Jennifer L. Miller

Female social networks influence male vocal development in brown-headed cowbirds, Molothrus ater

Previous work has found that adult female brown-headed cowbirds, who do not sing, shape male vocal structure when in restricted housing. The present work extends this finding to a flock setting to examine the role of social behaviour in shaping male vocal development. We housed juvenile males with either adult or juvenile females in large flocks. Over the course of a year, we recorded their song and social behaviour. We found in early autumn that juvenile males housed with adult females improvised more song elements than males housed with juvenile females. During late autumn, we switched the males across female age-class conditions for 6 days. The males switched to the adult female flocks increased the number of improvised elements in their vocal repertoires. Analysis of the sequences of female–male social contact revealed that juvenile females, but not adult females, interacted indiscriminately with the males. Social network measures such as betweenness and closeness centrality further showed that adult females are more selective in their interactions with males than juvenile females. This study suggests a systemic role for selective social behaviour in shaping male vocal development.

Prelinguistic infants’ communicative system: Role of caregiver social feedback:

Infants’ prelinguistic vocalizations and gestures are rarely studied as a communicative system. As a result, there are few studies examining mechanisms of change concurrently in prelinguistic vocal and gesture behavior. Here we report the first evidence that contingent caregiver social feedback to infant gestures influences not only gesture production, but also prelinguistic vocal behavior. Study 1 demonstrates the relationship between gesture and vocal behavior in 12-month-old infants and contingent caregiver social feedback. Caregiver feedback to infant gesture production was positively associated with infant gestures, gesture–vocal combinations, and vocalizations. To test the mechanism underlying changes in infant gesture production, Study 2 instructed caregivers to respond either contingently or noncontingently to their infants’ gestures. Infants given contingent social feedback produced more gestures, more gesture–vocal combinations and used their vocalizations differently compared to infants given noncontingent feedback. Thus, prelinguistic vocal and gesture behavior are mechanistically linked before the first word and should be studied concurrently to understand the development of the communicative system.

Different patterns of contingent stimulation differentially affect attention span in prelinguistic infants

The ability to sustain attention influences different domains including cognitive, motor, and communicative behavior. Previous research has demonstrated how an infants parent can influence sustained attention. The purpose of our study was to expose infants systematically to both sensitive and redirective patterns of behavior to examine how unfamiliar individuals could influence attention. Results revealed infants changed their patterns of looking with the unfamiliar individuals. Infants had longer durations of sustained attention when interacting with a sensitive unfamiliar individual who followed into their attentional focus as opposed to an intrusive person who led their attentional focus. This study demonstrates that infants discriminate patterns of contingency to persons seen for only a short period of time broadening the range of potential mentors for learning.

Uncovering sources of variation in female sociality: Implications for the development of social preferences in female cowbirds (Molothrus ater)

The purpose of this study was to investigate variation in female cowbird (Molothrus ater) sociality. We studied four captive flocks of brown-headed cowbirds, two composed of adult females and juvenile males and two composed of juvenile females and juvenile males. From September through December, we documented sociality using affiliation measures. From the outset, we found large age differences: juvenile females interacted more with each other and with males than did adult females. We conducted perturbations of flock composition to examine the differences between juvenile and adult females. When adult females were mixed with juvenile females and juvenile males, the adult females adopted the behavior of the juvenile females, with both becoming more interactive with males. The perturbations did not appear to be a consequence of juvenile male social behavior. The results are significant as they show a special role for juvenile females to regulate male-female interactions, which in turn affect vocal and social ontogeny as well as reproductive success.

Developmental origins of sociality in brown-headed cowbirds (Molothrus ater)

Five variables were studied relating to the emergence of sociality in hand-reared cowbirds (Molothrus ater): proximity, sex assortment, reactions to adults, head-down displays, and vocalizations. The authors were especially interested in female sociality because adult female birds influence male courtship, song content, and use through proximity, attention, and displays. The authors found that young female birds failed to show same-sex affiliation typical of the species at any point in the study. Brief introduction of adults did not affect social patterns. Adults used more head-down displays than juveniles, who used more displays with familiar peers. Directed and undirected singing emerged concurrently; directed singing was positively correlated with earlier hatching. This is the first demonstration of the need for early learning in the development of female sociality.

Effects of familiar contingencies on infants' vocal behavior in new communicative contexts

Recently, there has been a growing interest in understanding the mechanisms underlying vocal learning in songbirds and human infants. Research has demonstrated how contingent social feedback from social partners to immature vocalizations can play a role during vocal learning in both brown-headed cowbirds and prelinguistic infants. Contingencies in social interactions, particularly familiar contingencies, are important in developing preferences for social partners and shaping social exchanges Bigelow and Birch [1999]. Infant Behavior & Development 22:367-382]; however, little is known about how familiar contingencies that individuals experience during communicative exchanges play a role in new contexts. The current study examined differences in caregiver response patterns to infant vocal behavior and assessed how familiar contingencies influenced infant vocal behavior in novel communicative exchanges with caregivers. Infants were systematically exposed to high and low social feedback schedules during a play session. Results revealed the frequency of caregiver responsiveness to which infants were accustomed to affected infant vocal production during novel communicative situations. Infants with high responding caregivers vocalized with more mature vocalizations and used their vocalizations differently than infants with low responding caregivers during the high, but not low, response period. Specifically, infants with high responding caregivers directed more of their vocalizations at their caregiver and looked more at their caregiver after vocalizing, an indication of anticipating contingent responding. These results suggest that infants with high responding caregivers learned the association between vocalizing and contingent responses during the novel communicative interaction. This study demonstrates the need to understand how infants who experience a variety of contingencies in everyday interactions with caregivers carry over to other interactive situations.

Vocational Rehabilitation Service Patterns: An Application of Social Network Analysis to Examine Employment Outcomes of Transition-Age Individuals With Autism:

Young adults with autism spectrum disorder (ASD) face poor employment outcomes following transition from school to adult life. Social network analysis is a useful approach for examining service patterns associated with employment success for this population. An advantage of this approach is its focus on the interdependence of variables rather than individual predictors. This study applies network methodology to examine the relations between vocational rehabilitation services and young adults with ASD to predict employment status. Using the Rehabilitation Services Administration (RSA-911) data set, participants included 2,219 individuals with ASD between the ages of 16 and 24 served by the public vocational rehabilitation system and closed as either competitively employed or not employed. A two-mode network was constructed such that a relation was defined for each service an individual received. Results from a core-periphery analysis indicated that of the 22 services available, core services included assessment, counseling/guidance, job placement, on-the-job support, job search support, and transportation services. Follow-up analyses suggested that the greater number of these six core services an individual received, the better the employment outcome. Findings highlight that these services should be viewed as interconnected and suggest a set of six core services that may be particularly beneficial for this population.

Toys that squeak: Toy type impacts quality and quantity of parent–child interactions

Given the dependent nature of parent–infant interactions necessary for language development, it is important to understand how context may influence these interactions. This study examines how contextual variables influence communicative, cognitive and social measures of parent–infant interactions. Specifically, how do feedback toys and traditional toys associate with important parent and child measures necessary for learning and development? Here we report evidence that toy type is associated with quality and quantity of parent–child interactions. Condition 1 examined parent–child interactions during two separate play sessions; one contained feedback toys and the other contained traditional toys. Condition 2 combined the toys so dyads had access to both types at the same time. Infants produced higher levels of directed vocalizations and directed gestures, but had shorter durations of sustained attention, when interacting with traditional toys compared to feedback toys. Parents responded more to infants’ vocalizations and gestures when interacting with traditional toys. In general, these results suggest that toy properties can play a significant role in parent–infant interactions.

Principles for educational game development for young children

Abstract The use of media devices such as tablets is increasing with 41% of children engaged in more than two hours of screen time per day. The number of educational games has also significantly increased but little has been to done to assess the effectiveness and validity. Given the increase in access and use of devices, and increased popularity of educational games, a set of principles is needed. We present guiding principles that are useful for the design and development of educational games for children, under 5 years. We provide evidence from child development research findings that games should: (1) be developmentally appropriate content; (2) integrate the theoretical frameworks from the learning science field; (3) embed learning in socially rich contexts; (4) develop diverse content; and (5) create a balance between play and real-world learning opportunities. We build the principles around a hypothetical educational game designed to facilitate language development.

The evolution of the stimulus control of constricting behaviour: inferences from North American gartersnakes (Thamnophis)

Behavioural traits that have evolved relatively recently can provide unique insights into the nature of early evolutionary stages and the adaptive significance of such traits. We used this “recent origins” approach by examining the stimulus control of constricting behaviour in Western Terrestrial Gartersnakes (Thamnophis elegans), a species in which constriction evolved within the last several million years. Using mice and frogs as prey, we tested the hypothesis that prey struggling is a key stimulus eliciting constriction. Mean prey struggling intensity was significantly higher for mice than for frogs, and the snakes often constricted mice but rarely constricted frogs. Furthermore, for each prey type separately, the likelihood of constriction increased with increased prey struggling, while relative prey size was held constant. The context-dependent nature of constriction in T. elegans supports the notion that, as these snakes began feeding substantially on rodents, constricting behaviour was selected specifically to subdue these vigorously struggling prey. Thus, in this early evolutionary stage, prey struggling appears to be both a proximate cue and a selective factor promoting the spread of constricting behaviour. In some snake species representing more ancient origins of constriction, the behaviour is elicited by pre-strike cues that appear to be correlated with struggling ability. Therefore, if the behaviour of T. elegans is taken as a proxy for an early evolutionary stage of constriction in general, we can infer an evolutionary shift in the stimulus control of the behaviour. Our results suggest a general conceptual model for the sequence of evolutionary changes in the stimulus control of behaviour in which the critical cue changes from the actual object/event for which a response is beneficial to some feature correlated with that object/event.