Spatially Specific Changes in Infants' Muscle Coactivity as They Learn to Reach

Infants first reach out and touch objects between the ages of 3 and 5 months. This article reports changes in muscle coactivity associated with this transition. A group of 4 infants were observed weekly from 3 to 30 weeks and every 2 weeks from 30 to 52 weeks. Hand kinematics of both prereaching and reaching movements were collected, as was electromyographic activity from the trapezius, deltoid, biceps, and triceps. Before infants first reached for toys presented at midline, they used biceps and triceps to move their hands near the toy in front of them and 45° to the side of midline. After the transition, they used trapezius and deltoid to move the hand toward the toy and combinations of multiple muscles when their arms were high and extended near the toy. Thus, infants showed a dramatic change in which muscles worked together across the transition to reaching, even though their hands moved in similar spatial regions.     

Faces Attract Infants' Attention in Complex Displays

Infant's face preferences have previously been assessed in displays containing 1 or 2 faces. Here we present 6‐month‐old infants with a complex visual array containing faces among multiple visual objects. Despite the competing objects, infants direct their first saccade toward faces more frequently than expected by chance (Experiment 1). The attention‐grabbing effect of faces is not selective to upright faces (Experiment 2) but does require the presence of internal facial elements, as faces whose interior has been phase‐scrambled did not attract infants' attention (Experiment 3). On the contrary, when the number of fixations is considered, upright faces are scanned more extensively than both inverted and phase‐scrambled faces. The difference in selectivity between the first look measure and the fixation count measure is discussed in light of a distinction between attention‐grabbing and attention‐holding mechanisms.     

Disentangling the Effects of an Adult Model's Eye Gaze and Head Orientation on Young Infants' Processing of a Previously Attended Object

In order to disentangle the effects of an adult model's eye gaze and head orientation on infants' processing of objects attended to by the adult, we presented 4‐month‐olds with faces that either (1) shifted eye gaze toward or away from an object while the head stayed stationary or (2) that turned their head while maintaining gaze directed straight ahead. Infants' responses to the previously attended and unattended objects were measured using eye‐tracking and event‐related potentials. In both conditions, infants responded to objects that were not cued by the adult's head or eye gaze shift with more visual attention and an increased negative central (Nc) component relative to cued objects. This suggests that cued objects had been encoded more effectively, whereas uncued objects required further processing. We conclude that eye gaze and head orientation act independently as cues to direct infants' attention and object processing. Both head orientation and eye gaze, when presented in motion, even override the effects of incongruent stationary information from the other kind of cue.     

Developmental Differences in Infants' Attention to Social and Nonsocial Threats

Research has demonstrated that humans detect threatening stimuli more rapidly than nonthreatening stimuli. Although the literature presumes that biases for threat should be normative, present early in development, evident across multiple forms of threat, and stable across individuals, developmental work in this area is limited. Here, we examine the developmental differences in infants' (4‐ to 24‐month‐olds) attention to social (angry faces) and nonsocial (snakes) threats using a new age‐appropriate dot‐probe task. In Experiment 1, infants' first fixations were more often to snakes than to frogs, and they were faster to fixate probes that appeared in place of snakes vs. frogs. There were no significant age differences, suggesting that a perceptual bias for snakes is present early in life and stable across infancy. In Experiment 2, infants fixated probes more quickly after viewing any trials that contained an angry face compared to trials that contained a happy face. Further, there were age‐related changes in infants' responses to face stimuli, with a general increase in looking time to faces before the probe and an increase in latency to fixate the probe after seeing angry faces. Together, this work suggests that different developmental mechanisms may be responsible for attentional biases for social vs. nonsocial threats.     

Competition for Infants' Attention: The Interactive Influence of Attentional State and Stimulus Characteristics

The interactive effects of stimulus characteristics and attentional state on infants' distraction latency were studied. As 7‐month‐old infants explored initial stimuli that were composed of either a single nonmoving component or multiple moving components, one of several types of distractors was presented in the periphery. Infants' distraction latencies (the amount of time they took to turn from the initial stimulus to the distractor) varied as a function of the interaction between the infants' attentional state at distractor onset and the characteristics of the stimuli. Variations in the visual characteristics of the distractor stimulus (solid rectangle vs. checkerboard) had a larger effect on distraction latency when infants were in a focused attentional state than when they were in a casual attentional state. Similarly, variations in the auditory characteristic of the distractor stimulus (1 intermittent tone vs. 2 alternating tones) had a larger effect when infants were engaged in a focused attentional state toward the multicomponent toys. Thus, infants' distractibility in this context reflects an interaction between the infants' attentional state and the competition between external stimuli for their attentional focus.     

12‐Month‐Old Infants' Perception of Attention Direction in Static Video Images

Twelve‐month‐old infants' ability to perceive gaze direction in static video images was investigated. The images showed a woman who performed attention‐directing actions by looking or pointing toward 1 of 4 objects positioned in front of her (2 on each side). When the model just pointed at the objects, she looked straight ahead, and when she just looked, her hands were hidden below the tabletop. An eye movement system (TOBII) was used to register the gaze of the participants. We found that the infants clearly discriminated the gaze directions to the objects. There was no tendency to mix up the 2 object positions, located 10° apart, on the same side of the model. The infants spent more time looking at the attended objects than the unattended ones and they shifted gaze more often from the face of the model to the attended object than to the unattended objects. Pointing did not significantly increase the infants' tendency to move gaze to the attended object, irrespective of whether the pointing gesture was accompanied by looking or not. In all conditions the infants spent most of the time looking at the model's face. This tendency was especially noticeable in the pointing‐only condition and the condition where the model just looked straight ahead.     

Follow My Gaze: Face Race and Sex Influence Gaze‐Cued Attention in Infancy

Using the eye gaze of others to direct one's own attention develops during the first year of life and is thought to be an important skill for learning and social communication. However, it is currently unclear whether infants differentially attend to and encode objects cued by the eye gaze of individuals within familiar groups (e.g., own race, more familiar sex) relative to unfamiliar groups (e.g., other race, less familiar sex). During gaze cueing, but prior to the presentation of objects, 10‐month‐olds looked longer to the eyes of own‐race faces relative to 5‐month‐olds and relative to the eyes of other‐race faces. After gaze cueing, two objects were presented alongside the face and at both ages, infants looked longer to the uncued objects for faces from the more familiar‐sex and longer to cued objects for the less familiar‐sex faces. Finally, during the test phase, both 5‐ and 10‐month‐old infants looked longer to uncued objects relative to cued objects but only when the objects were cued by an own‐race and familiar‐sex individual. Results demonstrate that infants use face eye gaze differently when the cue comes from someone within a highly experienced group.     

Pemoline in Adult Attention Deficit Hyperactivity Disorder: Predictors of Nonresponse

Abstract

The psychostimulants are the most widely used treatment modality for attention deficit/hyperactivity disorder (ADHD). Although positive responses to psychostimulants have been demonstrated, 46% of adults with ADHD, on average, are nonresponsive or cannot tolerate the medications because of adverse effects. We reviewed the charts of 43 students treated with pemoline and studied parameters of nonresponse. Sixteen (37%) met the study definition of nonresponse. Of these, 5 (12%) were symptom nonresponders and 11 (25%) were nonresponders because of adverse effects. We found a significant relationship between age and nonresponse resulting from adverse effects, yet no other factors predicted nonresponse to pemoline. Clinicians should consider using smaller starting doses of pemoline in adults to minimize adverse effects.     

Gaze Behaviors of Preterm and Full‐Term Infants in Nonsocial and Social Contexts of Increasing Dynamics: Visual Recognition,Attention Regulation,and Gaze Synchrony

Although research has demonstrated poor visual skills in premature infants, few studies assessed infants’ gaze behaviors across several domains of functioning in a single study. Thirty premature and 30 full‐term 3‐month‐old infants were tested in three social and nonsocial tasks of increasing complexity and their gaze behavior was micro‐coded. In a one‐trial version of the visual recognition paradigm, where novel stimuli were paired with familiar stimuli, preterm infants showed longer first looks to novel stimuli. In the behavior response paradigm, which presented infants with 17 stimuli of increasing complexity in a predetermined “on‐off” sequence, premature infants tended to look away from toys more during presentation. Finally, during mother–infant face‐to‐face interaction, the most dynamic interpersonal context, preterm infants and their mothers displayed short, frequent episodes of gaze synchrony, and lag‐sequential analysis indicated that both mother and infant broke moments of mutual gaze within 2 sec of its initiation. The propotion of look away during the behavior response paradigm was related to lower gaze synchrony and more gaze breaks during mother–infant interactions. Results are discussed in terms of the unique and adaptive gaze patterns typical of low‐risk premature infants.     

Empty Looks or Paying Attention? Exploring Infants' Visual Behavior during Encoding of an Elicited Imitation Task

Recently, there has been an increased interest in the relationship between looking time during encoding and subsequent memory performance in imitation tasks. Hitherto, the results have been inconclusive: one line of research supporting the link between looking time and performance and another line finding no relation. The existing studies may, however, have been restricted by using small samples, limited looking time measures, and short retention intervals. We here examined the relationship between the encoding process by means of looking time as well as pupil dilation (by means of eye‐tracking technology) in sixty‐eight 20‐month‐old infants participating in an elicited imitation task and their subsequent memory performance (at an encoding test and at a 2‐week delayed recall test). Additional twenty‐two infants provided baseline measures. Simple looking time (assessed as fixation duration) did not correlate consistently with subsequent memory measures. In some cases, however, looking time correlated negatively with imitation scores. In contrast, positive correlations were found between pupil dilation and some of the memory measures, suggesting that pupil dilation may be a more sensitive tool compared to looking time measures.     

Sex Differences in Body Movement and Visual Attention: An Integrated Analysis of Movement and Gaze in Mixed-Sex Dyads

The body movement and visual behavior of women and men engaged in mixed-sex dyadic interactions were analyzed in a three-factorial design including the personal factor sex of the interactants, the situational factor partner familiarity, and the situational factor visual attention of the interaction partner. Measures of nonverbal activity were derived from integrated time-series protocols of body movement and gaze for both interaction partners. Data analysis revealed significant sex differences in individual frequency and duration of movement and gaze, as well as dyadic differences for both behavior measures. Men, in general, were more active while women were more visually attentive. Also, the results point to specific interaction effects between sex and familiarity. The data indicate that there were specific adaptational strategies for both sexes with familiar and unfamiliar partners.     

The Development of Affect Specificity in Infants' Use of Emotion Cues

This study examined the emergence of affect specificity in infancy. In this study, infants received verbal and facial signals of 2 different, negatively valenced emotions (fear and sadness) as well as neutral affect via a television monitor to determine if they could make qualitative distinctions among emotions of the same valence. Twenty 12‐ to 14‐month‐olds and 20 16‐ to 18‐month‐olds were examined. Results suggested that younger infants showed no evidence of referential specificity, as they responded similarly to both the target and distracter toys, and showed no evidence of affect specificity, showing no difference in play between affect conditions. Older infants, in contrast, showed evidence both of referential and affect specificity. With respect to affect specificity, 16‐ to 18‐month‐olds touched the target toy less in the fear condition than in the sad condition and showed a larger proportion of negative facial expressions in the sad condition versus the fear condition. These findings suggest a developmental emergence after 15 months of age for affect specificity in relating emotional messages to objects.     

The Nature of Infants' Visual Expectations for Event Content

Recent studies have revealed that young infants can form expectations for the spatial location of future visual events. Four experiments examined whether 3‐month‐old infants also form expectations for content features of events, defined as an invariant color combination. Infants viewed a spatially alternating (left–right) sequence of varying pictures in which pictures on one side (invariant colors) always appeared with the same color combination (e.g., red/green), while on the other side (varied colors) the pictures appeared with any of 4 possible color combinations. Results indicated that infants formed a content expectation for the invariant color combination on the invariant side, such that their anticipatory responding was disrupted by a novel color combination event and by a novel pattern event. A dissociation between reactive and anticipatory eye movements in their sensitivity to the content manipulation suggests that infants' expectations for spatial and content information engage somewhat different processes.     

If They Grow up: Exploring the Neighborhood Context of Adolescent and Young Adult Survival Expectations

Using data from the National Longitudinal Study of Adolescent Health, this study examines individual and neighborhood predictors of adolescent and young adult survival expectations—their confidence of surviving to age 35. Analyses revealed that within‐person increases in depression and violent perpetration decreased the odds of expecting to survive. Individuals who rated themselves in good health and received routine physical care had greater survival expectations. Consistent with documented health disparities, Black and Hispanic youth had lower survival expectations than did their White peers. Neighborhood poverty was linked to diminished survival expectations both within and between persons, with the between‐person association remaining significant controlling for mental and physical health, exposure to violence, own violence, and a wide range of sociodemographic factors.     

An Adult Protective Services' View of Collaboration With Mental Health Services

Mental Health Services (MHS) meet mental health needs of older adults through active, outpatient, community-based care. Adult Protective Services (APS) are involved with needs of older adults who have mental disability and mental illness. Adult Protective Services and MHS staff may to work together when they respond to the needs of victims and adults at risk for abuse, neglect, self-neglect, and exploitation. The purpose of this study was to understand effective APS–MHS collaborations (e.g., leadership, organizational culture, administration, and resources in predicting success). A survey that was sent to members of the National Adult Protective Services Association (NAPSA) revealed that both APS and MHS have strong commitments to protecting clients' rights and autonomy, but there appear to be differences between the two with regard to implementation, apparent in cases involving clients with diminished mental capacity who are at imminent risk, but who refuse help. Strengths of APS–MHS collaborations included improved communication and better service for at-risk clients.     

The Effect of Repetition on Infants' Imitation From Picture Books Varying in Iconicity

Although picture‐book reading is commonplace during infancy, little is known about the impact of this activity on learning. A previous study showed that 18‐ and 24‐month‐olds imitated a novel action sequence presented in a book that was illustrated with realistic color photos, whereas they failed to imitate from books illustrated with less realistic drawings. In the research reported here, we hypothesized that increasing infants' exposure to a picture book would increase learning from books illustrated with both color photos and drawings. Independent groups of 18‐and 24‐month‐olds were exposed to a picture book either twice in succession or 4 times in succession. The results showed that, regardless of the iconicity of the illustrations, increasing the number of reading sessions significantly improved the infants' imitation scores, compared to age‐matched, no‐demonstration controls. The results are discussed in relation to representational insight and cognitive flexibility.     

The Development of Gaze Following in a Third‐Party Context

Infants follow the gaze of an individual with whom they are directly interacting by the end of the first year. By 18 months infants are capable of learning novel words in observational (or third‐party) contexts (Floor & Akhtar, 2006). To examine third‐party gaze following in 12‐ and 18‐month‐olds, the parent and experimenter engaged in a conversation while the infant was present. For 8 trials approximately every 30 sec the experimenter would turn her head to the right or left to fixate on a toy placed on either side of the room with the parent following suit. In the first experiment, the parent was seated next to the infant and the experimenter opposite, whereas in the second experiment the positions of the adults were switched. In Experiment 1, 18‐month‐olds but not 12‐month‐olds followed gaze. In Experiment 2, 12‐month‐olds acquired a tendency to follow gaze during the experimental session. These results suggest that an incipient ability to follow third‐party gaze is present by 12 months and that infants acquire a more reliable and general ability to follow the gaze of noninteractive others between 12 and 18 months.     

Infants' identification of gender in biological motion displays

Infants' knowledge of social categories, including gender-typed characteristics, is a vital aspect of social cognitive development. In the current study, we examined 9- to 12-month-old infants' understanding of the categories “male” and “female” by testing for gender matching in voices or faces with biological motion depicted in point light displays (PLDs). Infants did not show voice–PLD gender matching spontaneously (Experiment 1) or after “training” with gender-matching voice–PLD pairs (Experiment 2). In Experiment 3, however, infants were trained with gender-matching face–PLD pairs and we found that patterns of visual attention to top regions of PLD stimuli during training predicted gender matching of female faces and PLDs. Prior to the end of the first postnatal year, therefore, infants may begin to identify gender in human walk motions, and perhaps form social categories from biological motion.     

Object Representation in Infants' Coordination of Manipulative Force

This study examined infants' use of object knowledge for scaling the manipulative force of object‐directed actions. Infants 9, 12, and 15 months of age were outfitted with motion‐analysis sensors on their arms and then presented with stimulus objects to examine individually over a series of familiarization trials. Two stimulus objects were used in the familiarization phase, and were identical in size, shape, and material, but different in color and weight. Following familiarization, two test objects that had been hidden from view were presented. The test objects were identical in appearance to the familiarization objects, but their color‐weight correspondence was reversed. Infants' actions on the test objects revealed selective, differential preparation for the specific weights experienced during familiarization. Because the objects were equivalent in their visual affordances for action, the differential preparation and coordination of manipulative force was based on knowledge acquired during the familiarization phase. Infants are capable of utilizing object representations to coordinate manipulative force in object‐directed actions.     

The Role of Gesture in Children's Comprehension of Spoken Language:Now They Need It, Now They Don't

Two experiments investigated gesture as a form of external support for spoken language comprehension. In both experiments, children selected blocks according to a set of videotaped instructions. Across trials, the instructions were given using no gesture, gestures that reinforced speech, and gestures that conflicted with speech. Experiment 1 used spoken messages that were complex for preschool children but not for kindergarten children. Reinforcing gestures facilitated speech comprehension for preschool children but not for kindergarten children, and conflicting gestures hindered comprehension for kindergarten children but not for preschool children. Experiment 2 tested preschool children with simpler spoken messages. Unlike Experiment 1, preschool children's comprehension was not facilitated by reinforcing gestures. However, children's comprehension also was not hindered by conflicting gestures. Thus, the effects of gesture on speech comprehension depend both on the relation of gesture to speech, and on the complexity of the spoken message.