Use Of Motion Cues Research Articles

Motion sequence analysis in the presence of figural cues.

The perception of 3D structure in dynamic sequences is believed to be subserved primarily through the use of motion cues. However, real-world sequences contain many figural shape cues besides the dynamic ones. We hypothesize that if figural cues are perceptually significant during sequence analysis, then inconsistencies in these cues over time would lead to percepts of non-rigidity in sequences showing physically rigid objects in motion. We develop an experimental paradigm to test this hypothesis and present results with two patients with impairments in motion perception due to focal neurological damage, as well as two control subjects. Consistent with our hypothesis, the data suggest that figural cues strongly influence the perception of structure in motion sequences, even to the extent of inducing non-rigid percepts in sequences where motion information alone would yield rigid structures. Beyond helping to probe the issue of shape perception, our experimental paradigm might also serve as a possible perceptual assessment tool in a clinical setting.

Moving and being moved: Differences in cerebral activation during recollection of whole-body motion

While moving through the world, humans as well as animals can make use of motion cues during both active and passive whole-body motion to track their own position in space. However, the functional neuroanatomy of self-motion processing remains poorly understood. In the present study we aimed to characterize brain networks reflecting whole-body self-motion experience. We used retrieval of previously experienced events, which is known to involve cortical representations of the modalities used to perceive these events. Recollection of self-motion experience may thus engage motor and sensory brain areas, reflecting the active or passive nature of the experienced movement, but may engage also common brain areas processing self-motion. We further compared the retrieval networks of self- and observed motion: even though actual action observation has been shown to recruit brain networks similar to those active during mental simulation, it is unclear to which extent recollection networks of these experiences overlap. Brain activation patterns were recorded using fMRI during mental simulation of recent episodes of (1) experiencing linear whole-body motion (active locomotion and passive transport) and (2) observing another person performing the same tasks. Following the experiential phase, participants recalled the episodes during a MR session. We found that primary sensorimotor brain areas dominate the composition of the recollection network of active walking, while recalling passive transport recruits higher level association areas. Common to both self-motion conditions was activation in the medial temporal lobe. Recollection of self-experienced and observed movement overlapped in motor planning areas. Our results provide evidence that the medial temporal lobe is specifically relevant for retrieval of self-motion information and that motor coding during action observation is reflected in recollection networks.

Concurrent task performance and the role of attention in change detection

Detecting a change in a scene is easy when motion cues are available to draw attention to the location of the change. However, when visual contact with the scene is even briefly disrupted, as in the flickering task of Rensink, O'Regan, and Clark (1997), change detection becomes difficult. A brief mask intervening between alternate versions of a photographed scene slowed change detection markedly relative to immediately successive presentations. The difficulty in the flickering task was attributed to the requirement of focused attention to maintain image components in memory for comparison and the need to direct attention serially to different components until the area of change became the focus of attention. However, attention was not manipulated directly. The present series of experiments tested whether limiting the attentional resources available would disrupt change detection by having participants perform concurrent n-back or number-repetition control tasks. Experiments 1 and 2 examined the effects on change detection when alternate forms of the images switched every 320 ms. Experiment 1 allowed the use of motion cues, in that alternate forms of images were presented in immediate succession. Change-detection performance was equivalent for the two concurrent tasks. Experiment 2 removed motion cues by using the flickering task with a mask between alternate forms. Change detection performance was adversely affected by concurrent performance of the n-back task relative to the control. Experiment 3 replicated two presentation conditions from the Rensink study, using a 640 ms image alternation rate. In addition to the mask between alternate forms, in one condition, the presentation time of each form was divided by a mask. In both versions of the task, concurrent performance of the n-back task slowed change detection. Overall, the results support the conclusion that attention is important for change detection when motion cues are not available.

The Paleolithic Stone Age Effect?

Most computer applications feature visual user interfaces that assume that all users have equivalent propensities to perceive, interpret, and understand the multidimensional spatial properties and relationships of the objects presented. However, the hunter-gatherer theory (Silverman & Eals, 1992) suggests that there are modern-day differences between the genders in spatial and cognitive abilities that stem from differentiated prehistoric sex roles. If true, there may be discrepancies in how males and females differentially utilize particular spatial visual cues and interface features. We report three experiments in which participants engage in visual spatial tasks using 2D and 3D virtual worlds: (1) matching object shapes; (2) positioning objects; and (3) resizing objects. Female subjects under-perform male subjects in the matching and positioning experiments, but they outperform male subjects in the resizing experiment. Moreover, male subjects make more use of motion cues. Implications for the design of gender-effective user interfaces and virtual environments are considered.

Real-time tracking for visual interface applications in cluttered and occluding situations

Visual interface systems require object tracking techniques with real-time performance for ubiquitous interaction. A probabilistic framework for a visual tracking system, which robustly tracks targets in real-time using color and motion cues, is presented. The algorithm is based on particle filtering techniques of the I-Condensation filter. An innovation of the paper is the use of motion cues to guide the propagation of particle samples which are being evaluated using color cues. This results in a probabilistic blob tracking method which is shown to greatly outperform conventional blob trackers when in the presence of occlusion and clutter. A second innovation presented is the use of motion-based temporal signatures for the visual recognition of an initialization cue. This allows for passive initialization of the tracking system. The application presented here is the task of digital video annotation using a hand-held marking device.

The relationships of cerebellar vermis morphology to neuropsychological functions in schizophrenia and normal controls

The perception of 3-D structure in dynamic sequences is believed to be subserved primarily through the use of motion cues. However, real-world sequences contain many figural shape cues besides the dynamic ones. We hypothesize that if figural cues are perceptually significant during sequence analysis, then inconsistencies in these cues over time would lead to percepts of non-rigidity in sequences showing physically rigid objects in motion. We develop an experimental paradigm to test this hypothesis and present results with two patients with impairments in motion perception due to focal neurological damage, as well as two control subjects. Consistent with our hypothesis, the data suggest that figural cues strongly influence the perception of structure in motion sequences, even to the extent of inducing non-rigid percepts in sequences where motion information alone would yield rigid structures. Beyond helping to probe the issue of shape perception, our experimental paradigm might also serve as a possible perceptual assessment tool in a clinical setting.

Intelligence, inspection time and cognitive strategies

The use of apparent motion cues to guide discriminations on the inspection time (IT) task has been taken to imply the vulnerability of IT to strategic processes by higher IQ subjects, and the questionable generality of the IT/IQ correlation. The current study examined verbal and non-verbal intelligence, personality and IT in 74 young adults, using light-emitting diodes to present IT, obtaining perceptual self-reports during IT itself. Forty-three (58 per cent) subjects in the sample reported using motion cues to guide IT discriminations; these subjects had faster ITs than individuals who did not use motion cues (t = 2.97, p < .005; effect size = .73). Cue users did not have higher verbal or non-verbal IQ than non-users. Although cue users were lower in neuroticism than non-cue users, this did not account for their faster ITs. Slower IT correlated with lower scores on a measure of non-verbal intelligence (r = -0.41, p < .001); the size of this correlation remained similar when the sample was divided into groups reporting the use of motion cues or not. Thus, despite motion cues enhancing performance on an IT task, the perception of these cues neither causes, nor reduces, the correlation between IT and IQ.

Can Specific Inspection Time Strategies be Inferred by their Latency?

The use of apparent motion cues to guide inspection time (IT) discriminations has been taken to imply the vulnerability of IT to strategic processes. The current study measured the response latency of IT and IT-like tasks, on the grounds that strategic processing tends to be slow, and reflects the conscious use of motion cues during IT. The possibility that cue-reporters have an information-processing advantage prior to perceiving these cues was examined by giving subjects a critical stimulus duration task. IT/IQ correlations were found, irrespective of whether subjects reported using motion cues during IT or not. With the exception of performance on an IT task, there were no psychometric, information-processing, or response time differences between subjects who reported consistent use of motion cues and those who did not. Examination of response times reflecting the different tasks required to complete IT did not isolate a processing stage unique to motion-reporting individuals. Results from this small s...

Model for human use of motion cues in vehicular control

A feedback model for human use of motion cues in tracking and regulation tasks is offered. The motion cue model is developed as a simple extension of a structural model of the human pilot, although other equivalent dynamic representations of the pilot could be used in place of the structural model. In the structural model,it is hypothesized that proprioceptive cues and an internal representation of the vehicle dynamics allow the human to create compensation characteristics that are appropriate for the dynamics of the particular vehicle being controlled. It is shown that an additional loop closure involving motion feedback can improve the pilot/vehicle dynamics by decreasing high-frequency phase lags in the effective open-loop system transfer function. Data from a roll-attitude tracking/regulation task conducted on a moving base simulator are used to verify the modeling approach.