Title: numbers, illicit a color (Hubbard, Arman, Boynton, 2005).

Title: Memory and Learning in SynesthetesResearch Question: To what extent does synesthesia impact memory and learning?Word Count: Table of ContentsIntroduction………………………………………………………………………………………1Synesthesia as an Advantage on Memory and Learning…………………………………………..3Synesthesia and Negative Impacts on Memory and LearningConclusionReferences Memory and Learning in SynesthetesIntroduction: Synesthesia is a condition that has been known for the past two centuries, but that has only in the past few decades been psychologically researched. Furthermore, only in the past twenty years or so, has significant progress been made in thorough empirical study of synesthesia, and in understanding the specific mechanisms that give rise to it (Ward, 2013). Even so, a general consensus on the nature and effects of synesthesia has not yet been reached. This is due to the varied nature of the condition. Synesthesia manifests itself in many different forms. A common type, and the one most frequently discussed in this paper, is color-grapheme synesthesia, in which graphemes, such as letters and numbers, illicit a color (Hubbard, Arman, Boynton, 2005).  As synesthetes seem to experience no physical side effects aside from those caused by a synesthetic experience, it can be inferred that their condition originates from the brain. It has been established that “synesthetic experience may arise from abnormal cross-activation between the grapheme area and the color areas in the fusiform gyrus due to altered local connections” (Rogowska, 2015). Furthermore, it has been discovered that synesthetes have increased grey matter volumes in the fusiform and intra parietal cortices of the brain, furthering the theory of cross-activation in the fusiform gyrus (Rogowska, 2015). As there have been significant findings of the physical effects of synesthesia on the brain, it must also be considered what that might mean for the everyday applications of those effects in the brain of the synesthete, and whether or not this increased grey matter and cross-activation benefits or potentially hinders the synesthete in any way. This paper will examine the following question: To what extent does synesthesia impact memory and learning? The question asks if synesthesia has an impact on the memory and learning capabilities of the synesthete, and how much of an advantage they have over those with average cognitive ability, or, alternatively, how much of a disadvantage they have compared to those with average cognitive ability. Furthermore, it implies a questioning of how synesthetes fit into the modern world, with a focus on education and advancement in society. This issue is an important one, as there are synesthetes integrated into the general population, and understanding the implications of their condition can allow synesthetes to not feel as if they must hide their condition for fear of stigma and rejection. Education of conditions affecting the brain raises awareness for their existence. Due to the nature of color-grapheme synesthesia, certain graphemes have specific colors. For example, the author of this paper considers the letter “S” to be purple. However, a different synesthete would not have the same colors for the same graphemes. As such, they could see “S” as blue. This brings in the issue of congruent and incongruent colors. A congruent color is one where a grapheme lines up with the experience of the synesthete. Alternatively, an incongruent color is where the color of the grapheme is one that contradicts the synesthetic experience. How do congruent and incongruent graphemes affect the memory and learning of the synesthete? In this paper, the author analyzes several studies which deal with different aspects of the memory and learning capabilities of synesthetes when compared to the average person. The studies are organized into two categories, one being studies that suggest how synesthesia is an advantage in terms of memory and learning, and the other being studies that suggest the probability of synesthesia being a hindrance to memory and learning to the synesthete. The results, as well as the limitations of the studies are explained. Synesthesia as an Advantage on Memory and Learning: The work of some researchers finds that synesthesia can have a positive effect on the learning methods and overall memory of the synesthete, leading to increased retention of information over time and absorption of information in general. However, many of the studies examined in this paper have a small sampling of synesthetes, likely due to the relative difficulty of locating enough synesthetes within a given area to have a large sample. As a result, it is very important to discuss the implications and limitations of a given study, as analyzings its possible shortcomings gives insight into the relative validity and usefulness of any findings. A study on the memory and learning methods of synesthetes was conducted in 2013 by Nathan Witthoft and Jonathan Winawer from Stanford University. They investigated data from color-grapheme synesthetes whose color pairings were mostly traced to the colors of childhood toys. First, they administered a speed congruency test to the synesthetes, to determine whether or not their synesthesia was genuine. It was established in the study that scoring “at or above 85% on the speeded congruency task is typical for synesthetes” (Witthoft and Winawer, 2013). In the speed congruency test, the synesthetes were shown a grapheme, such as a letter, and they were asked to match it to a color. The synesthetes were then retested 54 days later, and their grapheme-color pairings, according to the study, were highly reliable and consistent, the mean correlation being 0.96. This high average correlation suggests that the grapheme-color associations synesthetes have stick with them for a long period of time, to the point where their accuracy in reproducing those same associations later is remarkably high. This advanced visual learning synesthetes seem to possess can be applied to other areas as well, such as spelling. If graphemes signal a visual response in synesthetes, then they will be able to make an association between a letter combination and a word much easier, resulting in a way to spell-check their work manually. The study is limited, however, due to the lack of control subjects (non-synesthetes) and the variation in time between re-testings. The lack of control subjects means there there is nothing to compare the data of the synesthete to, meaning that no reference point for how an average person would score on a re-testing is given. A sample of similar size should have also been taken from the population to take part in the study, to give a baseline for how good the synesthetes’ scores are compared to average ones. It was also mentioned that while there was a regulated period of at least 54 days between testings, 10 out of the 11 test subjects had a delay of over one year. This variation in testing time means that the results of the experiment could possibly be skewed, as accuracy could decrease over time, yielding an inaccurate measurement. Despite these limitations, the study is useful in suggesting how synesthetes use their grapheme-color associations to possibly enhance their memory. An issue that should be addressed in further investigation is how synesthetes’ color-grapheme associations over time compare with those of non-synesthetes. Another interesting study that investigates the potential associative memory advantages of synesthetes is an investigation by Pfeifer, Rothen, Ward, Sigala, and Chan in 2014. In the study, synesthetes and non-synesthetes were tested, in order to determine if synesthetes have an associative memory advantage over non-synesthetes. 14 young synesthetes, along with 14 non-synesthetes and 14 older adults participated in the experiment. Eight black-and-white fractal images were presented as pairs, and all participants were asked to study the pairings and memorize them, through trial and error. After being given time to memorize the pairs, the participants were given a test to see how many of the pairings they would be able to get correct.  The study states that the most interesting relationships could only be observed after looking at cumulative hit-rates across the test (Pfeifer, Rothen, Ward, Sigala, Chan, 2014). The difference in cumulative hit-rates between old and young adults is described as “medium”, while the difference between synesthetes and older adults is described as “large”. Meanwhile, the study states that the difference between young adults and synesthetes is “medium”. The study also states that the results of their null hypothesis significance tests were in line with their overall hypothesis, suggesting that synesthetes do possess an associative learning advantage. Young adults showed no significant learning advantage to the older adults, which does suggest a positive effect of synesthesia on associative learning. In this case, colors were not involved, eliminating the possibility that synesthetic advantages stem only from colored graphemes. The results of this experiment suggest that synesthetic visual learning techniques are applicable to multiple situations, not just in situations where colored graphemes are present. The study does have weaknesses, however. The study states that the results of a power analysis suggests that there is only a 50-60% chance of replicating the results of the experiment (Pfeifer, Rothen, Ward, Sigala, Chan, 2014). Also, the small sample groups have differences in their results, however the results of the study cannot be extrapolated to a larger population for practicality reasons. Similarly, this experiment could not reasonably be conducted on a large enough scale. Despite this, the study is useful in suggesting an associative learning advantage for synesthetes, and backs up its claims with numerous references to other studies on similar subjects. Other work also supports the superior working memory of synesthetes. An experiment conducted by Radvansky, Gibson, and McNerney in 2014 investigates the verbal complex working memory and performance within 10 synesthetes, comparing their results to 48 control participants. There were three complex span tests that were conducted in the study. In complex span test one, participants were presented with a set of two to six sentences. In complex span test two, the participants were shown two to six math problem and word pairs. The task was to determine if the solution presented in the math problem was correct or not. The word paired with the math problem was read aloud upon completion of the math problem. Finally, for complex span test three, the Walters and Caplan (1996) comprehension span test was used. Participants were asked to determine whether a sentence made logical sense or not. At the end of a set in tests one, two, and three, participants were asked to read the last word in each of the sentences, in the order they were given. As shown in table 1 (Radvansky, Gibson, and McNerney, 2014), synesthetes consistently scored higher in sentence span, comprehension span, and operation span, when compared to the control groups. These results suggest that the working memory of synesthetes, as evaluated by this study, is above average when compared to non-synesthetes. The study states that synesthetes have “superior working memory span” (Radvansky, Gibson, and McNerney, 2014), however, according to the evaluation of the results by the researchers, there seemed to be no indication that the processing of event breaks was affected by synesthesia. The results of this psychological study suggests that synesthesia can influence processing at the surface form and textbase levels, as demonstrated by the results shown in table 1. As such, it can be concluded that synesthetes are more quickly able to absorb and memorize information, giving them a learning advantage over the average person that could be beneficial in their everyday lives. Although, the study does have its limits. All participants were students at Notre Dame. The limited sample group means that the results may not be accurate when applied to the general population. The same can be said of age, as a university student is unlikely to be much older than their mid-20s. The small age sample means that the results may not hold true for older and younger populations, again preventing this data from being extrapolated to the general population. With that being said, the study is still valuable, as it suggests a possible relationship between synesthesia and superior working memory that has been compared against a very similar population.