Xuelian Zang

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Hermann Müller

University of Munich

Johannes Hauser

Ludwig-Maximilians-Universität München

Alejandro Lleras

University of Illinois

Gustav Kuhn

Goldsmiths, University of London

University of Dundee

SUNY: Stony Brook University

Miguel Castelo-Branco

Coimbra

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Papers by Xuelian Zang

Invariant Spatial Context Is Learned but Not Retrieved in Gaze-Contingent Tunnel-View Search

Journal of experimental psychology. Learning, memory, and cognition, Jan 20, 2014

Our visual brain is remarkable in extracting invariant properties from the noisy environment, gui... more Our visual brain is remarkable in extracting invariant properties from the noisy environment, guiding selection of where to look and what to identify. However, how the brain achieves this is still poorly understood. Here we explore interactions of local context and global structure in the long-term learning and retrieval of invariant display properties. Participants searched for a target among distractors, without knowing that some "old" configurations were presented repeatedly (randomly inserted among "new" configurations). We simulated tunnel vision, limiting the visible region around fixation. Robust facilitation of performance for old versus new contexts was observed when the visible region was large but not when it was small. However, once the display was made fully visible during the subsequent transfer phase, facilitation did become manifest. Furthermore, when participants were given a brief preview of the total display layout prior to tunnel view search w...

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Vicariously Touching Products through Observing Others’ Hand Actions Increases Purchasing Intention, and the Effect of Visual Perspective in This Process: An fMRI Study

by Xuelian Zang and Leonardo Assumpcao

The growth of online shopping increases consumers' dependence on vicarious sensory experiences, s... more The growth of online shopping increases consumers' dependence on vicarious sensory experiences, such as observing others touching products in commercials. However, empirical evidence on whether observing others' sensory experiences increases purchasing intention is still scarce. In the present study, participants observed others interacting with products in the first- or third-person perspective in video clips, and their neural responses were measured with functional magnetic resonance imaging (fMRI). We investigated (1) whether and how vicariously touching certain products affected purchasing intention, and the neural correlates of this process; and (2) how visual perspective interacts with vicarious tactility. Vicarious tactile experiences were manipulated by hand actions touching or not touching the products, while the visual perspective was manipulated by showing the hand actions either in first- or third-person perspective. During the fMRI scanning, participants watched the video clips and rated their purchasing intention for each product. The results showed that, observing others touching (vs. not touching) the products increased purchasing intention, with vicarious neural responses found in mirror neuron systems (MNS) and lateral occipital complex (LOC). Moreover, the stronger neural activities in MNS was associated with higher purchasing intention. The effects of visual perspectives were found in left superior parietal lobule (SPL), while the interaction of tactility and visual perspective was shown in precuneus and precuneus-LOC connectivity. The present study provides the first evidence that vicariously touching a given product increased purchasing intention and the neural activities in bilateral MNS, LOC, left SPL and precuneus are involved in this process. Hum Brain Mapp 39:332-343, 2018.

© 2017 Wiley Periodicals, Inc.

What fixations reveal about oculomotor scanning behavior in visual search

Behavioral and Brain Sciences

Hulleman & Olivers' (H&O's) conceptual framework does not consider variation of fixation ... more Hulleman & Olivers' (H&O's) conceptual framework does not consider variation of fixation duration and its interaction with the size of the functional viewing field (FVF). Here we provide empirical evidence of a dynamic interaction between the two parameters, suggesting that fixations, as the central unit in H&O's framework, should be studied on both the spatial and temporal dimensions.

Contextual cueing in 3D visual search depends on representations in planar-, not depth-defined space

Journal of Vision

Learning of spatial inter-item associations can speed up visual search in everyday life, an effec... more Learning of spatial inter-item associations can speed up visual search in everyday life, an effect referred to as contextual cueing (Chun &amp;amp;amp;amp;amp;amp;amp;amp;amp; Jiang, 1998). Whereas previous studies investigated contextual cueing primarily using 2D layouts, the current study examined how 3D depth influences contextual learning in visual search. In two experiments, the search items were presented evenly distributed across front and back planes in an initial training session. In the subsequent test session, the search items were either swapped between the front and back planes (Experiment 1) or between the left and right halves (Experiment 2) of the displays. The results showed that repeated spatial contexts were learned efficiently under 3D viewing conditions, facilitating search in the training sessions, in both experiments. Importantly, contextual cueing remained robust and virtually unaffected following the swap of depth planes in Experiment 1, but it was substantially reduced (to nonsignificant levels) following the left-right side swap in Experiment 2. This result pattern indicates that spatial, but not depth, inter-item variations limit effective contextual guidance. Restated, contextual cueing (even under 3D viewing conditions) is primarily based on 2D inter-item associations, while depth-defined spatial regularities are probably not encoded during contextual learning. Hence, changing the depth relations does not impact the cueing effect.

From Foreground to Background: How Task-Neutral Context Influences Contextual Cueing of Visual Search

by Xuelian Zang, Leonardo Assumpcao, and Hermann Müller

Selective attention determines the effectiveness of implicit contextual learning (e.g., Jiang and... more Selective attention determines the effectiveness of implicit contextual learning (e.g., Jiang and Leung, 2005). Visual foreground-background segmentation, on the other hand, is a key process in the guidance of attention (Wolfe, 2003). In the present study, we examined the impact of foreground-background segmentation on contextual cueing of visual search in three experiments. A visual search display, consisting of distractor 'L's and a target 'T', was overlaid on a task-neutral cuboid on the same depth plane (Experiment 1), on stereoscopically separated depth planes (Experiment 2), or spread over the entire display on the same depth plane (Experiment 3). Half of the search displays contained repeated target-distractor arrangements, whereas the other half was always newly generated. The task-neutral cuboid was constant during an initial training session, but was either rotated by 90 • or entirely removed in the subsequent test sessions. We found that the gains resulting from repeated presentation of display arrangements during training (i.e., contextual-cueing effects) were diminished when the cuboid was changed or removed in Experiment 1, but remained intact in Experiments 2 and 3 when the cuboid was placed in a different depth plane, or when the items were randomly spread over the whole display but not on the edges of the cuboid. These findings suggest that foreground-background segmentation occurs prior to contextual learning, and only objects/arrangements that are grouped as foreground are learned over the course of repeated visual search.

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Temporal attention control system for multiple objects tracking

Proceedings of the 31st Chinese Control Conference, 2012

An important ability for mobile robots is to process multiple tasks in complex environments. Sinc... more An important ability for mobile robots is to process multiple tasks in complex environments. Since the sensor resources on a robot are limited, it is necessary to distribute the sensors attention to different tasks along the time scale. This paper proposes a temporal attention control method which aims at detecting multiple objects and estimating their poses with a single actuated camera. The proposed method is based on three criteria which are partially inspired by human behavior: (i) minimization of the overall object poses perception uncertainty and minimization of the variance of the perception uncertainty of different objects; (ii) minimization of the camera movements for completing the tasks; (iii) maximization of the number of objects in the cameras field of view.The proposed approach use Kalman filters to estimate object poses and to determine the perception uncertainty. The method was evaluated with both simulation and experiment on actual robot. The results show that the proposed approach is able to switch the camera's attention according to the objects poses and movements efficiently with a low frequency of the camera movements.

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Watching a real moving object expands tactile duration: The role of task-irrelevant action context for subjective time

Attention, perception & psychophysics, Jan 15, 2015

Although it is well established that action contexts can expand the perceived durations of action... more Although it is well established that action contexts can expand the perceived durations of action-related events, whether action contexts also impact the subjective duration of events unrelated to the action remains an open issue. Here we examined how the automatic implicit reactions induced by viewing task-irrelevant, real moving objects influence tactile duration judgments. Participants were asked to make temporal bisection judgments of a tactile event while seeing a potentially catchable swinging ball. Approaching movement induced a tactile-duration overestimation relative to lateral movement and to a static baseline, and receding movement produced an expansion similar in duration to that from approaching movement. Interestingly, the effect of approaching movement on the subjective tactile duration was greatly reduced when participants held lightweight objects in their hands, relative to a hands-free condition, whereas no difference was obtained in the tactile-duration estimates ...

Spatial reference frame of tactile context learning

Contextual cueing: implicit memory of tactile context facilitates tactile search

by Zhuanghua Shi and Xuelian Zang

Attention, Perception, & Psychophysics, 2015

In visual search, participants detect and subsequently discriminate targets more rapidly when the... more In visual search, participants detect and subsequently discriminate targets more rapidly when these are embedded in repeatedly encountered distractor arrangements, an effect termed contextual cueing (Chun & Jiang Cognitive Psychology, 36, 28-71, 1998). However, whereas previous studies had explored contextual cueing exclusively in visual search, in the present study we examined the effect in tactile search using a novel tactile search paradigm. Participants were equipped with vibrotactile stimulators attached to four fingers on each hand. A given search array consisted of four stimuli (i.e., two items presented to each hand), with the target being an odd-one-out feature singleton that differed in frequency (Exps. 1 and 2) or waveform (Exp. 3) from the distractor elements. Participants performed a localization (Exps. 1 and 2) or discrimination (Exp. 3) task, delivering their responses via foot pedals. In all three experiments, reaction times were faster when the arrangement of distractor fingers predicted the target finger. Furthermore, participants were unable to explicitly discriminate repeated from nonrepeated tactile configurations (Exps. 2 and 3). This indicates that the tactile modality can mediate the formation of configural representations and use these representations to guide tactile search.

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Does gaze-contingent limited view modify spatial contextual cueing in visual search?

by Xuelian Zang, H. Mueller, and Zhuanghua Shi

Invariant Spatial Context Is Learned but Not Retrieved in Gaze-Contingent Tunnel-View Search

by Zhuanghua Shi and Xuelian Zang

Journal of experimental psychology. Learning, memory, and cognition, Jan 20, 2014

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Transfer of contextual cueing in full-icon display remapping

by Zhuanghua Shi and Xuelian Zang

Journal of Vision, 2013

Invariant spatial context can expedite visual search, an effect that is known as contextual cuein... more Invariant spatial context can expedite visual search, an effect that is known as contextual cueing (e.g., . However, disrupting learned display configurations abolishes the effect. In current touchbased mobile devices, such as the iPad, icons are shuffled and remapped when the display mode is changed. However, such remapping also disrupts the spatial relationships between icons. This may hamper usability. In the present study, we examined the transfer of contextual cueing in four different methods of display remapping: position-order invariant, global rotation, local invariant, and central invariant. We used full-icon landscape mode for training and both landscape and portrait modes for testing, to check whether the cueing transfers to portrait mode. The results showed transfer of contextual cueing but only with the local invariant and the central invariant remapping methods. We take the results to mean that the predictability of target locations is a crucial factor for the transfer of contextual cueing and thus icon remapping design for mobile devices.

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Concurrent emotional pictures modulate temporal order judgments of spatially separated audio-tactile stimuli

by Zhuanghua Shi and Xuelian Zang

Brain Research, 2013

Although attention can be captured toward high-arousal stimuli, little is known about how perceiv... more Although attention can be captured toward high-arousal stimuli, little is known about how perceiving emotion in one modality influences the temporal processing of non-emotional stimuli in other modalities. We addressed this issue by presenting observers spatially uninformative emotional pictures while they performed an audio-tactile temporal-order judgment (TOJ) task. In Experiment 1, audio-tactile stimuli were presented at the same location straight ahead of the participants, who had to judge "which modality came first?".

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Temporal attention control system for multiple objects tracking

ABSTRACT An important ability for mobile robots is to process multiple tasks in complex environme... more ABSTRACT An important ability for mobile robots is to process multiple tasks in complex environments. Since the sensor resources on a robot are limited, it is necessary to distribute the sensors attention to different tasks along the time scale. This paper proposes a temporal attention control method which aims at detecting multiple objects and estimating their poses with a single actuated camera. The proposed method is based on three criteria which are partially inspired by human behavior: (i) minimization of the overall object poses perception uncertainty and minimization of the variance of the perception uncertainty of different objects; (ii) minimization of the camera movements for completing the tasks; (iii) maximization of the number of objects in the cameras field of view. The proposed approach use Kalman filters to estimate object poses and to determine the perception uncertainty. The method was evaluated with both simulation and experiment on actual robot. The results show that the proposed approach is able to switch the camera&#39;s attention according to the objects poses and movements efficiently with a low frequency of the camera movements.

Contextual Cueing of Tactile Search Is Coded in an Anatomical Reference Frame.

by Xuelian Zang and Leonardo Assumpcao

This work investigates the reference frame(s) underlying tactile context memory, a form of statis... more This work investigates the reference frame(s) underlying tactile context memory, a form of statistical learning in a tactile (finger) search task. In this task, if a searched-for target object is repeatedly encountered within a stable spatial arrangement of task-irrelevant distractors, detecting the target becomes more efficient over time (relative to nonrepeated arrangements), as learned target-distractor spatial associations come to guide tactile search, thus cueing attention to the target location. Since tactile search displays can be represented in several reference frames, including multiple external and an anatomical frame, in Experiment 1 we asked whether repeated search displays are represented in tactile memory with reference to an environment-centered or anatomical reference frame. In Experiment 2, we went on examining a hand-centered versus anatomical reference frame of tactile context memory. Observers performed a tactile search task, divided into a learning and test session. At the transition between the two sessions, we introduced postural manipulations of the hands (crossed ↔ uncrossed in Expt. 1; palm-up ↔ palm-down in Expt. 2) to determine the reference frame of tactile contextual cueing. In both experiments, target-distractor associations acquired during learning transferred to the test session when the placement of the target and distractors was held constant in anatomical, but not external, coordinates. In the latter, RTs were even slower for repeated displays. We conclude that tactile contextual learning is coded in an anatomical reference frame. (PsycINFO Database Record (c) 2017 APA, all rights reserved)

Invariant Spatial Context Is Learned but Not Retrieved in Gaze-Contingent Tunnel-View Search

Journal of experimental psychology. Learning, memory, and cognition, Jan 20, 2014

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Vicariously Touching Products through Observing Others’ Hand Actions Increases Purchasing Intention, and the Effect of Visual Perspective in This Process: An fMRI Study

by Xuelian Zang and Leonardo Assumpcao