Object-based attention: strength of object representation and attentional guidance

Two or more features belonging to a single object are identified more quickly and more accurately than are features belonging to different objects--a finding attributed to sensory enhancement of all features belonging to an attended or selected object. However, several recent studies have suggested that this "single-object advantage" may be a product of probabilistic and configural strategic prioritizations rather than of object-based perceptual enhancement per se, challenging the underlying mechanism that is thought to give rise to object-based attention. In the present article, we further explore constraints on the mechanisms of object-based selection by examining the contribution of the strength of object representations to the single-object advantage. We manipulated factors such as exposure duration (i.e., preview time) and salience of configuration (i.e., objects). Varying preview time changes the magnitude of the object-based effect, so that if there is ample time to establish an object representation (i.e., preview time of 1,000 msec), then both probability and configuration (i.e., objects) guide attentional selection. If, however, insufficient time is provided to establish a robust object-based representation, then only probabilities guide attentional selection. Interestingly, at a short preview time of 200 msec, when the two objects were sufficiently different from each other (i.e., different colors), both configuration and probability guided attention selection. These results suggest that object-based effects can be explained both in terms of strength of object representations (established at longer exposure durations and by pictorial cues) and probabilistic contingencies in the visual environment.     

A configural effect in visual short-term memory for features from different parts of an object

Previous studies have shown that change detection performance is improved when the visual display holds features (e.g., a colour and an orientation) that are grouped into different parts of the same object compared to when they are all spatially separated (Xu, 2002a, 2002b). These findings indicate that visual short-term memory (VSTM) encoding can be "object based". Recently, however, it has been demonstrated that changing the orientation of an item could affect the spatial configuration of the display (Jiang, Chun, & Olson, 2004), which may have an important influence on change detection. The perceptual grouping of features into an object obviously reduces the amount of distinct spatial relations in a display and hence the complexity of the spatial configuration. In the present study, we ask whether the object-based encoding benefit observed in previous studies may reflect the use of configural coding rather than the outcome of a true object-based effect. The results show that when configural cues are removed, the object-based encoding benefit remains for features (i.e., colour and orientation) from different parts of an object, but is significantly reduced. These findings support the view that memory for features from different parts of an object can benefit from object-based encoding, but the use of configural coding significantly helps enlarge this effect.     

动态范式中基于客体的返回抑制 ——是客体抑制还是空间抑制的动态更新？

对动态范式中基于客体的返回抑制进行了考察。实验1在双侧客体改变和不改变条件下考察了返回抑制效应,结果表明,在双侧客体改变条件下返回抑制仍然存在。实验2采用单侧客体变化技术对动态范式中基于客体的返回抑制进行了测量,结果发现,在有效线索化条件下,单侧客体改变和不改变条件下对靶子的反应时没有显著差异（p > 0.90）。这些结果表明动态范式中基于客体的返回抑制的机制是空间抑制的动态更新,而不是客体表征受到抑制     

Every moment counts: smooth transitions of object boundaries reflect constant updating in object-based attention

Detection of a target is faster when it is presented on an attended rather than an unattended object (i.e., object-based attention). Using the double-rectangle cuing paradigm (Egly, Driver, & Rafal, 1994), we previously showed that object-based attention operates on a dynamic representation: Object-based attentional guidance is affected by subsequent changes occurring to an attended object (Lin & Yeh, 2011). The present study provides further support for our dynamic-updating hypothesis, demonstrating that changes are indeed updated into the existing object representation. After a cue display, we introduced changes between the initial display (four hashes) and the final display (four squares with an occluder between them). We found object-based attention only with smooth transitions between the initial and final displays, not when transitions were in the reverse order (Exp. 1) or contained any single disruption of the smooth transition (Exp. 2). These results confirm our hypothesis that attention operates on a dynamic object representation that is constantly and continuously updated.     

The effect of viewing the moving limb and target object during the early phase of movement on the online control of grasping

Two experiments were conducted to investigate (1) during which phase of the movement vision is most critical for control, and (2) how vision of the target object and the participant's moving limb affect the control of grasping during that movement phase. In Experiment 1, participants, wearing liquid crystal shutter goggles, reached for and grasped a cylinder with a diameter of 4 or 6 cm under a shutting paradigm (SP) and a re-opening paradigm (RP). In SP, the goggles closed (turned opaque) 0 ms, 150 ms, 350 ms, 500 ms, or 700 ms after movement onset, or remained open (transparent) during the prehension movements. In RP, the goggles closed immediately upon movement onset, and re-opened 0 ms (i.e., without initially shutting), 150 ms, 350 ms, 500 ms, or 700 ms after the initial shutting, or remained opaque throughout the prehension movements. The duration of the prehension movements was kept relatively constant across participants and trials at approximately 1100 ms, i.e., the duration of prehension movements typically observed in daily life. The location of the target object was constant during the entire experiment. The SP and RP paradigms were counter-balanced across participants, and the order of conditions within each session was randomized. The main findings were that peak grip aperture (PGA) in the 150 ms-shutting condition was significantly larger than in the 350 ms-shutting condition, and that PGA in the 350 ms-re-opening condition was significantly larger than in the 150 ms-re-opening condition. These results revealed that online vision between 150 ms and 350 ms was critical for grasp control on PGA in typical, daily-life-speeded prehension movements. Furthermore, the results obtained for the time after maximal deceleration (TAMD; movement duration-time to maximal deceleration) demonstrated that early-phase vision contributed to the temporal pattern of the later movement phases (i.e., TAMD). The results thus demonstrated that online vision in the early phase of movement is crucial for the control of grasping. In addition to the apparatus used in Experiment 1, two liquid shutter plates placed in the same horizontal plane (25 cm above the experimental table) were used in Experiment 2 to manipulate the visibility of the target and the participant's moving limb. The plate closest to the participant altered vision of the limb/hand, while the more distant plate controlled vision of the object. The conditions were as follows: (1) both plates were open during movement (full vision condition); (2) both plates were closed 0, 150, or 350 ms following onset of arm movement (front-rear condition: FR); or (3) only the near plate closed 0, 150, or 350 ms following the onset of the arm movement (front condition: F). The results showed that shutting at 0 and 150 ms in the FR condition caused a significantly larger PGA, while the timing of shutting in the F condition had little influence on the PGA. These findings indicated that online vision, especially of the target object, during the early phase of prehension movements is critical to the control of grasping.     

Object-based attentional selection can modulate the Stroop effect

The Stroop (1935) effect is the inability to ignore a color word when the task is to report the ink color of that word (i.e., to say "green" to the word RED in green ink). The present study investigated whether object-based processing contributes to the Stroop effect. According to this view, observers are unable to ignore irrelevant features of an attended object (Kahneman & Henik, 1981). In three experiments, participants had to name the color of one of two superimposed rectangles and to ignore words that appeared in the relevant object, in the irrelevant object, or in the background. The words were congruent, neutral, or incongruent with respect to the correct color response. Words in the irrelevant object and in the background produced significant Stroop effects, consistent with earlier findings. Importantly, however, words in the relevant object produced larger Stroop effects than did the other conditions, suggesting amplified processing of all the features of an attended object. Thus, object-based processing can modulate the Stroop effect.     

Object-based attentional selection and aging

The authors conducted 2 studies to examine potential age-related differences in object-based attentional selection. Participants were briefly presented with pairs of wrenches and were asked to make 1 response if both target properties (i.e., an open end and a hexagonal end) were present and another response if only a single target property was present in the display. The critical manipulation was whether the target properties were present on 1 wrench or distributed between 2 wrenches. Space-based models of selective attention predict no difference in performance between these conditions. However, object-based attentional selection models predict better performance when both target properties appear on a single object. The results from both of the studies were consistent with object-based models of attentional selection. Furthermore, both young and old adults showed similar performance effects, suggesting the object-based attentional selection is insensitive to normal aging.     

Early activation of object names in visual search

In a visual search experiment, participants had to decide whether or not a target object was present in a fourobject search array. One of these objects could be a semantically related competitor (e.g.,shirt for the targettrousers) or a conceptually unrelated object with the same name as the target—for example,bat (baseball) for the targetbat (animal). In the control condition, the related competitor was replaced by an unrelated object. The participants’ response latencies and eye movements demonstrated that the two types of related competitors had similar effects: Competitors attracted the participants’ visual attention and thereby delayed positive and negative decisions. The results imply that semantic and name information associated with the objects becomes rapidly available and affects the allocation of visual attention.     

Effects of attention during encoding on sex differences in object location memory

Attention plays a key role in memory processes and has been widely studied in various memory tasks. The role of attention in sex differences in object location memory is not clearly understood. In the present study, two experiments involving 186 participants and using an object array presented on paper were conducted to examine two encoding conditions: incidental and intentional. In each experiment, the participants were randomly assigned to divided versus full attention conditions. In the first experiment, which involved incidental encoding, women outperformed men in memorising location‐exchanged objects in both the full and in the divided attention condition. In the second experiment, which involved intentional encoding, women outperformed men in memorising location‐exchanged objects in the full attention condition, but not the divided attention condition. These findings deepen our knowledge regarding the role of attention in object location memory, specifically in terms of the conditions under which females have an advantage for detecting changes in an array of objects.     

The role of color diagnosticity in object recognition and representation

The role of color diagnosticity in object recognition and representation was assessed in three Experiments. In Experiment 1a, participants named pictured objects that were strongly associated with a particular color (e.g., pumpkin and orange). Stimuli were presented in a congruent color, incongruent color, or grayscale. Results indicated that congruent color facilitated naming time, incongruent color impeded naming time, and naming times for grayscale items were situated between the congruent and incongruent conditions. Experiment 1b replicated Experiment 1a using a verification task. Experiment 2 employed a picture rebus paradigm in which participants read sentences one word at a time that included pictures of color diagnostic objects (i.e., pictures were substituted for critical nouns). Results indicated that the “reading” times of these pictures mirrored the pattern found in Experiment 1. In Experiment 3, an attempt was made to override color diagnosticity using linguistic context (e.g., a pumpkin was described as painted green). Linguistic context did not override color diagnosticity. Collectively, the results demonstrate that color information is regularly utilized in object recognition and representation for highly color diagnostic items.     

The return of object-based attention: selection of multiple-region objects

Objects can control the focus of attention, allowing features on the same object to be selected more easily than features on different objects. In the present experiments, we investigated the perceptual processes that contribute to such object-based attentional effects. Previous research has demonstrated that object-based effects occur for single-region objects but not for multiple-region objects under some conditions (Experiment 1, Watson & Kramer, 1999). Such results are surprising, because most objects in natural scenes are composed of multiple regions. Previous findings could therefore limit the usefulness of an object-based selection mechanism. We explored the generality of these single-region selection results by manipulating the extent to which different (i.e., multiple) regions of a single object perceptually grouped together. Object-based attentional effects were attenuated when multiple regions did not group into a single perceptual object (Experiment 1). However, when multiple regions grouped together based on (1) edge continuation (Experiments 2 and 3) or (2) part and occlusion cues (Experiment 4), we observed object-based effects. Our results suggest that object-based attention is a robust process that can select multiple-region objects, provided the regions of such objects cohere on the basis of perceptual grouping cues.     

Independent effects of colour on object identification and memory

We examined the effects of colour on object identification and memory using a study-test priming procedure with a coloured-object decision task at test (i.e., deciding whether an object is correctly coloured). Objects were selected to have a single associated colour and were either correctly or incorrectly coloured. In addition, object shape and colour were either spatially integrated (i.e., colour fell on the object surface) or spatially separated (i.e., colour formed the background to the object). Transforming the colour of an object from study to test (e.g., from a yellow banana to a purple banana) reduced priming of response times, as compared to when the object was untransformed. This utilization of colour information in object memory was not contingent upon colour falling on the object surface or whether the resulting configuration was of a correctly or incorrectly coloured object. In addition, we observed independent effects of colour on response times, whereby coloured-object decisions were more efficient for correctly than for incorrectly coloured objects but only when colour fell on the object surface. These findings provide evidence for two distinct mechanisms of shape-colour binding in object processing.     

客体表征质量在语义客体注意效应中的作用

已有研究表明,除自下而上因素外,自上而下因素也能够对客体知觉起到调节作用,从而影响注意的分配。本研究以不同词频（高频和低频）的汉语双字词为实验材料,采用双矩形线索范式变式考察不同语义客体表征质量对基于语义客体注意效应的影响。结果发现,在高语义客体表征质量的条件下出现了基于语义客体的注意效应,而在低语义客体表征质量的条件下并未出现基于语义客体的注意效应。该结果表明,语义客体表征质量的高低是影响基于语义客体注意效应的重要因素。     

Mechanisms for the object-based negative compatibility effect: voluntary versus involuntary inhibition

This study investigates whether the object-based negative compatibility effect (NCE) originates from involuntary or voluntary inhibition. We hypothesised that both supraliminally presented primes (the prime is a mug with its handle pointing either left or right) and experimental instructions (i.e., ignoring the prime) in previous studies might induce participants to develop a voluntarily inhibitory strategy that is responsible for the object-based NCE. To test this hypothesis, we conducted 3 experiments. Experiment 1 confirmed a suitable paradigm. Experiment 2 altered participants’ strategies by varying the frequency of compatible trials across blocks. The results revealed a significant NCE for the low-frequency condition, which suggested that voluntary strategy might be primarily responsible for the object-based NCE. Experiment 3 combined a free-choice target with an object-based NCE paradigm. The results showed equivalent frequencies and mean response times between the free-choice responses that corresponded to or were opposite from the orientations of the mug handle. Combined with the results of response time quartiles, which revealed NCEs in fast responses (Q1–Q3) but no compatibility effect in slow (Q4) responses, we concluded that the object-based NCE might be primarily based on voluntary inhibition. Moreover, this inhibition might take effect earlier than that of the arrow-based NCE.     

Infants' ability to use object kind information for object individuation.

The present studies investigate infants reliance on object kind information in solving the problem of object individuation. Two experiments explored whether adults, 10- and 12-month-old infants could use their knowledge of ducks and cars to individuate an ambiguous array consisting of a toy duck perched on a toy car into two objects. A third experiment investigated whether 10-month-old infants could use their knowledge of cups and shoes to individuate an array consisting of a cup perched on a shoe into two objects. Ten-month-old infants failed to use object kind information alone to resolve the ambiguity with both pairs of objects. In contrast, infants this age succeeded in using spatiotemporal information to segment the array into two objects, i.e. they succeeded if shown that the duck moved independently relative to the car, or the cup relative to the shoe. Twelve-month-old infants, as well as adults, succeeded at object individuation on the basis of object kind information alone. These findings shed light on the developmental course of object individuation and provide converging evidence for the Object-first Hypothesis [Xu, F., Carey, S., 1996; Xu, F., 1997b]. Early on, infants may represent only one concept that provides criteria for individuation, namely physical object; kind concepts such as duck, car, cup, and shoe may be acquired later in the first year of life.     

Cross‐cultural differences in object recognition: Comparing asylum seekers from Sub‐Saharan Africa and a matched Western European control group

Nowadays, more and more people report about their memories in cross‐cultural contexts. In international criminal settings and asylum procedures, object recognition tests can provide valuable information, for example, about weapons used during a crime or landmarks from the claimed region of origin. This study was the first to compare object recognition performance by asylum seekers from Sub‐Saharan Africa to a matched Western European control group. African participants performed worse than European participants on perceptual tests involving transformations from two‐ to three‐dimensional representations, but both groups performed equally well on an object recognition test that involved transformation from three‐ to two‐dimensional representations. However, African participants were significantly more likely to respond “yes” on the recognition test (i.e., an acquiescence response style) than European participants. Our findings elucidate cultural differences in responding on an object recognition test. Judges, juries, and immigration officials would be wise to take these differences into account when evaluating recognition performance in cross‐cultural contexts.     

Color makes a difference: two-dimensional object naming in literate and illiterate subjects

Previous work has shown that illiterate subjects are better at naming two-dimensional representations of real objects when presented as colored photos as compared to black and white drawings. This raises the question if color or textural details selectively improve object recognition and naming in illiterate compared to literate subjects. In this study, we investigated whether the surface texture and/or color of objects is used to access stored object knowledge in illiterate subjects. A group of illiterate subjects and a matched literate control group were compared on an immediate object naming task with four conditions: color and black and white (i.e., grey-scaled) photos, as well as color and black and white (i.e., grey-scaled) drawings of common everyday objects. The results show that illiterate subjects perform significantly better when the stimuli are colored and this effect is independent of the photographic detail. In addition, there were significant differences between the literacy groups in the black and white condition for both drawings and photos. These results suggest that color object information contributes to object recognition. This effect was particularly prominent in the illiterate group.     

无觉知条件下的客体注意效应

采用双矩形范式变式考察在对客体无觉知的条件下的客体注意效应,共包括两个实验：实验一考察对完整矩形客体无觉知的条件下能否出现客体注意效应,发现在完整矩形客体不可见的情况下依然出现了客体注意效应。实验二考察对虚拟矩形客体无觉知的情况下是否能够出现客体注意效应,发现在虚拟矩形客体不可见的情况下也能够出现客体注意效应。研究结果表明客体注意效应在无觉知条件下依然存在,为注意与觉知在功能上相互分离的观点提供了新的证据。     

The modulation of spatial congruency by object-based attention: analysing the "locus" of the modulation

Earlier studies have demonstrated that spatial cueing differentially reduces stimulus-stimulus congruency (e.g., spatial Stroop) interference but not stimulus-response congruency (e.g., Simon; e.g., Lupiá?ez & Funes, 2005). This spatial cueing modulation over spatial Stroop seems to be entirely attributable to object-based attention (e.g., Luo, Lupiá?ez, Funes, & Fu, 2010). In the present study, two experiments were conducted to further explore whether the cueing modulation of spatial Stroop is object based and/or space based and to analyse the "locus" of this modulation. In Experiment 1, we found that the cueing modulation over spatial Stroop is entirely object based, independent of stimulus-response congruency. In Experiment 2, we observed that the modulation of object-based attention over the spatial Stroop only occurred at a short cue-target interval (i.e., stimulus onset asynchrony; SOA), whereas the stimulus-response congruency effect was not modulated either by object-based or by location-based attentional cueing. The overall pattern of results suggests that the spatial cueing modulation over spatial Stroop arises from object-based attention and occurs at the perceptual stage of processing.     

Object-based visual selective attention and perceptual organization

We report the results of four experiments that were conducted to examine both the representations that provide candidate entities available for object-based attentional selection and the influence of bottom-up factors (i.e., geometric and surface characteristics of objects) and top-down factors (i.e., context and expectancies) on the selection process. Subjects performed the same task in each of the experiments. They were asked to determine whether two target properties, a bent end and an open end of a wrench, appeared in a brief display of two wrenches. In each experiment, the target properties could occur on a single wrench or one property could occur on each of two wrenches. The question of central interest was whether a same-object effect (faster and/or more accurate performance when the target properties appeared on one vs. two wrenches) would be observed in different experimental conditions. Several interesting results were obtained. First, depending on the geometric (i.e., concave discontinuities on object contours) and surface characteristics (i.e., homogeneous regions of color and texture) of the stimuli, attention was preferentially directed to one of three representational levels, as indicated by the presence or absence of the same-object effect. Second, although geometric and surface characteristics defined the candidate objects available for attentional selection, top-down factors were quite influential in determining which representational level would be selected. Third, the results suggest that uniform connectedness plays an important role in defining the entities available for attention selection. These results are discussed in terms of the manner in which attention selects objects in the visual environment.