Dissociative Effects of Prime Duration, Lexicality, and Word Frequency in Lexical Decision Mary L. Still Alison L. Morris Iowa State University. Experiment 2: High N Stimuli. Orthographic Priming. Experiment 1: Low N Stimuli.
Dissociative Effects of Prime Duration, Lexicality, and Word Frequency in Lexical DecisionMary L. Still Alison L. MorrisIowa State University
Experiment 2: High N Stimuli
Experiment 1: Low N Stimuli
High freq 176 10.3
Low freq 8 10.3
Nonwords ---- 9.3
Shared Neighbors Exp 1 Exp 2
Word-Word .38 3.41
NW – HF .06 3.84
NW – LF .08 3.98
CMOP Prediction – High N stimuli
will produce interference because
they are well encoded
* Interference effects were ubiquitous
* Marginally sig. interference for
HF targets preceded by nonword
* Priming is not obtained for High N
stimuli because they tend to
High freq 366 2.4
Low freq 5 2.2
Nonwords --- 2.9
* All sig. subject results are sig. in the
item analysis as well
* Differences > zero represent
facilitation; differences < zero
* The most pronounced lexicality
effect emerged at 250ms
* Replicated the frequency
effect, but it seems unlikely the
reversal in interference effects is
tied to prime awareness
* Priming effects seem to depend
on prime exposure duration as
opposed to awareness of the
Competition Model of Orthographic Priming
Computational model of repetition effects, originally implemented to predict and explain common repetition blindness findings (Morris, Still, & Caldwell-Harris,2007).
Benefit of Repetition
Repetition always results in a “cleaner” representation – higher signal to noise ratio. If the item is processed well the first time, repetition leads to less summed neural activation of the representation.
Costs of Repetition
Items compete for awareness based on summed neural activity; items with more activity outcompete those with less activity.
Strength of this Model
Accounts for lexicality, frequency, and prime duration effects in masked priming via two simple constructs – stimulus encoding and competition.
Ortho N Control Ortho N Control
Word Targets (96 trials)
High Freqaxle – ABLE thug – ABLE ible – ABLE shug – ABLE
Low Freqable – AXLE door – AXLE axue – AXLE doir – AXLE
Nonword Targets (48 trials)
duet – DUIT self – DUIT duin – DUIT sulf – DUIT
Lexicality Effect Frequency Effect
CMOP predicts this pattern of results without using lexical inhibition. Stimulus
encoding and prime-target competition are hypothesized to account for these results.
Primes that are poorly encoded (e.g., nonwords, LF words, Low N stimuli) tend to
produce facilitation, while primes that are better encoded (e.g., words, HF words,
High N stimuli) tend to produce interference earlier, i.e., with shorter prime durations.
In future versions of CMOP we intend to include a decision criterion so that both RTs
and error rates can be simulated. This will allow for more detailed analyses of CMOP.
Procedure: Lexical Decision
Davis, C. J., (2003). Factors underlying masked priming effects in competitive network models of visual word
recognition. In S. Kinoshita & S. J. Lupker (Eds.), Masked Priming: The State of the Art. New York:
Davis, C. J., & Lupker, S. J. (2006). Masked inhibitory priming in English: Evidence for lexical inhibition.
Journal of Experimental Psychology: Human Perception and Performance, 32, 668-687.
Forster, K. I., & Davis, C. (1991). The density constraint on form-priming in the naming task: Interference effects
from a masked prime. Journal of Memory and Language, 30, 1-25.
Morris, A. L., Still, M. L., & Caldwell-Harris, C. L. (2007). Repetition blindness: An emergent property of
inter-item competition. Manuscript submitted for publication.
Segui, J., & Grainger, J. (1990). Priming word recognition with orthographic neighbors: Effects of relative prime-
target frequency. Journal of Experimental Psychology: Human Perception and Performance,16, 65-76.