Do objects in working memory compete with objects in perception?

It is generally assumed that “perceptual object” is the basic unit for processing visual information and that only a small number of objects can be either perceptually selected or encoded in working memory (WM) at one time. This raises the question whether the same resource is used when objects are selected and tracked as when they are held in WM. In two experiments, we measured dual-task interference between a memory task and a Multiple Object Tracking task. The WM tasks involve explicit, implicit, or no spatial processing. Our results suggest there is no resource competition between working memory and perceptual selection except when the WM task requires encoding spatial properties.     

A case for inhibition: visual attention suppresses the processing of irrelevant objects

The present study investigated the ability to inhibit the processing of an irrelevant visual object while processing a relevant one. Participants were presented with 2 overlapping shapes (e.g., circle and square) in different colors. The task was to name the color of the relevant object designated by shape. Congruent or incongruent color words appeared in the relevant object, in the irrelevant object, or in the background. Stroop effects indicated how strong the respective area of the display was processed. The results of 4 experiments showed that words in the relevant object produced larger Stroop effects than words in the background, indicating amplification of relevant objects. In addition, words in the irrelevant object consistently produced smaller Stroop effects than words in the background, indicating inhibition of irrelevant objects. Control experiments replicated these findings with brief display durations (250 ms) and ruled out perceptual factors as a possible explanation. In summary, results support the notion of an inhibitory mechanism of object-based attention, which can be applied in addition to the amplification of relevant objects.     

On the relationship between visual imagery and visual perception: Evidence from priming studies

Two priming experiments using a perceptual identification task were conducted to explore the functional and representational overlap between visual imagery and visual perception. The first experiment included a study phase in which primes were either perceived or imaged objects and a perceptual identification test task in which targets were parts of studied and non-studied objects. Imagery primed identification when subjects were instructed to count the parts of the imaged objects in the study phase but not when they were instructed to focus on the global shape of the imaged objects. This result suggests that imagery involves perceptual representations identical to those involved in perception. It also suggests that the representational overlap between imagery and perception depends on the type of images generated, as some images may consist in global shapes only, whereas others may consist in detailed, multi-part shapes. In the second experiment, we used whole objects as target stimuli which provided subjects with more information to identify masked targets and thereby reduced top-down processing. Priming from imagery fell beneath significance, suggesting that this sort of priming is elicited in a large part by a transfer of top-down processes from study to test.     

Attention to local form information can prevent access to semantic information.

Humphreys and Boucart (1997) have shown that when processing of local form is required for response, surrounding global information is automatically processed to a semantic level. The generality of this effect was investigated in two experiments in which the perceptual load of the relevant local form information was manipulated, as was uncertainty about perceptual load. Participants attended to a single line segment inside a picture of an animal or a vehicle and then decided which of two pictures in the target/distractor display that followed contained a line segment that matched the first in orientation. The perceptual load of the relevant local form information was either low (the matching line segment was one of the solitary line segments presented in the centre ofthe target and distractor pictures), or high (the matching line segment was part of one of the solitary letters presented in the centre of the target and distractor pictures). The semantic relations among the pictures were manipulated, and when perceptual load remained constant across trials, semantic relations affected performance in the low-load but not in the high-load condition. When perceptual load varied from trial to trial, there was no evidence of any semantic processing on either low- or high-load trials. The results suggest that in form-matching tasks, attentional priority can be given to local information, thus preventing access to semantic information derived from global shape. They further suggest that the distribution of attention is not dictated entirely by the actual perceptual demands of the relevant stimulus, indicating an important role for top-down processing.     

New motion illusion caused by pictorial motion lines

Motion lines (MLs) are a pictorial technique used to represent object movement in a still picture. This study explored how MLs contribute to motion perception. In Experiment 1, we reported the creation of a motion illusion caused by MLs: random displacements of objects with MLs on each frame were perceived as unidirectional global motion along the pictorial motion direction implied by MLs. In Experiment 2, we showed that the illusory global motion in the peripheral visual field captured the perceived motion direction of random displacement of objects without MLs in the central visual field, and confirmed that the results in Experiment 1 did not stem simply from response bias, but resulted from perceptual processing. In Experiment 3, we showed that the spatial arrangement of orientation information rather than ML length is important for the illusory global motion. Our results indicate that the ML effect is based on perceptual processing rather than response bias, and that comparison of neighboring orientation components may underlie the determination of pictorial motion direction with MLs.     

Global Dominance Outside the Focus of Attention

Identification of the local aspect of a relevant compound stimulus has been found to be delayed by the presence of target-set members at the global aspect of an irrelevant compound stimulus, whereas identification of the global aspect is unaffected by the presence of local target-set members within the irrelevant object (Paquet & Merikle, 1988). This effect has been termed the global category effect , and it suggests that global dominance occurs for objects located outside the attentional focus, as well as within an attended hierarchical object. In the present experiments, attention was directed to the relevant one of two compound stimuli by using either shape information (Experiments 1 and 2) or a 100-msec peripheral rapid onset precue (Experiment 3). Results revealed a global category effect even when the physical features of the displays containing global target-set members within the irrelevant object were closely matched with those of the control displays. Critically, the magnitude of the global category effect was affected by how well attention could be focused on the relevant compound stimulus. These findings suggest (a) that the analysis of global information for irrelevant objects is more elaborate than the simple detection of features; and (b) that both perceptual and attentional mechanisms are involved in global dominance.     

Evidence for the integration of audiovisual emotional information at the perceptual level of processing

The present aim was to investigate how emotional expressions presented on an unattended channel affect the recognition of the attended emotional expressions. In Experiments 1 and 2, facial and vocal expressions were simultaneously presented as stimulus combinations. The emotions (happiness, anger, or emotional neutrality) expressed by the face and voice were either congruent or incongruent. Subjects were asked to attend either to the visual (Experiment 1) or auditory (Experiment 2) channel and recognise the emotional expression. The result showed that the ignored emotional expressions significantly affected the processing of attended signals as measured by recognition accuracy and response speed. In general, attended signals were recognised more accurately and faster in congruent than in incongruent combinations. In Experiment 3, possibility for a perceptual-level integration was eliminated by presenting the response-relevant and response-irrelevant signals separated in time. In this situation, emotional information presented on the nonattended channel ceased to affect the processing of emotional signals on the attended channel. The present results are interpreted to provide evidence for the view that facial and vocal emotional signals are integrated at the perceptual level of information processing and not at the later response-selection stages.     

When a Dog Has a Pen for a Tail: the Time Course of Creative Object Processing

Creative objects differ from ordinary objects in that they are created by human beings to contain novel, creative information. Previous research has demonstrated that ordinary object processing involves both a perceptual process for analyzing different features of the visual input and a higher-order process for evaluating the relevance of this visual information. However, it is unclear how and when these processes are influenced by the creative information of the object. This study utilized event-related potentials (ERPs) to investigate the time course of creative object processing. Behavioral results revealed that participants spent more time processing creative objects than they did ordinary objects. Analysis of scalp ERPs further revealed that creative objects elicited a more negative ERP deflection between 190 and 340 ms (N190–340) with an anterior scalp distribution. Additionally, creative objects elicited more positive ERP deflection than did ordinary objects between 400 and 700 ms (P400–700) with a right centro–parietal scalp distribution and between 700 and 1000 ms (late positive component) with a right anterior–central scalp distribution. Such results suggest that the processing of creative objects is composed of two distinct stages. The early perceptual stage involves the detection of visual differences exhibited by the creative objects, while the late stage involves the right-lateralized processes of understanding and encoding the creative information.     

Preconscious analysis of global structure: Evidence from masked priming

According to the global precedence hypothesis, the perceptual processing of complex objects proceeds from global structure to the analysis of local elements. In the present study, we used a masked priming paradigm to explore whether the global or the local level of hierarchical letters is analysed at preconscious processing stages. Experiment 1 found masked priming only after global prime letters in focused‐attention conditions. Experiment 2 used a divided‐attention task in which attention was not focused specifically on either level of hierarchy and did not find any priming. Experiment 3 used otherwise the same task as Experiment 2 but biased attention either to the global or the local level by manipulating the probability that targets appeared at one level. Priming was found after global prime letters in the global‐bias condition but not in the local‐bias condition. Experiments 4a and 4b suggest that the size of the local letters was not responsible for the lack of priming after local primes. The results suggest a priority for global processing already at a preconscious level and that attentional factors may modulate processes at this level.     

Coordinating cognitive information: task effects and individual differences in integrating information from several sources.

In many tasks people have to coordinate the information from several sources. An example would be driving a car while listening to directions. The driver has to establish a correspondence between a visual picture and verbal instructions. This paper addresses two questions concerning information coordination. Is there an ability to coordinate information received from several sources that is different from the ability to deal with information from each source, alone? Does coordination simply involve allocating resources to deal with the component tasks, or does the act of coordination itself constitute a separate task? Four experiments examined the coordination of a verbal component task with a visual-spatial and with an auditory component task. The results showed that the ability to coordinate perceptual and verbal information is separate from the ability to deal with either perceptual or verbal information, alone. A simple resource sharing model was not adequate in explaining how coordination occurred. We relate our results to a model in which perceptual reasoning occurs independently of verbal processing, but transforming perceptual information into a propositional form is affected by concurrent verbal processing.     

Direct selection by color for visual encoding

In two experiments, we used rapid serial visual presentation tasks to examine the usefulness of color for the direct selection of visual information for perceptual encoding. The participants' task was to make a discrimination as to whether a target letter within a rapid sequence appeared in its upper- or lowercase version, and an advance cue indicated the color in which the target letter was most likely to occur. To maximize the usefulness of the cued color, in validly cued trials, we used sequences in which the target was the only item appearing in the cued color. In both experiments, accuracy was highest for validly cued trials. A cost-benefit analysis revealed a facilitory effect of valid cues and an inhibitory effect of invalid ones. These results support the idea that color cuing allows the direct selection of objects for further perceptual processing.     

Pleasant emotional induction broadens the visual world of young children

These experiments aimed at studying the influence of emotional context on global/local visual processing in children. Children 5 years old, known to present an immature global visual bias, and 8 years old, known to pay attention predominantly to global information, were placed in either a neutral or pleasant emotional context and subsequently presented with a global/local visual judgement task. As with previous findings for adults, both age groups presented a pronounced perceptual bias toward global information following exposure to emotionally pleasant pictures. Interestingly, younger children, who do not present a global bias during the neutral exposure, presented the same preference for global information as older children when exposed to the pleasant context. These findings indicate that emotion may strongly affect visual perception in children, with important implications for educational practice and models of cognition.     

Pleasant emotional induction broadens the visual world of young children

These experiments aimed at studying the influence of emotional context on global/local visual processing in children. Children 5 years old, known to present an immature global visual bias, and 8 years old, known to pay attention predominantly to global information, were placed in either a neutral or pleasant emotional context and subsequently presented with a global/local visual judgement task. As with previous findings for adults, both age groups presented a pronounced perceptual bias toward global information following exposure to emotionally pleasant pictures. Interestingly, younger children, who do not present a global bias during the neutral exposure, presented the same preference for global information as older children when exposed to the pleasant context. These findings indicate that emotion may strongly affect visual perception in children, with important implications for educational practice and models of cognition.     

Objects with reduced visibility still contribute to size averaging

People can rapidly judge the average size of a collection of objects with considerable accuracy. In this study, we tested whether this size-averaging process relies on relatively early object representations or on later object representations that have undergone iterative processing. We asked participants to judge the average size of a set of circles and, in some conditions, presented two additional circles that were either smaller or larger than the average. The additional circles were surrounded by four-dot masks that either lingered longer than the circle array, preventing further processing with object substitution masking (OSM), or disappeared simultaneously with the circle array, allowing the circle representation to reach later visual processing stages. Surprisingly, estimation of average circle size was modulated by both visible circles and circles whose visibility was impaired by OSM. There was also no correlation across participants between the influence of the masked circles and susceptibility to OSM. These findings suggest that relatively early representations of objects can contribute to the size-averaging process despite their reduced visibility.     

Object-based selection within and beyond the focus of spatial attention

In a series of experiments, we examined the effect of perceptual objects on visual attentional processing in the presence of spatially cued attentional selection. Subjects made speeded judgments about two visual elements that were either both on the same object or on two different objects. Judgments were faster when the elements were on the same object than when they were on different objects, revealing an object advantage. Importantly, the object advantage remained even when either exogenous or endogenous spatial cues were used to direct the subjects' attention to a part of the display, contrary to earlier findings of other researchers. The object advantage, however, did disappear when the stimulus duration was shortened substantially. The results show that object-based selection is pervasive and is not diminished by the act of selective attention. The results are discussed in terms of their implications for the mechanisms that underlie attentional selection.     

Now you see it,now you don't: The context dependent nature of category-effects in visual object recognition

In two experiments, we test predictions regarding processing advantages/disadvantages for natural objects and artefacts in visual object recognition. Varying three important parameters—degree of perceptual differentiation, stimulus format, and stimulus exposure duration—we show how different category-effects can be provoked in normal subjects on the same task. We interpret the results in light of the Pre-semantic Account of Category Effects (PACE; Gerlach, 2009), and conclude that category-effects do not reflect absolute processing differences between categories. Rather, category-effects are products of common operations which are differentially affected by the structural similarity among objects (with natural objects being more structurally similar than artefacts). The potentially most important aspect of the present study is the demonstration that category-effects are very context dependent; an aspect which has been neglected in earlier literature on category-specificity. PACE provides a useful framework in this respect, as it specifies how category-effects are influenced by changes in task and stimulus characteristics.     

Dominance of global visual properties at birth

Six experiments are reported that were aimed at demonstrating the presence in newborns of a perceptual dominance of global over local visual information in hierarchical patterns, similar to that observed in adults (D. Navon, 1977, 1981). The first four experiments showed that, even though both levels of visual information were detectable by the newborn (Experiments 1A and 1B), global cues enjoyed some advantage over local cues (Experiments 2 and 3). Experiments 4A and 4B demonstrated that the global bias was strictly dependent on the low spatial frequency content of the stimuli and vanished after selective removal of low spatial frequencies. The results are interpreted as suggesting parallels between newborns' visual processing and processing later in development.     

A variable mapping task produces symmetrical interference between global information and local information

When processing global and local aspects of compound visual figures, a robust finding is that global targets are detected faster and more accurately than local targets. Moreover, unidirectional interference is often observed. Despite the convincing evidence that global information and local information are available together, when attention is focused on the global level, items from the local level often have very little, if any, effect on behavior. If local information is available with global information, then why is global dominance so often observed under such a wide range of conditions? This paper is concerned with the fate of the ignored, and apparently ineffective, local distractors. In our experiments, at least one critical factor was stimulus-response (S-R) mapping. We compared a consistent S-R task, which facilitated a speed advantage for global, with a variable S-R task, which required a higher degree of semantic analysis for each stimulus. The two tasks produced large differences in behavior, showing unidirectional interference in the consistent S-R task, and strong bidirectional interference in the variable S-R task. Thus, the identity of ignored local distractors was available, even under conditions that favored focused attention to global information. The results provide support for a model in which global processing proceeds more quickly at early perceptual stages and in which local processing can catch up if processing demands are increased at later stages.     

实物形状的知觉相似性对视觉隐喻加工的影响

视觉隐喻是众多研究者比较关注的领域, 当前多以物体简笔画、漫画及广告等方面的研究为主, 但对与生活密切相关的实物的视觉隐喻研究甚少。因此研究采用掩蔽启动范式、李克特9点量表及语音生成等研究方法, 在物体概念类型(概念相同、概念相异)及形状类型(形状相似、形状相异)条件下, 针对实物图片的形状知觉相似性是否对视觉隐喻加工产生影响进行探讨。结果发现无论物体概念是否相同, 形状相似性对个体的物体识别具有“促进”作用, 并有利于视觉隐喻加工; 在物体识别中, 当两个物体概念不同时, 个体会试图建立一个特设类别来对形状相似的物体进行归类, 从而实现了视觉隐喻的加工。因此研究进一步证明了实物形状的知觉相似性有利于视觉隐喻的加工。     

Categorization by schema relations and perceptual similarity in 5-year-olds and adults: A study in vision and in audition

This research explores the way in which young children (5 years of age) and adults use perceptual and conceptual cues for categorizing objects processed by vision or by audition. Three experiments were carried out using forced-choice categorization tasks that allowed responses based on taxonomic relations (e.g., vehicles) or on schema category relations (e.g., vehicles that can be seen on the road). In Experiment 1 (visual modality), prominent responses based on conceptually close objects (e.g., objects included in a schema category) were observed. These responses were also favored when within-category objects were perceptually similar. In Experiment 2 (auditory modality), schema category responses depended on age and were influenced by both within- and between-category perceptual similarity relations. Experiment 3 examined whether these results could be explained in terms of sensory modality specializations or rather in terms of information processing constraints (sequential vs. simultaneous processing).