Semantic and auditory factors in processing syntactic ambiguity
Filip Loncke, Beverly Colwell Adams, Kimberly Edwards, Laura Leviski, Janet Stack, Ji eun Kim, and Jennifer Starkey
Communication Disorders Program - University of Virginia
Previous studies
20071),
Although not without controversy (Loncke, Adams, Stack, et al.,
previous research has consistently reported that the high attachment
processing strategy is made initially and is indeed the preferred strategy for
interpretation. Loncke, et. al.’s results suggested that the final interpretation of
even syntactically ambiguous sentences may be influenced by semantics.
Percentages High-Low in different conditions
Percentage
100
80
60
High
40
Low
20
0
Pictures
Real objects
Geometric
figures
Drawings
The results of the 2007 study indicate that responses differ ,
depending on the conditions. The use of “abstract” sentences
[such as “the square is on top of the rectangle next to the
triangle”] helps us to understand the relation between
semantics and syntax.
Conditions
Our focus in the current study was to determine if pauses in spoken text can
change the preferred interpretation of syntactically ambiguous sentences.
1Loncke, F., Adams, B., Dodson, V., Cao, L., Stack, J., Kim, J., & Craig, J. (2007, November 17). Clinical
relevance of auditory perception of syntactic ambiguity. Poster presented at the Annual Convention of the
American Speech-Language and Hearing Association (ASHA). Boston.
Contact: Filip Loncke, [email protected] or
Beverly C. Adams, [email protected]
Which interpretation will the listener give to a syntactically ambiguous sentence? If the
syntactic structure is the sole or dominant force in determining the interpretation, a
preference for a high syntactic resolution can be expected.
If other factors interfere (such as acoustics, semantics, and/or pragmatics), other
responses can be expected along with high syntactic resolution.
Hypotheses
We examined the following hypotheses:
• Interpretation of syntactically ambiguous sentences will be made using
the high attachment strategy.
• Strategically placed pauses will shift the preferred high attachment
strategy to low.
Results
Sentence Type: There was a main effect of sentence type; F (2, 1403); p< .01
Consistent with Loncke et al. (2007), the present results show a preference for
the low attachment strategy for unambiguous and abstract sentences. The high
attachment strategy and the low attachment strategy were split fairly evenly
(92/110) between the syntactically ambiguous/semantically ambiguous
sentences, such as (1). (See Figure 1)
Pauses: The pattern of results for pauses, P0, P1, and P2, for both
unambiguous sentences and abstract ambiguous sentences, showed a
commanding preference for the low attachment interpretation (See Figures 2 and
3). Examining only the syntactically ambiguous sentences, in the P0 and P2
conditions, there was a clear preference for high attachment. Most interestingly,
however, for the P1 pause position condition, there was a dramatic increase in
the number of sentences that were interpreted with the low attachment strategy;
almost equaling the high attachment preference; t(38) = 5.085, p<.001 (see
Figure 4).
sketch of their interpretation of what they had heard.
Figure 2
Unambiguous total
180
160
140
120
Low
100
High
80
Low
High
60
40
20
0
unambiguous
Method
Participants: Thirty-nine participants, all undergraduate students of the
University of Virginia, participated in this study.
Materials: Thirty-six target sentences were developed with consideration to
the independent variable, sentence type. One third (12) of the sentences
were syntactically ambiguous and semantically ambiguous such as (1).
Twelve sentences were syntactically ambiguous, but semantically
unambiguous such as (2). Twelve sentences were syntactically and
semantically ambiguous using the names of geometric shapes in the noun
positions such as (3).
(3) The circle is in the rectangle next to the triangle.
The second independent variable was pauses. In the P0 condition, no
pauses were added to the auditorally-presented computer-generated
sentences. In P1, an exaggerated pause was inserted after the first
preposition; The apple is in // the bowl next to the banana (sink). In P2,
the pause was inserted after the first prepositional phrase; The apple is in
the bowl // next to the banana (sink).
Procedure: Each participant, tested individually, listened to each target
sentence, one-at-a-time. After listening, participants were asked to make a
Figure 1
Sentence types and responses
500
450
400
350
300
250
200
150
100
50
0
ambiguous
P0
abstract
P1
Figure 3
Pause effects in abstract sentences
160
140
120
100
P2
Figure 4
Pause effects in ambiguous sentences
120
100
Low
80
60
40
20
0
High
Response
Consider the syntactically ambiguous sentence (1).
(1) The apple is in the bowl next to the banana.
The sentence processing strategy, high attachment, guides sentence
processing to the interpretation that the apple and the banana are in the bowl.
In contrast, the low attachment strategy steers toward the interpretation that
the banana is located next to the bowl. This type of syntactically ambiguous
sentences such as (1) is also semantically ambiguous. Now, consider
syntactically ambiguous sentences that are semantically unambiguous like (2).
(2) The apple is in the bowl next to the sink.
Only one semantically plausible interpretation is produced by the low
attachment strategy; the apple is located in the bowl and the bowl is next to the
sink.
What factors influence our interpretation of
syntactically ambiguous sentences?
Response
Syntactic Ambiguity
80
Low
60
High
40
20
0
P0
P1
P2
P0
P1
P2
Pause position
Pause position
Discussion
In the psycholinguistic literature, syntactically ambiguous sentences are examined to
investigate the initial parsing strategy that guides the attachment of constituent phrases.
The assumption has been that the most efficient strategy (high attachment) guides the
initial attachment and unless semantics or pragmatics suggests a different interpretation,
the initial strategy was the final strategy. In the present study, we suggest that the final
interpretation of pre-tested syntactically ambiguous/ semantically ambiguous sentences,
maintain some level of subtle semantic/pragmatic influence. With sentences such as (3)
that incorporated only geometric shapes in the noun positions, we report that
participants made their final interpretation using the low attachment strategy—not high.
The results suggest, also, that the non-syntactic/non-semantic factor, time, strategically
placed, can alter interpretation.
Acknowledgment
Conduction of these studies were made possible through the participation of several groups of
students from the University of Virginia throughout the years 2005-2008. Special thanks to Valerie
Dodson, Amanda Spear and Alyssa Weltman who were instrumental in a pre-pilot study and a pilot
study.