In the article

In the article, “Not all synaesthetes are created equal: Projector versus associator synaesthetes” by Dixon, Smilek, and Merikle(2004), the authors conducted a study to prove the difference between two different kinds of synaesthetes (projectors and associators) and their implications by using synaesthetic stroop color naming task performance patterns. They used the synaesthetic Stroop color-naming task and Stroop photism naming task to determine the difference between associators and projectors. The purpose of this was to clarify previous discrepancies with biased reports and prove the difference of these two synaesthetes based on actual evidence. Projectors and associators not only reported differing in subjective reports but they were also revealed to be different in the stroop tasks. They found that some projectors claimed that they experienced their photisms through visual imagery and associators claimed to see their photisms through mental imagery, contrary to what previous biased reports had assumed. It was believed that both synaesthetes, projectors and associators, seen the same things when having a synaesthetic experience; however, the authors of this article thought otherwise, which was what led them to this conduct this study. To conduct this study, they separated the group of synaesthetes into two groups based on what the subjects had previously reported, and categorized them as projectors or associators. Then the two groups were evaluated to see if they performed differently on both the color and photism naming tasks. The authors came up with three hypotheses in this study. One was that projectors, when compared to associators, would show greater outcomes of Stroop effects in color naming due to their higher level of difficulty in their ability to ignore their photisms. They also hypothesized that video color intervention for projectors would be smaller than Stroop intervention from photisms, and for associators video colors would be bigger than stroop intervention from photisms. If photism colors are stronger than video colors for projectors then the photism color would be named faster than those of the video, and the opposite effects apply for associators.

In this study, there were twelve syneasthetes who have always had synesthesia and they were broken down into two groups. Based on what the subjects had previously reported, they were categorized as projectors or associators. The first group had 5 projectors which consisted of 4 females and 1 male with an average age of 34. The second group consisted of 7 females, with an average age of 42. In the first step of the procedure, Photism video color matching, there were a set of numbers in order from 0 to 9 next to a pallet of 256 squares with different colors. Then the synaesthetes would pick a color from the pallet that was closest to the color of their photism for that specific number, and they would rate how close the color experience of the video color was to the photism they experienced for each number. In the second step, color naming task, Synaesthetes had to ignore their photisms and quickly name the colors they were seeing in the video colors. In the last step, photos naming task, synaesthetes were to quickly name the color of the photism they see with the grapheme presented to them. The purpose of these tasks were to prove that there were at least two types of synaesthetes and they don’t experience synesthesia the same way. The errors made by the subjects and the response times were the two dependent variables in this study, and the tasks, (color naming vs. photism naming) congruency? (congruent vs. incongruent) ?, and synesthetic subtype (projectors vs. associators) being the independent variables. The error patterns showed that the patterns of response time were not affected by speed.
Response times were tested using a task, congruency and a synesthete subtype but the tests revealed a significant task, congruency and a subtype interaction. Projectors revealed a stroop effect very much larger than those of the associators when it came to the color naming task. The results showed that there was only one important effect of congruency. The congruency and synaesthete subtype interaction for naming the photism did not show a major effect.
It was faster for the projectors to name photisms than it was for them to name the video colors, and when it came to incongruent and congruent tests, there was a smaller difference on photism naming than there was on color naming. Associators responded quicker on congruent tests than on incongruent tests and were faster at color naming than they were at photism. For associators, interference of colors, outweighed the interference of photisms. The results of the study supported the authors’ hypothesis because when asked to ignore photisms, and name the video colors, projectors exhibited greater stroop effects than associators. The findings also proved that projectors turned out to be faster when naming photisms than video colors and associators were the opposite, naming video colors faster.
The results showed that there is a difference in every synaesthetes’ synesthetic experience, no two synaesthetes are the same. There are at least two types of syneasthetes (projectors and associators) and they do not experience synaesthesia the same way. For projector synaesthetes, the underlying activity that leads to a synaesthetic color experience are activated more spontaneous than the activity that leads to normal perception of the colors in a video, and when compared to associators, brain activity that leads to photisms were more spontaneous. The results of this study provides deeper understanding about what goes on in the brain that makes grapheme color synesthesia inevitable to ignore. Until the individual differences of the synaesthetes are acknowledged, research findings concerning grapheme color synesthesia will be inconsistent. Researchers must be careful when conducting group research of grapheme color synesthesia because there is great extent of difference in synaesthetes. The author suggests that more research should be conducted to determine which visual area is activated by grapheme induced photisms and they find that it is important for researchers to separate the projectors from associators when conducting their research.