. Ss' performance was still reliable in each experiment, and their performances were constrained by parameters of the gap and of their action systems. Probe variables, however, had surprisingly little influence on the judgments of crossability. Results are discussed in terms of potential roles for information in different perceptual modalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)