Laura-Ann Petitto | |
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Born | New York City, New York, United States |
Education | Ramapo College, New York University, Harvard University |
Awards | Guggenheim Fellowship (1998) |
Scientific career | |
Institutions | Harvard University, McGill University, Dartmouth College, University of Toronto, Gallaudet University |
Laura-Ann Petitto (born c. 1954) is a cognitive neuroscientist and a developmental cognitive neuroscientist known for her research and scientific discoveries involving the language capacity of chimpanzees, [1] [2] [3] [4] [5] the biological bases of language in humans, especially early language acquisition (be it language on the hands in signed languages or on the tongue in spoken languages), [6] [7] [8] early reading, [9] [10] and bilingualism, bilingual reading, and the bilingual brain. [11] [12] [13] [14] [15] Significant scientific discoveries include the existence of linguistic babbling on the hands of deaf babies (“manual babbling”) [16] [17] [18] and the equivalent neural processing of signed and spoken languages in the human brain. [19] [20] She is recognized for her contributions to the creation of the new scientific discipline, called educational neuroscience. [21] [22] Petitto chaired a new undergraduate department at Dartmouth College, called "Educational Neuroscience and Human Development" (2002-2007), and was a Co-Principal Investigator in the National Science Foundation and Dartmouth's Science of Learning Center, called the "Center for Cognitive and Educational Neuroscience" (2004-2007). [23] At Gallaudet University (2011–present), Petitto led a team in the creation of the first PhD in Educational Neuroscience program in the United States. [24] Petitto is the Co-Principal Investigator as well as Science Director of the National Science Foundation and Gallaudet University’s Science of Learning Center, called the "Visual Language and Visual Learning Center (VL2)". [25] Petitto is also founder and Scientific Director of the Brain and Language Laboratory for Neuroimaging (“BL2”) at Gallaudet University. [26] [27] [28]
Petitto received her Bachelor of Science degree in 1975 from Ramapo College of New Jersey while taking undergraduate classes and conducting cross-species language research with the chimpanzee "Nim Chimpsky" at Columbia University (New York City, New York). [29] [1] Petitto then conducted psycholinguistic research on American Sign Language (ASL) in the laboratory of Ursula Bellugi at The Salk Institute for Biological Studies (La Jolla, California), [30] along with Linguist, Edward Klima, of the University of California, San Diego (UCSD), where Petitto began graduate study in the Department of Linguistics (1976–1977). Petitto continued graduate study at New York University (Master's degree, 1978, specializing in Rehabilitative Counseling Psychology and Deafness, 1977–1978). Petitto then researched the phonological structure of ASL in "The Linguistics Research Laboratory" of William Stokoe at Gallaudet University in Washington, D.C. (1978–1979). In 1979, Petitto began graduate study at Harvard University, Department of Human Development and Psychology, in its "Language & Cognition" track. While Roger Brown (primary Graduate Advisor) [8] and Courtney Cazden (co-Advisor) were Petitto's mentors in "Cognition," Noam Chomsky at MIT was Petitto's mentor in "Language." Petitto first met the renowned Linguist when working with Nim Chimpsky on Project Nim in the mid 1970s and this intellectual mentorship endured throughout her Harvard graduate studies and for decades to follow. [6] Petitto was graduated from Harvard with a master's degree in 1981, and a Doctorate/Ed.D. in March, 1984. Leaving Harvard in fall 1983 to take up her first faculty appointment in McGill University's Department of Psychology (Montreal, Quebec, Canada), Petitto also won a John D. and Catherine T. MacArthur Foundation Postdoctoral Fellowship (awarded to 10 young scientists in the USA). Commuting between McGill and Salk in her first few faculty years, Petitto studied with Ursula Bellugi and Francis Crick (Salk), and Elizabeth Bates (UCSD), intellectual mentorships that would span decades thereafter. Petitto's McGill psychology department role expanded when she also became a research scientist at the Montreal Neurological Institute and Hospital, and a collaborating scientist on The McDonnell-Pew Centre Grant in Cognitive Neuroscience with Brenda Milner, Michael Petrides (PIs), as well as with Robert Zatorre (1990-2001). [31] [32]
Petitto's research and discoveries span several scientific disciplines. Her early work with Nim Chimpsky and her later work with humans, encompasses anthropology, comparative ethology, evolutionary biology, cognitive neuroscience, cognitive science, theoretical linguistics, philosophy, psychology, psycholinguistics, language acquisition, child development, evolutionary psychology, American Sign Language, deaf studies, and bilingualism. Her overall discoveries involve:
Advancement of New Discipline: Petitto had an early role in the creation of a new scientific discipline with her colleague and husband Kevin Niall Dunbar, which they termed Educational Neuroscience. [22] Educational Neuroscience is a sister discipline of Cognitive Neuroscience, in which basic neuroscience and behavioral science discoveries about the developing brain and the growing child are joined with their translational implications, towards the ultimate goal of solving core problems in society and the education of young children. [21] [22]
Advancement of Technology: Petitto's science shows a history of pushing technology in new directions so as to answer previously insoluble questions in science, involving, for example, novel use of Positron Emission Technology (PET) with anatomical Magnetic Resonance Imaging (MRI) so as to identify the brain tissue and systems underlying human signed languages as compared with the tissue/systems underlying spoken languages; [19] OPTOTRAK (high-speed kinetics and dynamic motion capture system) to build a device analogous to a speech spectrogram but for signed languages so as to study the fundamental frequency (fo or FF) of deaf and hearing infants’ linguistic manual babbling; [16] [17] and functional Magnetic Resonance Imaging (fMRI) neuroimaging to conduct original studies comparing bilingual and monolingual adult brains. [12] To surmount the discipline's widely known challenges of studying developing newborn brains over time with fMRI, Petitto used functional Near Infrared Spectroscopy (fNIRS) neuroimaging to conduct among the first studies of human infant brains as they develop over time while acquiring one versus two languages (monolingual and bilingual infant brains compared). [35] [36] Petitto uses Eye-Tracking; [37] and, with a team of collaborating scientists, Petitto led a research team to advance and integrate novel technology involving a Robot, an Avatar, Thermal Infrared Imaging plus fNIRS, with Eye-Tracking, and Kinect to build an artificial agent + human infant language learning tool (called RAVE) capable of socially-contingent and socially interactive communications with an infant when it is most engaged and "ready to learn." [38] [39] [40] [41]
Taken together, Petitto's research discoveries and scientific writings have offered testable hypotheses and theory regarding the neural basis for the brain's specialization for human language, the types of language features a child must minimally be exposed to (and when) in early life (sensitive or critical periods), what happens if early critical periods are missed, and how best to facilitate optimal language learning in all children acquiring all human languages be they signed or spoken. [42] [6] [7]
Beginning in 1973 in the Department of Psychology at Columbia University, Petitto attempted to teach signed language to a baby chimpanzee ("Project Nim Chimpsky," named after Noam Chomsky, with Professors Herbert Terrace and Thomas Bever). Petitto had a leading role on Project Nim Chimpsky as the "Primary Sign Language Teacher", "Project Coordinator", and primary "Surrogate Mother". [1] Despite the dangers of living with a chimpanzee, Petitto lived with and cared for Nim as a child in an attempt to create a natural language, cognitive, and highly caring and rich social environment, mirroring that of a human child. Most of the chimp's scientific training and accomplishments were achieved during Petitto's 4-year tenure on the Project as Nim's teacher and caretaker. [29] She and her colleagues have authored several of the world's seminal scientific papers on the question of language in chimpanzees, including now classic articles on the similarities and differences between the ape and human mind. [2] [3] [4] [5]
After her undergraduate work with Nim Chimpsky, Petitto went on to make discoveries about the linguistic structure, acquisition, and representation in the brain of the world's natural signed languages, especially American Sign Language (ASL). Using signed languages as a new "microscope" to discover the central/universal properties of human language in the brain (those that are distinct from the modality of language transmission and reception), Petitto focused on the following lines of research:
Petitto's research has contributed to the body of knowledge establishing that the signed languages of deaf people around the world are real languages with the full expressive capacity as spoken languages. [52] Petitto and colleagues were also the first to study experimentally the validity of a widely used educational practice with Deaf children in the 1970s, whereupon teachers (typically hearing) used parts of ASL signs and linguistic structure simultaneously while speaking English in the classroom, called "Simultaneous Communication" (or "Simcom"). The Petitto team's experimental study of Simcom with Deaf children demonstrated empirically that it was highly impoverished at representing either ASL or English, and, in turn, it was a non-optimal teaching method. Instead their work supported the use of a natural signed language with Deaf children from early life such as ASL, which would best provide a solid linguistic foundation upon which to learn other languages (such as English). They advanced the idea that Deaf Education would be best to move to a full Bilingual and Bicultural educational model, and that this course was most commensurate with the biological requirements in human brain development to achieve the most healthy language learning. This research had lasting implications for subsequent Deaf Education policy and practice. [53]
Petitto's more recent studies involve the use of a combination of four disciplines:
Since 2000, Petitto's cognitive neuroscience/educational neuroscience research program has continued. Petitto and her laboratory team are known for discovering that young bilingual children are not harmed, delayed, or confused by early dual language exposure. These children not only achieve their language milestones (in each language) on the same timetable as monolinguals, [11] [13] [56] they demonstrate the same semantic and conceptual development as monolinguals, with societal implications that early-life (rather than later) bilingual and multilingual language exposure is optimal for language and reading success. [45] [57] Petitto and her team have also identified the mechanisms that make possible the human infant's early capacity to phonetically discriminate (segment and categorize) the constantly varying linguistic stream around them, and they have articulated the developmental conditions required for this capacity to grow most vibrantly in all children. [33] [58] [34] [42] Petitto and team have identified fundamental processes that underlie human reading and spelling in all language users [59] and found evidence for select reading advantages in young bilingual children as compared to matched monolingual peers, termed the "bilingual reading advantage". [14] They have further discovered surprising ways in which bilingual schooling can ameliorate the deleterious effects of low SES. [14] They are also among the first group of researchers to compare directly adult bilingual and monolingual brains [60] [12] [15] and what happens when the adult brain learns two artificial languages as a second language. [61] She has conducted studies of how extensive training (expertise) in one domain of knowledge impacts or "transfers" to other domains of knowledge (and the extent of this transfer). Since 2014, Petitto (PI) and her team conduct behavioral, brain, and Artificial Intelligence (Robot, Avatar, Thermal Infrared Imaging) studies specifically to advance understanding of the human learning capacity across the lifespan, and especially the optimal conditions for language learning in young deaf and hearing children acquiring signed and spoken languages.
Petitto is the recipient of over twenty international prizes and awards including,
Language acquisition is the process by which humans acquire the capacity to perceive and comprehend language. In other words, it is how human beings gain the ability to be aware of language, to understand it, and to produce and use words and sentences to communicate.
Neam "Nim" Chimpsky was a chimpanzee and the subject of an extended study of animal language acquisition at Columbia University. The project was led by Herbert S. Terrace with the linguistic analysis headed up by psycholinguist Thomas Bever. Within the context of a scientific study, Chimpsky was named as a pun on linguist Noam Chomsky, who posits that humans are "wired" to develop language.
Babbling is a stage in child development and a state in language acquisition during which an infant appears to be experimenting with uttering articulate sounds, but does not yet produce any recognizable words. Babbling begins shortly after birth and progresses through several stages as the infant's repertoire of sounds expands and vocalizations become more speech-like. Infants typically begin to produce recognizable words when they are around 12 months of age, though babbling may continue for some time afterward.
Research into great ape language has involved teaching chimpanzees, bonobos, gorillas and orangutans to communicate with humans and each other using sign language, physical tokens, lexigrams, and imitative human speech. Some primatologists argue that the use of these communication methods indicate primate "language" ability, though this depends on one's definition of language. The cognitive tradeoff hypothesis suggests that human language skills evolved at the expense of the short-term and working memory capabilities observed in other hominids.
Cognitive development is a field of study in neuroscience and psychology focusing on a child's development in terms of information processing, conceptual resources, perceptual skill, language learning, and other aspects of the developed adult brain and cognitive psychology. Qualitative differences between how a child processes their waking experience and how an adult processes their waking experience are acknowledged. Cognitive development is defined as the emergence of the ability to consciously cognize, understand, and articulate their understanding in adult terms. Cognitive development is how a person perceives, thinks, and gains understanding of their world through the relations of genetic and learning factors. There are four stages to cognitive information development. They are, reasoning, intelligence, language, and memory. These stages start when the baby is about 18 months old, they play with toys, listen to their parents speak, they watch TV, anything that catches their attention helps build their cognitive development.
Language development in humans is a process which starts early in life. Infants start without knowing a language, yet by 10 months, babies can distinguish speech sounds and engage in babbling. Some research has shown that the earliest learning begins in utero when the fetus starts to recognize the sounds and speech patterns of its mother's voice and differentiate them from other sounds after birth.
Ellen Bialystok, OC, FRSC is a Canadian psychologist and professor. She carries the rank of Distinguished Research Professor at York University in Toronto, Ontario where she is director of the Lifespan Cognition and Development Lab. She is also an associate scientist at the Rotman Research Institute of the Baycrest Centre for Geriatric Care.
Bimodal bilingualism is an individual or community's bilingual competency in at least one oral language and at least one sign language, which utilize two different modalities. An oral language consists of a vocal-aural modality versus a signed language which consists of a visual-spatial modality. A substantial number of bimodal bilinguals are children of deaf adults (CODA) or other hearing people who learn sign language for various reasons. Deaf people as a group have their own sign language(s) and culture that is referred to as Deaf, but invariably live within a larger hearing culture with its own oral language. Thus, "most deaf people are bilingual to some extent in [an oral] language in some form". In discussions of multilingualism in the United States, bimodal bilingualism and bimodal bilinguals have often not been mentioned or even considered. This is in part because American Sign Language, the predominant sign language used in the U.S., only began to be acknowledged as a natural language in the 1960s. However, bimodal bilinguals share many of the same traits as traditional bilinguals, as well as differing in some interesting ways, due to the unique characteristics of the Deaf community. Bimodal bilinguals also experience similar neurological benefits as do unimodal bilinguals, with significantly increased grey matter in various brain areas and evidence of increased plasticity as well as neuroprotective advantages that can help slow or even prevent the onset of age-related cognitive diseases, such as Alzheimer's and dementia.
Bilingual–Bicultural or Bi-Bi deaf education programs use sign language as the native, or first, language of Deaf children. In the United States, for example, Bi-Bi proponents state that American Sign Language (ASL) should be the natural first language for deaf children in the United States, although the majority of deaf and hard of hearing being born to hearing parents. In this same vein, the spoken or written language used by the majority of the population is viewed as a secondary language to be acquired either after or at the same time as the native language.
The critical period hypothesis or sensitive period hypothesis claims that there is an ideal time window of brain development to acquire language in a linguistically rich environment, after which further language acquisition becomes much more difficult and effortful. It is the subject of a long-standing debate in linguistics and language acquisition over the extent to which the ability to acquire language is biologically linked to developmental stages of the brain. The critical period hypothesis was first proposed by Montreal neurologist Wilder Penfield and co-author Lamar Roberts in their 1959 book Speech and Brain Mechanisms, and was popularized by Eric Lenneberg in 1967 with Biological Foundations of Language.
Developmental linguistics is the study of the development of linguistic ability in an individual, particularly the acquisition of language in childhood. It involves research into the different stages in language acquisition, language retention, and language loss in both first and second languages, in addition to the area of bilingualism. Before infants can speak, the neural circuits in their brains are constantly being influenced by exposure to language. Developmental linguistics supports the idea that linguistic analysis is not timeless, as claimed in other approaches, but time-sensitive, and is not autonomous – social-communicative as well as bio-neurological aspects have to be taken into account in determining the causes of linguistic developments.
Patricia Katherine Kuhl is a Professor of Speech and Hearing Sciences and co-director of the Institute for Learning & Brain Sciences at the University of Washington. She specializes in language acquisition and the neural bases of language, and she has also conducted research on language development in autism and computer speech recognition. Kuhl currently serves as an associate editor for the journals Journal of the Acoustical Society of America, Neuroscience, and Developmental Science.
Neuroscience of multilingualism is the study of multilingualism within the field of neurology. These studies include the representation of different language systems in the brain, the effects of multilingualism on the brain's structural plasticity, aphasia in multilingual individuals, and bimodal bilinguals. Neurological studies of multilingualism are carried out with functional neuroimaging, electrophysiology, and through observation of people who have suffered brain damage.
John L. Locke is an American biolinguist who has contributed to the understanding of language development and the evolution of language. His work has focused on how language emerges in the social context of interaction between infants, children and caregivers, how speech and language disorders can shed light on the normal developmental process and vice versa, how brain and cognitive science can help illuminate language capability and learning, and on how the special life history of humans offers perspectives on why humans are so much more intensely social and vocally communicative than their primate relatives. In recent time he has authored widely accessible volumes designed for the general public on the nature of human communication and its origins.
Prelingual deafness refers to deafness that occurs before learning speech or language. Speech and language typically begin to develop very early with infants saying their first words by age one. Therefore, prelingual deafness is considered to occur before the age of one, where a baby is either born deaf or loses hearing before the age of one. This hearing loss may occur for a variety of reasons and impacts cognitive, social, and language development.
Manual babbling is a linguistic phenomenon that has been observed in deaf children and hearing children born to deaf parents who have been exposed to sign language. Manual babbles are characterized by repetitive movements that are confined to a limited area in front of the body similar to the sign-phonetic space used in sign languages. In their 1991 paper, Pettito and Marentette concluded that between 40% and 70% of deaf children's manual activity can be classified as manual babbling, whereas manual babbling accounts for less than 10% of hearing children’s manual activity. Manual Babbling appears in both deaf and hearing children learning American Sign Language from 6 to 14 months old.
Language acquisition is a natural process in which infants and children develop proficiency in the first language or languages that they are exposed to. The process of language acquisition is varied among deaf children. Deaf children born to deaf parents are typically exposed to a sign language at birth and their language acquisition follows a typical developmental timeline. However, at least 90% of deaf children are born to hearing parents who use a spoken language at home. Hearing loss prevents many deaf children from hearing spoken language to the degree necessary for language acquisition. For many deaf children, language acquisition is delayed until the time that they are exposed to a sign language or until they begin using amplification devices such as hearing aids or cochlear implants. Deaf children who experience delayed language acquisition, sometimes called language deprivation, are at risk for lower language and cognitive outcomes. However, profoundly deaf children who receive cochlear implants and auditory habilitation early in life often achieve expressive and receptive language skills within the norms of their hearing peers; age at implantation is strongly and positively correlated with speech recognition ability. Early access to language through signed language or technology have both been shown to prepare children who are deaf to achieve fluency in literacy skills.
Language deprivation in deaf and hard-of-hearing children is a delay in language development that occurs when sufficient exposure to language, spoken or signed, is not provided in the first few years of a deaf or hard of hearing child's life, often called the critical or sensitive period. Early intervention, parental involvement, and other resources all work to prevent language deprivation. Children who experience limited access to language—spoken or signed—may not develop the necessary skills to successfully assimilate into the academic learning environment. There are various educational approaches for teaching deaf and hard of hearing individuals. Decisions about language instruction is dependent upon a number of factors including extent of hearing loss, availability of programs, and family dynamics.
Language exposure for children is the act of making language readily available and accessible during the critical period for language acquisition. Deaf and hard of hearing children, when compared to their hearing peers, tend to face more hardships when it comes to ensuring that they will receive accessible language during their formative years. Therefore, deaf and hard of hearing children are more likely to have language deprivation which causes cognitive delays. Early exposure to language enables the brain to fully develop cognitive and linguistic skills as well as language fluency and comprehension later in life. Hearing parents of deaf and hard of hearing children face unique barriers when it comes to providing language exposure for their children. Yet, there is a lot of research, advice, and services available to those parents of deaf and hard of hearing children who may not know how to start in providing language.
Karen Denise Emmorey is a linguist and cognitive neuroscientist known for her research on the neuroscience of sign language and what sign languages reveal about the brain and human languages more generally. Emmorey holds the position of Distinguished Professor in the School of Speech, Language, and Hearing Sciences at San Diego State University, where she directs the Laboratory for Language and Cognitive Neuroscience and the Center for Clinical and Cognitive Neuroscience.