I. Introduction
A. syntactic parsing
1) in psycholinguistics, it's the the way you relate words to each other in sentences
B. semantic processes
1) in some ways dependent on syntactic parsing
ex: (1) The rat the cat the dog chased bit died.
When you look at this sentence, it's extremely hard to tell which verb applies to which noun at first. The sentence is too complicated for you to accurately understand on the first reading, as the rest of a language is supposed to be.
ex: (2) The dog chased the cat that bit the rat that died.
This sentence carries the same meaning as the first one, yet since the words are reorganized into a different syntactic structure (essentially, different ordering of words), it's easier to comprehend and reads relatively normally for us, even on the first try. You don't have to put much extra thought into understanding the sentence as you did with the first sentence.
C. ambiguity
1) globally ambiguous
If the entire sentence in question can be reorganized into different constituents (groupings of words)
ex: The spy saw the cop with the binoculars.
More often than not, we can assume that with the binoculars can attach to the verb saw. This makes more sense because of the semantic similarities between the two phrases.
ex: The spy saw the cop with the mustache.
As much as we'd love to assume that the cop has the mustache because of the stereotypical appearance of a cop, we can't say for sure. Unlike the last sentence, nothing in this sentence indicates one syntactic structure over the other.
2) temporarily ambiguous
ex: The critic wrote the book was enlightening.
When you hear this sentence, you can process The critic wrote the book as its own sentence. When you throw in the phrase was enlightening at the end, the brain takes a little time to process how that phrase can fit to the end of an already complete sentence. But, at least there's no way to completely reorganize the sentence and create an alternate meaning.
D. what syntactic parsing needs to do
1) explain which syntactic version of a sentence we choose and why (should the cop or the spy have the binoculars?)
2) explain if syntactic information is available before AND/OR is more important than other kinds of information (semantic, lexical, etc.)
3) explain if syntactic information is more important than other kinds of information (semantic, lexical, etc.)
II. The Cognitive Revolution
A. Chomsky decided that a finite-state model such as the Markov model couldn't analyze long-term dependencies such as subject-verb agreement, plurality, etc.
B. he proposed syntactical theories that took care of long-term dependencies
1) he proposed that words formed categories (nouns, verbs, prepositions, etc.) and that these words are modifies to follow grammatical rules
2) he said that each sentence has two syntactical structures:
a) surface structure
def: the words in their prescribed order and the meaning that carries
b) deep structure
def: using canonical form, the simplest form of a sentence, to convey the same idea; this canonical form of the sentence is then transformed to become the target sentence
*** the more transformations of the canonical form, the hardest it is for us to psychologically process ***
III. Garden-Path Theory
A. the theory that people will simplify things as much as possible
1) they will only consider one syntactic representation of a sentence at a time
2) they will select the simplest structure that can be built using the words in the sentence the way they're meant to be used
3) they won't consider every single possible structure; they will select the simplest one consistent with the sentence
4) late closure
def: a syntactic element (phrase) will be built as long as it can be built until it's broken
ex: Since Jay always jogs a mile seems like a short distance to him.
In this sentence, on first glance the phrase Since Jay always jogs a mile will be built until interrupted by seems like a short distance to him. On the first reading, you need to backtrack a little bit and realize that a mile seems short to him because he always jogs.
ex: Since Jay always jogs, a mile seems like a short distance to him.
In this sentence, the phrase Since Jay always jogs is interrupted by the comma, it is treated as its own syntactic unit and the temporary ambiguity is killed.
5) minimal attachment
def: the structure with the least syntactic constituents will be selected
ex: The girl knew the answer by heart.
the answer is an object of the verb knew, leading to a structure where the answer is related to the verb before the subject.
ex: The girl knew the answer was wrong.
Here, the answer is instead related to the subject the girl first, because the girl admitting her wrongdoing is more important to the sentence.
6) relativized relevance
def: when deciding where to attach a questionable phrase, understand it in a new way where you learn information as opposed to storing old information
ex: the recently divorced bishop's daughter
When reading this sentence, it is more natural for us in English to see that the recently divorced bishop has a daughter. If instead the sentence means that the bishop's daughter was recently divorced, it takes more effort for our brain because we have to remember that someone is recently divorced and we don't know fully until after we read the whole sentence and put those ideas together.
IV. Constraints
A. garden-path theory claims that usually, sentences are in the form of NP-V-NP (our default processing state)
B. if a sentence is a little more complicated than the basic NP-V-NP form, our processing will be wrong at first, but will then settle in to be correct
C. certain words line up with certain syntactic structures more often than others do
ex: The investor realized a profit...
The verb realized indicates that a certain type of syntactic structure (in this case, the sentence complement) is most likely to follow
ex: The investor realized a profit would help the company avoid layoffs. (sentence complement)
D. it's all about relative probability; a verb like realized and verbs similar to that have a much higher probability of preceding a sentence complement than a simple direct object.
E. subcategorization preference: basically the concept that guides this idea
ex: The investor knew a profit would help the company avoid layoffs.
In this case, the verb knew is associated with direct objects more than with sentence complements, so an initial reading of this sentence would be harder to understand than the previous example.
F. The defendant examined... vs. The evidence examined...
If you were tasked with continuing the above sentences, the first one would be easier because it aligns directly with our default processing state. If you had to consider the second one, it would be more difficult because you have to realize that the evidence examined is all one object instead of NP-V as in the first sentence.
G. when compared to modular parsers, constraint-based parsers have the advantage of visualization
ex: The thief blew up the safe with the rusty lock.
A modular parser would look at this and be confused: is with the rusty lock attached to the safe or to blew up? A constraint-based parser knows that it's impossible to blow up a safe using a rusty lock, so one of the possibilities this initially globally ambiguous sentence provides is ruled out.
H. using referential theory, we can say that the reason with the rusty lock was used at all in the previous example was because there could be a contextual ambiguity as to which safe we're talking about
I. referential theory: the parser will choose the meaning that is the least ambiguous
J. Gricean conversational maxim of quantity: don't tell more than you need to understand something
ex: There was a safe in the back of warehouse. The thief blew up the safe with the rusty lock.
vs.
ex: There were two safes, one brand new and the other old and beat up. The thief blew up the safe with the rusty lock.
In these two instances, the first passage actually causes more processing load for the reader because they'll be left wondering why the first sentence was that important. In the second sentence, the noun safe in the second sentence clarifies which of the two safes is being referred to.
***it's not always just syntactic complexity that determines how much it takes for us to process a passage***
K. modifier-goal ambiguities
ex: Put the frog on the towel in the box.
Are we being told to take the frog placed on the towel and put them into the box? Or are we being told that there's a towel in a box and we need to place the frog on that?
L. visual context/constraints
1) an experiment was run with that sentence in mind where there were two different setups.
a) One frog was placed in front of them.
b) Two frogs were placed in front of them, one on a towel and the other not.
2) in a) the subjects looked for a place to put the frog because at first glance, you need to place the frog in a specific place (on the towel in the box), but in b) they spent more time looking for the target frog, not as much at its location since it was clear that it was supposed to be placed in the box.
V. What Next?
A. research is indicating a shift towards incremental interpretation of language
B. readers don't always wait for a sentence to finish and then react to it when they understand it; they usually understand it along the way and make some predictions
C. the concept of entropy can help us understand relative processing load
1) predictability is directly proportional to the amount of entropy
2) the more entropy, the tougher it is to understand and more processing it takes
D. it also appears that lexical information is more important than syntactic information
ex: The mouse was eaten by the cheese.
Syntactically, not a difficult sentence, because it's just passive voice. But a reader would look at this and scratch their head because there's some unusual lexical-semantic information. Doesn't the mouse usually eat the cheese, not the other way around?
E. good enough parsing: we only need the bare minimum to understand the sentence to our content
F. also, simple repetition can help us process certain syntactic structures more accurately (we need additional research to prove if this lasts both short-term and long-term)