The Infant Sound Environment Project (ISEP) is a longitudinal study of the sound inputs to infants and the relationship of these inputs to the sound production of these same children as they emerge from infancy. While previous studies have often addressed the acquisition of words and grammar—how meaning and form emerge in the human mind—the present study will address a different aspect of this experience. The focus will be on the melodic and rhythmic elements of sound—both those encountered by the child, and those which the child eventually produces. These aspects in communicative behaviors such as language and music carry a fundamental level of emotion that has heretofore gone largely unexplored. Further their foregrounding in this study will permit us to explore patterning, imitation, and creativity, without prejudicing the linguistic context.
It is often posited that language is unique to our species, and that what it contributes to our being is nothing less than defining of our nature. The intent of this study is not directly to challenge this notion, but rather to put question to what fundamentally characterizes language in this vein. If language is the defining element of humanity, what is language? The answer to this question underlies all of this research. It is quite possible that the “what” that will emerge is not exclusive to the domain of language.
We will study the origins of sound comprehension and sound production in the individual, with particular attention paid to the rhythmic and melodic features of this sound. We will retain an interest in what this ontogenesis may have to say about the phylogenesis of these same qualities in the human species. Existing theories of the origins of human language, and of the uniqueness of the human animal with regards to language, have mostly focused on the higher level domain of words and grammar. By focusing on these lower-level elements of sound, we can begin to test the point at which our species’ uniqueness arises1.
The present attempt will begin with the data, rather than any presupposed theoretical framework, with a broad interest in sounds of all variety, without prejudicing language or any other behavior a priori. One key feature of the current project is its methodology. This is a painstaking effort to gather raw data that can be analyzed and dissected to yield fruitful information. No hypothesis is being tested. Rather the evidence is being gathered first, with an eye toward constructing a theory from this evidence. The basic research in this domain is yet to be done. This effort is an attempt to redress this failing.
While studies have been done both of the prenatal environment, and of the capacities for sound perception of neonates and young infants, no longitudinal study has yet been done to correlate the sound production of preschoolers with the sounds they have been exposed to earlier in life. It seems a reasonable assumption for example that young children will model the prosodic patterns that they have encountered. Yet so far this remains mostly an assumption. What can be empirically established regarding the relationship between the sound environment of infants and their own later sound productions? This study is intended to establish these relationships.
It is clear that infants (as the meaning of the word connotes) are born without speech. Their earliest indulgences with sound are described first as cries, then also as babbling. At what point does this babbling become intentional experimentation? What is the nature of this experimentation? If imitative, what is being imitated? These are some of the questions that we wish to elucidate. Previous studies have focused exclusively on the vocal output of the infants and children, or have considered the primarily linguistic utterances of parents and caregivers, described nowadays as infant-directed speech, but little work has been done to compare these facets, and what has been done presupposes an often ill-defined distinction between linguistic and nonlinguistic behaviors.
However, as noted by Trehub et al2, distinguishing language from other sounds is a non-trivial task for the infant. Put another way, until language has been acquired, the infant is tasked with making sense of a mass of meaningless sounds. Only by stipulating a hard-wired language module in the infant brain (for which at the moment there is scant empirical evidence) are we able to view their task as language acquisition. Yet language, to the infant, shares many features in common with nonlinguistic sounds in their environment.
Even to an adult, there remains overlap between musical and linguistic sound production. What are the features that distinguish language from other sound-producing behaviors? How does the infant come to understand these differences? To what extent are these features universal or culture-specific? Rather than beginning with the assumption that an infant’s task is to acquire language, perhaps we should seek to understand the child’s behavior in more general terms. If patterns emerge in the sound environment of infants, how do infants go about recognizing, understanding, and reproducing these patterns? Only a study that seeks to examine sound without presupposing the prominence of language will be capable of answering these questions.
The methodology we will adopt is based in a naturalistic approach. Rather than a laboratory setting that trades off naturalism for control in the environment, ISEP will collect data directly from the natural environment of the child. Daylong digital audio recordings will be made of the children within their natural home, play, and school contexts. The length of recordings will ensure a sufficient quantity of usable data, and will help mitigate against the self-consciousness of caregivers and others. These recordings will be captured at intervals of about once a month for the first two to three years of life.
Every effort will be made to maintain the confidentiality and privacy of the participants. However the data collected will have much broader application than the focus of this study, and thus we hope to make this data available to other researchers involved in complementary work. Similarly, it is likely that data collected for other projects, especially from diverse cultural contexts, will be useful for the present purpose. Thus efforts will be made to find outside collaborators for this project.
The question, which by some is supposed to have been settled in 1959 by the suppositions and arguments of Noam Chomsky regarding the unlearnability of many aspects of the linguistic system3, nonetheless remains: to what extent is language acquired from the environment; and to what extent is it innate? More broadly, what influence on a child’s cognitive development is directly played by the inputs to that child during maturation? Since the focus here in on the rhythmic and melodic aspects of sound, it is now possible to gather data which can be used to answer this question. Until recently, with the advent of long-term recordings of sound, this question has been constrained by the unreliability of report, or by extrapolations from limited data gathered in laboratories and elsewhere.
It is well-known that all normal children acquire the language(s) to which they are exposed, and no other. Little is known however about the acquisition of aspects of language and interactive behaviors beyond the domains of words and grammar, as for instance intonation, timing, stress. It has generally been supposed that language socialization (both socialization to learn language, and further socialization through language) is the dominant, even all-encompassing task of the prelinguistic infant. Additionally, it has been assumed that the principal or sole function of these behaviors has been communicative, while their possible role as part of the child’s mental construction of the world and oneself has mostly remained unconsidered.
The current study will dispose with any such prejudice, and suppose merely that sound exists in the environment in which an infant dwells; that this sound assuredly contains remarkable features in terms of its melodic and rhythmic content, and likely in other aspects such as timbre; that the infant’s brain is in some way predisposed by nature and biology to selectively attend to that sound4; and further that through some process, which is yet to be clearly understood, the child as it emerges from infancy begins to contribute its own sounds to that environment, which likely bear some resemblance to those it has experienced. The process by which the child’s own sound manipulations reflect natural dispositions or exhibit cultural or idiosyncratic features is little understood. The intent of the present study is to provide a means for measuring the impact of the sound environment of early life on the child’s own later productions of sound.
Surely, the patterning through time that rhythm presents can be found in a soundless environment as well. Other features, such as melody and timbre, may also be found to have silent correlates5. Later research should allow us to compare the normal development of hearing children to the cognitive, linguistic, and social development of the congenitally deaf in ways that have so far eluded comparison. Through the establishment of a baseline for development at the lower levels that will be exposed through this study, we will be able to more readily and more early identify certain deficits which may affect a child’s cognitive development and language acquisition.
Further, this study will permit us to uncover other elements in the maturation and socialization of the child through sound, which are extralinguistic, such as music acquisition. More broadly, by focusing not on the lexicon and syntax, but rather on melody, rhythm, and timbre, we will be able to discuss in finer-grained detail the child’s sound perception and production than has previously been the norm. In this way we will be able to see what features are shared among a variety of behaviors, without presuming their function and significance as linguistic or otherwise.