References

1. Dissociative Effects of Prime Duration, Lexicality, and Word Frequency in Lexical DecisionMary L. Still Alison L. MorrisIowa State University Experiment 2: High N Stimuli Orthographic Priming Experiment 1: Low N Stimuli • Orthographic priming has been used to investigate word recognition. • The logic is that processing of one item will facilitate or inhibit the • processing of a subsequent similar item. Recently orthographic priming • experiments have focused on testing models of word recognition, but • several issues remain problematic (Davis, 2003). • Potentially Problematic Findings – Lexical decision • Frequency effect(Segui & Grainger, 1990) • Masked primes: higher freq primes interfere with lower freq targets • Unmasked primes: lower freq primes interfere with higher freq targets • Neighborhood Density Constraint(e.g., Forster & Davis, 1991) • Orthographic priming occurs for targets with few neighbors (low density), but not for targets with many neighbors (high density) • Models of word recognition do not predict a difference • Prime Duration(Davis, 2003) • Models of word recognition predict that priming increases as prime exposure duration increases • Human results do not follow this pattern • Research Questions • Can interference effects be explained without lexical inhibition? • Can the frequency effect be explained without assuming differences between masked and unmasked priming? • Why is facilitation not found for High N targets? • Current Experiments – Experiment 1 extends Davis and Lupker’s (2006) Experiment 1 using their design and stimuli (replacing a few items). Experiment 2 has the same design but used high N stimuli. Frequency N Words 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 Results: * Interference effects were ubiquitous * Marginally sig. interference for HF targets preceded by nonword primes * Priming is not obtained for High N stimuli because they tend to produce interference Frequency N Words 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 represent interference Results: * 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 prime Competition Model of Orthographic Priming Implications 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. Conditions Prime Type WordNonword 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 References 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: Psychology Press. 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. http://www.psychology.iastate.edu/~almorris/Morris%20Lab/Presentations.htm