Developmental changes in infants' sensitivity to octave-band noises

Localization responses to octave-band noises with center frequencies at 200, 400, 1000, 2000, 4000, and 10,000 Hz were obtained from infants 6, 12, and 18 months of age. During an experimental trial, an octave-band noise was presented on one of two speakers located 45° to each side of the infant. A head turn to the noise (correct response) was rewarded by activating an animated toy on top of the speaker. The intensity of the noise was varied over trials (method of constant stimuli) to determine thresholds at each center frequency. Thresholds for the lower frequencies were approximately 5–8 db higher in the 6-month-old infants compared to the older infants. However, there were no consistent differences among groups at the higher frequencies. Infant thresholds were found to be 20–30 db higher than adult thresholds at the lower frequencies. At the higher frequencies thresholds for infants were approaching those of adults.     

A happy story: Developmental changes in children’s sensitivity to facial expressions of varying intensities

Using 20 levels of intensity, we measured children’s thresholds to discriminate the six basic emotional expressions from neutral and their misidentification rates. Combined with the results of a previous study using the same method (Journal of Experimental Child Psychology, 102 (2009) 503-521), the results indicate that by 5 years of age, children are adult-like, or nearly adult-like, for happy expressions on all measures. Children’s sensitivity to other expressions continues to improve between 5 and 10 years of age (e.g., surprise, disgust, fear) or even after 10 years of age (e.g., anger, sad). The results indicate that there is a slow development of sensitivity to the expression of all basic emotions except happy. This slow development may impact children’s social and cognitive development by limiting their sensitivity to subtle expressions of disapproval or disappointment.     

Developmental changes in the response to obstacles during prehension

Adults are proficient at reaching to grasp objects of interest in a cluttered workspace. The issue of concern, obstacle avoidance, was studied in 3 groups of young children aged 11-12, 9-10, and 7-8 years (n=6 in each) and in 6 adults aged 18-24 years. Adults slowed their movements and decreased their maximum grip aperture when an obstacle was positioned close to a target object (the effect declined as the distance between target and obstacle increased). The children showed the same pattern, but the magnitude of the effect was quite different. In contrast to the adults, the obstacle continued to have a large effect when it was some distance from the target (and provided no physical obstruction to movement).     

Developmental changes in mental rotation

Subjects from Grades 3, 4, 6, and college judged whether pairs of stimuli were identical or mirror-image reversals. One stimulus of a pair was presented upright; the other was rotated 0 to 150° from the standard. The pairs were either alphanumeric symbols or unfamiliar, letter-like characters of the type found on the PMA Spatial Ability Test. Response latencies were measured. The primary results were that (a) the speed of mental rotation increased with development, (b) unfamiliar characters were rotated more slowly than alphanumeric characters, by approximately the same amount at each grade, and (c) unfamiliar characters were encoded and compared more slowly than alphanumeric symbols, by an amount that declined with development. The results are discussed in terms of the component processes that underlie developmental change and individual variation in mental rotation skill.     

Developmental changes in source memory

Remembering how one learned a fact can be important in itself (e.g. for considering the value of information). However, source memory is also important, along with the temporal and perceptual information on which it is based, in giving memory an episodic or autobiographical quality. The present study investigated developmental changes in children’s ability to monitor source, in a paradigm adapted from Schacter, Harbluk and McLachlan (1984). This task, unlike previous source monitoring tasks used with children, has the potential to show the existence of a serious kind of source error called source amnesia. Children of 4, 6 and 8 years participated. They also completed measures believed to assess prefrontal function. Children showed a steady improvement with age in their ability to remember facts, but showed abrupt improvement between 4 and 6 years in their ability to monitor the source of those facts. Most notably, 4–year–old children displayed a great deal of source amnesia (i.e. errors of the kind committed by populations with frontal dysfunction), but 6– and 8–year–old children showed very few such errors. In addition, source memory was related, in some analyses although not in others, to behavioral measures often used to assess prefrontal functioning. The timing of the transition in source monitoring ability is discussed, including implications for childhood amnesia.     

Developmental changes in attention-deployment skills

The ability to efficiently allocate attention between two tasks differing in payoff was investigated developmentally. Ten subjects from each of three grade levels (second, fourth, and college) performed an auditory and a visual memory task simultaneously. Modality of the primary task, difficulty of the primary task, and difficulty of the secondary task were varied factorially within subjects. The difference between primary and secondary performances increased with age: All college students, about half of the fourth graders, and none of the second graders showed a meaningful degree of differentiation between primary and secondary tasks.     

Developmental changes in neural activity to familiar words and gestures

Infants younger than 20 months of age interpret both words and symbolic gestures as object names. Later in development words and gestures take on divergent communicative functions. Here, we examined patterns of brain activity to words and gestures in typically developing infants at 18 and 26 months of age. Event-related potentials (ERPs) were recorded during a match/mismatch task. At 18 months, an N400 mismatch effect was observed for pictures preceded by both words and gestures. At 26 months the N400 effect was limited to words. The results provide the first neurobiological evidence showing developmental changes in semantic processing of gestures.     

Developmental changes in face processing skills

Expertise in processing differences among faces in the spacing among facial features (second-order relations) is slower to develop than expertise in processing the shape of individual features or the shape of the external contour. To determine the impact of the slow development of sensitivity to second-order relations on various face-processing skills, we developed five computerized tasks that require matching faces on the basis of identity (with changed facial expression or head orientation), facial expression, gaze direction, and sound being spoken. In Experiment 1, we evaluated the influence of second-order relations on performance on each task by presenting them to adults (N=48) who viewed the faces either upright or inverted. Previous studies have shown that inversion has a larger effect on tasks that require processing the spacing among features than it does on tasks that can be solved by processing the shape of individual features. Adults showed an inversion effect for only one task: matching facial identity when there was a change in head orientation. In Experiment 2, we administered the same tasks to children aged 6, 8, and 10 years (N=72). Compared to adults, 6-year-olds made more errors on every task and 8-year-olds made more errors on three of the five tasks: matching direction of gaze and the two facial identity tasks. Ten-year-olds made more errors than adults on only one task: matching facial identity when there was a change in head orientation (e.g., from frontal to tilted up). Together, the results indicate that the slow development of sensitivity to second-order relations causes children to be especially poor at recognizing the identity of a face when it is seen in a new orientation.     

Developmental changes in death anxiety in childhood

A sample of 49 children divided into three age groups (3–4 years, 7–8 years, and 10–11 years) responded to a pictorial derivation of Spielberger's State Anxiety Inventory for Children (STAIC). Three pictures were used as stimuli, in addition to words, for the measure of death anxiety. The intensity measure was the response to six Hebrew mood adjectives as the child chose one of seven schematic face drawings ranging from positive to negative expressions. Reliabilities were comporable to the longer versions of the Hebrew STAIC with older children. Findings indicated significant differences in anxiety scores between the age groups, with older subjects showing higher levels of anxiety. The advantage of a single measure of death anxiety appropriate for a wide age range is discussed, as well as the implication for a developmental pattern of death anxiety.     

Developmental changes in mother-infant face-to-face communication: birth to 3 months

This study documented the growth of the earliest form of face-to-face communication in 16 mother-infant dyads, videotaped weekly during a naturalistic face-to-face interaction, between 1 and 14 weeks, in 2 conditions: with the infant in the mother's arms and with the infant semi-reclined on a sofa. Results showed a curvilinear development of early face-to-face communication, with a significant increase occurring between Week 4 and Week 9 depending on the dyad. After 2 months, trajectories diverged into 2 groups: I whose duration of face-to-face communication continued to increase and I whose duration peaked and then began to decrease. After the 1st month, the duration of face-to-face communication was significantly longer when the infant was on the sofa rather than in the mother's arms. In the latter condition, during the 3rd month, girls spent a significantly longer time than boys in face-to-face communication. These findings suggest that context (infant being held vs. not being held) interacts with the infant's age and sex in affecting mother-infant communication.     

Developmental changes in judgments of authentic objects

This study examined the development of an understanding of authenticity among 112 children (preschoolers, kindergarten, 1st graders, and 4th graders) and 119 college students. Participants were presented with pairs of photographs depicting authentic and non-authentic objects and asked to pick which one belongs in a museum and which one they would want to have. Results suggest that both children and adults recognize the special nature of authentic objects by reporting that they belong in a museum. However, this belief broadens with age, at first just for famous associations (preschool), then also for original creations (kindergarten), and finally for personal associations as well (4th grade). At all ages, an object's authentic nature is distinct from its desirability. Thus, from an early age, children appear to understand that the historical path of an authentic object affects its nature. This work demonstrates the importance of non-obvious properties in children's concepts. For preschool as well as older children, history (a non-visible property) adds meaning beyond the material or functional worth of an object.     

Developmental changes in the understanding of generics

Generic sentences (such as "Birds lay eggs") are important in that they refer to kinds (e.g., birds as a group) rather than individuals (e.g., the birds in the henhouse). The present set of studies examined aspects of how generic nouns are understood by English speakers. Adults and children (4- and 5-year-olds) were presented with scenarios about novel animals and questioned about their properties, using generic and non-generic questions. Three primary findings emerged. First, both children and adults distinguished generic from non-generic reference, interpreting generics as referring to kinds. Thus, under certain contexts children and adults accepted that "Dobles have claws" even when all the dobles in the available context were clawless. Second, adults further distinguished properties that are inborn from those that are acquired. Inborn properties were judged to be predicated of a generic kind, even when all available instances have lost the property, but this was not the case for acquired properties. Third, children did not distinguish inborn from acquired properties. These data suggest the existence of developmental changes in conceptual or semantic understanding, and are interpreted in light of recent theories of psychological essentialism.     

Developmental changes in associations between auditory-visual events

The goal of the present study was twofold: to examine the influence of two amodal properties, co-location and temporal synchrony, on infants' associating a sight with a sound, and to determine if the relative influence of these properties on crossmodal learning changes with age. During familiarization 2-, 4-, 6- and 8-month-olds were presented two toys and a sound, with sights and sounds varying with respect to co-location and temporal synchrony. Following each familiarization phase infants were given a paired preference test to assess their learning of sight-sound associations. Measures of preferential looking revealed age-related changes in the influence of co-location and temporal synchrony on infants' learning sight-sound associations. At all ages, infants could use temporal synchrony and co-location as a basis for associating an auditory with a visual event and, in the absence of temporal synchrony, co-location was sufficient to support crossmodal learning. However, when these cues conflicted there were developmental changes in the influence of these cues on infants' learning auditory-visual associations. At 2 and 4 months infants associated the sounds with the toy that moved in synchrony with the sound's rhythm despite extreme violation of co-location of this sight and sound. In contrast, 6- and 8-month-olds did not associate a specific toy with the sound when co-location and synchrony information conflicted. The findings highlight the unique and interactive effects of distinct amodal properties on infants' learning arbitrary crossmodal relations. Possible explanations for the age shift in performance are discussed.     

Developmental changes in memory source monitoring.

Previous research suggests that children are more likely than adults to confuse memories of actions they imagined themselves performing with memories of actions they actually performed (Realization Judgments), but are not more likely to confuse memories of actions they had imagined performing with memories of actions they saw another person perform (Reality Monitoring). We approach these findings in terms of a theory about the processes by which people identify the sources of their recollections (Source Monitoring). This approach suggests that children may be more likely than adults to confuse memories from different sources whenever the sources are highly similar to one another. Experiments 1 and 2 tested this hypothesis by manipulating the perceptual and semantic similarity of two sources of information and testing 4- and 6-year-old and adult subjects' recollection of the sources of particular pieces of information. Experiment 3 tested the hypothesis that children are more likely than adults to mistakenly identify memories of things they imagined another person doing as memories of things they witnessed that person doing. The findings indicate that (a) people are more likely to confuse memories from similar than dissimilar sources, (b) source monitoring improves during the preschool and childhood years, and (c) children may be especially vulnerable to the effects of source similarity.     

Developmental shifts in children's sensitivity to visual speech: a new multimodal picture-word task

This research developed a multimodal picture-word task for assessing the influence of visual speech on phonological processing by 100 children between 4 and 14 years of age. We assessed how manipulation of seemingly to-be-ignored auditory (A) and audiovisual (AV) phonological distractors affected picture naming without participants consciously trying to respond to the manipulation. Results varied in complex ways as a function of age and type and modality of distractors. Results for congruent AV distractors yielded an inverted U-shaped function with a significant influence of visual speech in 4-year-olds and 10- to 14-year-olds but not in 5- to 9-year-olds. In concert with dynamic systems theory, we proposed that the temporary loss of sensitivity to visual speech was reflecting reorganization of relevant knowledge and processing subsystems, particularly phonology. We speculated that reorganization may be associated with (a) formal literacy instruction and (b) developmental changes in multimodal processing and auditory perceptual, linguistic, and cognitive skills.     

Developmental changes in children's abilities to match and label emotionally laden situations

In two studies, male and female preschoolers and third- and fourth-graders were tested on their abilities to match and generate affective labels for 19 types of emotionally laden situations. Age changes were found in the accuracy with which situations were both labeled and matched; the ability to match similar situations was more strongly related to age than was the ability to label emotions. Matching and labeling abilities were positively related to each other. Both age groups were best at labeling situations depicting happiness, anger, and sadness, and at matching situations depicting sadness, anger, and disgust, but both age groups were capable of matching a wide variety of emotions depicted in situations at a better than chance rate. Only situations depicting fear, nervousness, and embarrassment were not matched better than chance by either preschoolers or third- and fourth-graders.This research was supported by a grant to the first author from Boston University Graduate School, No. GRS-661-PS. Portions of this paper were presented in Toronto at the Biannual Meeting of the Society for Research in Child Development, April 1985. The authors would like to thank Gail Desmond, Lesley Landau, Ana Ortiz, Phyllis Sternlight, Mark Steward, and Orna Wolfson for their help in various phases of this project, and especially the Lowell Day Nursery for its cooperation.