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.

John bought Mary a cake for her ___

The gardener talked as the barber trimmed the ___

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)

RESULTS

Red: Nonisland low

Black: Nonisland high

Green: Island low

Blue: Island high

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.