Meredith J. West - US grants

In my avian development work, we plan to explore whether females at the subspecies border influence male song development in different ways than nonborder populations by playing back song and by looking at female modifiability. We hope to discover the basis of the differences found between these two populations within the same subspecies. We are also studying male song perception by housing males with females with known song preferences and by housing males in groups to determine how such social influences affect repertoire development. In my infant vocal development work, we are investigating the infant's comprehension of infant vocal signals; in particular, vocal signals that are considered precursors to formal language (e.g., sounds that indicate requests, protests, deixis, emotional states, or early attempts at naming. Infants ranging in age from 6 - 18 months are used. In the first part, we have adopted Spelke's procedure to expose infants to two videotapes side-by-side in front of the infants at the same time as a soundtrack appropriate to only one of the videotapes is played back through a speaker in between the two monitors. We will investigate contrasts such as an infant pointing versus waving his arms as a deictic versus happy gesture. The dependent variables are latency and duration of looking to the tapes, synchrony of looking with the periodic onset of sounds that are matched to the infant's mouth movements, and infant vocalizations. The second part involves making high quality video and audio tapes of infants in the laboratory performing different tasks such as playing, fussing, exploring and interacting with familiar and unfamiliar people. We are especially curious to see how the ability to perceive communicative contrasts based on sound correlates with the ability to produce the vocal sounds themselves.

Major discoveries about how birds learn to sing have brought to light remarkable parallels with how human beings learn to speak. Just as human beings learn to speak the language that is spoken around them, many species of birds learn to sing the song that is sung by their neighbors. Just as human speech develops from infant babbling, bird song develops from simpler vocalizations of young birds. Drs. West and King have discovered that this development of song by male cowbirds is guided by visual signals from female cowbirds, just as signals from other people guide the development of speech by the human child. This important discovery of social shaping of vocal repertoires is the basis for the current research project, which will explore linkages between female perception and male vocal production in the development of avian communicative capacities. The species chosen for study, the brown-headed cowbird, is especially appropriate because it can be bred in captivity, affording the opportunity to study the development of individuals with known communicative histories. This research should lead to the delineation of new forms of non- imitative vocal learning, the elucidation of how reward mechanisms function in a naturally-occurring form of cultural transmission, and the investigation of how the visual system operates at behavioral and neural levels to affect vocal development.

Abstract (IBN 9423593) West, Meredith Experimental evidence has shown that many animal species show natal populational preferences with respect to reproductive patterns. In the present research, an avian model of cultural evolution is used to explore how social learning may be implicated in such reproductive patterns. Different populations of subjects are exposed for extensive periods to distinctive social populations prior to their breeding seasons. The reproductive preferences are then tested. Measurements are made of the proximate dynamics of the development of individuals' preferences. In addition, the behaviors by which individuals communicate reproductive preferences, in particular, the use of vocalizations and responses to vocalizations, are measured. Preliminary results confirm that social learning exerts direct effects on the transmission of reproductive preferences. The proposed studies explore in more depth the nature of the learning mechanisms and test whether learned preferences can be passed on to subsequent generations of individuals. If such cultural, transgenerational transmission occurs, current theories and concepts of the role of genetic programs in guiding and determining reproductive outcomes will have to re-evaluated. New theories will have to incorporate the exogenetic or cultural mechanisms deriving from models of social learning. In that human societies show analogous dependence on cultural transmission, the results of these studies will provide a new and more ecologically appropriate model of the evolution of complex behavior.

9722865 West/King The aim of the proposed research is to explore the role of different kinds of sensory experience on the ontogeny of avian communication, with a focus on reproductive skills and underlying neuroanatomical structures. Three objectives are outlined, using an avian model. First, the influence of adult stimulation on juvenile learners will be examined in a series of longitudinal studies. Measures of the effects of experience include vocal growth, vocal imitation, use of vocal signals, visual attention, and reproductive skills. Second, characteristics of female perception will be studied with special emphasis on modifiability of female mating preferences. New evidence suggests contextual influences on female preferences. Measures of preference include female responsiveness to auditory playback and female discrimination of potential mates. Finally, neural studies of the avian forebrain are planned to exploit new findings on females' use of song nuclei and males' use of a visual thalamic nucleus. The results of the proposed work should advance knowledge of the nature of developmental organization of vocal and perceptual learning and the integration of behavioral and neural plasticity. Finally, the neural analyses should broaden our understanding of the role of forebrain structures by revealing interdependencies between patterns of neural growth and availability of relevant ecological experience.

NON-TECHNICAL ABSTRACT Proposal Number: 9809883 Experiential Influences on Perceptual, Communicative, and Neural Capacities Meredith J., King, Andrew P. The aim of the research is to explore the effects of differences in social experience on the development of vocal communication through studies of song learning in birds. Three objectives are outlined. First, the influence of adult social models on juvenile learners will be examined by manipulating the nature of adult stimulation. Measures of the effects of social influence include vocal growth in the young, use of signals, and competence as adults. Second, female perceptual preferences for vocal signals will be studied to explore modifiability in receivers. Measures include responsiveness to vocal playback and discrimination of potential mates. Neural studies of the avian forebrain are included to relate brain organization to vocal comprehension in females and to social competence in males. The results of the work should advance knowledge of the effects of early social environments on vocal and perceptual learning, learning that is fundamental to an individual's success. This topic has broad implications for many species, including humans, as avian vocal learning is one of the premier models for identifying potential mechanisms of language learning. Of special significance is the possibility of identifying previously ignored sources of instruction including visual stimulation. The coordinated studies of brain and behavior also set the stage for measuring how behavioral experiences affect brain growth itself.

Meredith J. West: The role of social organization on development and learning

Lay abstract

The aim of the proposed research is to explore the effects of social organization on avian learning and to find developmental principles to guide research on vocal communication in other groups, including humans. Of special interest is how animals, when living in an information-rich environment, selectively attend, interact, and learn from other members of their species. Given that they do not or cannot learn equally from all individuals, what rules guide access and attention to social information?

Interest in the origins and nature of social organization stems from an interest in expanding the study of learning and development toward ecological concerns. It is proposed that much species-typical knowledge is delivered via social networks, social groups in which older organisms or peers facilitate or constrain exposure to information. The idea of networks has been bypassed in most laboratory research on learning because generally the animals are simply exposed to stimulation delivered with minimal species-typical context.

To study socially guided learning, higher-level patterns of social organization are to be investigated. These are patterns that result from flock dynamics, yielding different developmental effects for mature and immature males and females. To explore about such effects, birds are studied throughout the year in large aviaries in which the composition of groups is periodically altered and the effects measured. Social and vocal behavior is recorded, mate choice tests employed, and eggs collected and incubated to measure production, fertility, and viability. In addition, blood will be taken for DNA analyses. These procedures afford the chance to explore adaptive effects on communicative competence as a function of opportunities for social learning. The work is focused on questions regarding causation and function. First, are there simple rules to guide social assortment, and how does social organization affect learning? Second, how do specific behavioral traits, beyond age or sex, affect formation of groups and how do such groups affect developmental trajectories of individuals?

The proposed work has far-reaching implications for understanding complex communication systems, including the human communication system. In recently completed work with human parents and their infants, hypotheses were tested by us about prelinguistic vocal plasticity based on avian models of social learning. It was found that infant babbling could be socially shaped by parental responses. Parents did not vocally imitate infants' sounds, thus ruling out vocal matching as a mechanism. These are the first data to show such a relationship and they challenge long standing but untested ideas about the innate nature of early speech development. Thus, the proposed avian studies provide a new set of heuristic principles with which to formulate research questions on ecological approaches to vocal learning in many animals, as well as related phenomena such as human prelinguistic development.

DESCRIPTION (provided by applicant): The goal of this proposal is to develop network methodology to identify specific patterns of communicative interaction that predict Autism Spectrum Disorders (ASD) around a child's first birthday. At present it is difficult to diagnose ASD reliably prior to the age of two and yet parental assessment of infant communicative behavior shows promise in predicting ASD around the age of one year. Thus, there is a need to go beyond parental judgment to identify the specific communicative interactions that predict the diagnosis of ASD. In typically-developing (TD) infants, communicative development (e. g., vocal, gestural, attentive) is influenced by contingent dyadic interactions with their caregivers. These are the same communicative behaviors that are deficient in children with an ASD disorder. Thus, the sequencing of contingent dyadic interactions in children at risk for ASD could be a sensitive indicator of typical or atypical development. We propose to develop and test a new social network methodology based on the triadic census that can be used to identify the pattern of interactions (e.g., development of communicative behaviors like joint attention) that are predictive of the emergence of ASD. Triads are defined as directed interactions among up to three individuals or objects. We will use animal and a human model systems to test this new methodology. In both systems, there exist extensive data sets that can be used to develop and test the triad methodology as predictors of typical or atypical development. In the animal system, we can evaluate experimentally manipulated social groups, providing a means to describe the causal relationship between social interactions and the development of competent communicative behavior. In the human system we will use data currently being collected on infants at risk for ASD. In the human system, preliminary triadic analysis of infants at heightened biological risk for ASD revealed specific sequences of caregiver, infant and object interactions associated measures of comprehension at 14 months. PUBLIC HEALTH RELEVANCE: Relevance The purpose of this proposal is to development social network methodology to be used to detect typical and atypical communicative development in young infants. Both animal and human models will be studied. The goal is to develop a diagnostic tool with the ability to predict Autism Spectrum Disorder by the child's first birthday.

Within humans it is widely recognized that early differences in personality shape the development of behavior. For instance, extraverts commonly seek out interactions with unfamiliar individuals, while introverts consistently seek out interaction with fewer more familiar individuals. Thus, personality may shape an individual's behavioral development by exposing them to different social experiences from an early age. Recently there has been increasing awareness that like humans, animals also possess personality traits. The proposed research will investigate how variation in a personality trait, sociability, shapes behavioral development in Brown-headed Cowbirds (Molothrus ater). Cowbirds, like many other species, rely on social interaction in order to learn new skills and behaviors. Sociability describes an individual's tendency to seek out interaction with others. More sociable cowbirds will approach and interact with more individuals more often than less sociable cowbirds. Two studies will investigate if: 1) Variation in sociability predicts the development of adult like behavior in juvenile cowbirds, and 2) if early experience with more or less sociable adults shapes the development of juvenile personality traits. A new RFID based video system will be used in both studies to identify individuals and record their social behaviors over long periods of time. This system will allow measurement of the details of sociability and social behavior in a way that was unavailable to researchers before. Statistical time series models can be implemented to uncover how an individual's sociability reflects the development of new behaviors over the first year of life. In the second experiment, statistical time series models will be used to uncover if experience with more sociable adults can predict the emergence of adult-like behavior within a juvenile cowbirds' first year. These results will provide insights into how early personality differences shape the development of behavior by determining how individuals interact and learn from others.

Data will be stored and available at http://datadryad.org/