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This experiment examined adult age differences in the speed and accuracy of voluntary and involuntary shifts of visual attention. Younger and older adults performed two spatial cuing tasks using central cues and abrupt onset peripheral cues presented at stimulus onset asynchronies (SOAs) of 100, 150, 200, 250, and 300 ms. Analyses of the magnitudes of cuing effects revealed a similar time course for younger and older adults in the central cue condition, but not in the peripheral condition. Analyses of the Brinley plot for central cues across cue validity conditions indicated that as much as 93% of the variance could be attributed to age-related general slowing rather than to differential aging of a specific visual orienting mechanism.

Unilateral removal of all known visual cortical areas in the cat renders the animal hemianopic in the contralateral visual field as measured by visual perimetry and other behavioral tests. We have shown that visual orientation behavior can be restored to the previously blind hemifield by destruction of a critical zone in the substantia nigra pars reticulata contralateral to a cortical lesion (Wallace et al., J. Comp. Neurol. 296:222‐252, 1990). The model proposed to explain this recovery postulates that damage to the crossed nigrotectal projection disinhibits the superior colliculus ipsilateral to the cortical lesion and this leads to recovery. If disinhibition can account for recovery, then destruction of the uncrossed nigrotectal projection, which is known to exert a tonic inhibition on the superior colliculus, should also result in recovery. We made unilateral visual cortical ablations and ipsilateral ibotenic acid lesions of the substantia nigra pars reticulata. Visual orienting behavior was assessed in animals for a period of 4 to 31 weeks. Contrary to the prediction of the model, we failed to observe a recovery of visual orienting behavior in the blind hemifield in any of 23 animals. J Comp Neurol 377:596‐610, 1997. r 1997 Wiley-Liss, Inc. Indexing terms: basal ganglia; hemianopia; superior colliculus

One of the fundamental features of hearing is the ability to localize the sources of sounds, particularly brief sounds, which may warn of nearby animals. Yet not all mammals localize sound equally well with threshold acuity ranging from about 1 degree for elephants and humans to more than 25 degrees for gerbils and horses and a near absence of localization in some subterranean species. During the past decade evidence has accumulated that this variation cannot be accounted for simply by the availability of the physical cues for locus. Nor does it appear to be a function of an animal's lifestyle. Rather sound-localization acuity in mammals appears to be a function of the precision required of the visual orienting response to sound. Thus the neural integration of hearing and vision in cortex, as well as in multimodal subcortical structures, is a reflection of their behavioral integration and evolutionary coupling.

Three aspects of the development of visual orienting in infants of 2, 3, and 4 months of age are examined in this paper. These are the age of onset and sequence of development of (1) the ability to readily disengage gaze from a stimulus, (2) the ability to consistently show “anticipatory” eye movements, and (3) the ability to use a central cue to predict the spatial location of a target. Results indicated that only the 4--month-old group was easily able to disengage from an attractive central stimulus to orient toward a simultaneously presented target. The 4--month-old group also showed more than double the percentage of “anticipatory” looks than did the other age groups. Finally, only the 4--month-old group showed significant evidence of being able to acquire the contingent relationship between a central cue and the spatial location (to the right or to the left) of a target. Measures of anticipatory looking and contingency learning were not correlated. These findings are, in general terms, consistent with the predictions of matura-tional accounts of the development of visual orienting.

Stimuli that project onto central vision facilitate maintenance of eye position, a phenomenon called the fixation reflex. Endogenous control over this fixation reflex enables one to willfully look away. The current study investigated whether these behaviors, which are important for effective visual orienting, change with advancing age. Previous research established that patients with frontal lobe damage exhibit weaker fixation reflexes and reduced control over this reflex. In light of brain atrophy occurring during healthy aging, we predicted similar but less robust changes in neurologically healthy older relative to young adults. The results generally supported this prediction, which has negative implications for performance of time-sensitive visual-orienting tasks.

Abrupt click sounds can improve the visual processing of flashes in several ways. Here, we examined this in high functioning adolescents with Autism Spectrum Disorders (ASD) using three tasks: (1) a task where clicks improve sensitivity for visual temporal order (temporal ventriloquism); (2) a task where a click improves visual search (pip-and-pop), and (3) a task where a click speeds up the visual orienting to a peripheral target (clock reading). Adolescents with ASD were, compared to adolescents with typical development (TD), impaired in judgments of visual temporal order, but they were unimpaired in visual search and orienting. Importantly, in all tasks visual performance of the ASD group improved by the presence of clicks by at least equal amounts as in the TD group. This suggests that adolescents and young adults with ASD show no generalized deficit in the multisensory integration of low-level audiovisual stimuli and/or the phasic alerting by abrupt sounds.Keywords: Autism spectrum disorders, Multisensory integration, Temporal ventriloquism, Visual temporal order, Visual search, Visual orienting

Analysis of dynamics of biologically motivated neural networks allows for studying non-linear processes responsible for cognitive functions and thus provides adequate language to understand complex mental processes, including psychiatric syndromes and disorders. Problems with attention shifts that are at the roots of Autism Spectrum Disorders (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD), have been investigated using network model of Posner Visual Orienting Task (PVOT). Changing parameters that control biophysical properties of model neurons and cause network dysfunctions provides plausible explanations of many strange ASD and ADHD phenomena.

The behavioral capacities of the rhesus monkey for several sensory and cognitive tasks appear quite similar to those of humans. To evaluate the monkey's attentional capacities, we have compared monkey and human performance on a visuospatial attentional task, the cued target detection (CTD) paradigm. Animals were trained to fixate a small spot of light while a cue and a subsequent target, are flashed in the visual periphery. In valid trials, the cue and target appeared in the same spatial location; in invalid trials, the cue and target appeared in the opposite location; in double trials, two cues were presented and the target appeared in one of their locations; in no-cue trials, the cue was omitted and the target appeared in one location. In addition, we varied cognitive control over the task initiation by making the trial onset either self-paced or computer-paced. Reaction times (RTs) to target presentation, response accuracy, and frequency of aborted trials were measured for all subjects. No significant species differences were found for the patterns of RTs for different trial types or for attentional dynamics, as indexed by the decreases in RT with increasing cue-target interval. However, humans and non-human primates reacted differently to changes in cognitive control. Humans shows significant increases in no-cue trial RTs in the auto-paced task compared to the self-paced, but no differences in overall RT between tasks; monkeys showed a significant faster overall RT for the self-paced than the computer-paced task, but no difference between no-cue RTs. The performance differences between species may be related to the training history of the animals or to known anatomical differences in cortical organization, especially in the parietal lobe.

Between 1990 and 1994, Johnston and colleagues (K.J. Hawley, W.A. Johnston, & J.M. Farnham, 1994; W.A. Johnston, K.J. Hawley, J.M. Farnham, 1993; W.A. Johnston, K. J. Hawley, S.H. Plewe, J.M.G. Elliott, & M. J. DeWitt, 1990) published 3 articles on a phenomenon they designated novel popout. The typical interpretation of their findings is that a novel item rapidly and automatically attracts attention when displayed with familiar ones. J. Christie and R. Klein first show that the empirical pattem on which this claim is based can be easily explained in terms of a simple cognitive-load principle and note that effects not subject to this principle (or probability confounds) are rare in the target articles. We then show that these latter effects can be easily'explained without assuming visual orienting toward the novel item. Finally, we outline 2 criteria that must be satisfied in order to make claims about the rapid orienting of attention in arrays with familiar and unfamiliar items, neither of which were met in any of the reviewed experiments.

Conventional vestibular examination tests the function of the pair of horizontal semicircular canals and ignores the two pairs of vertical semicircular canals and otoliths. For complete vestibular testing, a four-axis gimbal system was constructed with two motor-driven axes and two axes which are manually adjustable. This apparatus allows stimulation of all semicircular canals and also-by rotation with respect to the gravity vector-of the otoliths. Positioning the subject in a light-proof sphere prevents visual orientation in space. Projected visual stimuli (light spot and full-field random dot pattern) complete the possibilities for oculomotor testing. Largely avoiding the use of metal offers the possibility of three-dimensional eye movement recording with the search coil method.

Adult humans demonstrate differential processing of stimuli that were recurrent threats to safety and survival throughout evolutionary history. Recent studies suggest that differential processing of evolutionarily ancient threats occurs in human infants, leading to the proposal of an inborn mechanism for rapid identification of, and response to, evolutionary fear-relevant stimuli. The current study provides novel data in support of this proposal, showing for the first time that human infants differentially process evolutionary threats presented in the auditory modality. Sixty-one 9-month-olds listened to evolutionary fear-relevant, modern fear-relevant, and pleasant sounds, while their heart rate, startle, and visual orienting behaviours were measured. Infants demonstrated significantly enhanced heart rate deceleration, larger eye-blinks, and more visual orienting when listening to evolutionary fear-relevant sounds compared to sounds from the other two categories. These results support the proposal that human infants possess evolved mechanisms for the differential processing of a range of ancient environmental threats.

Previous research suggested that specific pairings of stimulus and response modalities (visual-manual and auditory-vocal tasks) lead to better dual-task performance than other pairings (visual-vocal and auditory-manual tasks). In the present task-switching study, we further examined this modality compatibility effect and investigated the role of response modality by additionally studying oculomotor responses as an alternative to manual responses. Interestingly, the switch cost pattern revealed a much stronger modality compatibility effect for groups in which vocal and manual responses were combined as compared to a group involving vocal and oculomotor responses, where the modality compatibility effect was largely abolished. We suggest that in the vocal-manual response groups the modality compatibility effect is based on cross-talk of central processing codes due to preferred stimulus-response modality processing pathways, whereas the oculomotor response modality may be shielded against cross-talk due to the supra-modal functional importance of visual orientation.

It is demonstrated that the rheophilic fish dace (Leuciscus leuciscus) is able to detect the direction of its movements in a water flow by perceiving and analysing positive and negative accelerations from 15 up to 50 cm s−2, by the use of labyrinth organs. Tests were conducted on fish with ‘switched off’ mechanoreceptors and labyrinth organs, under conditions which eliminated the use of visual orientation. It was also demonstrated that the values of linear accelerations which stimulated dace compensatory movements against water currents were comparable with the values of accelerations which could arise in river flows as a result of pulsation in current velocity. The results support the hypothesis that rheophilic fish are able to use inertial stimuli for their spatial orientation.

Predators that hunt by sight should be constrained by light levels. This problem should be especially acute in aerial predators such as common poorwills (Phalaenoptilus nuttallii: Caprimulgidae), which capture small insects at night. The purpose of our study was to test the hypothesis that poorwills are constrained to catching larger insect taxa due to limitations of visual orientation under low light. We assessed diet by analysing poorwill faecal samples collected at nest and roost sites in the Cypress Hills of Saskatchewan where prey density is relatively low. Coleopterans (44% and 39% in 1991 and 1992, respectively) and lepidopterans (46% and 55%) dominated the diet, yet these two insect orders were rare in light-suction trap (22% lepidopterans and 1% coleopterans) and sticky trap samples (11% lepidopterans and 2% coleopterans). Based on measurements of femur length, all consumed coleopterans were > 5 mm long, even though 57% of those available were < 5 mm. Our results suggest that poorwills are constrained to taking prey above a certain size, but above this threshold, particular prey types and larger sizes may be selected. Selection for coleopterans may reflect the need to acquire polyunsaturated fat to facilitate the use of torpor.

Background Assessment of higher visual processing functions mostly requires active cooperation of participants, which is problematic in children with intellectual disabilities (ID). To circumvent this, we applied remote eye tracking to quantify (ab)normal visual orienting responses in children with ID in terms of reaction times to visual stimuli. Methods We presented visual stimuli (cartoon, coherent form, and coherent motion) to 127 children (2–14 years) with developmental and/or ID (risk group) and simultaneously measured their orienting ocular motor responses. Reaction times to fixation (RTF) in the risk group were compared with RTF values of an age-matched control group. Results Overall, in 72% of the children in the risk group, RTF values to cartoon were delayed, in 47% to form, and in 38% to motion. The presence of delayed reaction times was highest in the group of children >4 years with ID. Conclusion Our data show that a majority of children with developmental and/or ID have delayed visual orienting responses. This suggests that this group has increased risk for higher visual processing dysfunctions. Future studies are planned to correlate abnormal orienting responses to type of brain damage and to dissociate the responses from ocular motor disorders.

The ideomotor theory of action posits that the cognitive representation of an action includes the learned perceptual effects of the action. Support for this theory has come from studies demonstrating how perceptual features that match the outcome of a response can facilitate selection of that response. We investigated another, complementary implication of ideomotor theory: would a bias toward selecting a response result in a perceptual bias toward the known effect of the response? In other words, would an action tendency direct attention to the anticipated perceptual features? Through an initial acquisition phase, participants learned that two possible responses (left/right keypress) consistently produced two distinct colors. Next, in a test phase, we manipulated response bias at the beginning of each trial, using an uninformative spatial prime presented at the left or right periphery. We then examined the extent to which color transients that either matched or mismatched the induced response bias can orient participants’ visual attention. Results revealed a perceptual bias toward the color effect of the primed response, manifested in a stronger visual orienting toward this color. Thus, biasing response selection can bias perception. These findings extend the scope of the ideomotor theory to visual perceptual processes.

Visual orienting attention is well researched by using a visual cue. The tactile spatial attention and the tactile-visual spatial attention have been compared by the brain-imaging data. But the tactile temporal orienting of attention is little be researched or no have any researched.

Spatial asymmetries are an intriguing feature of directed attention. Recent observations indicate an influence of temperament upon the direction of these asymmetries. It is unknown whether this influence generalises to visual orienting behaviour. The aim of the current study was therefore to explore the relationship between temperament and measures of spatial orienting as a function of target hemifield. An exogenous cueing task was administered to 92 healthy participants. Temperament was assessed using Carver and White's (1994) Behavioural Inhibition System and Behavioural Activation System (BIS/BAS) scales. Individuals with high sensitivity to punishment and low sensitivity to reward showed a leftward asymmetry of directed attention when there was no informative spatial cue provided. This asymmetry was not present when targets were preceded by spatial cues that were either valid or invalid. The findings support the notion that individual variations in temperament influence spatial asymmetries in visual orienting, but only when lateral targets are preceded by a non-directional (neutral) cue. The results are discussed in terms of hemispheric asymmetries and dopamine activity.

Hemianopia and strabismus leads to severe disturbance of visual orientation and diplopia under binocular conditions if the deviated eye has a normal retinal localization.Four cases with homonymous (two) and bitemporal (two) hemianopia and strabismus will be described with respect to binocular visual field and diplopia/confusion. All of them were recommended for strabismus surgery. Preoperatively, prism adaptation test was carried out to analyze functional results and fusional competence. In three of the four cases, strabismus surgery was successfully performed to avoid diplopia/confusion. All three patients revealed normal retinal correspondence. Furthermore, in two cases surgery led to an extension of binocular visual field; in one case with a bitemporal hemianopia and hemifield-slide phenomenon, blurred central vision and reading problems reduced significantly postoperatively. In one patient with anomalous retinal correspondence due to early childhood trauma exotropia led to an extension of the binocular visual field. In this case, strabismus surgery would have been unfavourable.Case 1 showed a homonymous hemianopia to the left and acquired exotropia of the right eye, leading to binocular diplopia. Case 2 with homonymous hemianopia to the right and exotropia of right eye revealed anomalous retinal correspondence after history of perinatal brain injury, resulting in absence of diplopia and enlargement of visual field to the right. Cases 3 and 4 with bitemporal hemianopia suffered from sensory disturbances caused by additional acquired strabismus. The exodeviation of the right eye in case 3 led to a restriction of binocular visual field with overlap of the nasal parts causing diplopia, whereas the esodeviation of case 4 resulted in a "gap" between the nasal parts (blind area).Depending on the extent of visual field defects and on retinal correspondence, functional consequences for binocular vision and binocular visual field should be considered prior to surgery. In normal retinal correspondence, strabismus surgery will be indicated in most cases because of diplopia. However, surgery might result in a reduction of binocular visual field. Preoperatively, it is important to map monocular and binocular visual fields, to examine retinal correspondence, and to undertake prism adaptation test to imitate the postoperative functional result and risk of double vision.

We examined the effects of cue luminance on visual orienting. Experiment 1 established that the commonly-found early facilitation and late inhibition of return (IOR) effects were independent of cue luminance with single cues in terms of their amplitude, although IOR was delayed in the low compared to the high luminance cue condition. In contrast, Experiment 2 revealed that, with dual cues of mixed luminance, both facilitation and IOR effects were found only with bright cues. When cues had equal luminance, however, there were cueing effects for two cued locations but only when the cues were bright. The data were accommodated in a neural network model of biased competition in which cueing effects emerge at more than one location provided input activation is sufficient to overcome competitive damping of the selection system. © 2012 Psychology Press, an imprint of the Taylor and Francis Group, an Informa business.

The influence of paroxetine (1x20 mg/day) on safety-relevant performance was compared with the effects of doxepin (2x50 mg/day) and placebo. The medication covered a 3-week period. On day 20 of treatment, ethanol was additionally administered (0.05% BAC). The study group comprised 60 healthy male and female volunteers in the age range 37-60 years, who were assigned to the three structurally identical medication groups under randomized, double-blind conditions. The functional capacity of primary interest was investigated in seven tests to record visual orientation, forced concentration, simple reaction time, choice reaction time, reaction under stress, vigilance, and motor co-ordination. Test sessions took place before the treatment and five times during the medication phase. Paroxetine proved comparable to placebo in all cases, while in comparison with the two reference substances doxepin revealed loss of vigilance and motor coordination, as well as of concentration and the simple (acoustic) reaction time. Language: de

The purpose of this study was to determine whether the familiarity or the novelty of play objects available during mother-infant interaction has an effect on the mother's ability to capture and maintain the infant's attention. Twelve mother-infant dyads with 5- and 9-month-old infants were filmed during two 5-minute sessions with familiar or unfamiliar toys. Changes in the infant's visual orientation preceded by a maternal behaviour within a 3-sec interval were studied. In the familiar toy situation, the infants focused more frequently on the maternal referent than with the unfamiliar toys. The mother's verbal and non-verbal interventions were more effective at initiating and maintaining co-reference, because the infant was more frequently in an receptive state. Conversely, when the toys were unfamiliar, the baby was often the initiator. Unfamiliar objects, which appear more attractive, may compete with the mother's attempts to gain the child's attention.

This study describes the orderly changes in manipulation over the first 6 months in capuchin monkeys (Cebus apella). By 6 months of age, all the basic forms of manipulation seen in adults have appeared. Actions that occur frequently in the first 8 weeks are gentle and involve sustained visual orientation and aimed reaching. Later actions are more vigorous, and involve grasping. Large increases in the rate of activity are evident over the period of development studied. The increase from the first 8 weeks to the second may be due to (a) an increase in the amount of time spent alert and active, (b) a decrease in the amount of time spent in a ventral position, (c) improvements in postural control and stamina and (d) the onset of independent locomotion. Changes in form can be attributed primarily to postural factors and to neuromuscular development (precisely aimed and controlled movements appearing in the 5th and 6th months).

The present study investigated how visual orientation is modulated by subsequent orientation inputs. Observers were presented a near-vertical Gabor patch as a target, followed by a left- or right-tilted second Gabor patch as a distracter in the spatial vicinity of the target. The task of the observers was to judge whether the target was right- or left-tilted (Experiment 1) or whether the target was vertical or not (Supplementary experiment). The judgment was biased toward the orientation of the distracter (the postdictive modulation of visual orientation). The judgment bias peaked when the target and distracter were temporally separated by 100 ms, indicating a specific temporal mechanism for this phenomenon. However, when the visibility of the distracter was reduced via backward masking, the judgment bias disappeared. On the other hand, the low-visibility distracter could still cause a simultaneous orientation contrast, indicating that the distracter orientation is still processed in the visual system (Experiment 2). Our results suggest that the postdictive modulation of visual orientation stems from spatiotemporal integration of visual orientation on the basis of a slow feature matching process.

Visual orienting attention is well researched by using a visual cue. The tactile spatial attention and the tactile-visual spatial attention have been compared by the brain-imaging data.

Reduced gamma-aminobutyric acid (GABA) levels in cerebral cortex are thought to contribute to information processing deficits in patients with schizophrenia (SZ), and we have previously reported lower in vivo GABA levels in the visual cortex of patients with SZ. GABA-mediated inhibition plays a role in sharpening orientation tuning of visual cortical neurons. Therefore, we predicted that tuning for visual stimulus orientation would be wider in SZ. We measured orientation tuning with a psychophysical procedure in which subjects performed a target detection task of a low-contrast oriented grating, following adaptation to a high-contrast grating. Contrast detection thresholds were determined for a range of adapter-target orientation offsets. For both SZ and healthy controls, contrast thresholds decreased as orientation offset increased, suggesting that this tuning curve reflects the selectivity of visual cortical neurons for stimulus orientation. After accounting for generalized deficits in task performance in SZ, there was no difference between patients and controls for detection of target stimuli having either the same orientation as the adapter or orientations far from the adapter. However, patients' thresholds were significantly higher for intermediate adapter-target offsets. In addition, the mean width parameter of a Gaussian fit to the psychophysical orientation tuning curves was significantly larger for the patient group. We also present preliminary data relating visual cortical GABA levels, as measured with magnetic resonance spectroscopy, and orientation tuning width. These results suggest that our finding of broader orientation tuning in SZ may be due to diminished visual cortical GABA levels. © 2011 Rokem, Yoon, Ooms, Maddock, Minzenberg and Silver.

Behavioral experiments on fruit flies had shown that they are attracted by near objects and they prefer front-to-back motion. In this paper a visual orientation model is implemented on the Eye-Ris vision system and tested using a roving platform. Robotic experiments are used to collect statistical data regarding the system behaviour: followed trajectories, dwelling time, distribution of gaze direction and others strictly resembling the biological experimental setup on the flies. The statistical analysis has been performed in different scenarios where the robot faces with different object distribution in the arena. The acquired data has been used to validate the proposed model making a comparison with the fruit fly experiments.

How pilots judge an airplane's position and movement relative to objects on the earth's surface is considered in relation to the size distance invariance hypothesis. Factors that cause systematic departures from size, distance, and angular position constancies are identified, including effects of viewing real and virtual imaging displays. Bias errors in spatial judgments and associated problems in flight are analyzed in terms of the independent and intervening variables, most notably the misaccommodation of the eyes. Two theoretical partial explanations for the anomalous effect the zoom-lens hypothesis and the neural-signals hypothesis—are discussed in relation to recent experimental findings.

With their highly sensitive visual systems, the arthropods have evolved a remarkable capacity to orient and navigate at night. Whereas some navigate under the open sky, and take full advantage of the celestial cues available there, others navigate in more difficult conditions, such as through the dense understory of a tropical rainforest. Four major classes of orientation are performed by arthropods at night, some of which involve true navigation (i.e. travel to a distant goal that lies beyond the range of direct sensory contact): (1) simple straight-line orientation, typically for escape purposes; (2) nightly short-distance movements relative to a shoreline, typically in the context of feeding; (3) long-distance nocturnal migration at high altitude in the quest to locate favorable feeding or breeding sites, and (4) nocturnal excursions to and from a fixed nest or food site (i.e. homing), a task that in most species involves path integration and/or the learning and recollection of visual landmarks. These four classes of orientation – and their visual basis – are reviewed here, with special emphasis given to the best-understood animal systems that are representative of each.

Patients with schizophrenia demonstrate a variety of attentional impairments which have proven difficult to relate to specific neural systems. Posner et al. (1988) reported an asymmetric slowing of right visual field orienting in schizophrenia similar to that observed in patients with parietal lesions. We examined the visual orienting performance of 19 patients and controls using two different versions of the Posner paradigm. In overall ANOVAs we found main effects of group, cue condition, and delay interval. However, we did not observe any main effect of visual field or interactions involving visual field. There was some evidence of an asymmetric cost of invalid cues similar to those reported by Posner et al. The bulk of data suggests bilateral attentional deficits.

This prospective study documented developmental changes, individual stability, and the effects of early experience on the neurobehavioral repertoire of nursery-reared rhesus monkey neonates (Macaca mulatta) tested repeatedly across the first month of life. Thirty-six infants were tested three times weekly on a substantially modified version of the Neonatal Behavioral Assessment Scale. The infants were reared under several conditions in which their exposure to animate and inanimate objects varied. Eleven infants were reared with only a cloth, 8 were reared with an upright cloth-covered surrogate, 7 were reared with an upright movable cloth-covered surrogate, and 10 were reared with an upright movable cloth-covered surrogate and regular exposure to peers and novel toys. Infants reared with a movable surrogate demonstrated superior motor maturation in comparison to those reared with only a cloth or cloth-covered surrogate. However, infants reared with a movable surrogate as well as exposure to peers and novel toys showed not only greater motor maturation than cloth-reared infants but also greater responsiveness on orientation items and lower ratings of fearfulness when compared to infants in the three other conditions. Furthermore, the data indicate that behavioral stability of individual differences can be demonstrated in individuals undergoing rapid developmental change regardless of rearing conditions.

The development of changes in visual orientation, posture, activity budgets, and behavioral milestones was examined in five bongo calves which were observed from birth to 4 or 6 months of age. The only significant change in the calves' visual orientation was an increase in orientation to food. Reclining declined significantly over weeks, while standing increased and moving did not change. Overall, stationary behaviors dominated the activity budget, but decreased significantly over the study. The category that included locomotion, object exploration, and auto-play did not change, while forage and rumination increased significantly. Contrary to expectation, the decline in suckling was not significant. Affiliative interactions with the dam decreased significantly during the study, but increases in affiliation with other bongos were not significant. Levels of agonistic behavior between the calves and their dams and other herd members were low throughout the study, and did not change significantly. One female calf achieved several developmental milestones later than the others. It is suggested that these differences may have been influenced by the dominance status of her dam. The results conform to the general developmental pattern of “hider” bovids. Bongos, however, show somewhat different patterns of social development than eland, which are reported to be more precocial in expression of aggressive and sexual behaviors. © 1992 Wiley-Liss, Inc.

We tested 3D spatial memory for 59 college students in a 50-cm x 50-cm x 50-cm cube. An aperture in the center of each of the cube's six surfaces revealed a picture on a computer monitor. The pictures' locations and orientations changed to simulate multiple perspectives. A pre-trial icon indicated the simulated body orientation, entrance hatch (the picture behind the head), and the target. A trial began with no pictures, and the trainee pressed a key to indicate the target's remembered position. A trail concluded with pictures, and the trainee pressed a key to indicate the target's actual position. Visual orientation illusions suggested that supine trainees should perform better. Memory errors did not support this prediction. Groups who started erect and switch to supine were similar to groups that did the opposite, except for the first 12 trials in which the Erect-Supine Group was better.

Visual orienting tasks reveal an impaired disengagement of attention in schizophrenia. We explored visual orientation in 20 schizophrenia patients (SZ), 20 full siblings (FS), and 20 controls (C) using a cued target detection (gap vs. no gap) and a choice reaction time task. SZ but not FS had longer reaction time with comparable reactions to warning. In contrast to C, SZ and FS did not display a significant gap effect. The disengagement deficit in schizophrenia patients and their siblings provides arguments for altered early attention mechanisms (in schizophrenic patients and their nonpsychotic relatives).

Aims: The aim of this study was to analyse initial orienting processes as well as maintenance of attention towards alcohol cues in recently detoxified alcoholics and light social drinkers. Furthermore, we investigated the influence of pre-treatment alcohol consumption and abstinence duration onto alcohol-related attentional bias. Methods: We used an alcohol-visual-dot-probe-task with two different stimulus onset asynchronies (SOA) to examine processes of initial orienting and maintenance of attention separately (50 and 500 ms SOA). Results: With short SOA, we found a positive attentional bias towards alcohol cues in alcohol-dependent patients and light social drinkers that was positively associated with pre-treatment alcohol consumption in alcoholics. Using a longer SOA, a negative attentional bias was found in light social drinkers and in patients abstinent for more than 2 weeks indicating alcohol stimuli avoidance. In patients, we found a negative correlation between attentional bias and duration of abstinence. Conclusions: After initial visual orienting towards alcohol-related stimuli, light social drinkers as well as longer abstinent alcohol-dependent patients disengage their attention. In patients, this disengagement increased during the first 3 weeks after detoxification indicating assimilation to the attentional bias pattern of light social drinkers.

The aim of this study was to investigate the relation between the vestibular system and orientation in space and the role of acute vestibular lesions in spatial memory. In a first step it could be shown that determining the visual straight ahead is systematically influenced by caloric irrigation: deviations up to 10 degrees appeared, which are directed to the slow phase of the simultaneously provoked nystagmus. In a second step, 20 healthy subjects and 20 patients suffering from an acute vestibular disorder were asked to adjust a luminous point visual straight ahead. Whereas the healthy subjects' visual straight ahead was in a range of +/-2 degrees, the vestibular patients showed significantly greater deviations. If healthy subjects and patients were asked to replace a luminous point, which was exposed for a short time, to its original position, young and older healthy subjects showed good performance, with an error not greater than 3 degrees, whereas the vestibular patients showed significantly greater inaccuracy. We conclude that the visual straight ahead is a vestibular-dependent parameter of visual orientation and that spatial memory is influenced by acute vestibular lesions. For the first time it is shown that acute vestibular lesions impair spatial memory. This can be explained by the close relationship between the vestibular system and the hippocampus.

We have hypothesized that the size of the binocular field among mammals has been selected to maximize the visually surveyable region around the animal (Changizi and Shimojo, 2008). At first glance it may seem that this hypothesis should always predict lateral pointing eyes, and a consequently small binocular field width. However, the hypothesis does not predict lateral pointing eyes in cases where the environment is filled with leafy occlusions and the animal's interpupillary distance surpasses the typical widths of the leaves (when both of these apply, we call the environment “cluttered”). In such cases, within an animal's binocular region the eyes tend to sample the scene independently. Laterally directed eyes also sample the scene independently, but the binocular region benefits from a variety of binocular summation, lowering the threshold for the recognition of objects in the binocular field. Our hypothesis predicts that mammals outside of leafy environments should have small binocular fields, independent of the size of the animal; but it predicts that for animals in leafy environments, whereas small animals should have small binocular fields (because their interpupillary distance is small compared to the typical occlusion width), large animals should have large binocular fields (because the binocular region begins to become more powerful at object recognition). Our paper provided evidence consistent with these predictions.

The majority of studies investigating interactions between vision and touch have typically explored single events, presenting one object at a time. The present study investigates how tactile-visual interactions affect competition between multiple visual objects in more dynamic cluttered environments. Participants searched for a horizontal or vertical line segment among distractor line segments of various orientations, all continuously changing color. Search times and search slopes were substantially reduced when the target color change was accompanied by a tactile signal. These benefits were observed even though the tactile signal was uninformative about the location, orientation, or color of the visual target. We conclude that tactile-visual synchrony guides attention in multiple object environments by increasing the saliency of the visual event. © 2008 Elsevier Ireland Ltd. All rights reserved.

Contains fulltext : 76034.pdf (Publisher’s version ) (Open Access) Using the subjective visual vertical task (SVV), previous investigations on the maintenance of visual orientation constancy during lateral tilt have found two opposite bias effects in different tilt ranges. The SVV typically shows accurate performance near upright but severe undercompensation at tilts beyond 60 deg (A-effect), frequently with slight overcompensation responses (E-effect) in between. Here we investigate whether a Bayesian spatial-perception model can account for this error pattern. The model interprets A- and E-effects as the drawback of a computational strategy, geared at maintaining visual stability with optimal precision at small tilt angles. In this study, we test whether these systematic errors can be seen as the consequence of a precision-accuracy trade-off when combining a veridical but noisy signal about eye orientation in space with the visual signal. To do so, we used a psychometric approach to assess both precision and accuracy of the SVV in eight subjects laterally tilted at 9 different tilt angles (-120 degrees to 120 degrees). Results show that SVV accuracy and precision worsened with tilt angle, according to a pattern that could be fitted quite adequately by the Bayesian model. We conclude that spatial vision essentially follows the rules of Bayes' optimal observer theory. 16 p.

The majority of studies investigating interactions between vision and touch have typically explored single events, presenting one object at a time. The present study investigates how tactile-visual interactions affect competition between multiple visual objects in more dynamic cluttered environments. Participants searched for a horizontal or vertical line segment among distractor line segments of various orientations, all continuously changing color. Search times and search slopes were substantially reduced when the target color change was accompanied by a tactile signal. These benefits were observed even though the tactile signal was uninformative about the location, orientation, or color of the visual target. We conclude that tactile-visual synchrony guides attention in multiple object environments by increasing the saliency of the visual event. © 2008 Elsevier Ireland Ltd. All rights reserved.

The methods used by sarcophagid and calliphorid flies to locate and utilize an ephemeral resource were studied in the field. Their arrival sequences and orientation to an odorous food source on a vertical arena were examined. The first flies arrived at a feeding site soon after a resource became available, and subsequent flies followed rapidly. Sarcophagids tended to arrive before calliphorids. Smaller muscids and chloropids were the last to leave the patch, which indicates a size-based sequence of resource use among flies. The time required by flies to walk to the resource after they had landed nearby decreased significantly as the number of flies increased. This suggests that visual orientation to a group of other flies, in addition to olfactory orientation, improved resource localization. Trials were made with and without wind blowing across the resource. In the wind, flies approached using anemotaxis, landed downwind of the food source, and then walked upwind toward the resource. While walking, anemotactic orientation was more direct and more rapid than was nonanemotactic orientation.