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Priming effects depend on relative stimulus strength during continuous flash suppression

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posted on 2019-08-15, 11:33 authored by Christian ValuchChristian Valuch, Uwe Mattler
Poster session presented at the European Conference on Visual Perception, August 27-31, 2017, Berlin, Germany.

Visual awareness of a static stimulus presented to one eyecan be strongly suppressed by continuously flashing high-contrast patterns to the other eye. Here we employed Con-tinuous Flash Suppression (CFS) to examine stimulus pro-cessing in the absence of awareness. Simple arrow stimulipointing left or right were employed as primes which weresuppressed by CFS. Visible arrow stimuli (targets) followed100, 200, or 300 milliseconds after the onset of primes. Par-ticipants performed two tasks, randomly intermixed acrosstrials. In half of trials, participants gave speeded manual left/ right responses to the visible targets. In the other half oftrials, participants discriminated whether primes were point-ing left or right. In Experiment 1, we manipulated primestrength (low vs. high contrast). Response times and ac-curacy were reduced when prime and target were congruentrather than incongruent. This priming effect was larger withhigh-contrast primes than with low-contrast primes, wherethe effect increased with prime-target onset asynchrony.Moreover, priming effects varied considerably across partic-ipants with a strong linear relationship between individualdepth of suppression (indexed by prime discrimination per-formance) and the size of the priming effect. In Experiment2, we individually adjusted the contrast of CFS suppressorsto different prime discrimination thresholds. Thereby, weequalized relative stimulus strength across participants andconfirmed the results of Experiment 1 within participants.We discuss our data with regard to the notion of stimulusstrength in binocular rivalry and outline implications for theuse of CFS in priming experiments.