Conflicting Social Cues: Fourteen- and 24-Month-Old Infants' Reliance on Gaze and Pointing Cues in Word Learning

Language acquisition is a process embedded in social routines. Despite considerable attention in research to its social nature, little is known about developmental differences in the relative priority of certain social cues over others during early word learning. Employing an eye-tracking paradigm, we presented 14-month-old infants, 24-month-old infants, and adults with movies in which an actor repeatedly gazed at one and pointed to the other of two objects while presenting them with a novel word. The results show that the 14-month-old infants pay more attention to a model's eye gaze when learning to map a novel word to a referent, whereas 24-month-old infants and adults rely more on pointing cues. Our results provide evidence for a developmental change in the relative priority of pointing versus eye-gazing cues in language acquisition.     

Maternal correlates of stability and change in infant-mother attachment

The relations between maternal control style, sensitivity, and childrearing attitudes on one hand and the stability of the infant-mother attachment relationship on the other were examined in a sample of 38 mother-infant dyads. The mother-child pairs were observed during a structured play session and in Ainsworth's Strange Situation when the infants were 12 and 20 months old, a developmental period characterized by increased autonomous functioning. Our results suggested that infants whose mothers had nonpunitive childrearing attitudes, were sensitive, and supportive of their infants' striving toward autonomy remained, or became, secure in their attachment relationship over their second year of life. Mothers who were more punitive, more controlling, and less sensitive had infants who either remained or became insecurely attached across this developmental period. While previous research has linked attachment stability to socioeconomic factors, the present investigation points to the importance of more subtle interactive variables to the understanding of the attachment relationship.     

Toddlers’ Understanding of Peers’ Emotions

The second year of life sees dramatic developments in infants’ ability to understand emotions in adults alongside their growing interest in peers. In this study, the authors used a social-referencing paradigm to examine whether 12-, 18-, and 24-month-old children could use a peer's positive or negative emotion messages about toys to regulate their own behavior with the toys. They found that 12-month-olds decreased their play with toys toward which a peer had expressed either positive or negative emotion compared with play following a peer's neutral attention toward a toy. Also, 18-month-olds did not respond systematically, but 24-month-old children increased their toy play after watching a peer display negative affect toward the toy. Regardless of their age, children with siblings decreased their play with toys toward which they had seen a peer display fear, the typical social-referencing response. The authors discuss results in the context of developmental changes in social understanding and peer interaction over the second year of life.     

Fear of success in males and females

Horner's “fear of success” test was administered to 303 children between the 4th and 12th grades. There was an increase of fear of success imagery between the 4th and 10th grades and a decrease between 10th and 12th grades. Fear of success was related to sex only during high school, where it was associated with the course of study pursued by students. Thus, in a high school secretarial course, females showed the lowest fear of success while 12th-grade college-prep females showed fear of success higher than secretarial course females and college-prep males. The findings were interpreted as indicating developmental changes in fear of success due to increasing peer affiliation (4th–10th grades) and sex-linked competitive achievement (high school).     

Bayes nets and babies: infants' developing statistical reasoning abilities and their representation of causal knowledge

A fundamental assumption of the causal graphical model framework is the Markov assumption, which posits that learners can discriminate between two events that are dependent because of a direct causal relation between them and two events that are independent conditional on the value of another event(s). Sobel and Kirkham (2006) demonstrated that 8-month-old infants registered conditional independence information among a sequence of events; infants responded according to the Markov assumption in such a way that was inconsistent with models that rely on simple calculations of associative strength. The present experiment extends these findings to younger infants, and demonstrates that such responses potentially develop during the second half of the first year of life. These data are discussed in terms of a developmental trajectory between associative mechanisms and causal graphical models as representations of infants' causal and statistical learning.     

Facilitating Problem-Solving Performance Among 9- and 12-Month-Old Infants

The efficiency of infants' actions was observed as they picked up and used food-laden spoons that varied in orientation. Two interventions were designed to facilitate efficient action beyond when infants were presented with one spoon in alternating orientations: one spoon was presented in the same orientation for several consecutive trials to help the child use feedback from the previous trial, and two spoons were presented in different orientations to emphasize the effect of the spoon's orientation on performance. These interventions were given separately, and combined, to groups of 9- and 12-month-old infants. Performance was facilitated among 12-month-olds when one spoon was presented several times in the same orientation. The short-term facilitation of performance was limited both by developmental factors and by the type of intervention introduced.     

Mimicking emotions: how 3–12-month-old infants use the facial expressions and eyes of a model

While there is an extensive literature on the tendency to mimic emotional expressions in adults, it is unclear how this skill emerges and develops over time. Specifically, it is unclear whether infants mimic discrete emotion-related facial actions, whether their facial displays are moderated by contextual cues and whether infants’ emotional mimicry is constrained by developmental changes in the ability to discriminate emotions. We therefore investigate these questions using Baby-FACS to code infants’ facial displays and eye-movement tracking to examine infants’ looking times at facial expressions. Three-, 7-, and 12-month-old participants were exposed to dynamic facial expressions (joy, anger, fear, disgust, sadness) of a virtual model which either looked at the infant or had an averted gaze. Infants did not match emotion-specific facial actions shown by the model, but they produced valence-congruent facial responses to the distinct expressions. Furthermore, only the 7- and 12-month-olds displayed negative responses to the model’s negative expressions and they looked more at areas of the face recruiting facial actions involved in specific expressions. Our results suggest that valence-congruent expressions emerge in infancy during a period where the decoding of facial expressions becomes increasingly sensitive to the social signal value of emotions.     

Applicability and attachment findings of the Strange Situation Paradigm in infants with visual impairment

Attachment studies with diverse populations enrich the understanding of infants’ socioemotional development by documenting both universal and idiosyncratic aspects of attachment. Given the effects of attachment in children's socioemotional outcomes, such studies are necessary to investigate the impact of children's sensory impairments on attachment development. Yet, very little attachment research has focused on infants with visual impairment (VI infants), a population in which infant–caregiver emotional exchanges through visual means are reduced/absent. We investigated the applicability of the Strange Situation Paradigm (SSP), with added instructions to compensate for degraded visual input, in 20 VI infants (with no additional disabilities and who were receiving developmental counseling). In all but 1 of the SSPs coded, VI infants displayed observable attachment behavior that was classifiable. Nineteen VI infants showed attachment by 12 months of age. Across the ages tested (fractional age range = 0.9–2.33 months), most VI infants’ attachment patterns were classified as secure and organized.     

Precursors to infants'' perception of the causality of a simple event

Three habituation experiments examined the perception of causal and non-causal events by infants at 6 1/4, 5 1/2, and 4 months of age. Experiment 1 replicated previous studies showing that by 6 1/4 months, infants begin to respond to the interaction of simple objects in Michottian type launching events on the basis of causality. In Experiments 2 and 3, however, younger infants exposed to the identical event sequences responded on the basis of simpler perceptual features of the launching events, and not on the basis of causality. 4-month-old infants responded to continuous versus non-continuous movement. 5 1/2-month-old infants also responded somewhat on the basis of continuous movement. However, in addition they responded on the basis of the spatial and temporal perceptual features of the events. This change in the pattern of results over age suggests a multi-step developmental progression.     

Infants' fast saccades in the gap paradigm and development of visual attention

The saccadic reaction times (SRTs) in the overlap, no-overlap, and gap conditions of 2.5- to 12-month-old infants and adults were measured. In the overlap condition, the SRTs of younger infants were over 600 ms longer than those of older infants, whereas the SRTs in the gap condition of the younger infants were 300–350 ms, much faster than reported hitherto, and were shortened only by about 100 ms. The results indicate that the oculo-motor system and attention process for disengagement in the gap condition mature earlier than the attention process for disengagement in the overlap condition.     

Genetic and caregiving-based contributions to infant attachment: unique associations with distress reactivity and attachment security

In the longitudinal study reported here, we examined genetic and caregiving-based contributions to individual differences in infant attachment classifications. For 154 mother-infant pairs, we rated mothers' responsiveness to their 6-month-old infants during naturalistic interactions and classified infants' attachment organization at 12 and 18 months using the Strange Situation procedure. These infants were later genotyped with respect to the serotonin-transporter-linked polymorphic region (5-HTTLPR). Maternal responsiveness uniquely predicted infants' attachment security. Infants' 5-HTTLPR variation uniquely predicted their subtype of attachment security at 12 months and their subtype of attachment insecurity at 12 and 18 months. The short allele for 5-HTTLPR was associated with attachment classifications characterized by higher emotional distress. These findings suggest that 5-HTTLPR variation contributes to infants' emotional reactivity and that the degree to which caregivers are responsive influences how effectively infants use their caregivers for emotion regulation. Theoretical implications for the study of genetic and caregiving influences are discussed.     

Developmental history of care and control,depression and anger: Correlates of maternal sensitivity in toddlerhood

This study examined maternal sensitivity in response to toddler distress in relation to mothers' childhood care and control experiences with parents, maternal depression, and maternal anger. Fifty‐two mothers and infants participated. Mothers reported childhood care and control experiences prenatally. At 2½ years, mothers reported depressive symptoms and anger on questionnaires, and reported maternal behavior in a daily diary for 1 week, yielding ratings of maternal sensitivity to fear and anger. Results were as follows: (a) Mothers' acceptance during childhood correlated negatively with both maternal depression and maternal anger, and positively with maternal sensitivity to fear at 2½ years; (b) maternal anger mediated the association between childhood care and maternal sensitivity to fear at 2½ years; and (c) the interaction of maternal and paternal control during childhood predicted maternal sensitivity to anger at 2½ years, controlling for maternal education. When maternal control was low, paternal control was positively associated with maternal sensitivity to anger whereas when maternal control was high, paternal control was negatively associated with maternal sensitivity to anger. Results are discussed in relation to prior studies, with particular emphasis on attachment theory. Implications for preventive intervention efforts are considered.     

Increasing task precision demands reveals that the reach and grasp remain subject to different perception-action constraints in 12-month-old human infants

The reach and grasp follow different developmental trajectories, but are often considered to have achieved nearly adult-like precision and integration by 12 months of age. This study used frame-by-frame video analysis to investigate whether increasing precision demands, by placing small reaching targets on a narrow pedestal rather than on a flat table, would influence the reach and grasp movements of 12-month-old infants in a complementary or differential fashion. The results reveal that placing the target atop a pedestal impaired the infants’s ability to direct an appropriate digit towards the small target, but did not produce a corresponding decrease in the frequency with which they used an index-thumb pincer grip to grasp the target. This was due to the fact that, although infants were more likely to contact the target with a suboptimal part of the hand in the pedestal condition, a greater proportion of these suboptimal contacts ultimately transitioned to a successful index-thumb pincer grip. Thus, increasing task precision demands impaired reach accuracy, but facilitated index-thumb grip formation, in 12-month-old infants. The differential response of the reach and grasp to the increased precision demands of the pedestal condition suggests that the two movements are not fully integrated and, when precision demands are great, remain sensitive to different perception-action constraints in 12-month-old infants.     

Acquisition of early words from single-word and sentential contexts

Toddlers 15 and 18 months of age were exposed to audiovisual recordings of two novel words paired with novel toys. The words were presented in familiar sentence frames or in isolation. Linguistic context had a greater effect on younger than on older infants. Specifically, 15-month-old boys exhibited successful learning only in the context of single words, and 15-month-old girls did so only for words presented in sentences. Older infants acquired the new words from both contexts, and they learned more rapidly than younger infants. Receptive and expressive vocabulary made no independent contribution to performance.     

婴儿共同注意能力的发展

本研究采用严格的实验室测验法,从年龄趋势、学习能力、性别差异三方面考察了8～11个月婴儿共同注意能力的发展。结果表明：1）婴儿的共同注意力在8～11个月间逐步提高,9个月左右出现显著的发展性变化,但1岁以前,该能力的发展水平都较低;2）就共同注意而言,婴儿具有从练习经验中学习的可能性,且学习能力存在年龄差异,8个月的婴儿基本不能从练习中受益,而8个月以上的其他三组婴儿在练习后共同注意水平都有不同程度的提高;3）总体而言,女婴共同注意能力的发展水平显著地高于男婴。     

The development of young infants' intuitions about support

Previous research has shown that 3-month-old infants, like adults, expect a box to be stable when it is in full contact with a platform, and to fall when it loses all contact with the platform. Do young infants also have expectations about what should happen when the box is only in partial contact with the platform? The present research was designed to address this question. In Experiment 1, 6.5-month-old infants saw two test events: a full-contact and a partial-contact test event. In both events, the infants watched the extended finger of a gloved hand push a box along the top of a platform. In the full-contact event, the box was pushed until its leading edge reached the end of the platform. In the partial-contact event, the box was pushed until only 15% or 70% of its bottom surface remained on the platform. The infants looked reliably longer at the partial-than at the full-contact event when 15%, but not 70%, of the box rested on the platform. These results suggested that the infants were able to judge how much contact was needed between the box and the platform for the box to be stable. A control condition provided evidence for this interpretation. In Experiment 2, 5.5- to 6-month-old infants were found to look equally at the full- and the partial-contact events, even when only 15% of the box's bottom surface remained on the platform. This result suggested that prior to 6.5 months of age infants perceive any amount of contact between the box and the platform to be sufficient to ensure the box's stability. Interpretations of this developmental sequence are considered in the Conclusion.     

Individual differences in infant fearfulness and cognitive performance: a testing,performance, or competence effect?

The author conducted 2 studies to examine the relations between infant fear and cognitive testing performance in 12-month-old infants. In Study 1, fear was assessed by using 2 standard temperament questionnaires and a laboratory-based, standardized stranger approach. Individual differences in cognitive development were assessed using the Object Permanence Scale of the Infant Psychological Development Scales (I. C. Uzgiris & J. M. Hunt, 1975). All 3 assessments of fear significantly predicted object permanence performance, with correlations ranging from -.32 to -.35. In Study 2, fear was assessed via a maternal report questionnaire, and habituation performance was assessed via a basic-level categorization task. Familiarity with the examiner and with the testing environment was manipulated to test for a familiarity influence on performance. Testing revealed individual differences in both fear and habituation. Results suggest that highly fearful infants required more trials to habituate and were less likely to meet the habituation criterion than infants who were less fearful. Methodological and conceptual implications of these results are discussed.     

Video Versus Reality: Infants' Attention and Affective Responses to Video and Live Presentations

Television viewing by infants has become very common, yet relatively little is known about infants' reactions to video compared to live events. We conducted two experiments in order to compare 9- or 10-month-old infants' behavioral reactions to live events and video presentations of those events. In the first experiment, infants' were shown video and live presentations shown consecutively; their affective reactions were consistent, indicating that video conveys meaning and emotional impact even in infancy. However, infants generally looked longer at, reached more to, showed more interest in, and exhibited more fear to the real stimuli. In a second experiment, infants were shown identical live and video events simultaneously; they looked much longer at the live presentations, further confirming that they distinguished live events from video and preferred to watch real events. Implications for infants' television viewing and the use of video images in infancy research are discussed.     

Effects of Age on the Generalization and Incubation of Memory in the F344 Rat

Freezing (immobility) in the presence of aversive stimuli is a species-specific behavior that is used as an operational measure of fear. Conditioning of this response to discrete sensory stimuli and environmental context cues has been used as a tool to study the neuropsychology of memory dynamics and their development over the lifespan. Three age groups of F344 rats (3, 9, and 27 month) received tone–foot shock pairing (or tone only) in a distinctive chamber on two consecutive days. Separate subgroups of rats from each age group were then tested, at retention intervals of 1, 20, 40, or 60 days, for context-mediated fear in the environment in which they were trained, for generalization of the fear response to a novel chamber, and for fear of the tone. Beginning at day 20, the 27-month-old rats exhibited less freezing behavior than did younger rats when tested in the conditioning context. This age difference was a result of freezing behavior becoming progressively stronger with time in the two younger age groups, a phenomenon that has been referred to as memory incubation. Incubation of the contextual fear response was not detected in the old rats. In a novel context, all age groups exhibited significantly more freezing than did control animals. There was also pronounced incubation of this generalized freezing response, and the extent of incubation declined significantly with age. In the novel context, the freezing response to the tone was robust in all age groups and increased over time, in constant proportion to the degree of freezing elicited by the novel context itself, prior to tone onset. The fact that old animals are known to be relatively selectively impaired in forms of memory that depend on a functional hippocampus suggests a possible explanation for the reduced incubation effects seen in old rats; however, whether the increased expression of fear over time is mediated by a hippocampal-dependent memory consolidation process or whether it reflects a generalized increase in the gain of the circuitry mediating the fear response itself, remains to be determined.     

Infant wariness and stimulus discrepancy

Fifty-four 6-month-old and fifty-four 12-month-old infants were first familiarized on one of two standard stimuli representing two ends of a continuum of four graded stimuli and then presented with a discrepant stimulus. Measures of visual fixation show that both age groups are able to perceive differences in the range of stimuli. Measures of manipulative latency (indicating wariness) show that only the older group display wariness: the greater the discrepancy between the standard and the discrepant stimulus, the greater the wariness. The younger group indiscriminately approach and make contact with all stimuli, regardless of their degree of discrepancy. The findings are discussed in terms of the practical limit of the Discrepancy Hypothesis.