Effect Of Visual Context Research Articles

Automatic versus Voluntary Motor Imitation: Effect of Visual Context and Stimulus Velocity

Automatic imitation is the tendency to reproduce observed actions involutarily. Though this topic has been widely treated, at present little is known about the automatic imitation of the kinematic features of an observed movement. The present study was designed to understand if the kinematics of a previously seen stimulus primes the executed action, and if this effect is sensitive to the kinds of stimuli presented. We proposed a simple imitation paradigm in which a dot or a human demonstrator moved in front of the participant who was instructed either to reach the final position of the stimulus or to imitate its motion with his or her right arm. Participants' movements were automatically contaminated by stimulus velocity when it moved according to biological laws, suggesting that automatic imitation was kinematic dependent. Despite that the performance, in term of reproduced velocity, improved in a context of voluntary imitation, subjects did not replicate the observed motions exactly. These effects were not affected by the kind of stimuli used, i.e., motor responses were influenced in the same manner after dot or human observation. These findings support the existence of low-level sensory-motor matching mechanisms that work on movement planning and represent the basis for higher levels of social interaction.

On the mental representations originating during the interaction between language and vision

The interaction between vision and language processing is clearly of interest to both cognitive psychologists and psycholinguists. Recent research has begun to create understanding of the interaction between vision and language in terms of the representational issues involved. In this paper, we first review some of the theoretical and methodological issues in the current vision-language interaction debate. Later, we develop a model that attempts to account for effects of affordances and visual context on language-scene interaction as well as the role of sensorimotor simulation. The paper addresses theoretical issues related to the mental representations that arise when visual and linguistic systems interact.

Post-perceptual locus for visual context effects: ERP evidence from the Rod and Frame Illusion

Post-perceptual locus for visual context effects: ERP evidence from the Rod and Frame Illusion

Impact of item density on the utility of visual context in magic lens interactions

This article reports on two user studies investigating the effect of visual context in handheld augmented reality interfaces. A dynamic peephole interface (without visual context beyond the device display) was compared to a magic lens interface (with video see-through augmentation of external visual context). The task was to explore items on a map and look for a specific attribute. We tested different sizes of visual context as well as different numbers of items per area, i.e. different item densities. Hand motion patterns and eye movements were recorded. We found that visual context is most effective for sparsely distributed items and gets less helpful with increasing item density. User performance in the magic lens case is generally better than in the dynamic peephole case, but approaches the performance of the latter the more densely the items are spaced. In all conditions, subjective feedback indicates that participants generally prefer visual context over the lack thereof. The insights gained from this study are relevant for designers of mobile AR and dynamic peephole interfaces, involving spatially tracked personal displays or combined personal and public displays, by suggesting when to use visual context.

How reliable are visual context effects in the parahippocampal place area?

The parahippocampal place area (PPA) is a region of human cortex that responds more strongly to visual scenes (e.g., landscapes or cityscapes) than to other visual stimuli. It has been proposed that the primary function of the PPA is encoding of contextual information about object co-occurrence. Supporting this context hypothesis are reports that the PPA responds more strongly to strong-context than to weak-context objects and more strongly to famous faces (for which contextual associations are available) than to nonfamous faces. We reexamined the reliability of these 2 effects by scanning subjects with functional magnetic resonance imaging while they viewed strong- and weak-context objects, scrambled versions of these objects, and famous and nonfamous faces. "Contextual" effects for objects were observed to be reliable in the PPA at slow presentation rates but not at faster presentation rates intended to discourage scene imagery. We were unable to replicate the earlier finding of preferential PPA response to famous versus nonfamous faces. These results are difficult to reconcile with the hypothesis that the PPA encodes contextual associations but are consistent with a competing hypothesis that the PPA encodes scenic layout.

The effect of visual context on the identification of ambiguous environmental sounds

The influence of the specificity of the visual context on the identification of environmental sounds (i.e., product sounds) was investigated. Two different visual context types (i.e., scene and object contexts)—which varied in the specificity of the semantic information—and a control condition (meaningless images) were employed. A contextual priming paradigm was used. Identification accuracy and response times were determined in two context conditions and one control condition. The results suggest that visual context has a positive effect on sound identification. In addition, two types of product sounds (location-specific and event-specific sounds) were observed which exhibited different sensitivities to scene and object contexts. Furthermore, the results suggest that conceptual interactions exist between an object and a context that do not share the same perceptual domain. Therefore, context should be regarded as a network of conceptually associated items in memory.

Vestibular Nuclei and Cerebellum Put Visual Gravitational Motion in Context

Animal survival in the forest, and human success on the sports field, often depend on the ability to seize a target on the fly. All bodies fall at the same rate in the gravitational field, but the corresponding retinal motion varies with apparent viewing distance. How then does the brain predict time-to-collision under gravity? A perspective context from natural or pictorial settings might afford accurate predictions of gravity's effects via the recovery of an environmental reference from the scene structure. We report that embedding motion in a pictorial scene facilitates interception of gravitational acceleration over unnatural acceleration, whereas a blank scene eliminates such bias. Functional magnetic resonance imaging (fMRI) revealed blood-oxygen-level-dependent correlates of these visual context effects on gravitational motion processing in the vestibular nuclei and posterior cerebellar vermis. Our results suggest an early stage of integration of high-level visual analysis with gravity-related motion information, which may represent the substrate for perceptual constancy of ubiquitous gravitational motion.

The effect of the “rod-and-frame” illusion on grip planning in a sequential object manipulation task

We investigated the effect of visual context (i.e., a visual illusion) on the planning of a sequential object manipulation task. Participants (n = 13) had to grasp a rod embedded in a “rod-and-frame” illusion and insert the rod-end into a tight hole in a pre-defined way. The grip type (defined by start posture, either pronated or supinated; and end posture, either comfortable or uncomfortable) used to grasp the rod was registered as a macroscopic variable of motor planning. Different rod orientations forced the participants to switch between grip types. As expected, most participants switched between pronated and supinated start postures, such that they ended the movement with a comfortable end posture. As it has been argued that planning is dependent on visual context information, we hypothesized that the visual illusion would affect the specific rod orientation at which participants would switch into a different grip type. This hypothesis was confirmed. More specifically, the illusion affected the critical spatial information that is used for action planning. Collectively, these findings are the first to show an effect of an illusion on motor planning in a sequential object manipulation task.

Tracking the Continuity of Language Comprehension: Computer Mouse Trajectories Suggest Parallel Syntactic Processing

Although several theories of online syntactic processing assume the parallel activation of multiple syntactic representations, evidence supporting simultaneous activation has been inconclusive. Here, the continuous and non-ballistic properties of computer mouse movements are exploited, by recording their streaming x, y coordinates to procure evidence regarding parallel versus serial processing. Participants heard structurally ambiguous sentences while viewing scenes with properties either supporting or not supporting the difficult modifier interpretation. The curvatures of the elicited trajectories revealed both an effect of visual context and graded competition between simultaneously active syntactic representations. The results are discussed in the context of 3 major groups of theories within the domain of sentence processing.

線画を用いた対象検出における文脈効果

Participants detected a target from search stimuli which contained either eight (Experiment 1) or four (Experiment 2) living or nonliving common objects. Objects were represented either as pictures or as words. The target and other stimuli were from a same category, either living or nonliving, in the congruent condition, and were from a different category in the incongruent condition. The results of Experiment 1 showed that picture targets were detected more quickly in the incongruent than in the congruent condition while word targets were detected more quickly in the congruent than in the incongruent condition. These results indicate an interference effect of visual context in picture detection and a facilitation effect of semantic context in word detection. However, Experiment 2 using four stimuli did not show the same contextual effects as Experiment 1, probably because the task became easy.

Acquisition of second-language speech: Effects of visual cues, context, and talker variability

The influence of a talker's face (e.g., articulatory gestures) and voice, vocalic context, and word position were investigated in the training of Japanese and Korean English as a second language learners to identify American English /[invertedr]/ and /l/. In the pretest–posttest design, an identification paradigm assessed the effects of 3 weeks of training using multiple natural exemplars on videotape. Word position, adjacent vowel, and training type (auditory–visual [AV] vs. auditory only; multiple vs. single talker for Koreans) were independent variables. Findings revealed significant effects of training type (greater improvement with AV), talker, word position, and vowel. Identification accuracy generalized successfully to novel stimuli and a new talker. Transfer to significant production improvement was also noted. These findings are compatible with episodic models for the encoding of speech in memory.

Applied linguistics

04–669 Hardison, Debra M. (Michigan State U., USA; Email: hardiso2@msu.edu). Acquisition of second-language speech: effects of visual cues, context, and talker variability. Applied Psycholinguistics (Cambridge, UK), 24, 4 (2003), 495–522.04–670 Hirst, Elizabeth (Griffith U., Queensland, Australia; Email: e.hirst@griffith.edu.au) Diverse voices in a second language classroom: burlesque, parody and mimicry. Language and Education (Clevedon, UK), 17, 3 (2003), 174–191.04–671 Matsumura, Shoichi (Ryukoku U., Japan). Modelling the relationships among interlanguage pragmatic development, L2 proficiency, and exposure to L2. Applied Linguistics (Oxford, UK), 24, 4 (2003), 465–491.04–672 de Mattos Pimenta Parente, Maria Alice and Geiger, Lucienne (Rio Grande do Sul Federal U., Brazil) and Dunbar, Harriet and Nespoulous, Jean-Luc. The role of phonological loop components on children's story recall during the first years of schooling. Revue Parole (Mons, Belgium), 25/26 (2003), 45–74.

Differential effects of visual context on pattern discrimination by pigeons (Columba livia) and humans (Homo sapiens).

Three experiment examined the role of contextual information during line orientation and line position discriminations by pigeons (Columba livia) and humans (Homo sapiens). Experiment 1 tested pigeons' performance with these stimuli in a target localization task using texture displays. Experiments 2 and 3 tested pigeons and humans, respectively, with small and large variations of these stimuli in a same-different task. Humans showed a configural superiority effect when tested with displays constructed from large elements but not when tested with the smaller, more densely packed texture displays. The pigeons, in contrast, exhibited a configural inferiority effect when required to discriminate line orientation, regardless of stimulus size. These contrasting results suggest a species difference in the perceptionand use of features and contextual information in the discrimination of line information.

Eye movements and spoken language comprehension: Effects of visual context on syntactic ambiguity resolution

When participants follow spoken instructions to pick up and move objects in a visual workspace, their eye movements to the objects are closely time-locked to referential expressions in the instructions. Two experiments used this methodology to investigate the processing of the temporary ambiguities that arise because spoken language unfolds over time. Experiment 1 examined the processing of sentences with a temporarily ambiguous prepositional phrase (e.g., “Put the apple on the towel in the box”) using visual contexts that supported either the normally preferred initial interpretation (the apple should be put on the towel) or the less-preferred interpretation (the apple is already on the towel and should be put in the box). Eye movement patterns clearly established that the initial interpretation of the ambiguous phrase was the one consistent with the context. Experiment 2 replicated these results using prerecorded digitized speech to eliminate any possibility of prosodic differences across conditions or experimenter demand. Overall, the findings are consistent with a broad theoretical framework in which real-time language comprehension immediately takes into account a rich array of relevant nonlinguistic context.

The use of landmarks and panoramic context in the performance of local vectors by navigating honeybees.

Bees seem to use landmarks to segment familiar routes. They can associate, with a landmark, a memory that encodes the direction and distance of the path segment between that landmark and the next. The expression of the memory results in the performance of a local vector matching the distance and direction of the path segment. The memories of path segments appear to be 'chained' together, so that the performance of one local vector is sometimes sufficient to elicit the subsequent local vector, even in the absence of the associated landmark. We have investigated the effect of visual panoramic context on the expression of local vectors. Bees were trained to fly along a narrow channel to collect sucrose from a feeder positioned partway along it. Panoramic context was provided by various types of patterning on the walls. The channel was partitioned into different segments using landmarks of two kinds: a boundary landmark that marked a change in the pattern on one or both side-walls of the channel, and an isolated landmark, consisting of a baffle through which the bee passed, for which the wall pattern was the same before as after. In tests, we removed the feeder and analysed the search distribution of the bees for various arrangements of landmarks. Altering the spatial relationship between landmarks has different consequences for the two types of landmark. If the final boundary landmark is shifted, the centre of the search distribution shifts by approximately the same amount. Changes in the position of an isolated landmark have a weaker effect. In the absence of the final context, the search is disrupted. We suggest that for local vectors to be expressed the surrounding panoramic context needs to be appropriate. A comparison of search patterns from two different training configurations of landmarks supports the hypothesis that local vector memories merely encode route segments and that global positional coordinates are not linked to landmark memories.

Auditory–visual context effects in a speech and nonspeech condition

Perception of an auditory continuum can be changed by a preceding visual context [Norrix and Green, in Proc. AVSP’99, Santa Cruz, CA, August, 1999]. This study asked whether this perceptual shift requires that listeners experience the stimuli as speech. A sine-wave continuum (/ara–ala/) was presented to three groups of trained participants for identification (auditory-only condition). Tokens from the continuum were also paired with a point-light display of a talker saying /aba/ (auditory–visual condition) and presented to the same listeners for identification. Observers in group one (speech) identified the sounds as containing an /r/ or /l/ and reported after the experiment that they heard the sounds as speech. Group two, also instructed to identify the speech sounds as containing /r/ or /l/, reported they did not hear the sounds as speech. Group three (nonspeech) was instructed to identify the environmental sounds as most similar to the ‘‘first’’ or ‘‘last’’ sound of the continuum. Results indicated a reliable shift for the auditory–visual compared to the auditory-only identification function only in the speech group, suggesting that auditory–visual context effects might depend on observers interpreting the stimuli as speech. [Work supported by NSF Grant ♯SBR9809013 awarded to Kerry P. Green (deceased).]

Limited visual control of the intelligibility of speech in face-to-face dialogue.

Speakers are thought to articulate individual words in running speech less carefully whenever additional nonacoustic information can help listeners recognize what is said (Fowler & Housum, 1987; Lieberman, 1963). Comparing single words excerpted from spontaneous dialogues and control tokens of the same words read by the same speakers in lists, Experiment 1 yielded a significant but general effect of visual context: Tokens introducing 71 new entities in dialogues in which participants could see one another's faces were more degraded (less intelligible to 54 naive listeners) than were tokens of the same words from dialogues with sight lines blocked. Loss of clarity was not keyed to moment-to-moment visual behavior. Subjects with clear sight lines looked at each other too rarely to account for the observed effect. Experiment 2 revealed that tokens of 60 words uttered while subjects were looking at each other were significantly less degraded (in length and in intelligibility to 72 subjects) vis-à-vis controls than were spontaneous tokens of the same words produced when subjects were looking elsewhere. Intelligibility loss was mitigated only when listeners looked at speakers. Two separate visual effects are discussed, one of the global availability and the other of the local use of the interlocutor's face.

Eye movements induced by lateral acceleration steps. Effect of visual context and acceleration levels.

Eye movement responses were obtained from six normal subjects exposed to randomly ordered rightwards/leftwards linear acceleration steps of 0.05 g, 0.1 g or 0.24 g amplitude and 650 ms duration along the interaural axis. With the instruction to gaze passively into the darkness, compensatory nystagmus was evoked with slow-phase velocity sensitivity of 49 degrees s(-1) g(-1). When subjects viewed earth-fixed targets at 30 cm, 60 cm or 280 cm, eye movements at 130 ms from motion onset were proportional to acceleration and inversely proportional to target distance, before the onset of visually guided eye movements. Our results show that a modulation with viewing distances of the earliest human otolith-ocular reflexes occurs in the presence of pure linear acceleration. However, full compensation was not attained for the nearer targets and higher accelerations.

The effect of visual context on manual localization of remembered targets.

This paper examines the contribution of egocentric cues and visual context to manual localization of remembered targets. Subjects pointed in the dark to the remembered position of a target previously viewed without or within a structured visual scene. Without a remembered visual context, subjects pointed to within 2 degrees of the target. The presence of a visual context with cues of straight ahead enhanced pointing performance to the remembered location of central but not off-center targets. Thus, visual context provides strong visual cues of target position and the relationship of body position to target location. Without a visual context, egocentric cues provide sufficient input for accurate pointing to remembered targets.

Eye-Tracking

Participants following spoken instructions to touch or move either real objects or objects on a computer screen make saccadic eye movements (to the objects) that are closely time-locked to relevant information in the speech stream. Monitoring eye movements using a head-mounted eye-camera allows one to use the locations and latencies of fixations to examine spoken word recognition during continuous speech in natural contexts. Preliminary work using this paradigm provides striking evidence for the continuous and incremental nature of comprehension, as well as clear effects of visual context on the earliest moments of linguistic processing. We review the eye-movement paradigm and refer to recent experiments applying the paradigm to issues of spoken word recognition (e.g. lexical competitor effects), syntactic processing (e.g. the interaction of referential context and ambiguity resolution), reference resolution (disambiguating temporarily ambiguous referential phrases), focus (modulating the salience of certain objects via contrastive stress), as well as issues in cross-modality integration that are central to evaluating the modularity hypothesis.