Cognitive Science Program

Natural language processing and acquisition

What I want to try to figure out is where human language comes from, especially as it develops over the long term in the language learner, but also as it emerges over the short term in the course of communicative acts. One very influential position is that we are all born with a significant component of language (or of the concepts that language is about) already in our brains, that all that is left is to figure out the details of the particular language or languages that we're being exposed to. This position is based on the premise that the environment provides the language learner with such an impoverished set of linguistic data that the only way a language could be learned is for much of it to already be there. Of course this position is only tenable if human languages can be shown to share a sizable set of properties, and much of the research within this framework has been dedicated to finding that set of properties and showing that they are already in place as language is acquired.

A competing position, which is growing in influence, is based on the premise that there is considerable regularity in the environment, including regularity in the things that language is about, regularity in the language input itself, and unconscious strategies on the part of adults and older children to make language accessible. In place of innate constraints on language, this view posits that learners have access to powerful, general-purpose statistical learning mechanisms, to sophisticated perceptual and motor control systems, and to a propensity for social interaction. The research within this framework has been dedicated to elaborating the capacities of statistical learning, especially algorithms inspired by nervous systems and to studying the nature and the effects on learning of particular kinds oof regularities in the environment.

From early on I have gravitated to the second framework because it seems to me the simpler, default position. It is already obvious from other work in cognitive science that humans are sophisticated statistical learners. If this capacity and other general-purpose ones suffice, then we could do without the innate knowledge of language proposed by the proponents of the other view. In addition, calling something innate leaves open the question of how that innate knowledge gets implemented in neural hardware and, perhaps more significantly for cognitive science, how it could be linked to experience. Finally, the research in the other paradigm just has not been convincing. The search for what is universal, and presumably innate, in languages has had to resort to such abstract constructs that it seems less and less likely that such things have anything to do with what people know about language, let alone with their innate "endowment".

The strategy, then, is to take a phenomenon, a relatively simple linguistic behavior, and attempt to show how a simple statistical learning device, given plausible input, could acquire it. This normally leads to failure, and the simple device gets augmented in ways that make it more powerful. But power comes not from building in the solution to the problem by providing the knowledge that is needed to solve it. Power comes from special-purpose learning mechanisms and from modularity, from components of the system which learn to specialize as they are exposed to input. My recent projects have looked at three separate areas of linguistic behavior from this perspective.

1. How do words and sentences mean what they mean? One fruitful approach to this question is to treat it from the perspective of the young child. For the child, language takes on significance as it is grounded in experience, in perception, action, and affective states. Two questions of interest in this project are:
   1. How do the visual system and spatial language interact in the learning of spatial concepts?
   2. How do simple perceptual inputs, along with particular linguistic tasks, lead to the orders of acquisition for different forms that are observed in children?
   A major collaborator on all of this has been former IU Cognitive Science PhD student Eliana Colunga. I have also worked increasingly closely with IU Psychological & Brain Sciences Professor Linda B. Smith.
2. How do children learn the internal structure of words, how words are composed out of constituent morphemes (morphology) and how the primitive sounds of a language combine with one another (phonology)? My earlier work focused on the kind of computational device that could achieve this learning. The outcome of this project was a neural-network architecture which could be trained to recognize and produce words which are representative of the kinds of morphological combination that occur in the world's languages. One contribution was the discovery that separate modules responsible for learning roots (the basic forms of words) and for learning inflections (the prefixes, suffixes, etc. that get attached to roots) improved performance for all types of morphological combination. An early collaborator on this project was IU Cognitive Science student Chan-do Lee, now on the faculty at Taejon University, South Korea.
3. How are music and language organized in terms of nested periodic beats, and how do people process this structure? Another earlier project was concerned with developing computational models which can track the rhythm of simple musical and linguistic patterns and learn to beat along. Collaborators included former Cognitive Science PhD student Douglas Eck, now at IDSIA in Switzerland, and IU Linguistics and Computer Science Professor Robert F. Port.

Author: Hockema, S. A.
Dissertation title: Perception as Prediction (April 2004)
Committee: Gasser, M. (Co-Chair), Smith, L. (Co-Chair), Goldstone, R., Port, R., Hummel, J.

Author: Luo, J.
Dissertation title: The Dynamics of Permanence (December 2004)
Committee: Gasser, M. E. (Co-Chair), Smith, L. B. (Co-Chair), Cutu, F., Spencer, J. P.

Author: Martinez, M.
Dissertation title: Commonsense Reasoning Via Product State Spaces (July 2004)
Committee: Moss, L. (Co-Chair), Gasser, M. (Co-Chair), Maki, D., McCarty, D.

Author:Bauer, T. L.
Dissertation title: Wordsieve: Context Analysis For Personal Informational Retrieval (May 2003)
Committee: Leake, D. (Chair), Bramley, R., Gasser, M., Mostafa, J.

Author: Desai, R.
Dissertation title: Modeling Interaction of Syntax and Semantics in Language Acquisition (December 2002)
Committee: Gasser, M. (Co-Chair), Goldstone, R. (Co-Chair), Port, R., Smith, L.

Author: Drake, P. D.
Dissertation title: The Origins of Number: A Computational Account (July 2002)
Committee: Gasser, M. (Co-Chair), Mix, K., Hanson, A. (Co-Chair), Busey, T.

Author: Sandhofter, C. M.
Dissertation title: Language Input And The Process of Learning Words: Evidence From Dimensional Adjectives (April 2002)
Committee: Smith, L. B. (Chair), Gasser, M. E., Jones, S. S., Mix, K. S.

Author: Rehling, J. A.
Dissertation title: Letter Spirit (Part Two): Modeling Creativity in A Visual Domain (July 2001)
Committee: Hofstadter, D. R. (Chair), Gasser, M., Goldstone, R., Port, R. F.

Author: Baray, C.
Dissertation title: Evolution of Coordination in Reactive Multi-Agent Systems (December 1999)
Committee: Mills, J. (Chair), Gasser, M., Rawlins, G., Timberlake, W.

Author: Samuelson, L. K.
Dissertation title: Statistical Regularities in Vocabulary Guide Language Acquisition In 15-20-Month-Olds And Connectionist Models (June 2000)
Committee: Smith, L. B. (Co-Chair), Jones, S., Gasser, M., Shiffrin, R. (Co-Chair)

Author: Wagner, K.
Dissertation title: Simulation Models of Evolution: Communication And Cooperation (August 2000)
Committee: Gasser, M. (Chair), Leake, D., Port, R., Timberlake, W.

Author: Erickson, M. A.
Dissertation title: Rules and Exemplar Representation in Category Learning (June 1999)
Committee:Kruschke, J. (Co-Chair), Shiffrin, R. (Co-Chair), Gasser, M., Port, R. F., Nosofsky, R. N.

Author: Scheutz, M.
Dissertation title: The Missing Link: Implementation And Realization of Communication in Computer And Cognitive Science (September 1999)
Committee: Smith, B. (Co-Chair), Gasser, M. (Co-Chair), Moss, L., Port, R.

Author: McGraw, G. E. Jr.
Dissertation title: Letter Spirit (Part One): Emergent High-Level Perception of Letters Using Fluid Concepts (September 1995)
Committee: Hofstadter, D. R. (Chair), Gasser, M. Goldstone, R., Port, R. F., Rawlins, G. J. E.

Author: Yu-Houng Houng
Dissertation title: Classicism, Connectionism, And the Concept of Level (May 1991)
Committee: Dunn, J. M. (Chair), Castaneda, H., Eisenberg, P., Cochiarella, N., Gasser, M., Gelder, T. V.

Author: Nichols, Eric
Dissertation title: Musicat: A Computer Model of Musical Listening And Analogy-Making (December 2012)
Committee: Hofstadter, D. (Chair), Isaacson, E., Byrd, D., Gasser, M.

Author:Schrementi, Giancarlo
Dissertation title: Language in the Balance: Factors in the Emergence of Compositional Communication (June 2011)
Committee: Gasser, M. (Co-Chair), Leake, D. (Co-Chair), Yaeger, L., Yu, C.

Author: Mahabal, Abhijit
Dissertation title: Seqsee: A Concept-Centered Architecture for Sequence Perception (March 2010)
Committee:Hofstadter, D. (Chair), Gasser, M., Goldstone, R., Leake, D.

Author: Rojas, David
Dissertation title: Features and Methods for Automatic Dialect Identification (May 2010)
Committee: de Jong, K. (Co-Chair), Paolillo, J. (Co-Chair), Kuebler, S., Gasser, M., Chen, Y.

Author: Goldberg, Joshua
Dissertation title: When, Not Where A Dynamical Field Theory of Infant Gaze (January 2009)
Committee: Gasser, M. (Co-Chair), Smith, L. (Co-Chair), Jones, S., Port, R., Schoner, G., Spencer, J.

Author: Lara-Dammer, Francisco
Dissertation title: Modeling Human Discoverativity in Geometry (December 2009)
Committee: Hofstadter, D. (Chair), Gasser, M., Leake, D., Moss, L., Port, R.

Author: Shayan, Shakila
Dissertation title:Emergence of Roles in English Canonical Transitive Construction (June 2008)
Committee:Gasser, M. (Co-Chair), Gershkoff-Stowe, L. (Co-Chair), Leake, D., Goldstone, R., Smith, L.

Author: Gokcesu, Bahriye S.
Dissertation title: Metaphor Processing and Polysemy (December 2007)
Committee: Goldstone, R. (Co-Chair), Gasser, M. (Co-Chair), Gershkoff-Stowe L., Jones, M.

Author: Riordan, Brian
Dissertation title: Comparing Semantic Space Models Using Child-directed Speech (March 2007)
Committee: Gasser, M. (Co-Chair), Jones, M. (Co-Chair), Kubler, S., Yu, C.

Author: Son, Ji Y.
Dissertation title: Forces of Contextualization and Decontextualization: A Look at Symbols, Experience, and Language (August 2007)
Committee: Goldstone, R. (Co-Chair), Smith, L (Co-Chair), Gasser, M., Yu, C.

Author: Zapf, Jennifer
Dissertation title: Comprehension production, and meaning: What the regular English plural can tell us about language (July 2007)
Committee: Smith, L. (Co-Chair), Jones, S., Gierut, J (Co-Chair)., Gasser, M.

Author: Foundalis, Harry E.
Dissertation title: Phaeaco: A Cognitive Architecture Inspired by Bongard’s Problems (May 2006)
Committee:Hofstadter, D. (Chair), Gasser, M., Goldstone, R., Leake, D.

Author: Laine, Tei
Dissertation title: Agent-Based Model Selection Framework For Complex Adaptive Systems (August 2006)
Committee:Menczer, F. (Chair), Gasser, M., Busemeyer, J., Janssen, M.

Author: Scherle, Ryan
Dissertation title: Looking for a Haystack: Selecting Data Sources in a Distributed Retrieval System (November 2006)
Committee: Leake, D. (Co-Chair), Gasser, M. (Co-Chair), Mostafa, J., Rawlins, G.

Author: Bradley, Samuel
Dissertation title: Exploring the Validity and Reliability of the Acoustic Startle Probe as a Measure of Attention and Motivation to Television Programming (August 2005)
Committee: Lang, A. (Chair), Bucy, E., Fox, Julia, Gasser, M., Potter, R.

Author: Paik, Jae H
Dissertation title: Fraction Concepts: A Complex System of Mappings (May 2005)
Committee: Mix, K. (Co-Chair), Gasser, M., Goldstone, R. (Co-Chair), Smith, L.