Attention maintains mental extrapolation of target position: irrelevant distractors eliminate forward displacement after implied motion

Observers' judgments of the final position of a moving target are typically shifted in the direction of implied motion ("representational momentum"). The role of attention is unclear: visual attention may be necessary to maintain or halt target displacement. When attention was captured by irrelevant distractors presented during the retention interval, forward displacement after implied target motion disappeared, suggesting that attention may be necessary to maintain mental extrapolation of target motion. In a further corroborative experiment, the deployment of attention was measured after a sequence of implied motion, and faster responses were observed to stimuli appearing in the direction of motion. Thus, attention may guide the mental extrapolation of target motion. Additionally, eye movements were measured during stimulus presentation and retention interval. The results showed that forward displacement with implied motion does not depend on eye movements. Differences between implied and smooth motion are discussed with respect to recent neurophysiological findings.     

Localization of moving sound

The final position of a moving sound source usually appears to be displaced in the direction of motion. We tested the hypothesis that this phenomenon, termed auditory representational momentum, is already emerging during, not merely after, the period of motion. For this purpose, we investigated the localization of a moving sound at different points in time. In a dark anechoic environment, an acoustic target moved along the frontal horizontal plane. In the initial, middle, or final phase of the motion trajectory, subjects received a tactile stimulus and determined the current position of the moving target at the moment of the stimulus by performing either relative-judgment or pointing tasks. Generally, in the initial phase of the auditory motion, the position was perceived to be displaced in the direction of motion, but this forward displacement disappeared in the further course of the motion. When the motion stimulus had ceased, however, its final position was again shifted in the direction of motion. The latter result suggests that representational momentum in spatial hearing is a phenomenon specific to the final point of motion. Mental extrapolation of past trajectory information is discussed as a potential source of this perceptual displacement.     

Localization of moving sound

The final position of a moving sound source usually appears to be displaced in the direction of motion. We tested the hypothesis that this phenomenon, termed auditory representational momentum, is already emerging during, not merely after, the period of motion. For this purpose, we investigated the localization of a moving sound at different points in time. In a dark anechoic environment, an acoustic target moved along the frontal horizontal plane. In the initial, middle, or final phase of the motion trajectory, subjects received a tactile stimulus and determined the current position of the moving target at the moment of the stimulus by performing either relative-judgment or pointing tasks. Generally, in the initial phase of the auditory motion, the position was perceived to be displaced in the direction of motion, but this forward displacement disappeared in the further course of the motion. When the motion stimulus had ceased, however, its final position was again shifted in the direction of motion. The latter result suggests that representational momentum in spatial hearing is a phenomenon specific to the final point of motion. Mental extrapolation of past trajectory information is discussed as a potential source of this perceptual displacement.     

A comparison of visual and auditory representational momentum in spatial tasks

Similarities have been observed in the localization of the final position of moving visual and moving auditory stimuli: Perceived endpoints that are judged to be farther in the direction of motion in both modalities likely reflect extrapolation of the trajectory, mediated by predictive mechanisms at higher cognitive levels. However, actual comparisons of the magnitudes of displacement between visual tasks and auditory tasks using the same experimental setup are rare. As such, the purpose of the present free-field study was to investigate the influences of the spatial location of motion offset, stimulus velocity, and motion direction on the localization of the final positions of moving auditory stimuli (Experiment 1 and 2) and moving visual stimuli (Experiment 3). To assess whether auditory performance is affected by dynamically changing binaural cues that are used for the localization of moving auditory stimuli (interaural time differences for low-frequency sounds and interaural intensity differences for high-frequency sounds), two distinct noise bands were employed in Experiments 1 and 2. In all three experiments, less precise encoding of spatial coordinates in paralateral space resulted in larger forward displacements, but this effect was drowned out by the underestimation of target eccentricity in the extreme periphery. Furthermore, our results revealed clear differences between visual and auditory tasks. Displacements in the visual task were dependent on velocity and the spatial location of the final position, but an additional influence of motion direction was observed in the auditory tasks. Together, these findings indicate that the modality-specific processing of motion parameters affects the extrapolation of the trajectory.     

质量表征和眼动过度追踪对表征动量的影响

人们对运动目标最终位置的记忆常常会向运动方向发生偏移, 这种偏移被称为“表征动量”。现有研究对表征动量的解释涉及从低水平的知觉加工到高水平的认知加工等多个方面。本研究采用不同材质和滚动声音的球体作为刺激材料, 考察高水平的质量表征对表征动量的影响以及知觉水平的眼动信息在其中的作用。实验1探讨了对目标质量的主观表征对眼动追踪和表征动量的影响。结果显示, 质量表征会同时影响眼动追踪和表征动量。实验2通过不同的提示线索控制眼动追踪, 进一步探讨眼动过度追踪对表征动量的影响。我们发现, 非自然追踪的条件下, 表征动量会减小, 且质量表征对表征动量的影响不再显著。本研究结果表明, 高水平的质量表征对表征动量的影响会通过知觉水平的眼动过度追踪起作用; 然而, 表征动量还受其它因素影响, 眼动信息并非决定表征动量的唯一因素。     

The role of perception in the mislocalization of the final position of a moving target

The judged final position of a moving stimulus has been suggested to be shifted in the direction of motion because of mental extrapolation (representational momentum). However, a perceptual explanation is possible: The eyes overshoot the final position of the target, and because of a foveal bias, the judged position is shifted in the direction of motion. To test this hypothesis, the authors replicated previous studies, but instead of having participants indicate where the target vanished, the authors probed participants' perceptual focus by presenting probe stimuli close to the vanishing point. Identification of probes in the direction of target motion was more accurate immediately after target offset than it was with a delay. Another experiment demonstrated that judgments of the final position of a moving target are affected by whether the eyes maintain fixation or follow the target. The results are more consistent with a perceptual explanation than with a memory account.     

A Simon effect induced by induced motion and location: Evidence for a direct linkage of cognitive and motor maps

It has been argued that two distinct maps of visual space are formed: a cognitive map that is susceptible to illusions, and a motor map that represents the physical world veridically. In the present study, subjects responded to a nonspatial attribute of a visual target stimulus by pressing a left or right key, while an illusory horizontal displacement of the target was induced. A Simon-type effect was obtained to the induced target motion or position shift—that is, responses were faster when the illusory target motion or location corresponded to the response position. Further experiments indicated that the observed effects cannot be accounted for by attentional shifts. These results suggest that the content of the cognitive map does not only influence perceptual judgments but is also responsible for the automatic activation of response codes. In other words, perception and action seem to be fed by a common, cognitively penetrable, spatial representation.     

A Simon effect induced by induced moton and location: evidence for a direct linkage of cognitive and motor maps

It has been argued that two distinct maps of visual space are formed: a cognitive map that is susceptible to illusions, and a motor map that represents the physical world veridically. In the present study, subjects responded to a nonspatial attribute of a visual target stimulus by pressing a left or right key, while an illusory horizontal displacement of the target was induced. A Simon-type effect was obtained to the induced target motion or position shift-that is, responses were faster when the illusory target motion or location corresponded to the response position. Further experiments indicated that the observed effects cannot be accounted for by attentional shifts. These results suggest that the content of the cognitive map does not only influence perceptual judgments but is also responsible for the automatic activation of response codes. In other words, perception and action seem to be fed by a common, cognitively penetrable, spatial representation.     

Illusory motion and representational momentum

When a moving target vanishes abruptly, participants judge its final position as being ahead of its actual final position, in the direction of motion (representational momentum; Freyd & Finke, 1984). In the present study, we presented illusory motion and examined whether or not forward displacement was affected by the perceived direction and speed of the target. Experiments 1A and 1B showed that an illusory direction of movement of a target was perceived, and Experiment 2 showed that an illusory speed of a moving target was observed. However, neither the direction nor the magnitude of forward displacement was affected by these illusions. Therefore, it was suggested that the mechanism underlying forward displacement (or some extrapolation processing) uses different motion signals than does the perceptual mechanism.     

A matter of design: No representational momentum without predictability

When observers are asked to localize the final position of a moving target, a forward shift of the judged final position is observed. So far, the forward shift has been attributed to the influence of mental continuation of the final target position (representational momentum). However, studies investigating forward displacement have used highly predictable target motion. The direction of target motion and the final target position were often varied between subjects. Thus, observers may have expected the target to travel in a particular direction or vanish at a particular location before a given trial started. In this study, direction of motion and final position were treated as fixed or random factors. The forward shift and the reversal of the shift with time (memory averaging) were absent when both factors were randomized. Thus, the forward shift with implied motion is restricted to repeatedly observed motion sequences that allow for pre-trial motion prediction.     

Evidence for an attentional component of the perceptual misalignment between moving and flashing stimuli

If a pair of dots, diametrically opposed to each other, is flashed in perfect alignment with another pair of dots rotating about the visual fixation point, most observers perceive the rotating dots as being ahead of the flashing dots (flash-lag effect). This psychophysical effect was first interpreted as the result of a perceptual extrapolation of the position of the moving dots. Also, it has been conceived as the result of differential visual latencies between flashing and moving stimuli, arising from purely sensory factors and/or expressing the contribution of attentional mechanisms as well. In a series of two experiments, we had observers judge the relative position between rotating and static dots at the moment a temporal marker was presented in the visual field. In experiment 1 we manipulated the nature of the temporal marker used to prompt the alignment judgment. This resulted in three main findings: (i) the flash-lag effect was observed to depend on the visual eccentricity of the flashing dots; (ii) the magnitude of the flash-lag effect was not dependent on the offset of the flashing dot; and (iii) the moving stimulus, when suddenly turned off, was perceived as lagging behind its disappearance location. Taken altogether, these results suggest that neither visible persistence nor motion extrapolation can account for the perceptual flash-lag phenomenon. The participation of attentional mechanisms was investigated in experiment 2, where the magnitude of the flash-lag effect was measured under both higher and lower predictability of the location of the flashing dot. Since the magnitude of the flash-lag effect significantly increased with decreasing predictability, we conclude that the observer's attentional set can modulate the differential latencies determining this perceptual effect. The flash-lag phenomenon can thus be conceived as arising from differential visual latencies which are determined not only by the physical attributes of the stimulus, such as its luminance or eccentricity, but also by attentional mechanisms influencing the delays involved in the perceptual processing.     

Larger forward memory displacement in the direction of gravity

An observer's memory for the final position of a moving stimulus is shifted forward in the direction of its motion. Observers in an upright posture typically show a larger forward memory displacement for a physically downward motion than for a physically upward motion of a stimulus (representational gravity; Hubbard & Bharucha, 1988). We examined whether representational gravity occurred along the environmentally vertical axis or the egocentrically vertical axis. In Experiment 1 observers in either upright or prone postures viewed egocentrically upward and downward motions of a stimulus. Egocentrically downward effects were observed only in the upright posture. In Experiment 2 observers in either upright or prone postures viewed approaching and receding motions of a stimulus along the line of sight. Only in the prone posture did the receding motion produce a larger forward memory displacement than the approaching motion. These results indicate that representational gravity depends not on the egocentric axis but on the environmental axis.     

Environmental invariants in the representation of motion: Implied dynamics and representational momentum,gravity, friction,and centripetal force

Memory for the final position of a moving target is often shifted or displaced from the true final position of that target. Early studies of this memory shift focused on parallels between the momentum of the target and the momentum of the representation of the target and called this displacementrepresentational momentum, but many factors other than momentum contribute to the memory shift. A consideration of the empirical literature on representational momentum and related types of displacement suggests there are at least four different types of factors influencing the direction and magnitude of such memory shifts: stimulus characteristics (e.g., target direction, target velocity), implied dynamics and environmental invariants (e.g., implied momentum, gravity, friction, centripetal force), memory averaging of target and nontarget context (e.g., biases toward previous target locations or nontarget context), and observers’ expectations (both tacit and conscious) regarding future target motion and target/context interactions. Several theories purporting to account for representational momentum and related types of displacement are also considered.     

线索提示对表征动量的影响

研究结合线索提示和表征动量范式,实验1、2均采用2有无线索(有线索,无线索)×4诱导期间时距(1250ms,1750ms,2250ms,2750ms)混合实验设计,探讨线索呈现的加工阶段和时距对表征动量的影响。实验1恒定保持间隔时距,在不同时距的诱导期间呈现线索,发现线索主效应不显著,但表征动量呈减小趋势;时距主效应不显著。实验2变化诱导时距,在恒定的保持间隔呈现线索,发生向后偏移现象,线索主效应显著;时距主效应不显著。研究结果表明,随着注意的增加,表征动量效应减小;注意时距不显著影响表征动量,而注意阶段显著影响表征动量。研究结果为表征动量的双加工理论提供了实证支持。     

Auditory temporal cues can modulate visual representational momentum

In representational momentum (RM), the final position of a moving target is mislocalized in the direction of motion. Here, the effect of a concurrent sound on visual RM was demonstrated. A visual stimulus moved horizontally and disappeared at unpredictable positions. A complex tone without any motion cues was presented continuously from the beginning of the visual motion. As compared with a silent condition, the RM magnitude increased when the sound lasted longer than and decreased when it did not last as long as the visual motion. However, the RM was unchanged when a brief complex tone was presented before or after the target disappeared (Experiment 2) or when the onset of the long-lasting sound was not synchronized with that of the visual motion (Experiments 3 and 4). These findings suggest that visual motion representation can be modulated by a sound if the visual motion information is firmly associated with the auditory information.     

Lateral differences in visual inspection time? The role of apparent motion cues

There are a number of reports of a left hemisphere advantage for visual inspection time, but some investigators employing slightly different methodologies have failed to replicate the effect. The present experiment was an attempt to identify one of the factors that could have lead to these discrepant findings: The role of apparent motion cues. In Experiment 1, a lateralized version of the inspection time task was administered via a computer monitor wherein the pi stimulus was masked with a figure vulnerable to apparent motion cues. With this mask, a strong left hemisphere advantage was observed. In Experiments 2 and 3, the test was administered on a tachistoscope or computer monitor, but in both cases the stimulus was masked with a pattern "forest" mask. Under these conditions, there was no lateral difference. This result implies that the left hemisphere advantage for inspection time relies on apparent motion cues.     

虚拟学习环境下图形加工的认知负荷研究

基于单探测变化觉察和双任务范式,采用项目数量（3）×呈现时间（2）×文字线索（2）混合实验设计,对沉浸式虚拟学习环境图形加工特征和认知负荷进行探讨,以任务绩效法与主观测量法评定认知负荷。44名大学生的实验结果显示：（1）项目数量对虚拟空间图形识记主任务绩效和主观认知负荷有显著影响,项目数量越多,主任务正确率越低,反应时越长,主观评定认知负荷越高,同时加工刺激数量以4个为宜;（2）呈现时间对虚拟空间图形识记次任务绩效有显著影响,呈现时间越长,次任务正确率越高,呈现时间超过0.5s有利于次任务加工;（3）文字线索对虚拟图形识记认知负荷有显著影响,重复性文字线索会增加认知负荷。结果表明,在沉浸式虚拟环境中,图形加工的认知负荷特点与平面和三维图形基本一致,项目数量多、呈现时间短以及有重复性文字线索时,认知负荷更高;任务绩效和主观测量评定指标在反映认知负荷强度上不完全一致。     

线索呈现的时空特性对表征动量的影响

为揭示注意对表征动量的影响机制,我们结合线索提示和表征动量范式,通过两个实验比较高、低相关线索分别在诱导期间与保持间隔呈现对表征动量的影响,结果发现：(1)高相关线索的时间特性主效应不显著,最终位置均发生边缘性的向前偏移。(2)低相关线索呈现在诱导期间时,表征动量显著;呈现在保持间隔时,发生向后偏移。这些表明,随着注意增大,表征动量减小;高相关线索更有利于定位,而低相关线索易受时间特性的影响。研究结果验证表征动量的双加工理论。     

An effect of context on whether memory for initial position exhibits a Fr?hlich effect or an onset repulsion effect.

Memory for the initial and final positions of moving targets was examined. When targets appeared adjacent to the boundary of a larger enclosing window, memory for initial position exhibited a Fr?hlich effect (i.e., a displacement forward), and when distance of initial position from the boundary increased, memory for initial position exhibited a smaller Fr?hlich effect or an onset repulsion effect (i.e., a displacement backward). When targets vanished adjacent to the boundary of a larger enclosing window, memory for final position was displaced backward, and when distance of final position from the boundary increased, memory for final position did not exhibit significant displacement. These patterns differed from previously reported displacements of initial and final positions of targets presented on a blank background. Possible influences of attention and extrapolation of trajectory on whether memory for initial position exhibits a Fr?hlich effect or an onset repulsion effect and on backward displacement in memory for final position are discussed.     

Do as I say - or as I do?! How 18- and 24-month-olds integrate words and actions to infer intentions in situations of match or mismatch

Infants use behavioral and verbal cues to infer another person’s action intention. However, it is still unclear how infants integrate these often co-occurring cues depending on the cues’ coherence (i.e., the degree to which the cues provide coherent information about another’s intention). This study investigated how 18- and 24-month-olds’ (N = 88 per age group) action selection was influenced by varying the coherence of a model’s verbal and behavioral cues. Using a between-subjects design, infants received six trials with different stimulus objects. In the conditions Congruent, Incongruent, and Failed-attempt, the model uttered a telic verb particle that was followed by a matching or contradicting goal-directed action demonstration, or by a non goal-directed slipping motion, respectively. In the condition Pseudo-word, a nonsense word was combined with a goal-directed action demonstration. Infants’ action selection indicated an adherence to the verbal cue in Congruent, Incongruent, and Failed-attempt, and this was stronger in 24- than 18-month-olds. Additionally, in Incongruent and Failed-attempt, patterns of cue integration across the six trials varied in the two age groups. Regarding the behavioral cue, infants in Congruent and Pseudo-word preferentially followed this cue in both age groups, which also suggested a rather unspecific effect of the verbal cue in Congruent. Relatively longer first action-latencies in Incongruent and Failed-attempt implied that these types of coherence elicited higher cognitive demands than in Congruent and Pseudo-word. Results are discussed in light of infants’ flexibility in using social cues, depending on the cue’s coherence and on age-related social-cognitive differences.