Factors affecting infants' manual search for occluded objects and the genesis of object permanence

Two experiments systematically examined factors that influence infants’ manual search for hidden objects (N = 96). Experiment 1 used a new procedure to assess infants’ search for partially versus totally occluded objects. Results showed that 8.75-month-old infants solved partial occlusions by removing the occluder and uncovering the object, but these same infants failed to use this skill on total occlusions. Experiment 2 used sound-producing objects to provide a perceptual clue to the objects’ hidden location. Sound clues significantly increased the success rate on total occlusions for 10-month-olds, but not for 8.75-month-olds. An identity development account is offered for why infants succeed on partial occlusions earlier than total occlusions and why sound helps only the older infants. We propose a mechanism for how infants use object identity as a basis for developing a notion of permanence. Implications are drawn for understanding the dissociation between looking time and search assessments of object permanence.     

Experience with visual barriers and its effects on subsequent gaze‐following in 12‐ to 13‐month‐olds

Thirty 12‐ to 13‐month‐olds were tested to determine whether they could use the self as an analogy for understanding others' looking. Using a procedure similar to Brooks and Meltzoff (2002) , we examined gaze‐following when the adult's view of a target was occluded by a blindfold (blindfold without training). Some infants received experience with the blindfold's sight‐blocking qualities (blindfold with training). The control was a headband condition. Gaze‐following was highest in the headband condition. Gaze‐following in the headband and blindfold without training conditions, but not the blindfold with training conditions, were significantly greater than zero. These results demonstrate that 12‐ to 13‐month‐olds have some understanding of the looking behaviour of others. Only weak support was found for simulation theories of the development of social cognition.     

Infants can infer the presence of hidden objects from referential gaze information

Infants' apparent failure in gaze‐following tasks is often interpreted as a sign of lack of understanding the referential nature of looking. In the present study, 8‐ and 12‐month‐old infants followed the gaze of a model to one of two locations hidden from their view by occluders. When the occluders were removed, an object was revealed either at the location where the model had looked or at the other side. Infants at both ages looked longer at the empty location when it had been indicated by the model's looking behaviour, and this effect held up even when their first look after gaze following was discounted. This result demonstrates that even young infants hold referential expectations when they follow others' gaze and infer the location of hidden objects accordingly.     

Investigations of closure processes: What source-monitoring judgments suggest about what is “closing”

On many occasions, the perception of an object is based on incomplete information because portions of the object are occluded from view. Nevertheless, people are able to identify an occluded object, suggesting that the identification is mediated by the activation of completion processes which “fill in” the missing information. Although these completion processes are invoked as causal mechanisms for many phenomena, the processes mediating the “completion” have not been specified. The present experiments tested two potential explanations for closure processes. In each experiment, participants were presented with pictures, complete or incomplete in form, and, on a surprise source-monitoring task, they were then asked to remember whether pictures had been presented complete or incomplete in form. Whether viewing pictures of objects, faces, or camouflaged objects, participants showed a pronounced tendency to claim that incomplete pictures were actually presented complete in form. This bias was evident after the participants described functions for objects (Experiments 1, 1A, and 2), after they evaluated properties of faces (Experiment 4), and after they searched for objects hidden in a complex scene (Experiment 5). However, this bias was not evident after they simply named objects portrayed in pictures (Experiment 3). This bias is interpreted as evidence for the activation of implicit imaginal processing. The results of these experiments are informative in their contribution to our understanding of the bases of closure, an intuitively appealing notion frequently invoked to account for object identification, but, as yet, not fully understood.     

Effects of occlusion on pigeons' visual object recognition

Casual observation suggests that pigeons and other animals can recognize occluded objects; yet laboratory research has thus far failed to show that pigeons can do so. In a series of experiments, we investigated pigeons' ability to 'name' shaded, textured stimuli by associating each with a different response. After first learning to recognize four unoccluded objects, pigeons had to recognize the objects when they were partially occluded by another surface or when they were placed on top of another surface; in each case, recognition was weak. Following training with the unoccluded stimuli and with the stimuli placed on top of the occluder, pigeons' recognition of occluded objects dramatically improved. Pigeons' improved recognition of occluded objects was not limited to the trained objects but transferred to novel objects as well. Evidently, the recognition of occluded objects requires pigeons to learn to discriminate the object from the occluder; once this discrimination is mastered, occluded objects can be better recognized.     

Parents teaching young children home safety rules: Implications for childhood injury risk

Teaching safety rules is a common practice but little is known about this. Fifty-eight parents of children 2 to 2.5 or 3 to 3.5 years of age reported on the safety rules they have, the factors that prompted these rules, the strategies used to teach these rules, and how they react to noncompliance with these rules. Results revealed more safety rules for children in the older group than the younger group, and greater emphasis on teaching the rule than teaching the basis for the rule at younger than older ages. Only about half the rules restricted the child from doing the risk behavior completely, whereas the remaining rules allowed for the behavior under certain circumstances. Parents assumed safety rules would prevent injuries and mostly implemented rules in reaction to evidence of injury risk. Parents equated noncompliance with not understanding, assuming that if children understood they would comply. Implications for childhood injury risk are discussed.     

Children's Understanding of the Instrumental Value of Products and Brands

Gelman and Echelbarger (2019—this issue) provide a valuable discussion about children's understanding of the inferred or nonobvious features of objects, which has implications for how children value products. We further this conversation by examining how children value products and brands as a means for meeting important goals, which we refer to as instrumental valuation. Specifically, we examine developmental trends in instrumental valuation for three goals—self‐concept development, self‐presentation, and happiness. Across these areas, we find that children place greater value on products and brands for meeting these goals as they grow older, particularly during late childhood and early adolescence. We conclude with a discussion of how age differences in instrumental valuation add to the general conversation about how children of different ages value objects.     

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.     

It's Taking Shape: Shared Object Features Influence Novel Noun Generalizations

Children's early noun vocabularies are dominated by names for shape‐based categories. However, along with shape, material and colour are also important features of many early categories. In the current study, we investigate how the number of shared features among objects influences children's novel noun generalizations, explanations for these generalizations and spontaneous speech. Preschool children and adults were presented with test objects that shared only one feature (e.g. shape) or that shared two features (e.g. material and colour). After each trial, participants were asked, ‘how did you know that was your [novel name]?’ Overall, participants generalized novel names on the basis of shape more when objects shared shape and a second feature with the exemplar. All participants provided shape‐based explanations of their choices, but explanations were increasingly more abstract across development. Finally, children's spontaneous speech was dominated by references to the objects' shape, and this did not change across development or number of shared features. Overall, these data demonstrate that the shape bias is enhanced when objects share shape and a second feature but weakened for 3‐year‐old children when objects share two non‐shape features. These findings have implications for our understanding of how children learn names for objects that belong to multiple categories. Copyright © 2012 John Wiley & Sons, Ltd.     

The depth of distractor processing in search with clutter

Some search tasks involve looking for a category target in clutter. This is the task faced, for example, by a baggage screener looking for weapons in a suitcase. Such tasks presumably involve the segmentation and recognition of the target object, but it is unknown whether they also involve the segmentation and recognition of the distractor objects. To examine the depth of distractor processing in this task, we had observers search through cluttered displays composed of normal and chimerical distractors. The normal distractors were photographs of recognizable objects, while the chimerical distractors were created by interchanging parts between the normal objects. The obsever's task was to identify the display quadrant that contained an animal or a vehicle target. We varied the difficulty of the search task by varying target and distractor discriminability, target uncertainty, and target occlusion. Only when the target was partially occluded did we find an effect of distractor type. In this case, observers may have found the target through a process of mentally eliminating whole distractor objects. When the target was unoccluded, we found no evidence that observers selected and rejected whole distractors during search. This second result supports our previous claim that often the items for search in clutter are not whole objects.     

Engineering Objects for Collaboration: Strategies of Ambiguity and Clarity at Knowledge Boundaries

Prior research suggests that boundary objects gain meaning through group interaction. Drawing from the literature on strategic ambiguity, we explore the possibility that individuals strategically create potential boundary objects in an attempt to shape the meanings that groups develop. From ethnographic observations of automotive engineers, we identify 2 creation strategies: ambiguity (to create objects that support multiple meanings) and clarity (to create objects that permit a particular meaning). We detail design activities that engineers undertook to create objects under each strategy. We find that, when creating objects, engineers favored a strategy of ambiguity, which they believed would foster healthy long‐term group interactions, over a strategy of clarity, which they tended to employ only when they expected resistance to their ideas.     

When looking back to nothing goes back to nothing

Previous research showed that the eyes revisit the location in which the stimulus has been encoded when visual or verbal information is retrieved from memory. A recent study showed that this behavior still occurs 1 week after encoding, suggesting that visual, spatial and linguistic information is tightly associated with the oculomotor trace and stored as an integrated memory representation. However, it is yet unclear whether looking behavior simply remains stable between encoding and recall or whether it changes over time in a more fine-tuned manner. Here, we investigate the time course of looking behavior during recall in multiple sessions across 1 week. Participants encoded visual objects presented in one of the four locations on the computer screen. In five sessions during the week after encoding, they performed on a visual memory recall task. During retrieval, participants looked back to the encoding location, but only in the recall sessions within 1 day of encoding. We discuss different explanations for the temporal dynamics of looking behavior during recall, searching for the role of eye movements in memory.     

Ontogeny of manipulative behavior and nut‐cracking in young tufted capuchin monkeys (Cebus apella): a Perception–action perspective

How do capuchin monkeys learn to use stones to crack open nuts? Perception–action theory posits that individuals explore producing varying spatial and force relations among objects and surfaces, thereby learning about affordances of such relations and how to produce them. Such learning supports the discovery of tool use. We present longitudinal developmental data from semifree‐ranging tufted capuchin monkeys (Cebus apella) to evaluate predictions arising from Perception–action theory linking manipulative development and the onset of tool‐using. Percussive actions bringing an object into contact with a surface appeared within the first year of life. Most infants readily struck nuts and other objects against stones or other surfaces from 6 months of age, but percussive actions alone were not sufficient to produce nut‐cracking sequences. Placing the nut on the anvil surface and then releasing it, so that it could be struck with a stone, was the last element necessary for nut‐cracking to appear in capuchins. Young chimpanzees may face a different challenge in learning to crack nuts: they readily place objects on surfaces and release them, but rarely vigorously strike objects against surfaces or other objects. Thus the challenges facing the two species in developing the same behavior (nut‐cracking using a stone hammer and an anvil) may be quite different. Capuchins must inhibit a strong bias to hold nuts so that they can release them; chimpanzees must generate a percussive action rather than a gentle placing action. Generating the right actions may be as challenging as achieving the right sequence of actions in both species. Our analysis suggests a new direction for studies of social influence on young primates learning sequences of actions involving manipulation of objects in relation to surfaces.     

Level 1 perspective‐taking at 24 months of age

The current study sought to determine the age at which children first engage in Level 1 visual perspective‐taking, in which they understand that the content of what another person sees in a situation may sometimes differ from what they see. An adult entered the room searching for an object. One candidate object was out in the open, whereas another was visible for the child but behind an occluder from the adult's perspective. When asked to help the adult find the sought‐for object, 24‐month‐old children, but not 18‐month‐old children, handed him the occluded object (whereas in a control condition they showed no preference for the occluded toy). We argue that the performance of the 24‐month‐olds requires Level 1 visual perspective‐taking skills and that this is the youngest age at which these skills have been demonstrated.     

One‐year‐old infants use teleological representations of actions productively

Two experiments investigated whether infants represent goal‐directed actions of others in a way that allows them to draw inferences to unobserved states of affairs (such as unseen goal states or occluded obstacles). We measured looking times to assess violation of infants' expectations upon perceiving either a change in the actions of computer‐animated figures or in the context of such actions. The first experiment tested whether infants would attribute a goal to an action that they had not seen completed. The second experiment tested whether infants would infer from an observed action the presence of an occluded object that functions as an obstacle. The looking time patterns of 12‐month‐olds indicated that they were able to make both types of inferences, while 9‐month‐olds failed in both tasks. These results demonstrate that, by the end of the first year of life, infants use the principle of rational action not only for the interpretation and prediction of goal‐directed actions, but also for making productive inferences about unseen aspects of their context. We discuss the underlying mechanisms that may be involved in the developmental change from 9 to 12 months of age in the ability to infer hypothetical (unseen) states of affairs in teleological action representations.     

MENTAL IMAGERY AND THE VARIETIES OF AMODAL PERCEPTION

The problem of amodal perception is the problem of how we represent features of perceived objects that are occluded or otherwise hidden from us. Bence Nanay (2010 ) has recently proposed that we amodally perceive an object's occluded features by imaginatively projecting them into the relevant regions of visual egocentric space. In this paper, I argue that amodal perception is not a single, unitary capacity. Drawing appropriate distinctions reveals amodal perception to be characterized not only by mental imagery, as Nanay suggests, but also by genuinely visual representations as well as beliefs. I conclude with some brief remarks on the role of object‐directed bodily action in conferring a sense of unseen presence on an object's occluded features.     

Developmental Differences in the Naming of Contextually Non-Categorical Objects

This study investigates the naming process of contextually non-categorical objects in children from 3 to 9 plus 13-year-olds. 112 children participated in the study. Children were asked to narrate a story individually while looking at Mercer Mayer’s textless, picture book Frog, where are you? The narratives were audio recorded and transcribed. Texts were analyzed to find out how children at different ages name contextually non-categorical objects, tree and its parts in this case. Our findings revealed that increasing age in children is a positive factor in naming objects that are parts or extended forms of an object which itself constitutes a basic category in a certain context. Younger children used categorical names more frequently to refer to parts or disfigured forms of the object than older children and adults while older children and adults used specified names to refer to the parts or extended forms of the categorical names.     

THIS ARTICLE HAS BEEN RETRACTED: Enumeration of objects and substances in non‐human primates: experiments with brown lemurs (Eulemur fulvus)

Both human infants and adult non‐human primates share the capacity to track small numbers of objects across time and occlusion. The question now facing developmental and comparative psychologists is whether similar mechanisms give rise to this capacity across the two populations. Here, we explore whether non‐human primates’ object tracking abilities are subject to the same constraints as those of human infants. In particular, we examine whether one primate species, the brown lemur (Eulemur fulvus), also fails to represent and enumerate objects when they behave non‐rigidly or non‐cohesively. We presented lemurs with a series of expectancy violation studies involving simple 1 + 1 addition events in which we varied the entities to be enumerated. Like infants, lemurs successfully enumerated the two objects when those objects were rigid, cohesive individuals, but failed to enumerate similar‐looking non‐rigid piles of sand. In contrast to human infants, however, lemurs successfully enumerated non‐cohesive objects that broke into multiple pieces. These results are discussed in light of recent theories about object processing in human infants and adults.     

The Mere‐Measurement Effect: Why Does Measuring Intentions Change Actual Behavior?

Recent research has demonstrated that merely measuring an individual's purchase intentions changes his or her subsequent behavior in the market. Several different alternative explanations have been proposed to explain why this “mere‐measurement effect” occurs. However, these explanations have not been tested to date. The purpose of this article is to test several competing explanations for why measuring general intentions to purchase (e.g., How likely are you to buy a car?) changes specific brand‐level behavior (e.g., which specific brand of car is purchased). The results provide a clearer understanding of the cognitive mechanism through which the mere‐measurement effect operates. The results show that when asked to provide general intentions to select a product in a given category, respondents are more likely to choose options toward which they hold positive and accessible attitudes, and are less likely to choose options for which they hold negative and accessible attitudes, compared to a control group of participants who are not asked a general intentions question. These results provide support for the conjecture that asking a general purchase intent question influences behavior by changing the accessibility of attitudes toward specific options in the category.     

Two- and three-year-olds infer and reason about design intentions in order to categorize broken objects

In naming artifacts, do young children infer and reason about the intended functions of the objects? Participants between the ages of 2 and 4 years were shown two kinds of objects derived from familiar categories. One kind was damaged so as to undermine its usual function. The other kind was also dysfunctional, but made so by adding features that appeared to be intentional. Evidence that 2‐, 3‐ and 4‐year‐olds were more likely to apprehend the broken objects than the intentionally dysfunctional objects as members of the familiar lexical categories favors the conclusion that, in naming, children may spontaneously infer and reason about design intentions from an early age. This is the first evidence that 2‐ and 3‐year‐olds not only take design intentions into account in object categorization, but that they do so even without explicit mention of the objects’ accidental or intentional histories. The results cast doubt on a proposal that young children's lexical categorization is based on automatic, non‐deliberative processes.