Differential effects of shared attention on perception of heading and 3-D object motion

When a person moves in a straight line through a stationary environment, the images of object surfaces move in a radial pattern away from a single point. This point, known as the focus of expansion (FOE), corresponds to the person's direction of motion. People judge their heading from image motion quite well in this situation. They perform most accurately when they can see the region around the FOE, which contains the most useful information for this task. Furthermore, a large moving object in the scene has no effect on observer heading judgments unless it obscures the FOE. Therefore, observers may obtain the most accurate heading judgments by focusing their attention on the region around the FOE. However, in many situations (e.g., driving), the observer must pay attention to other moving objects in the scene (e.g., cars and pedestrians) to avoid collisions. These objects may be located far from the FOE in the visual field. We tested whether people can accurately judge their heading and the three-dimensional (3-D) motion of objects while paying attention to one or the other task. The results show that differential allocation of attention affects people's ability to judge 3-D object motion much more than it affects their ability to judge heading. This suggests that heading judgments are computed globally, whereas judgments about object motion may require more focused attention.     

Differential effects of shared attention on perception of heading and 3-D object motion

When a person moves in a straight line through a stationary environment, the images of object surfaces move in a radial pattern away from a single point. This point, known as thefocus of expansion (FOE), corresponds to the person’s direction of motion. People judge their heading from image motion quite well in this situation. They perform most accurately when they can see the region around the FOE, which contains the most useful information for this task. Furthermore, a large moving object in the scene has no effect on observer heading judgments unless it obscures the FOE. Therefore, observers may obtain the most accurate heading judgments by focusing their attention on the region around the FOE. However, in many situations (e.g., driving), the observer must pay attention to other moving objects in the scene (e.g., cars and pedestrians) to avoid collisions. These objects may be located far from the FOE in the visual field. We tested whether people can accurately judge their heading and the three-dimensional (3-D) motion of objects while paying attention to one or the other task. The results show that differential allocation of attention affects people’s ability to judge 3-D object motion much more than it affects their ability to judge heading. This suggests that heading judgments are computed globally, whereas judgments about object motion may require more focused attention.     

Perception of self-motion from visual flow

Accurate and efficient control of self-motion is an important requirement for our daily behavior. Visual feedback about self-motion is provided by optic flow. Optic flow can be used to estimate the direction of self-motion (‘heading’) rapidly and efficiently. Analysis of oculomotor behavior reveals that eye movements usually accompany self-motion. Such eye movements introduce additional retinal image motion so that the flow pattern on the retina usually consists of a combination of self-movement and eye movement components. The question of whether this ‘retinal flow’ alone allows the brain to estimate heading, or whether an additional ‘extraretinal’ eye movement signal is needed, has been controversial. This article reviews recent studies that suggest that heading can be estimated visually but extraretinal signals are used to disambiguate problematic situations. The dorsal stream of primate cortex contains motion processing areas that are selective for optic flow and self-motion. Models that link the properties of neurons in these areas to the properties of heading perception suggest possible underlying mechanisms of the visual perception of self-motion.     

Perceiving curvilinear heading in the presence of moving objects

Four experiments were directed at understanding the influence of multiple moving objects on curvilinear (i.e., circular and elliptical) heading perception. Displays simulated observer movement over a ground plane in the presence of moving objects depicted as transparent, opaque, or black cubes. Objects either moved parallel to or intersected the observer's path and either retreated from or approached the moving observer. Heading judgments were accurate and consistent across all conditions. The significance of these results for computational models of heading perception and for information in the global optic flow field about observer and object motion is discussed.     

When Group Influence Is More or Less Likely: The Case of Moral Judgments

We investigated whether group influence can change judgments even for high-consensus (i.e., unambiguous) moral norms. We found that participants often matched the judgment of the other current group members even when this moral judgment was normatively incorrect (nonstandard), and this occurred more for more ambiguous issues. Moreover, this social influence on public judgments was generally followed by private agreement and re-interpreting general values to be consistent with those judgements. We also found that participants who experienced a fit between their regulatory focus and their feelings of power (i.e., promotion/high power; prevention/low power) were less influenced by the group.     

Dynamic Occlusion and Optical Flow From Corrugated Surfaces

Dynamic occlusion (i.e., accretion and deletion of optical texture at the occluding edge) can occur under many different environmental conditions, for example, objects hidden behind other objects when viewed by a moving observer, objects moving in front of other objects, or an observer approaching a brink. Because each of these conditions may require the actor to respond differently, the actor may need to be able to differentiate these situations reliably. This study was directed at the optical pattern induced by dynamic occlusion that occurs when one locomotes over a rolling terrain (i.e., a corrugated surface). Two experiments were conducted for this purpose. Participants viewed displays simulating their translation along a corrugated surface in which surface corrugation, texture type, and texture density varied as part of experimental control. Results demonstrated that the visual system reliably extracts the global flow pattern for accurate perception of heading direction despite the presence of optical disturbances in optical flow. However, performance nearly failed in the unstructured texture displays wherein optical disturbances were less salient. Still, the results provide strong evidence that human observers are sufficiently sensitive to dynamic occlusion to extract information about heading direction.     

The role of a change heuristic in judgments of sound duration

The present study investigated whether the quality of a frequency change within a sound (i.e., smooth vs. abrupt) would influence perception of its duration. In three experiments, participants were presented with two consecutive sounds on each of a series of trials, and their task was to judge whether the second sound was longer or shorter in duration than the first. In Experiment 1, participants were more likely to judge sounds consisting of a smooth and continuous change in frequency as longer in duration than sounds that maintained a constant frequency. In Experiment 2, the same bias was observed for sounds incorporating an abrupt change in frequency, but only when the frequency change was relatively small. The results of Experiment 3 suggested that the application of a change heuristic when generating duration judgments depends on the perception of change as originating from a single, integrated perceptual object.     

Allocentric and egocentric updating of spatial memories

In 4 experiments, the authors investigated spatial updating in a familiar environment. Participants learned locations of objects in a room, walked to the center, and turned to appropriate facing directions before making judgments of relative direction (e.g., "Imagine you are standing at X and facing Y. Point to Z.") or egocentric pointing judgments (e.g., "You are facing Y. Point to Z."). Experiments manipulated the angular difference between the learning heading and the imagined heading and the angular difference between the actual heading and the imagined heading. Pointing performance was best when the imagined heading was parallel to the learning view, even when participants were facing in other directions, and when actual and imagined headings were the same. Room geometry did not affect these results. These findings indicated that spatial reference directions in memory were not updated during locomotion.     

On the signals underlying conscious awareness of action

To investigate whether conscious judgments of movement onset are based solely on pre-movement signals (i.e., premotor or efference copy signals) or whether sensory feedback (i.e., reafferent) signals also play a role, participants judged the onset of finger and toe movements that were either active (i.e., self initiated) or passive (i.e., initiated by the experimenter). Conscious judgments were made by reporting the position of a rotating clock hand presented on a computer screen and were then compared to the actual measured time of movement onset. In line with previous studies, judgment errors were found to be anticipatory for both finger and toe movements. There was a significant difference between judgment errors for active and passive movements, with judgments of active movements being more anticipatory than judgments of passive movements. This is consistent with a pre-movement (from here on referred to as an “efferent”) account of action awareness because premotor and efference copy signals are only present in active movements, whereas the main source of movement information in passive movements is sensory feedback which is subject to time delays of conduction (and hence predicts later judgment times for passive movements). However, judgments of active toe movement onset time were less anticipatory than judgments of active finger movement onset time. This pattern of results is not consistent with a pure efferent account of conscious awareness of action onset - as this account predicts more anticipatory judgments for toe movements compared to finger movements. Instead, the data support the idea that conscious judgments of movement onset are based on efferent (i.e., premotor, efference copy) and reafferent (i.e., feedback from the movement) components.     

Representations of interobject spatial relations in long-term memory

A growing body of evidence has indicated that human spatial memory is organized in terms of a small number of reference directions and that interobject spatial relations are represented in terms of these directions (e.g., McNamara, 2003). The goal of the present experiments was to investigate whether the selection of reference directions also affects the fidelity with which interobject spatial relations are represented in memory. In two experiments, participants memorized a layout of nine objects and then performed judgments of relative direction (e.g., “Imagine you are standing at the clock, facing the book. Point to the phone.”) at a remote location. Imagined heading (e.g., at the clock, facing the book) and allocentric target direction (e.g., the direction from clock to phone in the allocentric frame of reference used to define imagined heading) were manipulated independently. The results of both experiments showed that the same directions that were benefited in imagined headings were also benefited in allocentric target directions. These findings indicate that interobject spatial relations are preferentially represented when they coincide with a reference direction.     

Dissociating averageness and attractiveness: attractive faces are not always average

Although the averageness hypothesis of facial attractiveness proposes that the attractiveness of faces is mostly a consequence of their averageness, 1 study has shown that caricaturing highly attractive faces makes them mathematically less average but more attractive. Here the authors systematically test the averageness hypothesis in 5 experiments using both rating and visual adaptation paradigms. Visual adaptation has previously been shown to increase both preferences for previously viewed face types (i.e., attractiveness) and their perceived normality (i.e., averageness). The authors used a visual adaptation procedure to test whether facial attractiveness is dependent upon faces' proximity to average (averageness hypothesis) or their location relative to average along an attractiveness dimension in face space (contrast hypothesis). While the typical pattern of change due to visual adaptation was found for judgments of normality, judgments of attractiveness resulted in a very different pattern. The results of these 5 experiments conclusively support the proposal that there are specific nonaverage characteristics that are particularly attractive. The authors discuss important implications for the interpretation of studies using a visual adaptation paradigm to investigate attractiveness.     

Affective and cognitive meta-bases of attitudes: Unique effects on information interest and persuasion

The authors investigated the predictive utility of people's subjective assessments of whether their evaluations are affect- or cognition driven (i.e., meta-cognitive bases) as separate from whether people's attitudes are actually affect- or cognition based (i.e., structural bases). Study 1 demonstrated that meta-bases uniquely predict interest in affective versus cognitive information above and beyond structural bases and other related variables (i.e., need for cognition and need for affect). In Study 2, meta-bases were shown to account for unique variance in attitude change as a function of appeal type. Finally, Study 3 showed that as people became more deliberative in their judgments, meta-bases increased in predictive utility, and structural bases decreased in predictive utility. These findings support the existence of meta-bases of attitudes and demonstrate that meta-bases are distinguishable from structural bases in their predictive utility.     

Visual determinants of a cross-modal illusion

Contrary to the predictions of established theory, Schutz and Lipscomb (2007) have shown that visual information can influence the perceived duration of concurrent sounds. In the present study, we deconstruct the visual component of their illusion, showing that (1) cross-modal influence depends on visible cues signaling an impact event (namely, a sudden change of direction concurrent with tone onset) and (2) the illusion is controlled primarily by the duration of post-impact motion. Other aspects of the post-impact motion—distance traveled, velocity, acceleration, and the rate of its change (i.e., its derivative, jerk)—play a minor role, if any. Together, these results demonstrate that visual event duration can influence the perception of auditory event duration, but only when stimulus cues are sufficient to give rise to the perception of a causal cross-modal relationship. This refined understanding of the illusion’s visual aspects is helpful in comprehending why it contrasts so markedly with previous research on cross-modal integration, demonstrating that vision does not appreciably influence auditory judgments of event duration (Walker & Scott, 1981).     

Cross-cultural differences in mental representations of time: evidence from an implicit nonlinguistic task

Across cultures people construct spatial representations of time. However, the particular spatial layouts created to represent time may differ across cultures. This paper examines whether people automatically access and use culturally specific spatial representations when reasoning about time. In Experiment 1, we asked Hebrew and English speakers to arrange pictures depicting temporal sequences of natural events, and to point to the hypothesized location of events relative to a reference point. In both tasks, English speakers (who read left to right) arranged temporal sequences to progress from left to right, whereas Hebrew speakers (who read right to left) arranged them from right to left, replicating previous work. In Experiments 2 and 3, we asked the participants to make rapid temporal order judgments about pairs of pictures presented one after the other (i.e., to decide whether the second picture showed a conceptually earlier or later time-point of an event than the first picture). Participants made responses using two adjacent keyboard keys. English speakers were faster to make "earlier" judgments when the "earlier" response needed to be made with the left response key than with the right response key. Hebrew speakers showed exactly the reverse pattern. Asking participants to use a space-time mapping inconsistent with the one suggested by writing direction in their language created interference, suggesting that participants were automatically creating writing-direction consistent spatial representations in the course of their normal temporal reasoning. It appears that people automatically access culturally specific spatial representations when making temporal judgments even in nonlinguistic tasks.     

A stochastic detection and retrieval model for the study of metacognition

We present a signal detection-like model termed the stochastic detection and retrieval model (SDRM) for use in studying metacognition. Focusing on paradigms that relate retrieval (e.g., recall or recognition) and confidence judgments, the SDRM measures (1) variance in the retrieval process, (2) variance in the confidence process, (3) the extent to which different sources of information underlie each response, (4) simple bias (i.e., increasing or decreasing confidence criteria across conditions), and (5) metacognitive bias (i.e., contraction or expansion of the confidence criteria across conditions). In the metacognition literature, gamma correlations have been used to measure the accuracy of confidence judgments. However, gamma cannot distinguish between the first 3 attributes, and it cannot measure either form of bias. In contrast, the SDRM can distinguish among the attributes, and it can measure both forms of bias. In this way, the SDRM can be used to test competing process theories by determining the attribute that best accounts for a change across conditions. To demonstrate the SDRM's usefulness, we investigated judgments of learning (JOLs) followed by cued-recall. Through a series of nested and non-nested model comparisons applied to a new experiment, the SDRM determined that a reduction in variance during the confidence process is the most likely explanation of the delayed-JOL effect, and a stronger relation between information underlying JOLs and recall is the most likely explanation of the testing-JOL effect. Following a brief discussion of implications for JOL theories, we conclude with a broader discussion of how the SDRM can benefit metacognition research.     

自我参照和环境参照整合过程中的主方位判断

通过三个实验证明,自我参照和环境参照转化与整合过程中的主方位判断受拍摄方向和目标位置的影响。二者对主方位判断的作用模式不会随主方位判断任务的改变而改变,拍摄方向效表现为：朝北效应（匹配效应）和主方位效应,体现的是自我参照和环境参照整合过程中环境参照对主方位的影响;目标位置效应的认知加工时间模式可表示为：前-后轴<左-右轴<其他位置,体现的是自我参照和环境参照整合过程中自我参照对主方位的影响。本文以规范轴和规范方向为框架对数据结果进行了分析和解释。     

Perception of translational heading from optical flow

Radial patterns of optical flow produced by observer translation could be used to perceive the direction of self-movement during locomotion, and a number of formal analyses of such patterns have recently appeared. However, there is comparatively little empirical research on the perception of heading from optical flow, and what data there are indicate surprisingly poor performance, with heading errors on the order of 5 degrees-10 degrees. We examined heading judgments during translation parallel, perpendicular, and at oblique angles to a random-dot plane, varying observer speed and dot density. Using a discrimination task, we found that heading accuracy improved by an order of magnitude, with 75%-correct thresholds of 0.66 degrees in the highest speed and density condition and 1.2 degrees generally. Performance remained high with displays of 63-10 dots, but it dropped significantly with only 2 dots; there was no consistent speed effect and no effect of angle of approach to the surface. The results are inconsistent with theories based on the local focus of outflow, local motion parallax, multiple fixations, differential motion parallax, and the local maximum of divergence. But they are consistent with Gibson's (1950) original global radial outflow hypothesis for perception of heading during translation.     

Individual differences in the perception of similarity and difference

Thematically related concepts like coffee and milk are judged to be more similar than thematically unrelated concepts like coffee and lemonade. We investigated whether thematic relations exert a small effect that occurs consistently across participants (i.e., a generalized model), or a large effect that occurs inconsistently across participants (i.e., an individualized model). We also examined whether difference judgments mirrored similarity or whether these judgments were, in fact, non-inverse. Five studies demonstrated the necessity of an individualized model for both perceived similarity and difference, and additionally provided evidence that thematic relations affect similarity more than difference. Results suggest that models of similarity and difference must be attuned to large and consistent individual variability in the weighting of thematic relations.     

Recollection-based prospective metamemory judgments are more accurate than those based on confidence: judgments of remembering and knowing (JORKS)

Five experiments were conducted to examine whether the nature of the information that is monitored during prospective metamemory judgments affected the relative accuracy of those judgments. We compared item-by-item judgments of learning (JOLs), which involved participants determining how confident they were that they would remember studied items, with judgments of remembering and knowing (JORKs), which involved participants determining whether studied items would later be accompanied by contextual details (i.e., remembering) or would not (i.e., knowing). JORKs were more accurate than JOLs when remember-know or confidence judgments were made at test and when cued recall was the outcome measure, but not for yes-no recognition. We conclude that the accuracy of metamemory judgments depends on the nature of the information monitored during study and test and that metamemory monitoring can be improved if participants are asked to base their judgments on contextual details rather than on confidence. These data support the contention that metamemory decisions can be based on qualitatively distinct cues, rather than an overall memory strength signal.     

Geometric cues,reference frames,and the equivalence of experienced-aligned and novel-aligned views in human spatial memory

Spatial memories are often organized around reference frames, and environmental shape provides a salient cue to reference frame selection. To date, however, the environmental cues responsible for influencing reference frame selection remain relatively unknown. To connect research on reference frame selection with that on orientation via environmental shape, we explored the extent to which geometric cues were incidentally encoded and represented in memory by evaluating their influence on reference frame selection. Using a virtual environment equipped with a head-mounted-display, we presented participants with to-be-remembered object arrays. We manipulated whether the experienced viewpoint was aligned or misaligned with global (i.e., the principal axis of space) or local (i.e., wall orientations) geometric cues. During subsequent judgments of relative direction (i.e., participants imagined standing at one object, facing a second object, and pointed toward a third object), we show that performance was best when imagining perspectives aligned with these geometric cues; moreover, global geometric cues were sufficient for reference frame selection, global and local geometric cues were capable of exerting differential influence on reference frame selection, and performance from experienced-imagined perspectives was equivalent to novel-imagined perspectives aligned with geometric cues. These results explicitly connect theory regarding spatial reference frame selection and spatial orientation via environmental shape and indicate that spatial memories are organized around fundamental geometric properties of space.