Toddlers' attention to intentions-in-action in learning novel action words.

Toddlers' ability to use cues such as eye gaze and gestures to infer the meaning of novel action words was examined. In Experiment 1, 21- and 27-month-olds were taught labels for pairs of videotaped actions that were either similar or dissimilar in appearance. Similar actions differed mainly in the presence of behavioral cues related to the agents' intentions (e.g., extended arms). Only the older children were able to learn the labels for the similar actions. In Experiment 2, 3 new pairs of labels (2 similar, 1 dissimilar) were taught to children in the same age range. Eye gaze and gestures were the main features distinguishing the similar events. The same developmental effect was observed, with only the older children showing learning of both types of verbs and the younger children being impeded by the appearance of the actions. The results show that by the middle of the 2nd year, children begin to consider intentions-in-action when acquiring the meaning of novel action verbs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory retrieval by 18–30-month-olds: Age-related changes in representational flexibility.

Deferred imitation was used to trace changes in memory retrieval by 18–30-month-olds. In all experiments, an adult demonstrated 2 sets of actions using 2 different sets of stimuli. In Experiments 1A and 1B, independent groups of infants were tested immediately or after a 24-hr delay. Each infant was tested with 1 set of stimuli from the original demonstration and 1 set of stimuli that was different. Recall of the target actions when tested with different stimuli increased as a function of age, particularly after a delay. In Experiment 2, infants were provided with a unique verbal label for the stimuli during the demonstration and the test. The verbal label facilitated performance by 24-month-olds tested with different stimuli but had no effect on performance by 18-month-olds. One hallmark of memory development appears to be an age-related increase in the range of effective retrieval cues for a particular memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Producing and processing self-propelled motion in infancy.

Three experiments investigated 5- through 8-month-olds' ability to encode self-propelled and caused motion and examined whether processing of motion onset changes when crawling begins. Infants were habituated (Experiments 1 and 2) or familiarized (Experiment 3) with simple causal and noncausal launching events. They then viewed the caused-to-move and self-propelled objects from the events both stationary and side-by-side, and their preferential looking to the objects was assessed. Results revealed that 5- and 6-month-olds displayed a different pattern of looking than did 8-month-olds. More notably, noncrawling 7-month-olds and 7-month-olds with crawling experience also demonstrated such a differential pattern. These data suggest that processing of motion onset changes in concert with the commencement of self-locomotion. Findings are discussed in reference to the mechanisms underlying infants' ability to recognize self-propelled motion and the scope of the relationship between action production and action perception in infancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorical representation of facial expressions by 7-month-old infants.

We investigated the ability of 7-month-olds to categorize the facial expressions happy, fear, and surprise when these expressions varied both by the model depicting the expression and by how intensely the expression was portrayed in a series of three experiments. In Experiment 1, infants successfully discriminated a single model posing a mild versus an extreme version of happy and fear. In Experiment 2, infants categorized happy when depicted by for different models posing mild and extreme versions and discriminated happy from fear. In Experiment 3, infants categorized both happy and surprise posed by five models varying in degree of expressiveness and discriminated these expressions from fear. In both Experiments 2 and 3, there was no evidence that infants could also (a) categorize the fear expressions and discriminate fear from happy or from surprise or (b) discriminate surprise from happy after habituating to surprise. These results are discussed in the context of the importance of experience in recognizing facial expressions and of how such experience influences the ease with which various expressions can be encoded and discriminated from other expressions in the laboratory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tool use and the effect of action on the imagination.

Three studies examined the claim that hand movements can facilitate imagery for object rotations but that this facilitation depends on people's model of the situation. In Experiment 1, physically turning a block without vision reduced mental rotation times compared with imagining the same rotation without bodily movement. In Experiment 2, pulling a string from a spool facilitated participants' mental rotation of an object sitting on the spool. In Experiment 3, depending on participants' model of the spool, the exact same pulling movement facilitated or interfered with the exact same imagery transformation. Results of Experiments 2 and 3 indicate that the geometric characteristics of an action do not specify the trajectory of an imagery transformation. Instead, they point to people's ability to model the tools that mediate between motor activity and its environmental consequences and to transfer tool knowledge to a new situation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Generalization of learning from picture books to novel test conditions by 18- and 24-month-old children.

Researchers know little about whether very young children can recognize objects originally introduced to them in a picture book when they encounter similar looking objects in various real-world contexts. The present studies used an imitation procedure to explore young children's ability to generalize a novel action sequence from a picture book to novel test conditions. The authors found that 18-month-olds imitated the action sequence from a book only when the conditions at testing matched those at encoding; altering the test stimuli or context disrupted imitation (Experiment 1A). In contrast, the 24-month-olds imitated the action sequence with changes to both the test context and stimuli (Experiment 1B). Moreover, although the 24-month-olds exhibited deferred imitation with no changes to the test conditions, they did not defer imitation with changes to the context and stimuli (Experiment 2). Two factors may account for the pattern of results: age-related changes in children's ability to utilize novel retrieval cues as well as their emerging ability to understand the representational nature of pictures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syntactic form, semantic complexity, and short-term memory: Influences on children's acquisition of new linguistic structures.

30 children at 5 age levels (2–6 yrs) were exposed to novel actions involving 1, 2, or 3 semantic features. Simultaneously, they were taught novel labels for these actions. The labels marked the semantic features syntactically, with either a suffix, a prefix, or both a suffix and a prefix. In posttests Ss had to either supply the appropriate label for an action or produce an appropriate action for a label. Results show that (a) semantic complexity affected the difficulty of producing actions but not labels, (b) syntactic complexity affected the difficulty of producing labels but not actions, (c) there was an age below which little learning was evident on either test, (d) short-term memory (STM) was a better predictor of performance than was age, and (e) the STM value associated with each item corresponded approximately to the number of features, syntactic or semantic, that had to be processed to produce the form in question. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Young children associate novel words with complex objects rather than salient parts.

How do children learn associations between novel words and complex perceptual displays? Using a visual preference procedure, the authors tested 12- and 19-month-olds to see whether the infants would associate a novel word with a complex 2-part object or with either of that object's parts, both of which were potentially objects in their own right and 1 of which was highly salient to infants. At both ages, children's visual fixation times during test were greater to the entire complex object than to the salient part (Experiment 1) or to the less salient part (Experiment 2)--when the original label was requested. Looking times to the objects were equal if a new label was requested or if neutral audio was used during training (Experiment 3). Thus, from 12 months of age, infants associate words with whole objects, even those that could potentially be construed as 2 separate objects and even if 1 of the parts is salient. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of vowel length by Japanese- and English-learning infants.

This study investigated vowel length discrimination in infants from 2 language backgrounds, Japanese and English, in which vowel length is either phonemic or nonphonemic. Experiment 1 revealed that English 18-month-olds discriminate short and long vowels although vowel length is not phonemically contrastive in English. Experiments 2 and 3 revealed that Japanese 18-month-olds also discriminate the pairs but in an asymmetric manner: They detected only the change from long to short vowel, but not the change in the opposite direction, although English infants in Experiment 1 detected the change in both directions. Experiment 4 tested Japanese 10-month-olds and revealed a symmetric pattern of discrimination similar to that of English 18-month-olds. Experiment 5 revealed that native adult Japanese speakers, unlike Japanese 18-month-old infants who are presumably still developing phonological perception, ultimately acquire a symmetrical discrimination pattern for the vowel contrasts. Taken together, our findings suggest that English 18-month-olds and Japanese 10-month-olds perceive vowel length using simple acoustic?phonetic cues, whereas Japanese 18-month-olds perceive it under the influence of the emerging native phonology, which leads to a transient asymmetric pattern in perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do 9-month-old infants expect distinct words to refer to kinds?

In 3 experiments, 9-month-old infants' expectations for what distinct count noun labels refer to were investigated. In Experiment 1, a box was opened to reveal 2 objects inside during familiarization: either 2 identical objects or 2 different objects. Test trials followed the same procedure, except before the box was opened, the contents were described using 2 distinct labels ("I see a wug! I see a dak!") or the same label twice ("I see a zav! I see a zav!"). Infants who heard a label repeated twice looked longer at 2 different objects versus 2 identical objects, whereas infants who heard 2 distinct labels showed a different pattern of looking. Experiments 2 and 3 presented infants with object pairs that only differed in shape or color, and it was found that infants expected the different-shaped (but not the different-colored) objects to be labeled by distinct count nouns. Because the property of shape is a cue to kind membership and the property of color is not, these results suggest that even at the beginning of word learning, infants may expect distinct labels to refer to distinct kinds of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

It's a sign of the kind: Gestures and words guide infants' inductive inferences.

The role of words and gestures in guiding infants' inductive inferences about nonobvious properties was examined. One hundred seventy-two 14-month-olds and 22-month-olds were presented with novel target objects followed by test objects that varied in similarity to the target. Objects were introduced with a novel word or a novel gesture or with no label. When target and test objects were highly similar in shape, both 14- and 22-month-olds inferred that these objects shared a nonobvious property, regardless of whether the objects were labeled with a word or a gesture or with no label. When objects were labeled with the same word, both 14- and 22-month-olds generalized the nonobvious properties to objects that shared minimal perceptual similarity. Finally, when objects were labeled with the same gesture, 14-month-olds, but not 22-month-olds, generalized the nonobvious properties to objects that shared minimal perceptual similarity. These results indicate that 14-month-olds possess a more generalized symbolic system as they will rely on both words and gestures to guide their inferences. By 22-months of age, infants treat words as a privileged referential form when making inductive inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of fiber debonding and sliding experiments in brittle matrix composites

The use of a recent analysis of fiber debonding and sliding in brittle matrix composites to interpret the results of fiber pulling and pushing experiments is examined. The stress-displacement relations are expressed in normalized forms that are convenient for curve fitting to experimental measurements and the analysis is extended to provide stress-displacement relations for cyclic loading in addition to monotonic loading. The ranges of some of the important elastic parameters and their influence on the stress-displacement relations are examined. Differences between single and multiple fiber pulling and between pushing and pulling experiments are assessed.     

Young children's use of syntactic cues to learn proper names and count nouns.

In 6 experiments, 144 toddlers were tested in groups ranging in mean age from 20 to 37 months. In all experiments, children learned a novel label for a doll or a stuffed animal. The label was modeled syntactically as either a count noun (e.g., "This is a ZAV") or a proper name (e.g., "This is ZAV"). The object was then moved to a new location in front of the child, and a second identical-looking object was placed nearby. The children's task was to choose 1 of the 2 objects as a referent for the novel word. By 24 months, both girls (Experiment 2) and boys (Experiment 5) were significantly more likely to select the labeled object if they heard a proper name than if they heard a count noun. At 20 months, neither girls (Experiments 1 and 6) nor boys (Experiment 1) demonstrated this effect. By their 2nd birthdays, children can use syntactic information to distinguish appropriately between labels for individual objects and those for object categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of declarative memory in human infants: Age-related changes in deffered imitation.

In 2 experiments, deferred imitation procedures were used to trace age-related changes in declarative memory by human infants over the first 2 years of life. An adult modeled 3 actions with an object, and infants' ability to reproduce those actions was assessed 24 hr later. Some infants were tested with a new object or in a new context relative to the original demonstration. Changes in the context disrupted the performance of 6-month-olds but had no effect on the performance of 12- and 18-month-olds. Changes in the object disrupted the performance of 6- and 12-month-olds but had no effect on the performance of 18-month-olds. This age-related increase in representational flexibility may account for the decline of childhood amnesia during the 3rd year of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective and nonselective associations between speech segments and faces in human infants.

The role of affective correspondence between signal and outcome in associative learning was studied in 2 experiments with 4-month-olds. In Experiment 1, an infant-directed (ID) speech segment, categorized by adults as having consoling acoustic properties for infants, was either paired or unpaired with smiling or sad face reinforcers. In other groups, a sad adult-directed (AD) speech segment signaled the smiling or sad faces. Later, all speech segments were tested for their ability to increase infants' visual interest in a checkerboard. Positive summation was observed only when the consoling ID speech segment had signaled the sad face. In Experiment 2, an arousing ID speech segment signaled the smiling or sad face. Positive summation was evident in both conditions. These results show that infants sometimes selectively associate speech segments and faces. Discussion centers on the basis for the selective association. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When even arbitrary order becomes important: developments in reliable temporal sequencing of arbitrarily ordered events

By late in the first year of life, children show temporally ordered recall of event sequences, the orders of which are constrained by enabling relations; they do not reliably recall arbitrarily ordered events. Using elicited imitation, in two experiments, we examined age- and experience-related changes in young children's recall of events, the orders of which are arbitrary. The changes were found to have implications for the efficacy of verbal reminding and to be related to developments in language. Specifically, on the basis of a single experience, 16-month-olds did not accurately recall arbitrarily ordered event sequences either immediately or after a two-week delay (Experiment 1); 22-month-olds recalled the events immediately, but not after the delay; by 28 months, children recalled the events even after the delay (Experiment 2A). This development was accompanied by changes in the ability to benefit from verbal reminders: 28-month-olds' recall was facilitated by provision of verbal reminders, whereas that of the younger children was not. Moreover, age-related changes in accurate reproduction of lengthy arbitrarily ordered event sequences were found to be related to developments in language (Experiment 2B). Critically, the limitations on 1-year-olds' performance that are overcome with age are not absolute: After three experiences, 16-month-olds accurately recalled the events after a two-week delay; their recall was facilitated by verbal reminders (Experiment 1). The implications of these findings are discussed.     

Infants' attention to object structure in early categorization.

Three experiments with object-manipulation tasks examined the effect of object structure on 14-, 18-, and 22-month-olds' categorization. In Experiment 1, categorization of animals and vehicles was tested when object structure was normal and when it was violated by moving parts (legs or wheels) into a novel configuration. In Experiment 2, categorization of animals, vehicles, and furniture was examined when object structure was modified in orientation (e.g., legs inverted) or in configuration (e.g., legs at tangential angles). In Experiment 3, infants' attention to texture in categorization was tested. The results of the studies showed that 14- to 22-month-olds attend to object parts and structural configuration to categorize and that they do not attend to object texture. There is a perceptual basis for early categorization at the superordinate-like level, and infants are constrained in the parts and object structures they recognize in this process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forbidden fruit versus tainted fruit: Effects of warning labels on attraction to television violence.

Under growing public and government pressure, the television networks have adopted warning labels for violent programs. Tainted fruit theory posits that warning labels will decrease interest in violent programs, whereas forbidden fruit theory posits that warning labels will increase interest in violent programs. In Experiment 1, it was found that warning labels increased interest in violent programs, especially when the label source was authoritative. In Experiment 2, it was found that high-reactance individuals were especially interested in viewing violent programs with warning labels. In Experiment 3, it was found that warning labels increased interest in violent programs more than did information labels. These results are consistent with forbidden fruit theory. Those who are interested in reducing viewership of violent media might use these results as a caution against assuming that warning labels decrease viewership when warning labels may in fact increase viewership. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' ability to parse continuous actions.

In a series of 3 experiments, the authors examined 6- and 8-month-old infants' capacities to detect target actions in a continuous action sequence. In Experiment 1, infants were habituated to 2 different target actions and subsequently were presented with 2 continuous action sequences that either included or did not include the familiar target actions. Infants looked significantly longer at the sequences that were novel. Experiment 2 presented the habituation and test trials in the reverse order. The results showed that infants habituated to the sequence still showed reliable evidence of recognizing the target action during the test trials. Experiment 3 was comparable to Experiment 2, except it tested whether infants could detect a different event segment, namely the transitions between events. The results showed that infants did not discriminate between test trials suggesting that transitions between events are not as easy for infants to recognize. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Make the first move: How infants learn about self-propelled objects.

In 3 experiments, the author investigated 16- to 20-month-old infants' attention to dynamic and static parts in learning about self-propelled objects. In Experiment 1, infants were habituated to simple noncausal events in which a geometric figure with a single moving part started to move without physical contact from an identical geometric figure that possessed a single static part. Infants were then tested with an event in which the parts of the objects were switched. In Experiments 2 and 3, infants were habituated and tested with identical events except that the part possessed by each object during habitation was switched relative to the first experiment. Results of the experiments revealed that 16-month-olds failed to encode the relation between an object's part and its onset of motion, 18-month-olds were unconstrained in the relations involving self-propulsion that they would encode, and 20-month-olds were constrained in the relations they would encode. The results are discussed with regard to the developmental trajectory of learning about motion properties and the mechanism involved in early concept acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)