Mintao Zhao

Layout geometry in the selection of intrinsic frames of reference from multiple viewpoints

Four experiments investigated the roles of layout geometry in the selection of intrinsic frames of reference in spatial memory. Participants learned the locations of objects in a room from 2 or 3 viewing perspectives. One view corresponded to the axis of bilateral symmetry of the layout, and the other view(s) was (were) nonorthogonal to the axis of bilateral symmetry. Judgments of relative direction using spatial memory were quicker for imagined headings parallel to the symmetric axis than for those parallel to the other viewing perspectives. This advantage disappeared when the symmetric axis was eliminated. Moreover, there was more consistency across participants in the selection of intrinsic axes when the layout contained an axis of bilateral symmetry than when it did not. These results indicate that the layout geometry affects the selection of intrinsic frames of reference supporting the intrinsic model of spatial memory proposed by W. Mou and T. P. McNamara (2002) and by A. L. Shelton and T. P. McNamara (2001).

Integrative processing of invariant aspects of faces:Effect of gender and race processing on identity analysis

While separation of face identity and expression processing is favored by many face perception models, how the visual system analyzes identity and other face properties remains elusive. Here we investigated whether identity analysis is independent of or influenced by automatic processing of face gender and race. Participants searched for a target face among distractor faces whose gender or race was either the same as or different from the target face. Visual search was faster and more accurate when target and distractor faces differed in gender or race property than when not. The effect persisted for identification of both familiar and novel faces, and cannot be attributed to the low-level physical properties of stimuli or the earlier extraction of face gender/race information before identification. Together with complementary findings showing effects of identity analysis on gender and race categorization, these results indicate that invariant face properties are processed in an integrative way: visual analysis of one property involves, and is therefore affected by, automatic processing of the others. Implications for current theoretical models of face perception are discussed.

Holistic processing underlies gender judgments of faces

In three experiments, we investigated whether holistic processing underlies gender judgments about faces. Chinese participants were asked to make gender judgments for inverted, scrambled, or composite faces. Results showed that judgments were dramatically impaired by these manipulations (as compared with performance for normal upright faces), demonstrating three hallmark effects of holistic face processing that have been observed in perception of face identity. Whether the test faces were Chinese or Caucasian showed no effect on holistic processing of gender perception, in contrast to studies of identity analysis. These results suggest that holistic processing is a general mechanism for different aspects of face perception and are consistent with the idea that physiognomic properties that determine the gender of a face are universal, rather than race specific.

How You Get There From Here Interaction of Visual Landmarks and Path Integration in Human Navigation

How do people combine their sense of direction with their use of visual landmarks during navigation? Cue-integration theory predicts that such cues will be optimally integrated to reduce variability, whereas cue-competition theory predicts that one cue will dominate the response direction. We tested these theories by measuring both accuracy and variability in a homing task while manipulating information about path integration and visual landmarks. We found that the two cues were near-optimally integrated to reduce variability, even when landmarks were shifted up to 90°. Yet the homing direction was dominated by a single cue, which switched from landmarks to path integration when landmark shifts were greater than 90°. These findings suggest that cue integration and cue competition govern different aspects of the homing response: Cues are integrated to reduce response variability but compete to determine the response direction. The results are remarkably similar to data on animal navigation, which implies that visual landmarks reset the orientation, but not the precision, of the path-integration system.

Face format at encoding affects the other-race effect in face memory.

Memory of own-race faces is generally better than memory of other-races faces. This other-race effect (ORE) in face memory has been attributed to differences in contact, holistic processing, and motivation to individuate faces. Since most studies demonstrate the ORE with participants learning and recognizing static, single-view faces, it remains unclear whether the ORE can be generalized to different face learning conditions. Using an old/new recognition task, we tested whether face format at encoding modulates the ORE. The results showed a significant ORE when participants learned static, single-view faces (Experiment 1). In contrast, the ORE disappeared when participants learned rigidly moving faces (Experiment 2). Moreover, learning faces displayed from four discrete views produced the same results as learning rigidly moving faces (Experiment 3). Contact with other-race faces was correlated with the magnitude of the ORE. Nonetheless, the absence of the ORE in Experiments 2 and 3 cannot be readily explained by either more frequent contact with other-race faces or stronger motivation to individuate them. These results demonstrate that the ORE is sensitive to face format at encoding, supporting the hypothesis that relative involvement of holistic and featural processing at encoding mediates the ORE observed in face memory.

Environmental stability modulates the role of path integration in human navigation

Path integration has long been thought of as an obligatory process that automatically updates ones position and orientation during navigation. This has led to the hypotheses that path integration serves as a back-up system in case landmark navigation fails, and a reference system that detects discrepant landmarks. Three experiments tested these hypotheses in humans, using a homing task with a catch-trial paradigm. Contrary to the back-up system hypothesis, when stable landmarks unexpectedly disappeared on catch trials, participants were completely disoriented, and only then began to rely on path integration in subsequent trials (Experiment 1). Contrary to the reference system hypothesis, when stable landmarks unexpectedly shifted by 115° on catch trials, participants failed to detect the shift and were completely captured by the landmarks (Experiment 2). Conversely, when chronically unstable landmarks unexpectedly remained in place on catch trials, participants failed to notice and continued to navigate by path integration (Experiment 3). In the latter two cases, they gradually sensed the instability (or stability) of landmarks on later catch trials. These results demonstrate that path integration does not automatically serve as a back-up system, and does not function as a reference system on individual sorties, although it may contribute to monitoring environmental stability over time. Rather than being automatic, the roles of path integration and landmark navigation are thus dynamically modulated by the environmental context.

Holistic processing, contact, and the other-race effect in face recognition

Face recognition, holistic processing, and processing of configural and featural facial information are known to be influenced by face race, with better performance for own- than other-race faces. However, whether these various other-race effects (OREs) arise from the same underlying mechanisms or from different processes remains unclear. The present study addressed this question by measuring the OREs in a set of face recognition tasks, and testing whether these OREs are correlated with each other. Participants performed different tasks probing (1) face recognition, (2) holistic processing, (3) processing of configural information, and (4) processing of featural information for both own- and other-race faces. Their contact with other-race people was also assessed with a questionnaire. The results show significant OREs in tasks testing face memory and processing of configural information, but not in tasks testing either holistic processing or processing of featural information. Importantly, there was no cross-task correlation between any of the measured OREs. Moreover, the level of other-race contact predicted only the OREs obtained in tasks testing face memory and processing of configural information. These results indicate that these various cross-race differences originate from different aspects of face processing, in contrary to the view that the ORE in face recognition is due to cross-race differences in terms of holistic processing.

Spatial updating during locomotion does not eliminate viewpoint-dependent visual object processing

Two experiments were conducted to investigate whether locomotion to a novel test view would eliminate viewpoint costs in visual object processing. Participants performed a sequential matching task for object identity or object handedness, using novel 3-D objects displayed in a head-mounted display. To change the test view of the object, the orientation of the object in 3-D space and the test position of the observer were manipulated independently. Participants were more accurate when the test view was the same as the learned view than when the views were different no matter whether the view change of the object was 50° or 90°. With 50° rotations, participants were more accurate at novel test views caused by participants’ locomotion (object stationary) than caused by object rotation (observer stationary) but this difference disappeared when the view change was 90°. These results indicate that facilitation of spatial updating during locomotion occurs within a limited range of viewpoints, but that such facilitation does not eliminate viewpoint costs in visual object processing.

Processing of configural and componential information in face-selective cortical areas

We investigated how face-selective cortical areas process configural and componential face information and how race of faces may influence these processes. Participants saw blurred (preserving configural information), scrambled (preserving componential information), and whole faces during fMRI scan, and performed a post-scan face recognition task using blurred or scrambled faces. The fusiform face area (FFA) showed stronger activation to blurred than to scrambled faces, and equivalent responses to blurred and whole faces. The occipital face area (OFA) showed stronger activation to whole than to blurred faces, which elicited similar responses to scrambled faces. Therefore, the FFA may be more tuned to process configural than componential information, whereas the OFA similarly participates in perception of both. Differences in recognizing own- and other-race blurred faces were correlated with differences in FFA activation to those faces, suggesting that configural processing within the FFA may underlie the other-race effect in face recognition.

Beyond Faces and Expertise Facelike Holistic Processing of Nonface Objects in the Absence of Expertise

Holistic processing—the tendency to perceive objects as indecomposable wholes—has long been viewed as a process specific to faces or objects of expertise. Although current theories differ in what causes holistic processing, they share a fundamental constraint for its generalization: Nonface objects cannot elicit facelike holistic processing in the absence of expertise. Contrary to this prevailing view, here we show that line patterns with salient Gestalt information (i.e., connectedness, closure, and continuity between parts) can be processed as holistically as faces without any training. Moreover, weakening the saliency of Gestalt information in these patterns reduced holistic processing of them, which indicates that Gestalt information plays a crucial role in holistic processing. Therefore, holistic processing can be achieved not only via a top-down route based on expertise, but also via a bottom-up route relying merely on object-based information. The finding that facelike holistic processing can extend beyond the domains of faces and objects of expertise poses a challenge to current dominant theories.