harnad@phoenix.Princeton.EDU (Stevan Harnad) (12/21/90)
(1) Greenfield: Language, Tools and Brain
(2) Crain: Language Acquisition in the Absence of Experience
(3) Velmans: Is Human Information Processing Unconscious?
Below are the abstracts of these three forthcoming target articles,
which are to appear in Behavioral and Brain Sciences (BBS), an
international, interdisciplinary journal that provides Open Peer
Commentary on important and controversial current research in the
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____________________________________________________________________
(1) Language, Tools, and Brain: The development and evolution of
hierarchically organized sequential behavior
Patricia Marks Greenfield
Department of Psychology
University of California, UCLA
Los Angeles, CA 90024-1563
electronic mail: rygreen@uclasscf.bitnet
Abstract: During the first two years of life a common neural substrate
(roughly, Broca's area) underlies the hierarchically organized
combination of elements in the development of both speech and manual
action, including tool use. The neural evidence implicates relatively
specific cortical circuitry underlying a grammatical "module."
Behavioral and neurodevelopmental data suggest that the modular
capacities for language and manipulation are not present at birth but
come into being gradually during the third and fourth years of life.
An evolutionary homologue of the common neural substrate for language
production and manual action during the first two years of human life
is hypothesized to have provided a foundation for the evolution of
language before the divergence of hominids and the great apes. Support
comes from the discovery of a Broca's area analogue in contemporary
primates. In addition, chimpanzees have an identical constraint on
hierarchical complexity in both tool use and symbol combination. Their
performance matches that of the two-year-old child who has not yet
developed the differentiated neural circuits for the relatively
modularized production of complex grammar and complex manual
construction activity.
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(2) Language Acquisition in the Absence of Experience
Stephen Crain
University of Connecticut
and Haskins Laboratories
electronic mail: linqadm@uconnvm.bitnet
KEYWORDS: acquisition, child language, development, innate competence,
grammar, language learnability, parameter theory, maturation,
syntactic development, psycholinguistics.
ABSTRACT: A fundamental goal of linguistic theory is to explain how
natural languages are acquired. This paper describes some recent
findings on how learners acquire syntactic knowledge for which there is
little, if any, decisive evidence from the environment. The first
section presents several general observations about language
acquisition that linguistic theory has sought to explain and discusses
the thesis that certain linguistic properties are innate because they
appear universally and in the absence of corresponding experience. A
third diagnostic for innateness, early emergence, is the focus of the
second section of the paper, in which linguistic theory is tested
against recent experimental evidence on children's acquisition of
syntax.
____________________________________________________________________
(3) IS HUMAN INFORMATION PROCESSING CONSCIOUS?
Max Velmans
Department of Psychology
Goldsmiths College
University of London
electronic mail: MLV@gold.lon.ac.uk
KEY WORDS: consciousness, information processing, brain, unconscious,
attention, mind, functionalism, reductionism, complementarity.
ABSTRACT: Investigations of the function of consciousness in human
information processing have focused mainly on two questions: (1) where
does consciousness enter into the information processing sequence and
(2) how does conscious processing differ from preconscious and
unconscious processing. Input analysis is thought to be initially
"preconscious," "pre-attentive," fast, involuntary, and automatic. This
is followed by "conscious," "focal-attentive" analysis which is
relatively slow, voluntary, and flexible. It is thought that simple,
familiar stimuli can be identified preconsciously, but conscious
processing is needed to identify complex, novel stimuli. Conscious
processing has also been thought to be necessary for choice, learning
and memory, and the organization of complex, novel responses,
particularly those requiring planning, reflection, or creativity.
This target article reviews evidence that consciousness performs none
of these functions. Consciousness nearly always results from
focal-attentive processing (as a form of output) but does not itself
enter into this or any other form of human information processing. This
suggests that the term "conscious process" needs re-examination.
Consciousness appears to be necessary in a variety of tasks because
they require focal-attentive processing; if consciousness is absent,
focal-attentive processing is absent. From a first-person perspective,
however, conscious states are causally effective. First-person accounts
are complementary to third-person accounts. Although they can be
translated into third-person accounts, they cannot be reduced to them.
Stevan Harnad Department of Psychology Princeton University
harnad@clarity.princeton.edu / harnad@pucc.bitnet / srh@flash.bellcore.com
harnad@learning.siemens.com / harnad@elbereth.rutgers.edu / (609)-921-7771