Department of Enrollment


Faculty Mentor Name

Dr. Michal Temkin Martinez

Report Date

Spring 6-1-2013

Document Type

Student Project


In this project, we have created an online portal containing a multi-faceted demonstration of categorical perception. We utilized the 2I2AFC (two-interval, two alternative forced choice) stimulus presentation method which should elicit more categorical results from students, helping to better demonstrate the phenomenon (Gerrits & Schouten, 2004), and provided different acoustic cues illustrating CP. In addition to illustrations of CP for F2 formant transition, the new online portal is used to illustrate voice onset timing (VOT; the cue that distinguishes between the sounds [b] and [p]), as well as how contextual factors and participants’ linguistic backgrounds affect CP. The contextual factors used are that of phonological context where categorical boundaries are shifted in order to accommodate phonological variation as described in Sumner (2011), and that of lexical context wherein categorical boundaries are shifted to give preference to perception of a word compared to a non-word, as described in Miller (2001). In demonstrating the effect of linguistic background on CP, the portal includes streams that demonstrate variation in native English speakers’ and native Japanese speakers’ CP of the sound, containing a set of previously collected results for each participant group, allowing students to compare their own results to others’ (McCandliss, et al., 2002; Minagawa-Kawai, Mori, & Sato, Running Head: DEVELOPMENT OF A NEW EXPERIMENT 2005; McKain, Best, & Strange, 1981). Finally, a stream within the portal demonstrates to what extent English-speaking participants’ can categorically perceive the contrast between two non- English sounds. The goal of designing this experiment is to equip instructors with a detailed and effective tool to supplement their instruction and facilitate a broader understanding of the complexities of speech perception.