Date on Senior Honors Thesis


Document Type

Senior Honors Thesis


Psychological and Brain Sciences

Degree Program

College of Arts and Sciences

Author's Keywords

spectral contrast; auditory perception; sound; speech


Spectral contrast effects are context-dependent effects that influence the way we perceive certain sounds. Evidence of these effects can be seen in experiments where a precursor sound (e.g. a sentence) is followed by a target vowel sound (like /ɪ/ as in "bit" or /ɛ/ as in "bet"). If the precursor's frequency was emphasized in areas more consistent with the frequency of /ɛ/, listeners tend to perceive the target sound to be the opposite i.e. /ɪ/. A recent study shows using sentence precursors from 200 different talkers diminishes these effects questioning previous claims that talker variability has no influence on spectral contrast effects (Assgari & Stilp, 2015; Lain, Liu, Lotto, & Holt 2012). This study investigated the influence of one, four, eight, and sixteen talkers using conversational speech. Sentences were filtered with +5 dB filter gain to emphasize frequency regions consistent with either /ɛ/ or /ɪ/. One-talker, four-talker, and eighttalker conditions all produced contrast effects while the sixteen-talker condition failed to produce an effect. Results suggest talker variability has a greater influence on spectral contrast effects than previously thought.