Top-down vs bottom-up processes in synesthetic perception

Synesthesia is a phenomenon in which individuals experience multi-sensory perceptions when presented with a single stimulus. Grapheme-color synesthetes perceive color when presented with black text. There are conflicting reports in synesthesia research regarding top-down & bottom-up processes; both are believed to be responsible for percepts experienced in grapheme-color synesthetes. Paradigms that can tease apart these two competing mechanisms should be utilized. Priming studies have been utilized in the past to observe top-down & bottom-up processes in synesthesia; however, presently compelling evidence exists supporting both mechanisms & additional investigation is needed. The current experiment observed reaction times of grapheme-color synesthetes who completed a task utilizing competing primes. Findings from this research reveal patterns that lend themselves to better understanding the driving processes in this phenomenon.