多目标追踪的任务难度对不同类型非目标选择性抑制的影响

采用多目标追踪（MOT）与点探测刺激觉察任务相结合的实验范式,分别通过改变运动与静止非目标数量,考察追踪难度变化对不同类型非目标选择性抑制的影响。实验一通过改变运动非目标数量为4、5、6,发现当运动非目标数量为6时,追踪难度显著增加,静止非目标上的抑制量也显著增加,而运动非目标上的抑制量则不随追踪难度的变化而变化;实验二改变静止非目标数量为4、5、6,同样发现当静止非目标数量为6时,追踪难度显著增加,静止非目标上的抑制量也显著增加,而运动非目标上的抑制量仍不随追踪难度的变化而变化,且当静止非目标数量为6时,静止非目标上的抑制量显著大于运动非目标,出现了反转现象,其原因可能是视野范围内总的对象数量超出了视觉索引容量,被试改变了对静止与运动非目标的抑制策略。综合实验结果表明,静止非目标上的抑制程度随追踪难度的提高而增加;而运动非目标上的抑制程度对追踪难度的变化不敏感,在不同难度水平上保持相对稳定。     

Selective nontarget inhibition in Multiple Object Tracking

We previously reported that in the Multiple Object Tracking (MOT) task, which requires tracking several identical targets moving unpredictably among identical nontargets, the nontargets appear to be inhibited, as measured by a probe-dot detection method. The inhibition appears to be local to nontargets and does not extend to the space between objects—dropping off very rapidly away from targets and nontargets. In the present three experiments we show that (1) nontargets that are identical to targets but remain in a fixed location are not inhibited and (2) moving objects that have a different shape from targets are inhibited as much as same-shape nontargets, and (3) nontargets that are on a different depth plane and so are easily filtered out are not inhibited. This is consistent with a task-dependent view of item inhibition wherein nontargets are inhibited if (and only if) they are likely to be mistaken for targets.     

多目标追踪任务中不同运动方式非目标的抑制机制

采用多目标追踪范式结合点探测技术的方法, 考察视觉系统对不同运动方式(静止和规则运动)非目标的抑制机制。实验一将部分非目标设置为静止, 考察静止非目标的抑制机制; 实验二将部分非目标设置为规则运动, 以提高任务难度, 考察规则运动非目标的抑制机制。结果发现: (1) 实验一中静止非目标受到抑制, 抑制量与运动非目标没有差异; (2) 实验二中规则运动非目标受到抑制, 抑制量显著小于随机运动非目标; (3)综合两实验发现, 随着任务难度的提高, 只有随机运动非目标的抑制量显著增加, 而静止非目标与规则运动非目标的抑制量差异不显著。最后, 就视觉系统对不同运动方式非目标的抑制机制进行了讨论。     

目标与非目标数量变化对多目标追踪的选择性抑制效应

采用多目标追踪和点探测刺激觉察任务相结合的实验范式,考察目标和非目标数量变化对多目标追踪的选择性抑制效应。实验一设置非目标恒定而变化目标数量,结果发现：随着目标数量的增加,目标与非目标间的抑制差异量不随目标数量变化而变化。实验二设置目标恒定而变化非目标数量,结果发现：在非目标数量变化的三种水平下,目标与非目标间的抑制差异量也无显著差异。综合实验结果表明：在多目标追踪的追踪容量或抑制容量范围内,抑制差异量对目标数量或非目标数量变化是不敏感的;注意资源分配方式在一定范围内保持相对稳定。     

Close encounters of the distracting kind: Identifying the cause of visual tracking errors

Why can we track only so many objects? We addressed this question by asking when and how tracking errors emerge. To test the hypothesis that many tracking errors are target/nontarget confusions emerging from close encounters, we compared standard multiple-object tracking trials with trials on which a nontarget turned a random color whenever it approached within 4° of a target. This manipulation significantly improved performance by alleviating the correspondence challenge of a close encounter. Two control experiments showed that color change benefits were not merely due to target recovery. Follow-up experiments demonstrated that color change benefits did not accrue monotonically with distance but, instead, seemed to obey a step function; and an additional experiment demonstrated that, without color changes, the frequency of close encounters predicts tracking performance. Taken together, these experiments suggest that uncertainty about target location imposes the primary constraint on tracking, at times causing errors by leading to confusions between targets and nontargets.     

多身份追踪中基于表情特征的分组效应

探讨了表情因素作为身份特征对多身份追踪中分组效应的影响。采用多身份追踪范式, 8个客体为表情图片(正性、负性、中性)其中4个为目标, 对45名被试进行了有无眉毛线索对追踪表现影响的测查。实验条件分别为：目标表情与非目标表情完全不相同组(4水平, 简称分组)、目标表情与非目标表情都由两种相同数量的表情混合组成(3水平, 简称配对)与基线组(8个客体表情相同)。发现分组水平的成绩显著优于基线组, 配对水平的成绩显著低于基线组, 并表现出了负性表情的追踪优势; 另外, 有无眉毛线索对追踪表现无显著影响。这一结果说明多身份追踪中存在基于表情特征的分组效应, 负性表情的分组知觉高于正性表情。     

ERP evidence for the control of emotional memories during strategic retrieval

Neural evidence for the strategic retrieval of task-relevant ‘target’ memories at the expense of less relevant ‘nontarget’ memories has been demonstrated across a wide variety of studies. In ERP studies, this evidence consists of the ERP correlate of recollection (i.e. the ‘left parietal old/new effect’) being evident for targets and attenuated for nontargets. It is not yet known, however, whether this degree of strategic control can be extended to emotionally valenced words, or whether these items instead reactivate associated memories. The present study used a paradigm previously employed to demonstrate the strategic retrieval of neutral words (Herron & Rugg, Psychonomic Bulletin and & Review, 10(3), 703-–710, 2003b) to assess the effects of stimulus valence on behavioural and event-related potential (ERP) measures of strategic retrieval. While response accuracy and reaction times associated with targets were unaffected by valence, negative nontargets and new items were both associated with an elevated false alarm rate and longer RTs than their neutral equivalents. Both neutral and negative targets and nontargets elicited early old/new effects between 300 and 500 ms. Critically, whereas neutral and negative targets elicited robust and statistically equivalent left parietal old/new effects between 500 and 800 ms, these were absent for neutral and negative nontargets. A right frontal positivity associated with postretrieval monitoring was evident for neutral targets versus nontargets, for negative versus neutral nontargets, and for targets versus new items. It can therefore be concluded that the recollection of negatively valenced words is subject to strategic control during retrieval, and that postretrieval monitoring processes are influenced by emotional valence.     

Depth of nontarget processing in an attention task

Two studies examined the effect of the sensory discriminability of targets from nontargets on depth of nontarget processing. Subjects shadowed target words that were binaurally presented with coincident nontarget words. Targets and nontargets were spoken in the same male voice under low sensory discriminability and in male and female voices, respectively under high sensory discriminability. Across the two studies, depth of nontarget processing was assessed in three ways: extent to which shadowing accuracy was disrupted by a semantic overlap between targets and nontargets, expenditure of capacity (reaction time to subsidiary light signals), and nontarget recall. All three possible measures of depth of nontarget processing decreased as sensory discriminability increased. The data support the assumption of multiple-loci theories of attention that nontargets can be perceptually inhibited; they contraindicate the assumption of late-selection theories that perceptual processing is automatic and irrepressible.     

自闭症儿童视觉动态信息的注意加工特点——来自多目标追踪任务的证据

为了考察中低功能自闭症儿童在动态条件下的多目标注意加工特点,研究采用多目标追踪实验范式,具体追踪任务采用多目标随机运动和碰撞反弹算法。实验设计为两因素混合设计,组间变量为年龄和性别匹配的中低功能自闭症和正常儿童组,组内变量为追踪目标数量（分别为1、2、3、4个目标）,因变量为被试在多目标追踪任务中的追踪正确率和追踪容量。结果发现：（1）中低功能自闭症儿童在目标数量为1到目标数量为4时的正确率均明显低于正常儿童,且标准差变异较大,中低功能自闭症儿童的多目标的持续追踪能力和稳定性存在一定的缺陷;（2）当目标数量为1时,正常组儿童与中低功能自闭症儿童的追踪容量差异不显著;目标为2、3、4时,两组追踪容量差异均显著。不同目标数量情况下中低功能自闭症儿童平均的注意容量为0.83~1.24个（平均容量约为1个）明显低于正常儿童的0.95~3.72个（最大容量接近4个）。中低功能自闭症儿童在多目标追踪上表现为单焦点注意加工的特点,存在一定程度的注意转移缺陷。     

Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndrome

The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo‐spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3‐ and 4‐year‐olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k‐statistic) showed similar developmental profiles in typically developing 3‐ and 4‐year‐old children, but the WS profile differed from either age group. People with WS could track more objects than 3‐year‐olds, and the same number as 4‐year‐olds, but they could remember the locations of more static objects than both 3‐ and 4‐year‐olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4‐year‐olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development.     

Target localization after saccades and at fixation: Nontargets both facilitate and bias responses

ABSTRACT

The image on our retina changes every time we make an eye movement. To maintain visual stability after saccades, specifically to locate visual targets, we may use nontarget objects as “landmarks”. In the current study, we compared how the presence of nontargets affects target localization after saccades and during sustained fixation. Participants fixated a target object, which either maintained its location on the screen (sustained-fixation trials), or displaced to trigger a saccade (saccade trials). After the target disappeared, participants reported the most recent target location with a mouse click. We found that the presence of nontargets decreased response error magnitude and variability. However, this nontarget facilitation effect was not larger for saccade trials than sustained-fixation trials, indicating that nontarget facilitation might be a general effect for target localization, rather than of particular importance to post-saccadic stability. Additionally, participants’ responses were biased towards the nontarget locations, particularly when the nontarget-target relationships were preserved in relative coordinates across the saccade. This nontarget bias interacted with biases from other spatial references, e.g., eye movement paths, possibly in a way that emphasized non-redundant information. In summary, the presence of nontargets is one of several sources of reference that combine to influence (both facilitate and bias) target localization.     

Visual marking inhibits singleton capture

This paper is concerned with how we prioritize the selection of new objects in visual scenes. We present four experiments investigating the effects of distractor previews on visual search through new objects. Participants viewed a set of to-be-ignored nontargets, with the task being to search for a target in a second set, added to the first after 1000ms. This second set could contain a salient feature singleton, defined in terms of its color, orientation, or both color and orientation. When the singleton was a distractor, search was slowed relative to when there was no singleton. Search was facilitated when the singleton was a target. Interestingly, both the interference and facilitation effects were modulated when the preview shared features with the singleton. Follow-up experiments showed that this reduction of singleton effects was not due to: (i) low-level sensory aspects of the displays, (ii) increased heterogeneity in the search set in the preview condition, or (iii) color-based grouping of old and new items. Instead, we suggest that there is an inhibitory carry-over from the first to the second set of items based on feature similarity. We suggest the suppression stems from a process termed visual marking, which suppresses irrelevant visual objects in anticipation of more relevant new objects (Watson & Humphreys, 1997). The findings argue against alternative explanations such as the automatic capture by abrupt new onsets account.     

The costs of target prioritization and the external requirements for using a recall-to-reject strategy in memory exclusion tasks: a meta-analysis

In event-related potential (ERP) studies, the left-parietal old/new effect is commonly considered as a neural correlate of recollection. In memory exclusion tasks, the effect is usually observed when the targeted information is identified, but it is not necessarily present when studied items are rejected as nontargets. Interestingly, both the presence and the absence of such old/new effects to nontargets have been regarded as indicator for strategic retrieval. We reviewed previous ERP studies using memory exclusion tasks to analyze the reaction time (RT) pattern in such studies, as well as the influence of task difficulty on the occurrence of nontarget retrieval. We identified 44 test conditions, reported in 24 studies, and subjected the behavioral data to a meta-analysis. The RTs to correctly rejected new items were shorter than the RTs to hits, in particular in studies that required differentiating conceptual or perceptual information at test. When the retrieval of target information was prioritized, RTs to nontargets were delayed relative to targets. Without such prioritization, no such RT differences were observed. For test conditions with nontarget retrieval, the retrieval accuracy was poorer compared with test conditions without such retrieval. The findings support previous studies that claimed that nontarget retrieval becomes more likely when target retrieval is difficult, but the strong overlap in task difficulty between conditions with and without nontarget retrieval indicates that other, partly yet to-be-identified factors contribute to the occurrence of nontarget retrieval as well.     

Dogs do look at images: eye tracking in canine cognition research

Despite intense research on the visual communication of domestic dogs, their cognitive capacities have not yet been explored by eye tracking. The aim of the current study was to expand knowledge on the visual cognition of dogs using contact-free eye movement tracking under conditions where social cueing and associative learning were ruled out. We examined whether dogs spontaneously look at actual objects within pictures and can differentiate between pictures according to their novelty or categorical information content. Eye movements of six domestic dogs were tracked during presentation of digital color images of human faces, dog faces, toys, and alphabetic characters. We found that dogs focused their attention on the informative regions of the images without any task-specific pre-training and their gazing behavior depended on the image category. Dogs preferred the facial images of conspecifics over other categories and fixated on a familiar image longer than on novel stimuli regardless of the category. Dogs’ attraction to conspecifics over human faces and inanimate objects might reflect their natural interest, but further studies are needed to establish whether dogs possess picture object recognition. Contact-free eye movement tracking is a promising method for the broader exploration of processes underlying special socio-cognitive skills in dogs previously found in behavioral studies.     

Areas of Interest as a Signal Detection Problem in Behavioral Eye‐Tracking Research

Decision researchers frequently analyze attention to individual objects to test hypotheses about underlying cognitive processes. Generally, fixations are assigned to objects using a method known as area of interest (AOI). Ideally, an AOI includes all fixations belonging to an object while fixations to other objects are excluded. Unfortunately, due to measurement inaccuracy and insufficient distance between objects, the distributions of fixations to objects may overlap, resulting in a signal detection problem. If the AOI is to include all fixations to an object, it will also likely include fixations belonging to other objects (false positives). In a survey, we find that many researchers report testing multiple AOI sizes when performing analyses, presumably trying to balance the proportion of true and false positive fixations. To test whether AOI size influences the measurement of object attention and conclusions drawn about cognitive processes, we reanalyze four published studies and conduct a fifth tailored to our purpose. We find that in studies in which we expected overlapping fixation distributions, analyses benefited from smaller AOI sizes (0° visual angle margin). In studies where we expected no overlap, analyses benefited from larger AOI sizes (>.5° visual angle margins). We conclude with a guideline for the use of AOIs in behavioral eye‐tracking research. Copyright © 2015 John Wiley & Sons, Ltd.     

Familiarity-Matching: An Ecologically Rational Heuristic for the Relationships-Comparison Task

Previous studies have shown that people often use heuristics in making inferences and that subjective memory experiences, such as recognition or familiarity of objects, can be valid cues for inferences. So far, many researchers have used the binary choice task in which two objects are presented as alternatives (e.g., “Which city has the larger population, city A or city B?”). However, objects can be presented not only as alternatives but also in a question (e.g., “Which country is city X in, country A or country B?”). In such a situation, people can make inferences based on the relationship between the object in the question and each object given as an alternative. In the present study, we call this type of task a “relationships-comparison task.” We modeled the three inference strategies that people could apply to solve it (familiarity-matching [FM; a new heuristic we propose in this study], familiarity heuristic [FH], and knowledge-based inference [KI]) to examine people's inference processes. Through Studies 1, 2, and 3, we found that (a) people tended to rely on heuristics, and that FM (inferences based on similarity in familiarity between objects) well explained participants' inference patterns; (b) FM could work as an ecologically rational strategy for the relationships–comparison task since it could effectively reflect environmental structures, and that the use of FM could be highly replicable and robust; and (c) people could sometimes use a decision strategy like FM, even in their daily lives (consumer behaviors). The nature of the relationships–comparison task and human cognitive processes is discussed.     

The role of eye fixations in concentration and amplification effects during multiple object tracking

When tracking spatially extended objects in a multiple object tracking task, attention is preferentially directed to the centres of those objects (attentional concentration), and this effect becomes more pronounced as object length increases (attentional amplification). However, it is unclear whether these effects depend on differences in attentional allocation or differences in eye fixations. We addressed this question by measuring eye fixations in a dual-task paradigm that required participants to track spatially extended objects, while simultaneously detecting probes that appeared at the centres or near the endpoints of objects. Consistent with previous research, we observed concentration and amplification effects: Probes at the centres of objects were detected more readily than those near their endpoints, and this difference increased with object length. Critically, attentional concentration was observed when probes were equated for distance from fixation during free viewing, and concentration and amplification were observed without eye movements during strict fixation. We conclude that these effects reflect the prioritization of covert attention to particular spatial regions within extended objects, and we discuss the role of eye fixations during multiple object tracking.     

Failure to detect changes to attended objects in motion pictures

Our intuition that we richly represent the visual details of our environment is illusory. When viewing a scene, we seem to use detailed representations of object properties and interobject relations to achieve a sense of continuity across views. Yet, several recent studies show that human observers fail to detect changes to objects and object properties when localized retinal information signaling a change is masked or eliminated (e.g., by eye movements). However, these studies changed arbitrarily chosen objects which may have been outside the focus of attention. We draw on previous research showing the importance of spatiotemporal information for tracking objects by creating short motion pictures in which objects in both arbitrary locations and the very center of attention were changed. Adult observers failed to notice changes in both cases, even when the sole actor in a scene transformed into another person across an instantaneous change in camera angle (or “cut”).     

Effects of similarity, difficulty, and nontarget presentation on the time course of visual attention

Long-lasting interference from an initial visual target on a subsequent one has been measured in two paradigms: rapid serial presentation of targets and nontargets at a single location, and simple presentation of two spatially separated targets. We note that comparisons between these paradigms might be invalid, since interference in each paradigm can be attributed to a different source: demands on selective attention, or demands to switch locations. We use a novel target presentation that both minimizes selection demands and eliminates location switching, yet we still find long-lasting interference. We suggest that all three paradigms discussed tap a common attentional limit. We also examine effects of similarity between targets, and effects of discrimination difficulty on the initial target. We find that similarity effects are more pronounced when nontargets are present, and we find no effect of discrimination difficulty on subsequent interference.     

The role of color information on object recognition: a review and meta-analysis

In this study, we systematically review the scientific literature on the effect of color on object recognition. Thirty-five independent experiments, comprising 1535 participants, were included in a meta-analysis. We found a moderate effect of color on object recognition (d = 0.28). Specific effects of moderator variables were analyzed and we found that color diagnosticity is the factor with the greatest moderator effect on the influence of color in object recognition; studies using color diagnostic objects showed a significant color effect (d = 0.43), whereas a marginal color effect was found in studies that used non-color diagnostic objects (d = 0.18). The present study did not permit the drawing of specific conclusions about the moderator effect of the object recognition task; while the meta-analytic review showed that color information improves object recognition mainly in studies using naming tasks (d = 0.36), the literature review revealed a large body of evidence showing positive effects of color information on object recognition in studies using a large variety of visual recognition tasks. We also found that color is important for the ability to recognize artifacts and natural objects, to recognize objects presented as types (line-drawings) or as tokens (photographs), and to recognize objects that are presented without surface details, such as texture or shadow. Taken together, the results of the meta-analysis strongly support the contention that color plays a role in object recognition. This suggests that the role of color should be taken into account in models of visual object recognition.