The Role of Figurativeness and Modality on Semantic Processing: An N400 Study Stephen Agauas and Elizabeth Miller Faculty Advisor: Dr. Gwenda SchmidtBackground Words depicting actions (“jump”) produce activation of the primary motor cortex or motion processing regions of the brain in addition to language areas. (Hauk, Shtyrov, Pulvermuller, 2008) The neural substrate for the semantic processing of figurative language may be different than for literal language. (Schmidt, Seger, 2009) Results are conflicting. Many confounding variables. (Schmidt, Kranjec, Cardillo, Chatterjee, 2009) The most negative wave 400 ms post-stimulus (N400) is a measure of semantic processing. Participants Human participants ages (N=20) were native English speakers, right handed and had no self-reported psychological conditions. Hypothesis Motion and auditory metaphors have unique neural substrates. Discussion The interaction of modality and scalp location was significant. Neither modality nor figurativeness was shown to be significantly different. Trend present of auditory words eliciting higher N400 than motion. Scalp distribution changes suggest activation of different regions of the brain. Limitations Familiarity, naturalness, and imageability were measured but not controlled. The effect of figurativeness upon the N400 is still unclear. Response task was not normed. Future Studies Control for more known confounds. Consider adjusting response task. Acknowledgements Hope College Psychology Department Provost Ray Stimuli System Eprime Biosemi Actiview Analysis EMSE Suite Eliminated Participants who blinked too much (n=16) Filters Digital Reference – Linked Mastoids FIR – Bandpass (low – 0.1 Hz High 35 Hz) Averaging Time (-0.2 – 0.7) Magnitude (±100μV) Tracked correct responses Detrend (Polynomial 1) ConditionSentenceEndingDoes the statement make sense? (Y/N) Auditory LiteralThe cat's reproach was ahissThe kitty loved strangers. Auditory MetaphorHis posture was a cat'shissThe posture was threatening. Auditory LiteralHis advice was amumbleHe had the perfect solution for them. Auditory MetaphorHis handshake was amumbleThe handshake was strong. Motion LiteralThe grandfather's accident was afallHe had a cast on his arm for a month. Motion MetaphorThe divorce was a hardfallThe couple was given x-rays immediately. Motion LiteralThe skater's entrance was aglideHer grace was noticed by the judges. Motion MetaphorThe art major was aglideThe art major was floating. Results Cardillo Sentences Cardillo, E. R., Schmidt, G. L., Kranjec, A., & Chatterjee, A. (2010). Stimulus design is an obstacle course: 560 matched literal and metaphorical sentences for testing neural hypotheses about metaphor. Behavior Research Methods, 42, Cloze Probabilities Measured predictability of the last word sentence Response Statements Confirm participant comprehension Normed on Familiarity, Naturalness, Imageability Counterbalancing of blocks 1 practice, 12 tracked blocks 16 sentences (4 of each condition) per block Stimulus word was separated by 6 blocks Sample Sentences PASW Separated Electrodes in quadrants Repeated Measures Manova (2x2x4) 3 Explanatory Variables Modality (Auditory, Motion) Figurativeness (Literal, Metaphor) Quadrant (I, II, III, IV) Response Variable N400 Area under the curve ( s) Anova – Behavioral Statistics Reaction Time Accuracy Sentence + Ending xxxx Response + (Participant Initiated) (300ms) (200ms) (900ms) (5000ms) ( ms) Randomizing within blocks Paradigm counterbalancing 4 Paradigms Participant Reaction Time for Each Sentence Type Four Conditions at Anterior Frontal Central Electrode Scalp Activity Across Four Conditions * P < The green box represents ~100 ms of measurement. N400 was measured within this range. Motion literal sentences elicited higher reaction time compared to motion metaphor sentences (P< 0.05). Rerferences Hauk, O., Shtyrov, Y., Pulvermuller, F. (2008) The time course of action and action-word comprehension in the human brain as revealed by neurophysiology. Journal of Physiology-Paris, 102, Schmidt, G.L, Seger, C.A. (2009) Neural Correlates of metaphor processing: The roles of figurativeness and difficulty. Brain and Cognition, 71, Schmidt, G.L., Kranjec, A., Cardillo, E.R., Chatterjee, A. (2009) Beyond Laterality: A Critical Assessment of Research on the Neural Basis of Metaphor. Journal of the International Neuropsychological Society, 1-5 Note: Y-axis is reversed due to negative values