Neighbour priming in eye movements during reading
Kevin PatersonUniversity of Leicester
Samantha McCormickRoyal Holloway, University of London
Colin DavisRoyal Holloway, University of London
Simon LiversedgeUniversity of Southampton
Lexical Priming in Eye Movements
o Orthographic similarity between words affects performance in studies of isolated word recognition.
o Are similar effects observed for words read normally in sentences?
o How do these effects influence eye movement behaviour?
Substitution Neighbours
o Widespread view that reading a word activates lexical entry for that word and for orthographically similar words, known as neighbours.
o A word’s neighbours traditionally defined as those words that can be formed by substituting one letter for another while preserving letter position and length (e.g., Coltheart et al.,1977).
e.g., “tank” has “rank”, “sank”, “task”, etc. as neighbours.
Addition & Deletion Neighbours
o Can also define neighbours in terms of words created by adding or deleting letters. (e.g., De Moor & Brysbaert, 2000; Davis, Perea, & Acha, 2009).
o For example:
“public” is an addition neighbour of “pubic”
“water” is a deletion neighbour of “waiter”.
Isolated Word Recognition
o Words with HF neighbours identified more slowly than matched controls. (e.g., Carreiras et al., 1997; Davis et al., 2009; Davis & Taft, 2005; Grainger, 1990; Grainger et al., 1989; Huntsman & Lima, 1996).
o Neighbour word primes slow target word recognition.
o Masked Priming: Greater inhibition for HF primes. (e.g., Brysbaert, et al., 2000; Davis & Lupker, 2006; De Moor & Brysbaert, 2000; Segui & Grainger, 1990)
o Unmasked Priming: greater inhibition for LF primes. (Colombo, 1986; Lupker & Colombo, 1994; Segui & Grainger, 1990)
Eye Movement Studies Words with HF neighbours have longer reading times and
receive more regressions than controls. (e.g., Davis et al., 2009; Perea & Pollatsek, 1998; Pollatsek et al., 1999; Slattery, 2010)
Effect attributed to misidentification of target word.
Eye Movement Studies
Other research using boundary paradigm shows preview of HF neighbour can facilitate word processing, by activating letter representations shared with target. (Williams et al., 2006)
He felt the cold sweet on his face. *
He felt the cold sleet on his face. *
Present Studieso Growing interest in whether lexical priming is observed
between words read normally in sentences. (e.g., Carreiras et al., 2005; Frisson et al., 2009; Paterson et al., 2009, in press; Warren & Morris, 2009)
o Experiment 1: Substitution neighbour priming.o Experiment 2: Addition/Deletion neighbour priming.
o Are effects inhibitory or facilitatory?o What influence do they have on eye movements?o What is the time course of effects?
Experiment 1: Substitution Neighbours
o Sentences contained prime-target pairs or control-target pairs matched for length and frequency.
o Primes / controls displayed normally earlier in sentence than targets (mean 1.8 words apart).
o Prime was higher or lower in frequency than target (HF = 316, LF = 8, p<.05).
Paterson, Liversedge, & Davis, PB&R, 2009.
Stimuli Low freq prime – high freq target
There was a blurprime as the bluetarget lights spill-over of the police car whizzed down the street.
There was a gaspcontrol as the bluetarget lights spill-over of the police car whizzed down the street.
High freq prime – low freq target
In the photograph, the blueprime lights were a blurtarget against spill-over the cold night.
In the photograph, the towncontrol lights were a blurtarget against spill-over the cold night.
Method & Procedure
Participants’ right eye movements recorded using DPI eye tracker at the University of Leicester.
48 sets of sentences (using word stimuli from Davis & Lupker, 2006).
40 participants from University of Leicester.
Target word reading times
Robust inhibitory priming effects unaffected by prime-target frequency.
First fixation durations: 12 ms effect (Fs>5.8). No interaction (Fs<1).
Gaze durations: 15 ms effect (Fs>4). No interaction (Fs<1).
Total reading times: 45 ms effect (Fs>8). No interaction.
First Fixation Durations
Gaze durations
Spill-over region
More regressions from post-target region when target follows neighbour (Fs>4). Interaction not significant.
Evidence for misidentification of target words?
Summary
o Prior exposure to word’s neighbour earlier in a sentence slows subsequent processing of that word.
o Effect is observed in eye movement measures associated with early word processing.
o Priming influences decisions about when to move the eyes during reading.
o Unlike in word recognition research, effect was not modulated by prime-target frequency.
Experiment 2: Addition / Deletion Neighbours
1. Are inhibitory priming effects observed for addition and deletion neighbours?
public-pubic beast-breast
2. Are effects influenced by the separation of prime and target words in the sentence?
3 factors manipulated: Primes were LF neighbours of targets or non-neighbours. Primes & targets were close together or further apart in
sentence. Neighbour primes were addition or deletion neighbours.
Created by adding/deleting an interior letter. Deletion: prime = beast, target = breast Addition: prime = window, target = widow
60 sets of sentences (30 deletion, 30 addition) 56 participants from University of Leicester.
Method
stimuliClose prime-target pairs1. The beast prime at his breast target looked scary and was desperate for
a meal.
2. The snake control at his breast target looked scary and was desperate for a meal.
Distant prime-target pairs3. The beast prime that sat quivering at his breast target looked scary and
was desperate for a meal.
4. The snake control that sat quivering at his breast target looked scary and was desperate for a meal.
Target word reading timesInhibitory effect for addition neighbour primes only, that is larger when words are closer together.
close distant close distantdeletion addition
200
250
300
First Fixation Durations
prime control
mse
c
Target word reading timesSimilar effects for addition and deletion neighbours.
close distant close distantdeletion addition
200
250
300
Gaze Durationsprime control
mse
c
Target word reading timesAgain, similar effects for addition and deletion neighbours.
close distant close distantdeletion addition
300
350
400
450
500
Total Reading Timesprime control
mse
c
Spill-over Region
close distant close distantdeletion addition
0%
5%
10%
15%
20%
25%
30%
Spill-over Regressionsprime control
% R
egre
ssio
nsFurther evidence for target word misidentification.
Regressions to Target Word
close distant close distantdeletion addition
0%
5%
10%
15%
20%
25%
30%
Regressions to Target Wordprime control
% R
egre
ssio
ns
Summary & Conclusionso Further evidence of inhibitory neighbour priming.
o Observed in range of eye movement measures, but effect emerges earliest in eye movement record for addition neighbour primes. o May reflect competitive advantage for longer words.
o Effects for both close and distant targets, but disruption greater when words are close together.
o Together, the studies clearly demonstrate that eye movements are sensitive to intra-sentential, inter-lexical influences that occur naturally within sentences.
Target Word Reading Times
Inhibitory priming effect for close prime-target pairs only (21 ms effect, interaction Fs>6).
close distant250
300
350
First Fixation Durationsprime control
mse
c
Target Word Reading Times
Inhibitory priming effect for both close and distant prime-target pairs (14 ms prime effect, Fs>7; interaction Fs<1).
close distant250
300
350
Gaze Durationsprime control
mse
c
Target Word Reading Times
Inhibitory priming effect for both close and distant prime-target pairs (prime effect Fs>16; interaction Fs>6).
close distant300
350
400
450
500
Total Reading Timesprime control
mse
c
Spill-over Region EffectsMore regressions from spill-over region when target followed close or distant neighbour prime (Fs>15).
close distant0%
10%
20%
30%
Post-target Regressionsprime control
% re
gres
sion
s
What is the underlying mechanism?
What Colin might say…Effect due to spreading
activation in mental lexicon. A prime word
activates its lexical entry and lexical entries for related words. This
activation decays over time. However, there is
sufficient ongoing activation to produce orthographic priming.
What Erik might think…This is an episodic
memory effect. When prime and target words
are read separately, target word processing
evokes an episodic memory trace encoded
during prime word processing, and this
affects word identification.
1. Decay in lexical activation
The prime activates its lexical entry and lexical entries for related words.
This activation decays rapidly, and would be expected to carry across just a few words in the sentence.
2. Episodic memory effect.
Target word processing evokes an episodic memory trace encoded during prime word processing, and this affects word identification.
Predicts longer lasting priming effects.
