Modifying guided search: Preattentive object files.

Many models of visual search behaviour consist of a first stage in which basic features are processed "in parallel" at all locations across the visual field and a second, limited-capacity stage in which processing is restricted to a single item or location. Perhaps the best known of these models is Feature Integration Theory (FIT) (e.g. Treisman, 1993). The original FIT was the starting point for our Guided Search (Wolfe, 1994). The heart of Guided Search is the proposal that the parallel first stage can guide the spatial deployment of the limited resources of the second stage. For example, consider a conjunction search for a red vertical line among green vertical lines and red horizontal lines. There is good reason to believe that no first stage mechanism is specifically designed to be sensitive to conjunctions of colour and orientation. Nevertheless, searches for conjunctions of this sort are quite efficient; more efficient than they ought to be if second stage resources were deployed from item to item in a random, serial search. This efficiency can be obtained if information is combined from two first stage feature processors. If a colour processor guides attention toward all red items while an orientation processor guides all attention toward the vertical items, attention would be guided most strongly toward the red vertical items. Even if we assume that guidance is not perfect, the combination of these two sources of information will make the search for a conjunction more efficient that it would have been in the absence of guidance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognizing Impossible Object Relations: Intuitions About Support in Chimpanzees (Pan troglodytes).

Using looking-time measures, the authors examined untrained chimpanzees' (Pan troglodytes) ability to distinguish between adequate and inadequate support. In 3 experiments, the chimpanzees' sensitivity to different support relations between 2 objects was assessed. In each experiment, the chimpanzees saw a possible and an impossible test event, presented as digital video clips. Looking times in the 3 experiments suggest that chimpanzees use amount of contact between 2 objects, but not type of contact, to distinguish between adequate and inadequate support relations. These results indicate that chimpanzees have some intuition about support phenomena but their sensitivity to relational object properties may differ from that of human infants (Homo sapiens) in this domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning by selection: Visual search and object perception in young infants.

The authors examined how visual selection mechanisms may relate to developing cognitive functions in infancy. Twenty-two 3-month-old infants were tested in 2 tasks on the same day: perceptual completion and visual search. In the perceptual completion task, infants were habituated to a partly occluded moving rod and subsequently presented with unoccluded broken and complete rod test stimuli. In the visual search task, infants viewed displays in which single targets of varying levels of salience were cast among homogeneous static vertical distractors. Infants whose posthabituation preference indicated unity perception in the completion task provided evidence of a functional visual selective attention mechanism in the search task. The authors discuss the implications of the efficiency of attentional mechanisms for information processing and learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The spectrum of category effects in object and action knowledge in dementia of the Alzheimer's type.

The validity and origin of category effects in the anomia demonstrated by individuals with dementia of the Alzheimer's type (DAT) remains controversial. Twenty DAT subjects were tested with picture naming and semantic association judgement tests. Picture and word stimuli were drawn from biological, nonbiological, and actions–verbs categories, all of equal difficulty and previously normed on elderly controls. DAT subjects made significantly more naming and semantic judgement errors in the biological category than in the nonbiological category. They were relatively more accurate in naming and making judgements for actions–verbs when presented as words or as 5-s animations. When line drawings of actions were shown for naming, performance deteriorated significantly. Converging results from these 2 tasks provide strong evidence for a semantic memory impairment preferentially affecting biological items to a greater extent than nonbiological items or action verbs in DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context effects on the processing of action-relevant object features.

In 4 experiments, we investigated the effects of object affordance in reach-to-grasp actions. Participants indicated whether a depicted small or large object was natural or manmade by means of different object-grasping responses (i.e., with a power or a precision grip). We observed that the size of the depicted object affected the grasping kinematics (grip aperture) and the reach-onset times of compatible and incompatible actions. Additional experiments showed that the effect of perceived object size on motor response was modulated by contextual action information and the observation of others’ actions with the object. Thus, beyond the observation of object affordance effects in natural grasping actions, this study suggests that the coupling between object perception and action is not static and obligatory. Behavioral effects of action-relevant object features seem rather to depend on contextual action information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic prototypicality effects in visual search.

In recent studies, researchers have discovered a larger neural activation for stimuli that are more extreme exemplars of their stimulus class, compared with stimuli that are more prototypical. This has been shown for faces as well as for familiar and novel shape classes. We used a visual search task to look for a behavioral correlate of these findings regarding both simple geometrical shapes and more complex, novel shape classes. The latter stimulus set enabled us to control for the physical properties of the shapes, establishing that the effects are solely due to the positions of the particular stimuli in a particular shape space (i.e., more extreme versus more central in shape space) and not to specific shape features. The results indicate that finding an atypical instance of a shape class among more prototypical ones is easier and faster than the other way around. The prototypical status of a shape in our experiment could change very quickly, that is, within minutes, depending on the subset of shapes that was shown to the participants. Manipulating the degree of familiarity toward the shapes by selectively increasing familiarity for the extreme shapes did not influence our results. In general, we show that the prototypical status of a stimulus in visual search is a highly dynamic property, depending on the distribution of stimuli within a shape space but not on familiarity with the prototype. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Acquistion of structural versus object landmark knowledge.

Three experiments investigated the acquisition and retention of structural and object landmarks in virtual indoor environments. The experiments investigated the rate of acquisition and memory retention for hallway structure (structural landmarks) and pictures (object landmarks). The experiments investigated the rate of acquisition, the role of information content, and memory retention of this information when participants were trained and tested in novel virtual indoor environments. The results from these experiments suggest that (a) even initially, participants are biased toward encoding building structure over object landmarks; (b) participants are sensitive to the information content of landmarks and will allocate memory resources to landmarks that are more informative; and (c) information about these landmarks is retained even after a 1-year delay. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object naming and semantic knowledge in temporal lobe epilepsy.

Object-naming impairment is common among temporal lobe epilepsy (TLE) patients, but other aspects of semantic memory have received limited attention in this population. This study examined object-naming ability and depth of semantic knowledge in healthy controls (n?=?29) and patients with early onset TLE (n?=?21). After administration of the Boston Naming Test (BNT), the authors asked participants to provide detailed definitions of 6 BNT objects. The TLE group demonstrated a significant deficit relative to controls in both object-naming ability and semantic knowledge for the target objects, even after controlling for IQ. In a multiple regression analysis that included other neuropsychological test scores as independent variables, the semantic knowledge score was the only significant predictor of patients' object-naming performance. Thus, at the group level, early onset TLE patients have a semantic knowledge deficit that contributes to dysnomia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of measures of adaptive behaviors in preschool children.

Compared 6 measures of adaptive behavior to determine which tests and items best discriminate between behavior problem and nonproblem preschool children. 11 nonproblem and 13 problem children, matched on age (4 yrs) and IQ (110–215), were compared on the following tests: the Minnesota Child Development Inventory, the Classroom Adjustment Rating Scale, the Ottawa School Behavior Survey, the AML (Acting out, Moodiness, Learning disorders) Behavior Rating Scale, the Teacher Rating Scale, and the Denver Developmental Screening Test. Problem Ss scored significantly lower than nonproblem Ss on all 6 measures. In addition, fine-motor items discriminated better than gross-motor, language, social, and behavioral items. The Minnesota Child Development Inventory items were the best discriminators, followed by items on the Ottawa School Behavior Survey and the Teacher Rating Scale. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for object location: A span study in children.

The aim of the present study was to analyze the developmental changes in three spatial processes, namely, in positional reconstruction involving the retention of spatial locations per se (Positional encoding task), in the assignment of objects to positions (Object-to-position assignment task), and in the integration of these two (Combined task). A span procedure was used to assess the development of spatial memory in children aged 6, 8, and 10 years tested in these three tasks. The findings of the present study provide developmental spans for each relocation task. Results show an age-dependent improvement in all tasks, suggesting that spatial position is not automatically encoded. The results also show different developmental patterns for the relocation tasks considered, suggesting that spatial memory comprises a number of different component processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related deficits in guided search using cues.

The ability of young and older adults to engage in guided conjunction search was tested in 2 experiments. In the cued condition, a picture of the target was presented before the search. In the noncued condition, there was no picture of the target. In Experiment 1, the cue was presented for 200 ms; the magnitude of the cuing effect (noncued response time - cued response time) was greater for the young than for the older observers. In Experiment 2 (older observers only), the cue duration was doubled, and older observers had a larger magnitude of cuing effect than found in Experiment 1 but not as large as what would be expected under generalized slowing. The results indicated that older observers had difficulty with interpreting the cue and setting search parameters when the target varied across trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What does the object decision task measure? Reflections on the basis of evidence from semantic dementia.

The authors investigated the impact of semantic knowledge on visual object analysis by assessing the performance of patients with semantic dementia on a different-views object matching test and on 2 object decision tests differing, for example, in whether the nonreal items were nonsense objects or chimeras of 2 real objects. On average, the patients scored normally on both the object matching and the object decision test including nonsense objects but were impaired on the object decision test including chimeras; this latter was also the only visual object test that correlated significantly with degree of semantic impairment. These findings demonstrate that object decision is not a single task or ability and that it is not necessarily independent of conceptual knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Plasticity of feature-based selection in triple-conjunction search.

Two experiments examined the disruption of feature-based selection in triple-conjunction search at multiple target transfers. In Experiment 1, after 10 training sessions, a new target possessing previous distractor features was introduced. This produced disruption in RT and fixation number, but no disruption in feature-based selection. Specifically, there was a tendency to fixate objects sharing the target's contrast polarity and shape and this did not change even upon transfer to the new target. In Experiment 2, 30 training sessions were provided with three target transfers. At the first transfer, the results replicated Experiment 1. Subsequent transfers did not produce disruption on any measure. These findings are discussed in terms of strength theory, Guided Search, rule-based approaches to perceptual learning, and the area activation model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensorimotor prediction and memory in object manipulation.

Notes that when people lift objects of different size but equal weight, they initially employ too much force for the large object and too little force for the small object. However, over repeated lifts of the two objects, they learn to suppress the size–weight association used to estimate force requirements and appropriately scale their lifting forces to the true and equal weights of the objects. Thus, sensorimotor memory from previous lifts comes to dominate visual size information in terms of force prediction. Here the authors ask whether this sensorimotor memory is transient, preserved only long enough to perform the task, or more stable. After completing an initial lift series in which they lifted equally weighted large and small objects in alternation, 24 18–28 yr olds then repeated the lift series after delays of 15 min or 24 hrs. In both cases, participants retained information about the weights of the objects and used this information to predict the appropriate fingertip forces. This preserved sensorimotor memory suggests that participants acquired internal models of the size–weight stimuli that could be used for later prediction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of a moving distractor object on time-to-contact judgments.

The effects of moving task-irrelevant objects on time-to-contact (TTC) judgments were examined in 5 experiments. Observers viewed a directly approaching target in the presence of a distractor object moving in parallel with the target. In Experiments 1 to 4, observers decided whether the target would have collided with them earlier or later than a standard (absolute identification task). A contrast effect was observed: If the distractor arrived later than the target, it caused a bias toward early responses, relative to the condition without a distractor. The early-arriving distractor had no significant effect. The pattern of results was unaltered when potentially confounding information from individual visual cues was removed. The availability of stereoscopic information reduced the effect. The contrast effect was also observed if target and distractor were abstract geometric objects rather than simulations of real-world vehicles, rendering less likely a simple safety strategy activated by a potentially threatening distractor. Experiment 5 showed that the effect of the late-arriving distractor generalized to a prediction-motion task. The results indicate that task-irrelevant information in the background has to be considered in revision of time-to-contact theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional consequences of object appearance and disappearance.

This study compared the attentional effects of object appearances (onsets) and disappearances (offsets) in moderately complex displays. Four experiments showed that onsets produce the inhibition of return (IOR) effect that has been found with simpler displays. In contrast, although offsets did produce inhibitory effects, these effects did not follow the spatial or temporal pattern of IOR. Two further experiments used a very salient object disappearance to determine whether the typical pattern for IOR could be instantiated; it was not. The results indicate that object appearances are more potent perceptual events than object disappearances. In addition, object disappearances have different attentional consequences than object appearances: Disappearances provoke earlier and spatially narrower inhibition. The results are consistent with the view that inhibition serves a functional role in increasing the efficiency of visual search processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A clash of bottom-up and top-down processes in visual search: The reversed letter effect revisited.

[Correction Notice: An erratum for this article was reported in Vol 37(4) of Journal of Experimental Psychology: Human Perception and Performance (see record 2011-12773-001). The authors have requested a number of corrections. The corrections are given in the erratum.] It is harder to find the letter “N” among its mirror reversals than vice versa, an inconvenient finding for bottom-up saliency accounts based on primary visual cortex (V1) mechanisms. However, in line with this account, we found that in dense search arrays, gaze first landed on either target equally fast. Remarkably, after first landing, gaze often strayed away again and target report was delayed. This delay was longer for target “N” We suggest that the delay arose because bottom-up saliency clashed with top-down shape recognition. Thus, although gaze landed accurately and quickly to the distinctive feature in the target shape (the orientation of the diagonal bar in “N” or “И”), the identical zigzag shape of target and distractors was registered, leading to temporary confusion. In sparser search arrays with smaller set sizes, top-down target shape recognition occurs earlier and bottom-up saliency is weaker. The clash in this case causes search asymmetry even before target location at first gaze landing. Our findings rule out previous suggestions that search asymmetry stems from stronger preattentive salience for the reversed target and/or faster rejection of familiar distractors. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The development of phonological awareness in preschool children.

A short-term longitudinal study was carried out on a group of 67 preschool children. At three points in time over a 12-month period, the children were given tests measuring their syllable, rime, and phoneme awareness, speech and language skills, and letter knowledge. In general, children's rime skills developed earlier than their phoneme skills. Structural equation models showed that articulatory skills and syllable and rime awareness predicted later phoneme awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

People versus object orientation, social behavior, and intellectual abilities in preschool children.

Relative preference for interacting with people vs objects (i.e., orientation) was observed in 38 4-5 yr olds during nursery-school free play. As expected, Ss who showed greater orientation to objects performed better on tests assessing ability to organize and classify physical objects. Contrary to expectations, greater orientation toward people was unrelated to tests assessing social knowledge (e.g., role-taking ability and moral judgment). Degree of social knowledge was found instead to relate to sociometric popularity with peers and to ratings of several aspects of social competence (e.g., peer leadership). Results suggest that interest in and knowledge of the physical environment form a mutually facilitating interactive system. A similar but separate interactive system may be formed between the effectiveness of social functioning and social knowledge. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of grammatical gender on object categorization.

In 3 experiments, we investigated the effect of grammatical gender on object categorization. Participants were asked to judge whether 2 objects, whose names did or did not share grammatical gender, belonged to the same semantic category by pressing a key. Monolingual speakers of English (Experiment 1), Italian (Experiments 1 and 2), and Spanish (Experiments 2 and 3) were tested in their native language. Italian and Spanish participants responded faster to pairs of stimuli sharing the same gender, whereas no difference was observed for English participants. In Experiment 2, the pictures were chosen in such a way that the grammatical gender of the names was opposite in Italian and Spanish. Therefore, the same pair of stimuli gave rise to different patterns depending on the gender congruency of the names in the languages. In Experiment 3, Spanish speakers performed the same task under an articulatory suppression condition, showing no grammatical gender effect. The locus where meaning and gender interact can be located at the level of the lexical representation that specifies syntactic information: Nouns sharing the same grammatical gender activate each other, thus facilitating their processing and speeding up responses, either to semantically related pairs or to semantically unrelated pairs. (PsycINFO Database Record (c) 2011 APA, all rights reserved)