Does binocular disparity or familiar size information override effects of relative size on judgements of time to contact?

Previous studies indicate that non-tau sources of depth information, such as pictorial depth cues, can influence judgements of time to contact (TTC). The effect of relative size on such judgements, the size-arrival effect, is particularly robust. However, earlier studies of the size-arrival effect did not include binocular disparity or familiar size information. The effects of these cues on relative TTC judgements were measured. Results suggested that disparity can eliminate the size-arrival effect but that the amount of disparity needed to do so is greater than typical stereoacuity thresholds. In contrast, familiar size eliminated the size-arrival effect even when disparity information was not available. Furthermore, disparity contributed more to performance when familiar size was present than when it was absent. Consistent with previous studies, TTC judgements were influenced by multiple sources of information. The present results suggested further that familiar size is one such source of information and that familiar size moderates the influence of binocular disparity information.     

How do world-class cricket batsmen anticipate a bowler's intention?

Four experiments are reported that examine the ability of cricket batsmen of different skill levels to pick up advance information to anticipate the type and length of balls bowled by swing and spin bowlers. The information available upon which to make the predictive judgements was manipulated through a combination of temporal occlusion of the display and selective occlusion or presentation of putative anticipatory cues. In addition to a capability to pick up advance information from the same cues used by intermediate and low-skilled players, highly skilled players demonstrated the additional, unique capability to pick up advance information from some specific early cues (especially bowling hand and arm cues) to which the less skilled players were not attuned. The acquisition of expert perceptual-motor skill appears to involve not only refinement of information extraction but also progression to the use of earlier, kinematically relevant sources of information.     

How do world-class cricket batsmen anticipate a bowler's intention?

Four experiments are reported that examine the ability of cricket batsmen of different skill levels to pick up advance information to anticipate the type and length of balls bowled by swing and spin bowlers. The information available upon which to make the predictive judgements was manipulated through a combination of temporal occlusion of the display and selective occlusion or presentation of putative anticipatory cues. In addition to a capability to pick up advance information from the same cues used by intermediate and low-skilled players, highly skilled players demonstrated the additional, unique capability to pick up advance information from some specific early cues (especially bowling hand and arm cues) to which the less skilled players were not attuned. The acquisition of expert perceptual-motor skill appears to involve not only refinement of information extraction but also progression to the use of earlier, kinematically relevant sources of information.     

Effects of head orientation on gaze perception: How positive congruency effects can be reversed

Several past studies have considered how perceived head orientation may be combined with perceived gaze direction in judging where someone else is attending. In three experiments we tested the impact of different sources of information by examining the role of head orientation in gaze-direction judgements when presenting: (a) the whole face; (b) the face with the nose masked; (c) just the eye region, removing all other head-orientation cues apart from some visible part of the nose; or (d) just the eyes, with all parts of the nose masked and no head orientation cues present other than those within the eyes themselves. We also varied time pressure on gaze direction judgements. The results showed that gaze judgements were not solely driven by the eye region. Gaze perception can also be affected by parts of the head and face, but in a manner that depends on the time constraints for gaze direction judgements. While “positive” congruency effects were found with time pressure (i.e., faster left/right judgements of seen gaze when the seen head deviated towards the same side as that gaze), the opposite applied without time pressure.     

Effects of head orientation on gaze perception: how positive congruency effects can be reversed

Several past studies have considered how perceived head orientation may be combined with perceived gaze direction in judging where someone else is attending. In three experiments we tested the impact of different sources of information by examining the role of head orientation in gaze-direction judgements when presenting: (a) the whole face; (b) the face with the nose masked; (c) just the eye region, removing all other head-orientation cues apart from some visible part of the nose; or (d) just the eyes, with all parts of the nose masked and no head orientation cues present other than those within the eyes themselves. We also varied time pressure on gaze direction judgements. The results showed that gaze judgements were not solely driven by the eye region. Gaze perception can also be affected by parts of the head and face, but in a manner that depends on the time constraints for gaze direction judgements. While “positive” congruency effects were found with time pressure (i.e., faster left/right judgements of seen gaze when the seen head deviated towards the same side as that gaze), the opposite applied without time pressure.     

Embodied information affects judgements about politicians: The impact of haptic weight sensations and hand cleansing

Politicians' characteristics attract voters' attention and dominate impression formation. Thereby, social judgements are deduced from different information being available in a certain situation. The literature suggests that incidental bodily sensations can influence judgement processes. Here, two bodily treatments—the haptic sensation of weight and the act of hand cleansing—simultaneously contribute to judgements about politicians. This study expands previous works by (a) investigating potential interactions of two haptic information cues, (b) providing evidence for the significant role of conceptual closeness between embodied cues and judgement dimensions, (c) showing that hand cleansing leads to harsher moral judgements independently of whether a misconduct has been committed or not, and (d) showing that the familiarity of the target to be judged does not moderate the effect of embodied information. The results demonstrate that judgements can be modulated by basal sensorimotor experiences. We discuss implications and the important issue of result generalisation and replicability.     

The sounds of dominance.

A study was conducted to determine the effects of vocal cues on judgements of dominance in an interpersonal influence context. Physical measures of human vocal cues and participant ratings of dominance were obtained from videotapes of actors delivering short influence messages. After controlling for linguistic and visual content of messages, results indicated that mean amplitude and amplitude standard deviation were positively associated with dominance judgments, whereas speech rate was negatively associated with dominance judgments. An unexpected interaction revealed that mean fundamental frequency (F₀) was positively associated with dominance judgments for male speakers but not significantly associated with dominance judgments for female speakers. F₀ standard deviation was not significantly associated with dominance judgments. Results support the conclusion that dominance judgments are inferred from multiple sources of information and that some vocal markers of dominance are more influential than others.     

The visual control of reaching and grasping: binocular disparity and motion parallax

The primary visual sources of depth and size information are binocular cues and motion parallax. Here, the authors determine the efficacy of these cues to control prehension by presenting them in isolation from other visual cues. When only binocular cues were available, reaches showed normal scaling of the transport and grasp components with object distance and size. However, when only motion parallax was available, only the transport component scaled reliably. No additional increase in scaling was found when both cues were available simultaneously. Therefore, although equivalent information is available from binocular and motion parallax information, the latter may be of relatively limited use for the control of the grasp. Binocular disparity appears selectively important for the control of the grasp.     

Perceiving limb position in normal and abnormal control: An equilibrium point perspective

Two potential sources of information allow the nervous system to determine limb position in egocentric space: (i) limb kinaesthesis and (ii) extraretinal cues to direction and distance. We argue that both of these information sources arise from essentially similar physiological origins – copies of the central commands issued by the nervous system together with afferent discharge fed back from the relevant peripheral effectors. A number of studies have demonstrated that judgements of limb position are more accurate when limb kinaesthesis is combined with extraretinal cues. We review some recent studies which suggest that the weighting attached to these two sources of information varies as a function of the amount of retinal detail present within the environment. We conclude by considering how the perception of limb position may be affected in cases of abnormal movement control.PsycINFO classification: 2221; 3250; 3299     

Depth from binocular half-occlusions in stereoscopic images of natural scenes

Over the past two decades psychophysical experiments have firmly established that binocular half-occlusions are useful sources of information for the human visual system. The existing literature has focused on simplified stimuli that have no additional cues to depth, apart from stereopsis. From this large body of work we can be confident that the visual system is able to exploit binocular half-occlusions to aid depth perception; however, we do not know if this signal has any influence on perception when observers view complex stereoscopic stimuli with multiple sources of depth information. This issue is addressed here with the use of stereoscopic images of natural scenes, some of which have been digitally altered to manipulate a major half-occlusion signal. Our results show that depth-ordering judgments for these relatively complex stimuli are significantly affected by the nature of the half-occlusion signal, but only when highly textured surfaces are viewed. Under such conditions, the replacement of a binocular half-occlusion with background texture slows reaction time relative to performance when the occluded region is consistent with the foreground object. This result is specific to conditions when the depth ordering is correct (ie not reversed) and depends upon the size of the half-occlusion. The influence of the half-occlusion information in the presence of potent depth cues such as perspective, texture gradient, shading, and interposition is convincing evidence that this information plays a significant role in human depth perception.     

Pictorial and motion-based information for depth perception.

When computer-generated objects approached the viewpoint in midair, a large far object appeared to be nearer than a small near object and appeared to hit the viewpoint before the small object, which was specified by time-to-contact information to arrive sooner. These judgements were consistent with relative size and occurred even when motion-based information was potentially above threshold. The effects of relative size persisted with higher resolution animated films of approaching objects, were weakened by ground-intercept information, and were not as robust with laterally translating objects. Although it is often asserted that the kinds of information that have traditionally been called static depth cues are superseded by motion-based depth information, this article attempts to show that the reverse also can occur in distance perception, as has been shown in form perception.     

Size-arrival effects: The potential roles of conflicts between monocular and binocular time-to-contact information, and of computer aliasing

With computer simulations of self-motion, participants approached a floating object and tried to “jump” over it without collision. Participants “jumped” significantly later over small objects than they did over larger objects. This occurred when the displays were viewed monocularly or binocularly, a finding that suggests that such size-arrival effects (DeLucia & Warren, 1994) were not due to a conflict between monocular and binocular cues to time-to-contact (TTC) information (Tresilian, 1994,1995). Moreover, the results further suggest that size-arrival effects are not due to irregularities in TTC information that can occur from computer abasing and that the latter does not always affect TTC estimation; visual information used in such judgments does not seem to be extracted on a frame-by-frame basis.     

Size-arrival effects: the potential roles of conflicts between monocular and binocular time-to-contact information, and of computer aliasing.

With computer simulations of self-motion, participants approached a floating object and tried to "jump" over it without collision. Participants "jumped" significantly later over small objects than they did over larger objects. This occurred when the displays were viewed monocularly or binocularly, a finding that suggests that such size-arrival effects (DeLucia & Warren, 1994) were not due to a conflict between monocular and binocular cues to time-to-contact (TTC) information (Tresilian, 1994, 1995). Moreover, the results further suggest that size-arrival effects are not due to irregularities in TTC information that can occur from computer aliasing and that the latter does not always affect TTC estimation; visual information used in such judgments does not seem to be extracted on a frame-by-frame basis.     

Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic,familiar scenes by older and younger adults

Estimating time to contact (TTC) involves multiple sensory systems, including vision and audition. Previous findings suggested that the ratio of an object’s instantaneous optical size/sound intensity to its instantaneous rate of change in optical size/sound intensity (τ) drives TTC judgments. Other evidence has shown that heuristic-based cues are used, including final optical size or final sound pressure level. Most previous studies have used decontextualized and unfamiliar stimuli (e.g., geometric shapes on a blank background). Here we evaluated TTC estimates by using a traffic scene with an approaching vehicle to evaluate the weights of visual and auditory TTC cues under more realistic conditions. Younger (18–39 years) and older (65+ years) participants made TTC estimates in three sensory conditions: visual-only, auditory-only, and audio–visual. Stimuli were presented within an immersive virtual-reality environment, and cue weights were calculated for both visual cues (e.g., visual τ, final optical size) and auditory cues (e.g., auditory τ, final sound pressure level). The results demonstrated the use of visual τ as well as heuristic cues in the visual-only condition. TTC estimates in the auditory-only condition, however, were primarily based on an auditory heuristic cue (final sound pressure level), rather than on auditory τ. In the audio–visual condition, the visual cues dominated overall, with the highest weight being assigned to visual τ by younger adults, and a more equal weighting of visual τ and heuristic cues in older adults. Overall, better characterizing the effects of combined sensory inputs, stimulus characteristics, and age on the cues used to estimate TTC will provide important insights into how these factors may affect everyday behavior.     

Separation of encoding fluency and item difficulty effects on judgements of learning

The fluency of information encoding has frequently been discussed as a major determinant of predicted memory performance indicated by judgements of learning (JOLs). Previous studies established encoding fluency effects on JOLs. However, it is largely unknown whether fluency takes effect above and beyond the effects of item difficulty. We therefore tested whether encoding fluency still affects JOLs when numerous additional cues indicating the difficulty of an item are available as well. In three experiments, participants made JOLs for another participant while observing his or her self-paced study phase. However, study times were swapped in one experimental condition, so that items with short study times (indicating high fluency) were presented for long durations, whereas items with long study times (indicating low fluency) were presented for short durations. Results showed that both item difficulty and encoding fluency affected JOLs. Thus, encoding fluency in itself is indeed an important cue for JOLs that does not become redundant when difficulty information is available in addition. This observation lends considerable support to the ease-of-processing hypothesis.     

Judgments of relative time-to-contact of more than two approaching objects: Toward a method

Observers reported which of as many as eight computer-generated approaching objects would “hit” them first. Accuracy was above chance probability except when two-object displays contained pictorial relative size information that contradicted relative time-to-contact (TTC) information. Mean d’ and response time was greater, but mean efficiency (Barlow, 1978) was smaller with eight objects than with two. Performance was less effective when global expansion contradicted TTC information than when local expansion contradicted TTC. Results suggest that observers can judge relative TTC with as many as eight objects when certain sources of information are consistent with TTC and that observers rely on information other than, or in conjunction with, optical TTC. Also, the sources of visual information that affect performance may vary with set size, and identification (but not detection) judgments may be constrained by limited-capacity processing.     

Audio-visual integration of emotional cues in song

We examined whether facial expressions of performers influence the emotional connotations of sung materials, and whether attention is implicated in audio-visual integration of affective cues. In Experiment 1, participants judged the emotional valence of audio-visual presentations of sung intervals. Performances were edited such that auditory and visual information conveyed congruent or incongruent affective connotations. In the single-task condition, participants judged the emotional connotation of sung intervals. In the dual-task condition, participants judged the emotional connotation of intervals while performing a secondary task. Judgements were influenced by melodic cues and facial expressions and the effects were undiminished by the secondary task. Experiment 2 involved identical conditions but participants were instructed to base judgements on auditory information alone. Again, facial expressions influenced judgements and the effect was undiminished by the secondary task. The results suggest that visual aspects of music performance are automatically and preattentively registered and integrated with auditory cues.     

Landmark use by Clark’s nutcrackers (Nucifraga columbiana): influence of disorientation and cue rotation on distance and direction estimates

Many species have been shown to encode multiple sources of information to orient. To examine what kinds of information animals use to locate a goal we manipulated cue rotation, cue availability, and inertial orientation when the food-storing Clark’s nutcracker (Nucifraga columbiana) was searching for a hidden goal in a circular arena. Three groups of birds were used, each with a different goal–landmark distance. As the distance between the goal and the landmark increased, nutcrackers were less accurate in finding the correct direction to the goal than they were at estimating the distance (Experiment 1). To further examine what cues the birds were using to calculate direction, the featural cues within the environment were rotated by 90° and the birds were either oriented when searching (Experiments 2 and 3) or disoriented (Experiment 3). In Experiment 4, all distinctive visual cues were removed (both internal and external to the environment), a novel point of entry was used and the birds were either oriented or disoriented. We found that disorienting the nutcrackers so that they could not use inertial cues did not influence the birds’ total search error. The birds relied heavily but not completely on cues within the environment, as rotating available cues caused them to systematically shift their search behavior. In addition, the birds also relied to some extent on Earth-based cues. These results show the flexible nature of cue use by the Clark’s nutcracker. Our study shows how multiple sources of spatial information may be important for extracting multiple bearings for navigation.