Catastrophic individuation failures in infancy: A new model and predictions

Infants' individuation of human faces across race and identity

Young infants' face perception capabilities quickly tune to the features of their primary caregiver. The current study examines whether infants distinguish faces in a more conceptual manner using a manual-search, violation of expectation task that has previously been used to test kind-based individuation. We tested how well infants between 11 and 27 months of age individuated faces that varied by superordinate category (human vs. non-human in Experiment 1) subordinate category (individual identity in Experiment 2) or by race (White vs. Black, Experiments 1 & 2). We assessed individuation by quantifying the difference in infants' duration of reaching within an empty box between trials when the box was unexpectedly empty and expectedly empty. We found evidence of individuation across all ages and conditions, but with within-infant variation. On average, infants individuated face from non-face stimuli (Experiment 1), individual face identities (Experiment 2), and White versus Black faces (Experiments 1 & 2). These findings suggest that 1- to 2-year-old infants use distinct human face features to represent individuals across time and space. We discuss this evidence for race-based individuation and related complexities of face identity in terms of implications for conceptual development for faces in the first years of life.

Infants infer and predict coherent event interactions: Modeling cognitive development

Mental representations of the environment in infants are sparse and grow richer during their development. Anticipatory eye fixation studies show that infants aged around 7 months start to predict the goal of an observed action, e.g., an object targeted by a reaching hand. Interestingly, goal-predictive gaze shifts occur at an earlier age when the hand subsequently manipulates an object and later when an action is performed by an inanimate actor, e.g., a mechanical claw. We introduce CAPRI2 (Cognitive Action PRediction and Inference in Infants), a computational model that explains this development from a functional, algorithmic perspective. It is based on the theory that infants learn object files and events as they develop a physical reasoning system. In particular, CAPRI2 learns a generative event-predictive model, which it uses to both interpret sensory information and infer goal-directed behavior. When observing object interactions, CAPRI2 (i) interprets the unfolding interactions in terms of event-segmented dynamics, (ii) maximizes the coherence of its event interpretations, updating its internal estimates and (iii) chooses gaze behavior to minimize expected uncertainty. As a result, CAPRI2 mimics the developmental pathway of infants' goal-predictive gaze behavior. Our modeling work suggests that the involved event-predictive representations, longer-term generative model learning, and shorter-term retrospective and active inference principles constitute fundamental building blocks for the effective development of goal-predictive capacities.

Children's understanding of demonstratives: an experimental study with German-speaking children between 5 and 7 years of age

Demonstratives ("this"/"that") express a speaker-relative distance contrast and need to be substituted for each other systematically: depending on their relative position, what one speaker refers to by saying "this" another speaker has to refer to by saying "that." This substitution aspect of demonstratives poses additional difficulties for learning demonstratives, because it requires recognizing that two speakers have to refer to the same thing with different words, and might be one reason for the reportedly protracted acquisition of demonstratives. In an online study conducted in German, it was investigated whether children in the estimated upper age range of demonstrative acquisition (5 to 7 years) understand demonstratives' substitution aspect with familiar ("dies"/"das") and novel ("schmi"/"schmu") demonstratives, and whether they understand novel words ("schmi"/"schmu") when used non-demonstratively as labels (N = 73; between-subject). Children's accuracy was compared with adult performance (N = 74). The study shows that children between 5 and 7 years of age perform less accurately than adults in all conditions. While adults' performance was highly accurate in all conditions (between 75% and 92% correct), children performed below chance in both demonstrative conditions and above chance in the labeling condition. This suggests that children do not understand demonstratives in the presented setup. More detailed analyses of children's response patterns indicate that they instead treat words as mutually exclusive labels in any condition.

Infants can use temporary or scant categorical information to individuate objects

In a standard individuation task, infants see two different objects emerge in alternation from behind a screen. If they can assign distinct categorical descriptors to the two objects, they expect to see both objects when the screen is lowered; if not, they have no expectation at all about what they will see (i.e., two objects, one object, or no object). Why is contrastive categorical information critical for success at this task? According to the kind account, infants must decide whether they are facing a single object with changing properties or two different objects with stable properties, and access to permanent, intrinsic, kind information for each object resolves this difficulty. According to the two-system account, however, contrastive categorical descriptors simply provide the object-file system with unique tags for individuating the two objects and for communicating about them with the physical-reasoning system. The two-system account thus predicts that any type of contrastive categorical information, however temporary or scant it may be, should induce success at the task. Two experiments examined this prediction. Experiment 1 tested 14-month-olds (N = 96) in a standard task using two objects that differed only in their featural properties. Infants succeeded at the task when the object-file system had access to contrastive temporary categorical descriptors derived from the objects' distinct causal roles in preceding support events (e.g., formerly a support, formerly a supportee). Experiment 2 tested 9-month-olds (N = 96) in a standard task using two objects infants this age typically encode as merely featurally distinct. Infants succeeded when the object-file system had access to scant categorical descriptors derived from the objects' prior inclusion in static arrays of similarly shaped objects (e.g., block-shaped objects, cylinder-shaped objects). These and control results support the two-system account's claim that in a standard task, contrastive categorical descriptors serve to provide the object-file system with unique tags for the two objects.

Infants' biased individuation of in-group members

Adults tend to construe members of their group as "unique individuals" more than members of other groups. This study investigated whether infants exhibit this tendency, even in regard to unfamiliar arbitrary groups. Ninety-six White 1-year-olds were assigned to an Ingroup, Outgroup, or No-Group condition, based on whether or not they shared two preferences (food and shirt color) with women appearing on video sequences. In the critical trial, infants saw two women (Ingroup, Outgroup, or No-Group) - one at a time - appearing from behind a curtain. The curtain opened to reveal only one woman. Infants in the Ingroup condition looked longer at this display than infants in the other two conditions. This suggests that infants in the Ingroup condition had a stronger expectation than those in the other two conditions that there would be two women behind the curtain. In other words, infants individuated in-group members more than out-group members.

Is core knowledge in the format of LOT?

Object individuation provides a test case for the claim that infants already have a prelinguistic language-of-thought (LOT). By 12 months, infants represent several sortal-kinds: Object, agent, animate, and perhaps artifact. Infants have also encountered many words for object kinds, animals, people, and artifacts, therefore it remains a viable hypothesis that language learning may play a causal role in the acquisition of sortal-kinds, contra Quilty-Dunn et al.

The language-of-thought hypothesis as a working hypothesis in cognitive science

The target article attempted to draw connections between broad swaths of evidence by noticing a common thread: Abstract, symbolic, compositional codes, that is, language-of-thoughts (LoTs). Commentators raised concerns about the evidence and offered fascinating extensions to areas we overlooked. Here we respond and highlight the many specific empirical questions to be answered in the next decade and beyond.

Undercompression errors as evidence for conceptual primitives

The Meaning First Approach offers a model of the relation between thought and language that includes a Generator and a Compressor. The Generator build non-linguistic thought structures and the Compressor is responsible for its articulation through three processes: structure-preserving linearization, lexification, and compression via non-articulation of concepts when licensed. One goal of this paper is to show that a range of phenomena in child language can be explained in a unified way within the Meaning First Approach by the assumption that children differ from adults with respect to compression and, specifically, that they may undercompress in production, an idea that sets a research agenda for the study of language acquisition. We focus on dependencies involving pronouns or gaps in relative clauses and wh-questions, multi-argument verbal concepts, and antonymic concepts involving negation or other opposites. We present extant evidence from the literature that children produce undercompression errors (a type of commission errors) that are predicted by the Meaning First Approach. We also summarize data that children's comprehension ability provides evidence for the Meaning First Approach prediction that decompression should be challenging, when there is no 1-to-1 correspondence.

The best game in town: The reemergence of the language-of-thought hypothesis across the cognitive sciences

Mental representations remain the central posits of psychology after many decades of scrutiny. However, there is no consensus about the representational format(s) of biological cognition. This paper provides a survey of evidence from computational cognitive psychology, perceptual psychology, developmental psychology, comparative psychology, and social psychology, and concludes that one type of format that routinely crops up is the language-of-thought (LoT). We outline six core properties of LoTs: (i) discrete constituents; (ii) role-filler independence; (iii) predicate-argument structure; (iv) logical operators; (v) inferential promiscuity; and (vi) abstract content. These properties cluster together throughout cognitive science. Bayesian computational modeling, compositional features of object perception, complex infant and animal reasoning, and automatic, intuitive cognition in adults all implicate LoT-like structures. Instead of regarding LoT as a relic of the previous century, researchers in cognitive science and philosophy-of-mind must take seriously the explanatory breadth of LoT-based architectures. We grant that the mind may harbor many formats and architectures, including iconic and associative structures as well as deep-neural-network-like architectures. However, as computational/representational approaches to the mind continue to advance, classical compositional symbolic structures - that is, LoTs - only prove more flexible and well-supported over time.

The development of reasoning by exclusion in infancy

How do humans develop the capacity to reason? In five studies, we examined infants' emerging ability to make exclusion inferences using negation, as in the disjunctive syllogism (P or Q; not P; therefore Q). Inspired by studies of non-human animals and older children, Experiments 1-3 used an exclusion task adapted from Call's (2004) 2-cup paradigm and Experiments 4-5 used an exclusion task adapted from the blicket detector paradigm (Sobel & Kirkham, 2006). In both tasks, we found failure to make exclusion inferences at 15 months, fragile success at 17 months, and robust success by 20 months of age. These data converge with some prior evidence that fails to find a capacity to represent negation in infants younger than 15 months of age and conflict with other evidence from different paradigms that suggests infants do have this capacity. We discuss three different resolutions of these conflicting data, and suggest lines of further work that might adjudicate among them.

Individuation of agents based on psychological properties in 10 month-old infants

What makes agents fundamentally different from each other from the viewpoint of a 10-month-old infant? While infants at this age can already individuate human-like objects from non-humanlike ones and self-propelled agents from inert objects, little is known of when and how they start individuating within the domain of agents. What is clear from previous studies is that differences in surface and dynamic features are not sufficient. We hypothesized that mental properties-in this case the agents' preferences-can serve as an individuating property. In our study, we familiarized infants with two animated agents who had different preferences. The agents sequentially and repeatedly emerged from behind an occluder, and then each agent approached one of two target objects before returning behind the occluder. After familiarization, the occluder was lifted, revealing either one agent or two agents. While infants successfully individuated the agents in the preference-demonstration condition, they failed to do so in the exposure-only condition in which perceptually similar surface and dynamic features of the agents were presented but without indicating preferences. Our study thus provides evidence that mental properties can help individuate agents, grounding the claim that infants understand agents as mental entities at their core.

The role of language in building abstract, generalized conceptual representations of one- and two-place predicates: A comparison between adults and infants

Theories of relations between language and conceptual development benefit from empirical evidence for concepts available in infancy, but such evidence is comparatively scarce. Here, we examine early representations of specific concepts, namely, sets of dynamic events corresponding either to predicates involving two variables with a reversible, asymmetric relation between them (such as the set of all events that correspond to a linguistic phrase like "a dog is pushing a car,") or to comparatively simpler, one-variable predicates (such as the set of events corresponding to a phrase like "a dog is jumping."). We develop a non-linguistic, anticipatory eye-tracking task that can be administered to both infants and adults, and we use this task to gather evidence for the formation and use of such one-and two-place-predicate classes (which we refer to as event sortals) in 12-24-mo-old infants, and in adults with and without concurrent verbal prose shadowing. Using visually similar stimuli for both the simpler (one-place) and the more complex (reversible, asymmetric, two-place) concepts, we find that infants only show evidence for forming and generalizing one-place event sortals, and, while adults succeed with both kinds in the absence of verbal shadowing, shadowing hampers their ability to form and use the asymmetric two-place event sortals. In a subsequent experiment with adults, we find that if the shadowing material is grammatically impoverished, adults now succeed in forming and using both one- and two-place event sortals. We discuss implications of these results for theories of concept acquisition, and the role of language in this process.

Five-month-old infants attribute inferences based on general knowledge to agents

To make sense of others' actions, we generally consider what information is available to them. This information may come from different sources, including perception and inference. Like adults, young infants track what information agents can obtain through perception: If an agent directly observes an event, for example, young infants expect the agent to have information about it. However, no investigation has yet examined whether young infants also track what information agents can obtain through inference, by bringing to bear relevant general knowledge. Building on the finding that by 4 months of age most infants have acquired the physical rule that wide objects can fit into wide containers but not narrow containers, we asked whether 5-month-olds would expect an agent who was searching for a wide toy hidden in her absence to reach for a wide box as opposed to a narrow box. Infants looked significantly longer when the agent selected the narrow box, suggesting that they expected her (a) to share the physical knowledge that wide objects can fit only into wide containers and (b) to infer that the wide toy must be hidden in the wide box. Three additional conditions supported this interpretation. Together, these results cast doubt on two-system accounts of early psychological reasoning, which claim that infants' early-developing system is too inflexible and encapsulated to integrate inputs from other cognitive processes, such as physical reasoning. Instead, the results support one-system accounts and provide new evidence that young infants' burgeoning psychological-reasoning system is qualitatively similar to that of older children and adults.

Nonverbal category knowledge limits the amount of information encoded in object representations: EEG evidence from 12-month-old infants

To what extent does language shape how we think about the world? Studies suggest that linguistic symbols expressing conceptual categories ('apple', 'squirrel') make us focus on categorical information (e.g. that you saw a squirrel) and disregard individual information (e.g. whether that squirrel had a long or short tail). Across two experiments with preverbal infants, we demonstrated that it is not language but nonverbal category knowledge that determines what information is packed into object representations. Twelve-month-olds (N = 48) participated in an electroencephalography (EEG) change-detection task involving objects undergoing a brief occlusion. When viewing objects from unfamiliar categories, infants detected both across- and within-category changes, as evidenced by their negative central wave (Nc) event-related potential. Conversely, when viewing objects from familiar categories, they did not respond to within-category changes, which indicates that nonverbal category knowledge interfered with the representation of individual surface features necessary to detect such changes. Furthermore, distinct patterns of γ and α oscillations between familiar and unfamiliar categories were evident before and during occlusion, suggesting that categorization had an influence on the format of recruited object representations. Thus, we show that nonverbal category knowledge has rapid and enduring effects on object representation and discuss their functional significance for generic knowledge acquisition in the absence of language.

How do the object-file and physical-reasoning systems interact? Evidence from priming effects with object arrays or novel labels

How do infants reason about simple physical events such as containment, tube, and support events? According to the two-system model, two cognitive systems, the object-file (OF) and physical-reasoning (PR) systems, work together to guide infants' responses to these events. When an event begins, the OF system sends categorical information about the objects and their arrangements to the PR system. This system then categorizes the event, assigns event roles to the objects, and taps the OF system for information about features previously identified as causally relevant for the event category selected. All of the categorical and featural information included in the event's representation is interpreted by the PR system's domain knowledge, which includes core principles such as persistence and gravity. The present research tested a novel prediction of the model: If the OF system could be primed to also send, at the beginning of an event, information about an as-yet-unidentified feature, the PR system would then interpret this information using its core principles, allowing infants to detect core violations involving the feature earlier than they normally would. We examined this prediction using two types of priming manipulations directed at the OF system, object arrays and novel labels. In six experiments, infants aged 7-13 months (N = 304) were tested using different event categories and as-yet-unidentified features (color in containment events, height in tube events, and proportional distribution in support events) as well as different tasks (violation-of-expectation and action tasks). In each case, infants who were effectively primed reasoned successfully about the as-yet-unidentified feature, sometimes as early as six months before they would typically do so. These converging results provide strong support for the two-system model and for the claim that uncovering how the OF and PR systems represent and exchange information is essential for understanding how infants respond to physical events.

Why Not Just Features? Reconsidering Infants' Behavior in Individuation Tasks

It counts as empirically proven that infants can individuate objects. Object individuation is assumed to be fundamental in the development of infants' ontology within the object-first account. It crucially relies on an object-file (OF) system, representing both spatiotemporal ("where") and categorical ("what") information about objects as solid, cohesive bodies moving continuously in space and time. However, infants' performance in tasks requiring them to use featural information to detect individuation violations appears to be at odds with the object-first account. In such cases, infants do not appear to be able to develop correct expectations about the numerosity of objects. Recently, proponents of the object-first account proposed that these individuation failures result from integration errors between the OF system and an additional physical reasoning system. We are going to argue that the predictions of a feature-based physical-reasoning (PR) system are sufficient for explaining infants' behavior. The striking predictive power of the PR system calls into question the relevance of the OF system and, thereby, challenges the assumption that infants can individuate objects early on.

Infants' use of motion cues in object individuation processes

We investigated 10-month-old infants' and adults' numerical expectations in scenarios where information on self-motion and static object features may give rise to numerically incongruent representations. A red circle or a blue box with yellow stripes appeared on the left side of a screen, moved autonomously sideways and then moved back behind the screen. Next, on the opposite side, an identical object was first brought in view by a hand and then pushed back behind the screen (Experiments 1 and 2). The screen was finally removed, revealing either one or two objects. Infants looked longer at one-object test events, suggesting that they expected to find two objects. Adults were also shown these animations and were asked for their numerical expectations. Contrary to infants, they expected one single object (Experiment 3). Whereas preverbal infants' numerical expectations appeared to be dominated by information on object autonomous and induced motion, adults' expectations were mainly guided by information about object shape, size, and color. These findings were discussed in relation to current models on the development of object individuation processes.

The Developmental Origins of Syntactic Bootstrapping

Children use syntax to learn verbs, in a process known as syntactic bootstrapping. The structure-mapping account proposes that syntactic bootstrapping begins with a universal bias to map each noun phrase in a sentence onto a participant role in a structured conceptual representation of an event. Equipped with this bias, children interpret the number of noun phrases accompanying a new verb as evidence about the semantic predicate-argument structure of the sentence, and therefore about the meaning of the verb. In this paper, we first review evidence for the structure-mapping account, and then discuss challenges to the account arising from the existence of languages that allow verbs' arguments to be omitted, such as Korean. These challenges prompt us to (a) refine our notion of the distributional learning mechanisms that create representations of sentence structure, and (b) propose that an expectation of discourse continuity allows children to gather linguistic evidence for each verb's arguments across sentences in a coherent discourse. Taken together, the proposed learning mechanisms and biases sketch a route whereby simple aspects of sentence structure guide verb learning from the start of multi-word sentence comprehension, and do so even if some of the new verb's arguments are omitted due to discourse redundancy.

Do Infants in the First Year of Life Expect Equal Resource Allocations?

Recent research has provided converging evidence, using multiple tasks, of sensitivity to fairness in the second year of life. In contrast, findings in the first year have been mixed, leaving it unclear whether young infants possess an expectation of fairness. The present research examined the possibility that young infants might expect windfall resources to be divided equally between similar recipients, but might demonstrate this expectation only under very simple conditions. In three violation-of-expectation experiments, 9-month-olds (N = 120) expected an experimenter to divide two cookies equally between two animated puppets (1:1), and they detected a violation when she divided them unfairly instead (2:0). The same positive result was obtained whether the experimenter gave the cookies one by one to the puppets (Experiments 1–2) or first separated them onto placemats and then gave each puppet a placemat (Experiment 3). However, a negative result was obtained when four (as opposed to two) cookies were allocated: Infants looked about equally whether they saw a fair (2:2) or an unfair (3:1) distribution (Experiment 3). A final experiment revealed that 4-month-olds (N = 40) also expected an experimenter to distribute two cookies equally between two animated puppets (Experiment 4). Together, these and various control results support two broad conclusions. First, sensitivity to fairness emerges very early in life, consistent with claims that an abstract expectation of fairness is part of the basic structure of human moral cognition. Second, this expectation can at first be observed only under simple conditions, and speculations are offered as to why this might be the case.