Islands of Interpretation: The potential role of
prediction inhibition in grammatically accurate
sentence comprehension
Elliot Murphy
Division of Psychology and Language Sciences
24 April 2015
INTRODUCTION
• Language is a cognitive system with biological
constraints (Chomsky 2000, Poeppel 2012, Murphy
2015). These manifest themselves grammatically.
• We all talk so frequently about language, or languages,
that we tend to forget that there are no such things in the
world; there are only people and their various written and
acoustical products. This point, obvious in itself, is
nevertheless easy to forget.
Donald Davidson (1990)
INTRODUCTION
• The evolution of the capacity for language (Murphy
forthcoming) likely yielded what Boeckx (2010) calls a
‘universal currency’ which carries out cross-modular
mental transactions between distinct ‘core knowledge
systems’ (Number Sense, Object Mechanics, Natural
Geometry etc). Through interacting with various
modules language ‘make[s] available a new range of
potential actions’ (Spelke 2010: 208). Once concepts
were lexicalised, they were ‘freed’ from their residing
modules and capable of being constructed in novel
ways.
INTRODUCTION
What Mark Liberman calls
‘Escher sentences’ display
the kind of automatic
responses to stimuli seen in
M. C. Escher’s paintings,
which yield ‘impossible’
entities.
More people have been to Russia than I have.
Un-Escher sentence: Girl movie catalogue shop directory recycle bin.
INTRODUCTION
• Natural language parsing has the capacity for rich and
complex forms of prediction. More generally, Llinás
(2001: 21) notes that prediction ‘is, most likely, the
ultimate and most common form of all global brain
functions’. With the brain being ‘a self-referential,
closed system, a functional reality emulator that
constructs the world, rather than reconstruct it’ (Vaas
2001: 88), prediction is a core method of informing
mental computations.
SYNTAX
• The operation of word movement (see Boeckx 2014 for
technical definitions) leads to displaced constituents,
being pronounced in one place and interpreted in
another.
(1) John told Peter that Mary likes the first book.
(2) Which book did John tell Peter that Mary likes ___?
‘Which book’ interpreted as the object of ‘likes’
Sensorimotor interface interpretation: Which book … likes?
Conceptual-Intentional interface interpretation: Which book
… Mary likes which book?
SYNTAX
• In theoretical syntax, locality theory deals with the
constraints placed on movement, exposing the ‘islands’
out of which movement cannot take place.
(1) a. You think that Mary visited Peter before calling
John.
b. *Who do you think that Mary visited Peter before
calling ___?
(2) a. Your picture of John was funny.
b. *Who was you picture of ___ funny?
(1) = adjunct island (2) = subject noun phrase island
SYNTAX
(1) a. Susan likes Fred.
b. Who does Susan like ___?
(2) a. Susan likes Fred’s car.
b. *Whose does Susan like ___ car?
c. Whose car does Susan like ___?
The entire noun phrase, [NP Fred’s [N car]], needs to be
moved, not just it’s ‘left branch’, Fred.
No conceptual reason for this – an artificial language
could be constructed which allowed this – but language
does not allow it.
PREDICTION
• Predictive processes play a key role in language
comprehension.
• Van Berkum et al (2005) measured event-related brain
potentials (ERPs) as subjects listened to particular
sentences and discovered that an adjective would yield
an early positive wave (indicated of reanalysis
processes) when its grammatical gender was
inconsistent with that of the predicted noun.
HYPOTHESIS
• Previous research has shown that the real-time processing
of wh-dependencies is immediately sensitive to grammatical
constraints (islands), and engages predictive mechanisms.
• What is the potential role of prediction inhibition in
comprehenders’ online sensitivity to syntactic islands? Do
comprehenders stop predicting (inhibit their existing
predictions) when they encounter a syntactic island?
HYPOTHESIS
• N400
– Semantic ambiguity
– Predictability (e.g. cloze probability manipulations)
• P600
– Syntactic reanalysis. e.g. ‘garden path sentences’ such as:
(1) The horse raced past the barn fell.
(2) Fat people eat accumulates.
(3) The complex houses married and single soldiers and their
families.
(4) Time flies like an arrow, fruit flies like a banana.
EXPERIMENT
Present study (EEG) - 2 conditions: high vs low cloze
probability words, island vs no island.
(1) The exterminator inquired which neighbour the landlord
had evicted the night before. H,N
(2) The neighbour inquired which exterminator the landlord
had evicted the night before. L,N
(3) The exterminator inquired which neighbour the landlord
who had evicted the poor man had spoken to. H,I
(4) The neighbour inquired which exterminator the landlord
who had evicted the poor man had spoken to. L,I
EXPERIMENT
• Predictions:
(1) Cloze probability manipulation: Greater N400
amplitude for low versus high cloze words
(2) Island manipulation: No difference in N400 if islands
inhibit prediction
METHODS
• 4 participants (mean age = 26 yrs., range = 21-31)
• Stimuli and conditions
– High vs low & island vs no island (N = 120)
– Fillers: Cloze probability: High vs. Low (N = 60)
• E.g. ‘The robber attempted to snatch the purse / gloves from the
lady on the sidewalk.’ (adapted from Chow et al, under review)
– Fillers: Syntactic integration: Whether vs. Which (N = 60)
• E.g. ‘Angie asked whether the officer at the airport had arrested some
immigrants / which immigrants the officer at the airport had arrested for
possession of drugs.’ (adapted from Kaan et al, 2000)
METHODS
• Procedure
– Sentence reading (word by word), plausibility judgment
– 5 blocks (10 min) + breaks
• EEG recording
– BioSemi ActiveTwo
– 64 channels
– Sampling rate: 2048 Hz
• (re-sampled offline: 512 Hz)
DISCUSSION
• Main findings
– Cloze probability manipulation (fillers)
• N400 effect
• Late Positivity effect
– Island manipulation (experimental stimuli)
• Slight N400 effect for island high, less so for island low
• Most likely due to small number of subjects (standard number
for seeing an N400 effect = 20-30 subjects)
REFERENCES
Boeckx, C. (2010). Language in Cognition: Uncovering Mental Structures and the Rules Behind Them. Wiley-Blackwell.
Chomsky, N. (2000). New Horizons in the Study of Language and Mind. Cambridge University Press.
Chow, W. Y., Smith, C., Lau, E., & Phillips, C. (under review). A ‘bag-of-arguments’ mechanism for initial verb
predictions.
Davidson, D. (1990). The second person. Ms. University of California, Berkeley.
Kaan, E., Harris, A., Gibson, E., & Holcomb, P. (2000). The P600 as an index of syntactic integration difficulty.
Language and Cognitive Processes 15(2): 159-201.
Llinás, R. (2001). I of the Vortex: From Neurons to Self. MIT Press.
Murphy, E. 2015. Review of Elementary Syntactic Structures: Prospects of a Feature-Free Syntax by Cedric Boeckx.
Journal of Linguistics. Available on CJO2015 doi:10.1017/S0022226715000146.
Murphy, E. Forthcoming. Reference, phases and individuation: Topics at the labeling-interpretive interface.
Opticon1826.
Poeppel, D. (2012). The maps problem and the mapping problem: Two challenges for a cognitive neuroscience
of speech and language. Cognitive Neuropsychology 29(1-2): 34-55.
Spelke, E. (2010). Innateness, choice, and language. Bricmont, J., & Franck, J. (eds.). Chomsky Notebook. Columbia
University Press. 203-210.
Vaas, R. (2001). It binds, therefore I am! Review of Rodolfo Llinás’ ‘I of the Vortex’. Journal of Consciousness
Studies 8(4): 85-88.
Van Berkum, J.J.A., Brown, C.M., Zwitserlood, P., Kooijman,V., Hagoort, P. (2005). Anticipating upcoming words
in discourse: evidence from ERPs and reading times. Journal of Experimental Psychology: Learning, Memory, and
Cognition 31 (3): 443–467.
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