Showing posts with label information structure. Show all posts
Showing posts with label information structure. Show all posts

Thursday, March 14, 2013

Eviatar and Just: "Brain correlates of discourse processing" (2006)

This paper shows that three different kind of text snippets lead to three different patterns of brain activity. This is interpreted as showing how literal, metaphorical, and ironic language is processed.

However, a closer look at the experimental materials show that these labels should be approached with some caution. The literal statements are not all "literal" by the standards of cognitive metaphor theory, and the metaphorical statements are in many cases not as conventional as they are claimed to be.

Are the Literal Sentences Literal?

Here are some examples of text snippets that Eviatar and Just categorized as "literal," with underscores added by me:
  • Betsy and Mary were on the basketball team. Mary scored a lot of points in the game. Betsy said, “Mary is a great player.”
  • Harry waited in line for 3 h to see the movie. He enjoyed himself. He said, “That was worth waiting for.”
  • George promised to be quiet in the library. He sat in a corner looking at a book. His dad said, “Thanks for keeping your promise.”
  • Laura was out sick for a week. Johnny called her every day. Laura said, “Thanks for worrying about me.”
  • Betty and Laura were in the same class. Laura finished her homework before Betty. Laura said, “You sure are a slow worker.”
Several of these should not be categorized as literal according to the standards of cognitive metaphor theory.

For instance, great is typically taken as an example of a metaphor with size as its source domain. Similarly, worth, keeping, and perhaps worrying are here used in senses that are not their most "basic" ones. Further, slow worker should probably be categorized as a metonymy.

Are the Metaphorical Sentences Conventional?

Here are some examples that they consider to be "frozen" metaphors (p. 2350):
  • In the morning John came to work early. He started to work right away at a fast pace. His boss said, “John is a hurricane.”
  • Mary got straight A’s on her report card. Her parents were proud of her. They said, “You are as sharp as a razor.”
  • Susie helped her mom when her brother got sick. She took good care of him. Her mom said, “You are an angel from heaven.”
  • Donna was always late for everything. Today she made it home on time for supper. Her dad said, “You have turned over a new leaf.”
  • George went to Betty’s birthday party. Fifty people crowded into her small apartment. He said, “I feel like a sardine.”
  • Betty and Laura were in the same class. Laura finished her homework before Betty. Laura said, “You work like a snail.”
No doubt that these examples constitute metaphors; it's only that they are a very different kind of metaphors than unemployment is growing or I'll handle the press. One is very overt and almost cries out for attention, while the other is quiet and discreet.

Some Factors Causing the Metaphors to Grab Attention

We can hardly expect a sentence like
  • You are an angel from heaven
to be processed the same way as
  • The chocolate cake was divine
The resonance of angel with heaven, the quotation marks in the original story, and the syntactic clumsiness of the sentences all contribute to provoke a very vivid mental picture in the reader. This would probably not be the case for the divine chocolate cake.

Other sentences from the materials provoke such images because they are not really conventional, or occur in an abnormal form. For instance, the common "sardine" metaphor virtually always occurs in the plural form like sardines and never in the form like a sardine.

Lastly, because the subject-predicate form in sentences like You are X or John is X is so semantically weak in its subject, it draws a lot of attention to the metaphor which is its topic. Compare for instance
  • He was a tallish man with a mind as sharp as a razor. (BNC)
  • You are a razor.
To my intuitions, the razor in the first sentence seems to recede very much into the background, while in the second sentence, it is being put forward as the explicit topic of the sentence. The reasons are probably both syntactic (information is spread unevenly over constituents) and semantic (the first sentence contains more competing content words).

Are the Metaphors Metaphorical?

One last thing that I should mention is that at least one of the "metaphorical" examples could be interpreted as literal:
  • Ken was worried about having his hair cut. When the barber finished, Ken’s ears stuck out. He said, “You’ve turned me into a clown.”
Without a more specific theory of what "metaphor" means, this is a very problematic borderline case.

So What?

This doesn't mean that the data that Eviatar and Just has collected is useless, or that it should be discarded. But it does mean that, once again, the notion of "metaphor" is so vague and contested that it can't just be transplanted from one field to another without some problems.

In particular, linguists should be careful not to take evidence from brain scans at face value; we need to look carefully into the details of what the neuroscience actually shows, and be explicit about what our own semantic theory actually say.

In this case, that means the following: First, some sentences provoke mental imagery more strongly than others; this is a product of several interacting factors, including word frequencies and resonance effects. And second, it is not at all clear what the relation between mental imagery and meaning is, and this relation cannot be made clear unless we come clean about what we thing linguistic meaning is.

Wednesday, April 11, 2012

Helen de Hoop: "On the Interpretation of Stressed Pronouns" (2003)

This paper by Helen de Hoop is essentially about pronoun resolution. It focuses on two clues that can be used to narrow down the field of possible resolution candidates, contrastive stress and local coherence.

Concepts
Contrastive stress has to do with the fact that changes in focus often come in explicitly marked forms:
  • Paul1 hit Jim2. Then he1 kicked him2. (= Paul kicked Jim)
  • Paul1 hit Jim2. Then HE2 kicked HIM1. (= Jim kicked Paul)
Topic continuity is the constraint which is known from centering theory. In a simplified form, it says that pronouns refer to things that had high salience in the previous sentence. This explains differences like this one:
  • Paul1 is not around. He1 is talking to Alan2. He1 will be back later.
  • Paul1 is not around. He1 is talking to Alan2. *He2 will be back later.
Other clues exists as well (e.g., syntactic parallelism and more subtle salience differences), but these are the ones de Hoop discusses. I should note that centering does not actually fare very well when tested on corpus material.

Conclusions
In the last five pages of her paper, de Hoop formulates her observations about anaphor resolution in terms of an optimality-theoretic constraint system. This system consists of two constraints: one requiring all pronouns to refer to high-salience topics of the previous sentence, and one requiring stressed pronouns to be read in a way that introduces a shift of attention.

De Hoop claims that the Contrastive Stress constraint (S) is stronger than the Continuing Topic (T) constraint. This means that we get the following linear ordering on constraint violations:
None > only T > only S > both S and T.
So if some reading violates, e.g., the constraint S, it must mean that no readings were available that violated only T or nothing at all.

I don't find her argument for ordering the constraints this way entirely convincing, though. She gives examples that violate T but not S, and examples that violate both constraints, but she does not exclude the possibility that other examples might violate S but not T. If such counterexamples exist, they will look more or less like the following:
  • John1 hit Paul2. Then HE1 kicked Paul2.
I don't know if one could find such an example in naturally occurring discourse, but I'm not entirely convinced of the opposite, either. And this strong claim is the prediction that falls out of the optimality-theoretic analysis.