Syntacticians often act like parochial snobs. They are snobs in that some (e.g. me) believe
that the kinds of data and explanations offered within syntax are deeper than
those offered in other domains. There really is non-trivial syntactic theory
and a whole budget of effects that these theories explain. Syntacticians (e.g. me) can be parochial in believing
that only these kinds of questions are worth asking and investigating. A
consequence of this is the oft-exhibited habit of evaluating the interest of other
linguistic questions in terms of how much they address questions in
syntax. This habit can be especially pronounced
when syntacticians consider work in psycholinguistics. When evaluating psycho work, it is not
uncommon for syntacticians to expect psycholinguists to provide evidence/methods
for helping to choose among competing cutting edge syntactic alternatives. As this rarely happens, syntacticians often
come to have jaundiced views about the intellectual contributions of
psycholinguistic research.
This is clearly a rather perverse way of evaluating psycho research.
The issue is not whether psycholinguistics can answer syntactic questions but whether they have their own interesting
questions concerning the form and function of FL. Over the years I have made it
a habit to sit in on lab meetings of my psycho colleagues and two things have struck
me. First, that wrt syntactic theory, to date, psycho techniques have
contributed little that purely syntactic methods have not delivered more
cleanly and quickly (but see below) and, second, that psycholinguists have
found fascinating effects and have developed interesting theories of these
effects that greatly expand our understanding of how FL is used in real time,
both learning and processing. Let me elaborate
each point just a bit.
A good deal of the questions in language processing and
acquisition can proceed just fine in blissful ignorance of the latest findings
in syntax. For example, studying the
acquisition or processing of long distance dependencies will not be greatly
affected by whether one assumes that movement is actually an expression of
Merge (I-merge) or an independent operation in its own right. The differences
between these two conceptions is too fine grained to be captured by (at least current) psycho methods. However, this does not mean that there is
nothing worth studying. For example, regardless of how a WH gets to clause
initial position, we have an interesting question: how eagerly does the parser
try to find the gap the WH is related to? One possibility is that it waits to
find a gap and then tries to relate the WH to it. A second option is that it
tries to link the WH immediately on sighting a theta marking host predicate without
waiting to see if there is a gap after the predicate to fill. Thus in a sentence like (1), we can ask if the parser tries
to interpret who as complement of tell after/before seeing if there is a
gap there.
(1) Who
did you tell Bill about
So given the question ‘how “eager” is the parser?’, the
next question is how to study its eagerness? Via a
very interesting phenomenon discovered in the 1980s (Laurie Stowe in 1984), the
so-called “Filled Gap Effect” (FGE). If you put people in front of a computer and
have them read a sentence word by word and measure how they doe this, it turns
out that in a sentence like (1) readers will pause longer at Bill than they would in reading a
sentence like (2):
(2) Who
did you tell about Bill
This is a very reliable effect. Interpretation? Readers are
trying to thematically interpret who
when they get to tell and must
rescind this when they get to Bill in
(1) but not in (2). In other words, readers “prefer” giving a thematic role to who even at the cost of having to
rescind this assignment soon after over waiting to see if there is an available
role to assign, even if this means just waiting one word. Conclusion: parsers
are very eager to interpret
uninterpreted material. And this eagerness can be measured and used to probe how
parsers use grammars to construct sentence interpretations in real time, i.e. FGE
is a marvelous tool for probing the relation between grammars and parsers.
Let me give an illustrative example. Consider the following
question: Given that parsers use grammars what is the relation between
competence grammars (ones beloved of syntacticians) and parsing grammars? A strong position is that there is a very
high level of “transparency” between the two.[1]
What’s this mean? Well, that the categories and relations that the grammar
specifies are identical to those that the parser exploits/respects in real time. For example, the categories that grammars
deploy (e.g. DP, VP, CP) are what the parser tries to recover and the
conditions the grammar respects (e.g. minimality, c-command, subjacency) the
parser does as well. A good deal of work in parsing over the last 15 years has
been aimed at specifying the degree of transparency between competence grammars
and parsing grammars. For example,
psycholinguists have investigated whether parsers respect c-command in trying
to find a bound anaphors possible antecedents and whether parsers display
cross-over effects.[2]
My colleague, Colin Phillips, has a really beautiful set of results bearing on
how parsers “do” movement, particularly does gap filling “obey” islands (see
here). The answer is “yes.” How does he
know? Building on earlier work by others, he shows that the FGE only appears if
the “gap” sits in a possible movement
site. Gaps within islands do not trigger FGEs (unless they are licensable parasitic gaps (this is
Colin’s great find)). Gaps generable by
movement do trigger FGEs. The argument is subtle and well worth reading
(if you’ve read it already, read it again to your kids; it makes for a lively
bedtime experience!). All this makes sense if parsing grammars and competence
grammars are (largely) the same. Ergo…
Note that these psycho results build on what syntactic
research has revealed about competence. It uses these results to address a
related very interesting question, viz. the Transparency Thesis (TT) and it
does so by exploiting a psycho probe, viz. FGE, manifest in online reading
tasks. Most interestingly in my view, as
TT becomes more and more empirically grounded (and the evidence in its
favor is already pretty good IMO), syntacticians may finally get what they’ve been
asking for: psycholinguistic constraints on adequate competence theories
(Syntacticians, careful what you ask for lest you get it!). After all, if TT is right, then syntactic
theories that fail to support transparent parsing grammars should be less
valued than those that do. In other words if TT proves empirically tenable,
then online psycho results will prove highly relevant to evaluating the
empirical adequacy of proposed competence grammars.
How far away is this day? Well, I want to end by presenting
a possible glimpse of the future. In
some recent work Shevaun Lewis, Dave Kush and Brad Larson (LKL) have used FGEs
to probe the syntactic derivation of constructions like (3) (see here for some
slides):
(3) What
and when will we eat
Not surprisingly, these coordinated WH questions have rather
elaborate syntactic properties. I will not detail them for you (read the slides), except to say that LKL are led to analyze these by
treating the two WHs rather differently. LKL propose that the inner WH lands in
clause initial position via movement while the outer one is base generated
there. The evidence for this conclusion is two-fold. First, there is an
acceptability contrast between (4a) and (4b), the latter being quite a bit
worse than the former (and yes they ran the relevant acceptability judgment
studies to show this). Second, the what
in (4a) fails to induce an FGE. If FGEs
are diagnostic of movement dependencies (as above) then the absence of these in
(4a) is just what we would expect, and apparently receive. To my knowledge this
is the first time a technique borrowed from psycho has been pressed into
service to support a novel syntactic conclusion. Terrific!
(4) a. What
and when will we eat something
b.
When and what will we eat something
It is the sign of a progressing research program that novel
questions and techniques keep springing up. The aim is to conciliate these
producing a bigger and bigger coherent picture.
To date, in my view, a great deal of what we have discovered about how
FL does syntax has come from the careful analysis of natural language grammars.
The LKL results are signaling a slightly different future: I have a
dream that is deeply rooted in the Generative enterprise. I have a dream that
one day linguistics will rise up and live the true meaning of its biolinguistic
roots. I have a dream that one day syntacticians and psycholinguists (and eventually neuroscientists) will use
each other’s work to strongly constrain their common research project of understanding how FL is structured and how it is used. I have a dream, and LKL
provides a glimpse of that wonderful and glorious future.
