Object detection and basic-level categorization: Sometimes you know it is there before you know what it is

A tight temporal coupling between object detection (is an object there?) and object categorization (what kind of object is it?) has recently been reported (Grill-Spector &; Kanwisher, 2005), suggesting that image segmentation into different objects and categorization of those objects at the basic level may be the very same mechanism. In the present work, we decoupled the time course of detection and categorization through two task manipulations. First, inverted objects were categorized significantly less accurately than upright objects across a range of image presentation durations, but no significant effect on object detection was observed. Second, systematically degrading stimuli affected categorization significantly more than object detection. The time course of object detection and object categorization can be selectively manipulated. They are not intrinsically linked. As soon as you know an object is there, you do not necessarily know what it is.     

Visual categorization of social interactions

Prominent theories of action recognition suggest that during the recognition of actions the physical patterns of the action is associated with only one action interpretation (e.g., a person waving his arm is recognized as waving). In contrast to this view, studies examining the visual categorization of objects show that objects are recognized in multiple ways (e.g., a VW Beetle can be recognized as a car or a beetle) and that categorization performance is based on the visual and motor movement similarity between objects. Here, we studied whether we find evidence for multiple levels of categorization for social interactions (physical interactions with another person, e.g., handshakes). To do so, we compared visual categorization of objects and social interactions (Experiments 1 and 2) in a grouping task and assessed the usefulness of motor and visual cues (Experiments 3, 4, and 5) for object and social interaction categorization. Additionally, we measured recognition performance associated with recognizing objects and social interactions at different categorization levels (Experiment 6). We found that basic level object categories were associated with a clear recognition advantage compared to subordinate recognition but basic level social interaction categories provided only a little recognition advantage. Moreover, basic level object categories were more strongly associated with similar visual and motor cues than basic level social interaction categories. The results suggest that cognitive categories underlying the recognition of objects and social interactions are associated with different performances. These results are in line with the idea that the same action can be associated with several action interpretations (e.g., a person waving his arm can be recognized as waving or greeting).     

Detecting objects is easier than categorizing them

Two experiments compared performance in an object detection task, in which participants categorized photographs as objects and nonobject textures, and an object categorization task, in which photographs were categorized into basic-level categories. The basic-level categorization task was either easy (e.g., dogs vs. buses) or difficult (e.g., dogs vs. cats). Participants performed similarly in the detection and the easy-categorization tasks, but response times to the difficult-categorization task were slower. This latter finding is difficult to reconcile with the conclusions of Grill-Spector and Kanwisher (2005) who reported equivalent performance on detection and basic-level categorization tasks and took this as evidence that figure-ground segregation and basic-level categorization are mediated by the same mechanism.     

Visual search and the collapse of categorization

Categorization researchers typically present single objects to be categorized. But real-world categorization often involves object recognition within complex scenes. It is unknown how the processes of categorization stand up to visual complexity or why they fail facing it. The authors filled this research gap by blending the categorization and visual-search paradigms into a visual-search and categorization task in which participants searched for members of target categories in complex displays. Participants have enormous difficulty in this task. Despite intensive and ongoing category training, they detect targets at near-chance levels unless displays are extremely simple or target categories extremely focused. These results, discussed from the perspectives of categorization and visual search, might illuminate societally important instances of visual search (e.g., diagnostic medical screening).     

Training experts: individuation without naming is worth it

There is growing evidence that individuation experience is necessary for development of expert object discrimination that transfers to new exemplars. Individuation training in human studies has primarily used label association tasks where labels are learned at both the individual and more abstract (basic) level, and expertise criterion requires that individual-level judgments become as fast as basic-level judgments. However, there are training situations when the use of labels is not practical (e.g., with animals or some clinical populations). Moreover, labeling itself can facilitate object discrimination, thus it is unclear what role labels play in the acquisition of expertise in such training paradigms. Here, participants completed an online game that did not require labels in which they interacted with novel objects (Greebles) or control objects (Yufos). Games either required individuation or categorization. We then assessed the impact of this exposure on an abridged Greeble training paradigm. As expected, participants who played Yufo games or Greeble categorization games showed a significant basic-level advantage for Greebles in the abridged training paradigm, typical of novices. However, participants who played the Greeble identity game showed a reduced basic-level advantage, suggesting that individuation without labels may be sufficient to acquire perceptual expertise.     

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.     

Global influences on the development of spatial and object perceptual categorization abilities: Evidence from preterm infants

Influences on the development of perceptual categorization were examined by comparing the performance of three groups of infants on spatial and object categorization tasks. The groups consisted of 1) fullterm infants tested at 3 to 4 months of age, 2) healthy preterm infants tested 3 to 4 months from birth (postnatals), and 3) healthy preterm infants tested 3 to 4 months from their due date (postterms). Four experiments showed that fullterms and postterms outperformed postnatals on a spatial categorization task (i.e., ‘above’ vs. ‘below’, and that fullterms outperformed both postnatals and postterms on object categorization tasks (i.e., dogs vs. cats, and cats vs. birds). These results suggest that maturation may be the predominant influence on the early development of the ability to form categorical representations of spatial information, while preterm birth may exert a limiting influence on the development of object categorization abilities.     

Dr. Angry and Mr. Smile: when categorization flexibly modifies the perception of faces in rapid visual presentations

Are categorization and visual processing independent, with categorization operating late, on an already perceived input, or are they intertwined, with the act of categorization flexibly changing (i.e. cognitively penetrating) the early perception of the stimulus? We examined this issue in three experiments by applying different categorization tasks (gender, expressive or not, which expression and identity) to identical face stimuli. Stimuli were hybrids: they combined a man or a woman with a particular expression at a coarse spatial scale with a face of the opposite gender with a different expression at the fine spatial scale. Results suggested that the categorization task changes the spatial scales preferentially used and perceived for rapid recognition. A perceptual set effect is shown whereby the scale preference of an important categorization (e.g. identity) transfers to resolve other face categorizations (e.g. expressive or not, which expression). Together, the results suggest that categorization can be closely bound to perception.     

Getting to know you: From view-dependent to view-invariant repetition priming for unfamiliar faces

Recent research suggests that repetition priming (RP) for unfamiliar faces is highly view dependent and is eliminated when the viewpoint of target faces changes between study and test. The current research examined whether increased familiarity with novel faces from a single viewpoint at study would support RP from an alternative viewpoint at test. Participants passively viewed novel face images from a single viewpoint at study (i.e., either front or three-quarters), with half of the images seen once and half seen on five occasions. During a sex classification task at test, participants were faster to respond to face images seen from the same view as that at study than they were to previously unseen distractor faces for both single exposure faces and faces seen on five occasions (i.e., standard RP). When, however, face images at test were shown from a different viewpoint from that at study, RP only occurred for faces viewed on five occasions.     

Getting to know you: from view-dependent to view-invariant repetition priming for unfamiliar faces

Recent research suggests that repetition priming (RP) for unfamiliar faces is highly view dependent and is eliminated when the viewpoint of target faces changes between study and test. The current research examined whether increased familiarity with novel faces from a single viewpoint at study would support RP from an alternative viewpoint at test. Participants passively viewed novel face images from a single viewpoint at study (i.e., either front or three-quarters), with half of the images seen once and half seen on five occasions. During a sex classification task at test, participants were faster to respond to face images seen from the same view as that at study than they were to previously unseen distractor faces for both single exposure faces and faces seen on five occasions (i.e., standard RP). When, however, face images at test were shown from a different viewpoint from that at study, RP only occurred for faces viewed on five occasions.     

从毕生发展的角度看个体分类倾向的两次转变——材料的生命性和可操作性的作用

研究从毕生发展的视角考察了个体分类倾向的发展轨迹,并探讨任务材料内容可能对其产生的影响。选取幼儿园、小学、中学、大学和中老年个体各30名作为研究对象,记录他们面对不同的分类材料(有/无生命、高/低可操作性)的分类倾向。结果表明个体的分类倾向经历了两次转变:(1)进入小学后主题分类倾向逐渐降低,并在2、3年级时最低;(2)进入中学之后,个体逐渐恢复对主题分类倾向的偏好,中学和大学的个体面对含有生命体或是可操作性高的材料会比面对非生命体或可操作性低的材料时,更倾向于使用主题分类的策略。这一结果表明,个体对不同材料内容的分类倾向的发展轨迹存在差异,研究结果有助于理解个体概念组织的形成和发展过程。     

The training and transfer of real-world perceptual expertise

A hallmark of perceptual expertise is that experts classify objects at a more specific, subordinate level of abstraction than novices. To what extent does subordinate-level learning contribute to the transfer of perceptual expertise to novel exemplars and novel categories? In this study, participants learned to classify 10 varieties of wading birds and 10 varieties of owls at either the subordinate, species (e.g., "great blue crown heron,"eastern screech owl") or the family ("wading bird,"owl") level of abstraction. During training, the amount of visual exposure was equated such that participants received an equal number of learning trials for wading birds and owls. Pre- and posttraining performance was measured in a same/different discrimination task in which participants judged whether pairs of bird stimuli belonged to the same or different species. Participants trained in species-level discrimination demonstrated greater transfer to novel exemplars and novel species categories than participants trained in family-level discrimination. These findings suggest that perceptual categorization, not perceptual exposure per se, is important for the development and generalization of visual expertise.     

Crowded and sparse domains in object recognition: consequences for categorization and naming

Some models of object recognition propose that items from structurally crowded categories (e.g., living things) permit faster access to superordinate semantic information than structurally dissimilar categories (e.g., nonliving things), but slower access to individual object information when naming items. We present four experiments that utilize the same matched stimuli: two examine superordinate categorization and two examine picture naming. Experiments 1 and 2 required participants to sort pictures into their appropriate superordinate categories and both revealed faster categorization for living than nonliving things. Nonetheless, the living thing superiority disappeared when the atypical categories of body parts and musical instruments were excluded. Experiment 3 examined naming latency and found no difference between living and nonliving things. This finding was replicated in Experiment 4 where the same items were presented in different formats (e.g., color and line-drawn versions). Taken as a whole, these experiments show that the ease with which people categorize items maps strongly onto the ease with which they name them.     

The entry point of face recognition: evidence for face expertise.

Previous studies have shown that experts (e.g., birdwatchers) are as fast to recognize objects at subordinate levels of abstraction (e.g., robin) as they are to recognize the same object at the basic level (e.g., bird). As a test of face expertise, the current study found that adults identify faces more frequently (Experiment 1) and as quickly (Experiment 2) at the subordinate level (e.g., Bill Clinton) as at the basic level (e.g., human). Whereas brief presentation (75 ms) impaired subordinate-level recognition of nonface objects, it did not impair the subordinate level recognition of faces (Experiment 3). Finally, in an identity-matching task, subordinate-level primes facilitated the matching responses of faces but not nonface objects (Experiment 4). Collectively, these results indicate that face expertise, like expert object expertise, promotes a downward shift in recognition to more subordinate levels of abstraction.     

How do associative and phonemic overlap interact to boost illusory recollection?

This project investigated the underlying mechanisms that boost false remember responses when participants receive study words that are both semantically and phonologically similar to a critical lure. Participants completed a memory task in which they were presented with a list of words all associated with a critical lure. Included within the list of semantic associates was a target that was either semantically associated (e.g., yawn) to the critical lure (e.g., sleep) or shared the initial (e.g., slam) or final (e.g., beep) phoneme(s) with the critical lure. After hearing the list, participants recalled each list item and indicated whether they just knew it was on the list or if they instead recollected specific contextual details of that item’s presentation. We found that inserting an initial phonemic overlap target boosted experiences of recollection, but only when semantically related associates were presented beforehand. The results are consistent with models of spoken word recognition and show that established semantic context plus initial phonemic overlap play important roles in boosting false recollection.     

Slow categorization but fast naming for photographs of manipulable objects

Previous research investigating the influence of object manipulability (the properties of objects that make them appropriate for manual action) on object identification has not tightly controlled for effects of both object familiarity and age of acquisition of objects. The current research carefully controlled these two variables on a balanced set of 120 photographs and showed significant effects of object manipulability during object categorization (Experiment 1) and object naming (Experiment 2). Critically, the effects showed a manipulability-effect reversal, with faster categorization of non-manipulable objects, but faster naming of manipulable objects, suggesting that task moderates the direction of the manipulability effect. Exposure duration (the amount of time the object was visible to participants) was also investigated, but no interactions between exposure duration and manipulability were found. These results indicate that not only can manipulability influence object identification, but the way in which it does depends on the task.     

Evidence for two kinds of low-typical instances in a categorization task

Three experiments examined the relationship between instance typicality and reaction time (RT) in a semantic categorization task. In all three experiments, first the instance was presented, and then the category. High-typicality high-imagery instances (e.g., robin) and lowtypicality low-imagery instances (e.g., grackle) were categorized faster than low-typicality highimagery instances (e.g., penguin). Instructing subjects to generate images of the instances had no influence on the pattern of results. The difference in categorization RT for lowimagery low-typicality instances vs. high-imagery high-typicality instances suggests that these instances may be represented differently in memory.     

Rapid activation of the lexicon: a further investigation with behavioral and computational results

Priming effects were observed in a categorization task for both prime-target synonym pairs (e.g., boat-ship) and first-associate pairs (e.g., boat-sea). However, the amount and onset of priming were different for synonyms and associated pairs. The effect appeared sooner for synonyms (at prime duration of 43 ms) than for associated words (57 ms onset) but was present for both these relationships at 71 ms of prime presentation. A prime visibility pretest was conducted with the same participants in order to determine the rate of recognition of our prime words. Last, a French matrix of the HAL model was built, which showed that synonyms pairs were semantically closer than associated pairs. These results are in accordance with our previous study (Frenck-Mestre & Bueno, 1999) and are discussed in relation with semantic models, such as Plaut's (1995) distributed model.     

The Effects of Prior Processing Episodes on Basic level Superiority

Four experiments were conducted to investigate the effects of prior processing episodes on people's preference for categorizing objects at the basic level (e.g. dog) relative to their preference for categorizing at the superordinate (e.g. animal) and the subordinate (e.g. Dalmation) levels. The prior processing episode in Experiment 1 was designed to induce subjects to activate representations at the superordinate level, and those in the remaining experiments were designed to induce subjects to differentiate objects at the subordinate level. After the prior processing episodes, subjects performed either a free naming or a picture categorization task that required them to decide whether an illustrated object belonged to a specified category. Results showed that prior processing episodes modestly reduced the superiority of basic level to superordinate level and subordinate level in categorization but not in free naming. The results suggest that the basic-level advantage is subject to the effects of context, but the effects are not as strong as the context effects on other aspects of categorization behaviour (e.g. rating typicality of a category member). Hence, the preference for the basic level is a somewhat more stable, invariant aspect of conceptual representation. Possible determinations of this stability are discussed.