In the cognitive control literature, there is a group of effects called the proportion congruency effects that change the magnitude of the Stroop effect. Context-specific proportion congruency effect (CSPC) is one of this group of effects. In the related CSPC studies, Stroop stimuli are presented mostly congruent at one particular location and mostly incongruent at the other location. The Stroop effect for the mostly congruent location is larger as compared to the mostly incongruent condition and the reaction time difference between these two effects is called the CSPC effect (Crump, Gong, & Milliken, 2006). However, this effect has some replicability problems (Hutcheon & Spieler, 2017). Besides, most of the studies which founded CSPC effect used the prime-probe version of the Stroop task which is different from the tasks conventionally used in the literature. This specific version of the Stroop task might create uncertainty on stimuli since the color words are presented at the center of the screen for 100 ms, before the presentation of the color patch at the bottom or top half of the screen. In this way, participants always know the location of the prime word, but they never know the location of the color patch. Therefore, the uncertainty on the color dimension may affect the magnitude of Stroop effect and consequently inflate the CSPC effect. Additionally, participants may lose time while looking up or down for the color patch and this also may contribute the existing effect. By taking all these considerations into account, this study aims to examine the contribution of the prime-probe version of the Stroop task on the CSPC effect. For this purpose, there will be one experiment which has two between participant conditions. The first condition aims to manipulate the uncertainty of the word dimension. The second condition aims to eliminate the uncertainty of both word and color dimensions. In this condition, only the fixation cross' location will be uncertain. These experiments are expected to shed light on a possible confound in the CSPC effect.