The distributional and embodied contexts of verbs in caregiver-infant interactions.

The process by which infants learn verbs through daily social interactions is not well-understood. This study investigated caregivers' use of verbs, which have highly abstract meanings, during unscripted toy-play. We examined how verbs co-occurred with distributional and embodied factors including pronouns, caregivers' manual actions, and infants' locomotion, gaze, and object-touching. Object-action verbs were used significantly more often during caregiver-infant joint attention interactions. Movement and cognition verbs showed distinct co-occurrences with different contexts. Cognition and volition verbs were differentiated by pronouns. These findings provide evidence for how verb acquisition may be supported by the distributional and embodied contexts in caregiver-infant interactions.

The slow emergence of gaze- and point-following: A longitudinal study of infants from 4 to 12 months.

Acquisition of visual attention-following skills, notably gaze- and point-following, contributes to infants' ability to share attention with caregivers, which in turn contributes to social learning and communication. However, the development of gaze- and point-following in the first 18 months remains controversial, in part because of different testing protocols and standards. To address this, we longitudinally tested N = 43 low-risk, North American middle-class infants' tendency to follow gaze direction, pointing gestures, and gaze-and-point combinations. Infants were tested monthly from 4 to 12 months of age. To control motivational differences, infants were taught to expect contingent reward videos in the target locations. No-cue trials were included to estimate spontaneous target fixation rates. A comparison sample (N = 23) was tested at 9 and 12 months to estimate practice effects. Results showed gradual increases in both gaze- and point-following starting around 7 months, and modest month-to-month individual stability from 8 to 12 months. However, attention-following did not exceed chance levels until after 6 months. Infants rarely followed cues to locations behind them, even at 12 months. Infants followed combined gaze-and-point cues more than gaze alone, and followed points at intermediate levels (not reliably different from the other cues). The comparison group's results showed that practice effects did not explain the age-related increase in attention-following. The results corroborate and extend previous findings that North American middle-class infants' attention-following in controlled laboratory settings increases slowly and incrementally between 6 and 12 months of age. RESEARCH HIGHLIGHTS: A longitudinal experimental study documented the emergence and developmental trajectories of North American middle-class infants' visual attention-following skills, including gaze-following, point-following, and gaze-and-point-following. A new paradigm controlled for factors including motivation, attentiveness, and visual-search baserates. Motor development was ruled out as a predictor or limiter of the emergence of attention-following. Infants did not follow attention reliably until after 6 months, and following increased slowly from 7 to 12 months. Infants' individual trajectories showed modest month-to-month stability from 8 to 12 months of age.

Variability in infant social responsiveness: Age and situational differences in attention-following.

Attention following (AF) is a cornerstone of social cognitive development and a longstanding topic of infancy research. However, there is conflicting evidence regarding the development of AF. One reason for discrepant findings could be that infants' AF responses do not generalize across settings, and are influenced by situational factors. Theories of AF development based on data collected in laboratory paradigms might skew our understanding of infants' everyday AF. To reveal more generalizable patterns of infant AF development, we compared healthy, North American infants' (N = 48) AF developmental trajectories between a controlled laboratory paradigm and a naturalistic, home-based, parent-directed paradigm. Longitudinal micro-behavioral coding was analyzed to compare individual infants' AF between the two settings every month from 6 to 9 months of age. We aimed to (1) examine longitudinal development of infant AF in two settings; (2) compare AF development between settings, and (3) explore differences in adult cueing behaviors that influence AF. We found that longitudinal trajectories of AF differed between home and lab, with more AF at home in earlier months. Additionally, AF at home was related to maternal cueing variables including bid duration and frequency. These results have implications for the assessment of infants' developing social attention behaviors.

Adjacent and Non-Adjacent Word Contexts Both Predict Age of Acquisition of English Words: A Distributional Corpus Analysis of Child-Directed Speech.

Children show a remarkable degree of consistency in learning some words earlier than others. What patterns of word usage predict variations among words in age of acquisition? We use distributional analysis of a naturalistic corpus of child-directed speech to create quantitative features representing natural variability in word contexts. We evaluate two sets of features: One set is generated from the distribution of words into frames defined by the two adjacent words. These features primarily encode syntactic aspects of word usage. The other set is generated from non-adjacent co-occurrences between words. These features encode complementary thematic aspects of word usage. Regression models using these distributional features to predict age of acquisition of 656 early-acquired English words indicate that both types of features improve predictions over simpler models based on frequency and appearance in salient or simple utterance contexts. Syntactic features were stronger predictors of children's production than comprehension, whereas thematic features were stronger predictors of comprehension. Overall, earlier acquisition was predicted by features representing frames that select for nouns and verbs, and by thematic content related to food and face-to-face play topics; later acquisition was predicted by features representing frames that select for pronouns and question words, and by content related to narratives and object play.

Maternal discourse continuity and infants' actions organize 12-month-olds' language exposure during object play.

Infant language learning depends on the distribution of co-occurrences within language-between words and other words-and between language content and events in the world. Yet infant-directed speech is not limited to words that refer to perceivable objects and actions. Rather, caregivers' utterances contain a range of syntactic forms and expressions with diverse attentional, regulatory, social, and referential functions. We conducted a distributional analysis of linguistic content types at the utterance level, and demonstrated that a wide range of content types in maternal speech can be distinguished by their distribution in sequences of utterances and by their patterns of co-occurrence with infants' actions. We observed free-play sessions of 38 12-month-old infants and their mothers, annotated maternal utterances for 10 content types, and coded infants' gaze target and object handling. Results show that all content types tended to repeat in consecutive utterances, whereas preferred transitions between different content types reflected sequences from attention-capturing to directing and then descriptive utterances. Specific content types were associated with infants' engagement with objects (declaratives, descriptions, object names), with disengagement from objects (talk about attention, infant's name), and with infants' gaze at the mother (affirmations). We discuss how structured discourse might facilitate language acquisition by making speech input more predictable and/or by providing clues about high-level form-function mappings.

Cultural variation in cognitive flexibility reveals diversity in the development of executive functions.

Cognitive flexibility, the adaptation of representations and responses to new task demands, improves dramatically in early childhood. It is unclear, however, whether flexibility is a coherent, unitary cognitive trait, or is an emergent dimension of task-specific performance that varies across populations with divergent experiences. Three- to 5-year-old English-speaking U.S. children and Tswana-speaking South African children completed two distinct language-processing cognitive flexibility tests: the FIM-Animates, a word-learning test, and the 3DCCS, a rule-switching test. U.S. and South African children did not differ in word-learning flexibility but showed similar age-related increases. In contrast, U.S. preschoolers showed an age-related increase in rule-switching flexibility but South African children did not. Verbal recall explained additional variance in both tests but did not modulate the interaction between population sample (i.e., country) and task. We hypothesize that rule-switching flexibility might be more dependent upon particular kinds of cultural experiences, whereas word-learning flexibility is less cross-culturally variable.

Intensity of Caring About an Action's Side-Effect Mediates Attributions of Actor's Intentions.

The side-effect effect (SEE) is the observation that people's intuition about whether an action was intentional depends on whether the outcome is good or bad. The asymmetric response, however, does not represent all subjects' judgments (Nichols and Ulatowski, 2007). It remains unexplored on subjective factors that can mediate the size of SEE. Thus, the current study investigated whether an individual related factor, specifically, whether adults' intensity of caring about an outcome of someone's actions influences their judgments about whether that person intended the outcome. We hypothesized that participants' judgments about fictional agents' responsibility for their action's side-effects would depend on how much they care about the domain of the side-effect. In two experiments, the intensity of caring affected participants' ascription of intention to an agent's negative unintended side-effect. The stronger ascription of intentionality to negative than positive side-effects (i.e., the SEE; Knobe, 2003) was found only in domains in which participants reported higher levels of caring. Also, the intensity of caring increased intentionality attributions reliably for negative side-effects but not for positive side-effects. These results suggest that caring about a domain mediates an asymmetrical ascription of intentionality to negative more than positive side-effects.

Sensorimotor Decoupling Contributes to Triadic Attention: A Longitudinal Investigation of Mother-Infant-Object Interactions.

Previous developmental accounts of joint object activity identify a qualitative "shift" around 9-12 months. In a longitudinal study of 26 dyads, videos of joint object interactions at 4, 6, 9, and 12 months were coded for all targets of gaze and manual activity (at 10 Hz). At 12 months, infants distribute their sensorimotor modalities between objects handled by the parent and others controlled by the infant. Analyses reveal novel trajectories in distributed joint object activity across the 1st year. At 4 months, infants predominantly look at and manipulate a single object, typically held by their mothers. Between 6 and 9 months, infants increasingly decouple their visual and haptic modalities and distribute their attention between objects held by their mothers and by themselves. These previously unreported developments in the distribution of multimodal object activity might "bridge the gap" to coordinated joint activity between 6 and 12 months.

Disarming smiles: irrelevant happy faces slow post-error responses.

When we make errors, we tend to experience a negative emotional state. In addition, if our errors are witnessed by other people, we might expect those observers to respond negatively. However, little is known about how implicit social feedback like facial expressions influences error processing. We explored this using the cognitive control phenomenon of post-error slowing: the tendency to slow the response immediately following an error. Adult participants performed a difficult perceptual task: estimating which of two lines (horizontal or vertical) was longer. The background showed an irrelevant distractor face with a happy, sad, or neutral expression. Participants slowed after errors only when the subsequent distractor face was happy, but not when the subsequent distractor was sad or neutral nor when a happy face followed a correct response. This suggests that information about others' affect, even non-interactive, task-irrelevant information, has performance- and valence-dependent effects on adaptive cognitive control.

Cognitive flexibility in young children: General or task-specific capacity?

Cognitive flexibility is the ability to adapt to changing tasks or problems. To test whether cognitive flexibility is a coherent cognitive capacity in young children, we tested 3- to 5-year-olds' performance on two forms of task switching, rule-based (Three Dimension Changes Card Sorting, 3DCCS) and inductive (Flexible Induction of Meaning-Animates and Objects, FIM-Ob and FIM-An), as well as tests of response speed, verbal working memory, inhibition, and reasoning. Results suggest that cognitive flexibility is not a globally coherent trait; only the two inductive word-meaning (FIM) tests showed high inter-test coherence. Task- and knowledge-specific factors also determine children's flexibility in a given test. Response speed, vocabulary size, and causal reasoning skills further predicted individual and age differences in flexibility, although they did not have the same predictive relation with all three flexibility tests.

Development of adaptive tool-use in early childhood: sensorimotor, social, and conceptual factors.

Tool-use is specialized in humans, and juvenile humans show much more prolific and prodigious tool-use than other juvenile primates. Nonhuman primates possess many of the basic motor and behavioral capacities needed for manual tool-use: perceptual-motor specialization, sociocultural practices and interactions, and abstract conceptualization of kinds of functions, both real and imagined. These traits jointly contribute to the human specialization for tool-using. In particular, from 2 to 5 years of age children develop: (i) more refined motor routines for interacting with a variety of objects, (ii) a deeper understanding and awareness of the cultural context of object-use practices, and (iii) a cognitive facility to represent potential dynamic human-object interactions. The last trait, which has received little attention in recent years, is defined as the ability to form abstract (i.e., generalizable to novel contexts) representations of kinds of functions, even with relatively little training or instruction. This trait might depend not only on extensive tool-using experience but also on developing cognitive abilities, including a variety of cognitive flexibility: specifically, imagistic memory for event sequences incorporating causal inferences about mechanical effects. Final speculations point to a possible network of neural systems that might contribute to the cognitive capacity that includes sensorimotor, sensory integration, and prefrontal cortical resources and interconnections.

Watch the hands: infants can learn to follow gaze by seeing adults manipulate objects.

Infants gradually learn to share attention, but it is unknown how they acquire skills such as gaze-following. Deák and Triesch (2006) suggest that gaze-following could be acquired if infants learn that adults' gaze direction is likely to be aligned with interesting sights. This hypothesis stipulates that adults tend to look at things that infants find interesting, and that infants could learn by noticing this tendency. We tested the plausibility of this hypothesis through video-based micro-behavioral analysis of naturalistic parent-infant play. The results revealed that 3- to 11-month-old infants strongly preferred watching caregivers handle objects. In addition, when caregivers looked away from their infant they tended to look at their own object-handling. Finally, when infants looked toward the caregiver while she was looking at her own hands, the infant's next eye movement was often toward the caregiver's object-handling. In this way infants receive adequate naturalistic input to learn associations between their parent's gaze direction and the locations of interesting sights.

Young children's flexible use of semantic cues to word meanings: converging evidence of individual and age differences.

A new test of children's flexible use of semantic cues for word learning extended previous results. In Experiment 1, three- to five-year-olds (N = 51) completed two tests of interpreting several novel words for the same stimulus arrays. Within-sentence phrasal cues implied different stimulus referent properties. Children's cue-using flexibility in the new Flexible Induction of Meanings [Words for Animates] test (FIM-An) was strongly correlated with an established test (Flexible Induction of Meanings [Words for Objects]; Deák, 2000). Individual children showed between-test consistency in using cues to flexibly assign words to different referent properties. There were large individual differences, as well as limited age differences, in the distribution of flexible and inflexible response patterns. The comprehensibility of specific cues, and perceptual salience of specific properties, explained much of the variance. Proportions of flexible and inflexible patterns shifted with age. Experiment 2 replicated these results in N=36 three- and four-year-olds, using a modified FIM-An with more distinctive cues.

Young children's fast mapping and generalization of words, facts, and pictograms.

To test general and specific processes of symbol learning, 4- and 5-year-old children learned three kinds of abstract associates for novel objects: words, facts, and pictograms. To test fast mapping (i.e., one-trial learning) and subsequent learning, comprehension was tested after each of four exposures. Production was also tested, as was children's tendency to generalize learned items to new objects in the same taxon. To test for a bias toward mutually exclusive associations, children learned either one-to-one or many-to-many mappings. In Experiment 1, children learned words, facts (with or without incidental novel words), or pictograms. In Experiment 2, children learned words or pictograms. In both of these experiments, children learned words slower than facts and pictograms. Pictograms and facts were generalized more systematically than words, but only in Experiment 1. Children learned one-to-one mappings faster only in Experiment 2, when cognitive load was increased. In Experiment 3, 3- and 4-year-olds were taught facts (with novel words), words, and pictograms. Children learned facts faster than words; however, they remembered all items equally well a week later. The results suggest that word learning follows non-specialized memory and associative learning processes.

Category label effects on Chinese children's inductive inferences: modulation by perceptual detail and category specificity.

Inductive generalization of novel properties to same-category or similar-looking objects was studied in Chinese preschool children. The effects of category labels on generalizations were investigated by comparing basic-level labels, superordinate-level labels, and a control phrase applied to three kinds of stimulus materials: colored photographs (Experiment 1), realistic line drawings (Experiment 2), and cartoon-like line drawings (Experiment 3). No significant labeling effects were found for photos and realistic drawings, but there were significant effects for cartoon-like drawings. Children made mostly (>70%) category-based inferences about photographs whether or not labels were provided (Experiment 1). Children showed a bias toward category-based inferences about realistic drawings (Experiment 2) but did so only when labels were provided. Finally, children made mostly appearance-based generalizations for cartoon-like drawings (Experiment 3). However, labels (basic or superordinate level) reduced appearance-based responses. Labeling effects did not depend on having identical labels; however, identical superordinate labels were more effective than different basic-level labels for the least informative stimuli (i.e., cartoons). Thus, labels sometimes confirm the identity of ambiguous items. This evidence of labeling effects in Mandarin-speaking Chinese children extends previous findings beyond English-speaking children and shows that the effects are not narrowly culture and language specific.

Micro-analysis of infant looking in a naturalistic social setting: insights from biologically based models of attention.

A current theory of attention posits that several micro-indices of attentional vigilance are dependent on activation of the locus coeruleus, a brainstem nucleus that regulates cortical norepinephrine activity (Aston-Jones et al., 1999). This theory may account for many findings in the infant literature, while highlighting important new areas for research and theory on infant attention. We examined the visual behaviors of n = 16 infants (6-7 months) while they attended to multiple spatially distributed targets in a naturalistic environment. We coded four measures of attentional vigilance, adapted from studies of norepinergic modulation of animal attention: rate of fixations, duration of fixations, latency to reorientation, and target 'hits'. These measures showed a high degree of coherence in individual infants, in parallel with findings from animal studies. Results also suggest that less vigilant infants showed greater habituation to the trial structure and more attentiveness to less salient stimuli during periods of high attentional competition. This pattern of results is predicted by the Aston-Jones model of attention, but could not be explained by the standard information processing model.

This ought to be good: brain activity accompanying positive and negative expectations and outcomes.

The current study employed a modified gambling task, in which probabilistic cues were provided to elicit positive or negative expectations. Event-related potentials (ERPs) to "final outcome" and "probabilistic cues" were analyzed. Difference waves between the negative condition and the corresponding positive condition were examined. The results confirm that feedback related negativity (FRN) amplitude is modulated by the interaction of outcome valence and expectancy by showing larger FRN difference waves for unexpected than expected outcomes. More interestingly, the difference wave between ERPs elicited by positive and negative expectations showed a negative deflection, with a frontal midline source density around 280 ms after onset of the predictive cue. Negative expectations were associated with larger FRN amplitudes than positive expectations. This suggests that FRN is elicited by probabilistic cues to pending outcomes.

To Model or Not to Model? A Dialogue on the Role of Computational Modeling in Developmental Science.

All sciences use models of some variety to understand complex phenomena. In developmental science, however, modeling is mostly limited to linear, algebraic descriptions of behavioral data. Some researchers have suggested that complex mathematical models of developmental phenomena are a viable (even necessary) tool that provide fertile ground for developing and testing theory as well as for generating new hypotheses and predictions. This paper explores the concerns, attitudes, and historical trends that underlie the tension between two cultures: one in which computational simulations of behavior are an important complement to observation and experimentation, and another which emphasizes evidence from behavioral experiments and linear models enhanced by verbal descriptions. This tension is explored as a dialogue between three characters: Ed (Experimental Developmentalist), Mira (Modeling Inclusive Research Advocate), and Phil (Philosopher of Science).

Driven from distraction: how infants respond to parents' attempts to elicit and re-direct their attention.

This experiment examined how parents' verbal and non-verbal behavioral cues cause infants to shift and share attention within environments where many objects compete for infants' attention. Fifteen- and 21-month-old infants played with toys while their parent periodically shifted attention to a distal object within a larger array. Parents' attention-shifts were indicated by a change in direction of gaze, a pointing gesture, and/or verbalizations. Verbalizations were either attention-eliciting or attention-directing. In some trials parents covered their eyes to occlude line-of-gaze. Both ages seldom followed simple gaze shifts, but frequently followed gaze with-points or gaze-with-directing verbalizations. Attention-eliciting verbalizations increased infants' looks to the parent. Gaze occlusion reduced infants' responses to directing verbalizations. Responses to eliciting verbalizations increased with age. Infant receptive vocabulary did not predict attention-sharing, even when parents named objects (i.e., directing verbalizations). Implications for development of attention-sharing, language and understanding of visual attention are discussed.

Do children really confuse appearance and reality?

Our understanding of many mental, social and physical phenomena hinges on a general understanding that appearances can differ from reality. Yet young children sometimes seem unable to understand appearance-reality dissociations. In a standard test, children are shown a deceptive object and asked what it really is and what it looks like. Many preschool children give the same answer to both questions. This error has been attributed to children's inflexible conceptual representations or inflexibility in representing their own changing beliefs. However, evidence fails to support either hypothesis: new tests show that young children generally understand appearance-reality discrepancies as well as fantasy-reality distinctions. These tests instead implicate children's failure to understand the unfamiliar discourse format of the standard test. This misunderstanding might reveal a subtler difficulty in making logical inferences about questions.