Cognitive Markers Of Synesthesia: A Study Of Stroop Test

Summary of the experiments

Synesthesia is recognized as the rare experience that becomes an interesting subject for psychological research (Weiss, Greenlee & Volberg, 2018). The psychological phenomena of Synesthesia have been developed decades ago but little research study provided a deep insight into the cognitive factor associated with the phenomena.    However, Globally, one in 2,000 people are synesthetes which further drives the current research where researchers are able to gain extensive knowledge of Synesthesia (APA, 2022). It also drives the authors of two articles discussed in this paper to gain knowledge of cognitive markers of Synesthesia.   Mattingley et al. (2001) and Lupiáñez and Callejas (2006), both aim to conduct research regarding Synesthesia. From Layman’s perception, Synesthesia is a neurological condition which causes a blending of the senses.  Therefore, individuals having Synesthesia are able to connect color with letters and numbers, connect touch to vision and smell and taste to music (Spiller et al., 2019).  Hence, the primary research question focused by Mattingley et al. (2001) is   how Unconscious priming eliminates automatic binding of color as well as alphanumeric for the individuals having synesthesia. On the other hand, Lupiáñez and Callejas (2006) conducted research based on the question “What is the automaticity of synesthetic perception and degree of control synesthetes able to apply?”  However, both researchers used Stroop test to support their hypothesis and contribute to the knowledge base of this psychological phenomenon. The paper aims to discuss the summary of the experiment, resembles the research experiment and findings in the following paragraphs.

From a psychological perspective, this phenomenon is an experience of an ethical dual perception where one sensory modality induces another vivid sensation of another sensory in response to a particular stimulus. The emerging literature emphasized on the fact that it is not a memory-based effect rather typically sensory (Weiss, Greenlee & Volberg, 2018).  Some of these experiences are developed from the stimulus created by mind’s eye.  Hence, it is become area of interest for the cognitive psychologists for carrying out basic studies that will show whether it is automatic phenomenon or not an whether it can be controlled by the individuals or not (Van Leeuwen, 2017).  However, the previous researchers unable to frame appropriate research method, especially experimental study that can provide comprehensive and clear knowledge of the phenomena and cognitive marker of the research.    However, discovery of Stroop test facilitates the research process by outlining a clear set of experimental components that can provide idea of clear phenomena (Scarpina and Tagini, 2017). Several researchers have used versions of the Stroop test to investigate synesthesia. This report will discuss the experimental components of   Stroop test in following paragraphs.

Summary of experimental study of first article

Mattingley et al. (2001), Investigated color-graphemic synesthesia amongst individuals who are able to experience idiosyncratic and connect color with the letters. Initially researchers compared synesthetes and control   using Stroop tests for assessing Any baseline differences in the susceptibility to the interference.  The researchers included 15 color graphemic synesthetes (13 females with mean age of 41.26) and 15 non-synesthetic controls. All of these individuals are screened for their impairment in neurological and color vision.  In this case, the experimental hypothesis is that   synesthetic experiences cannot be suppressed consciously (Mattingley et al. 2001). In this case, the independent variable is individuals having Synesthesia and able to embody synesthetic experiences because it has the ability to influence the sensory experience. On the other hand, experiences of overlapped sensory experience are dependent variables and perception of numbers and letters is associated with color (Mattingley et al., 2001).  All of these individuals are provided with a 150-item list containing a to z alphabet and words and there provided with opportunity to describe their color experience each item.  For experimental groups, three months later the same least again asked to indicate the synesthetic color experience for each item. However, for the control group the items provided for re-test for just one month.   All of the participants were tested in a sound attenuated booth (Mattingley et al., 2001). In a standard stupid task later are usually present in Times new Roman and each color appeared is time for with the actual color and four with incompatible. However, unlike classic research, the researchers modified the Stroop task by blocks of 36 trials where compatible and incompatible alphanumeric characters were presented with non-alphanumeric symbols (Mattingley et al., 2001).  By following the same modification of the Stroop test, the researchers conducted Priming experiments where they provided the opportunity to name the color of target patches having six overlapped typographical symbols.  Therefore, these patterns are developed by masks for proceeding primers and Stimuli and display sequences were identical to color task and untimed responses were recorded verbatim. In this case the visual stimuli that are displayed briefly and open blinded and hence participants may receive unconscious processing. The screen then remained blank for 372 or 344 ms before arriving at another target for 500 MS time duration (Mattingley et al., 2001). Hence, the Aim of the research is to test the prime identification in where participants able to name the alphanumeric prime rather than color of the target path. The main aim of the research is to a assess the dependable variables as individuals with the issue able to connect color with the letters. For analyzing the results researchers used descriptive statistics such as for   consistency of color associations, Mean, Mean percentage to assess correct identification of primer.

Summary of experimental study of second article

Lupiáñez and Callejas (2006), conducted two experiments, one for the control experiment by including standard Stroop color-naming task and second synesthesia experiments.  In this case research has focused on the experience of photism ,  vision or hallucination of light based. The research aims to assess whether it is an automatic process or not and additional focus on the triggers created by Black numbers and letters which induce experience of highly specific colors for the experimental groups. In standard Stroop color naming control experiment approximately 10 control participants voluntarily participated and all of them were female Psychology students from university and have had normal color vision (Lupiáñez &Callejas , 2006). The initial four colors were used as stimuli by writing colors with alphabets and each of them was displayed differently in different colors in different trials. On the other hand, 486 computers running MEL software where the color of the stimulus Will be displayed on the skin and participants are required to suggest the color when it is presented on the screen. The whole experiment consists of a block of practice trials 5 blocks of 36 trials each analysis of the Stroop effect, a function of the congruency was recorded as coding for matching with the actual color and others incompatible with the actual color and four with incompatible (Lupiáñez &Callejas, 2006).  The whole research followed incongruent trials preceded by incongruent trials   which were selected for the control condition. The effect of the congruency context was investigated using similar conditions and hence, it is conducted to ensure the appropriateness of the procedure being used in research.  On the other hand, for synesthesia experiments, Stroop and NP effects were assessed with different trials by including a female synesthete with 13 control participants (Lupiáñez &Callejas , 2006). They have two within-item factors such as N-Congruency (NCongruent, N-Incongruent) as well as N-1 Congruence (N-1 Congruent, N-1 Incongruent). For example, B in blue or incongruent B in red to identify the color and letter.  For analysis of research, three experiments and 2 Repetition of ANOVA were performed to gather findings of experimental research (Lupiáñez &Callejas , 2006).. The researchers also used other small independent variables such as Photos-naming participants, color, naming participants and color naming participants.

Synesthesia is a rare experience where one property of a stimulus evokes a second experience not associated with the first (Nanay,2020). The findings of the first experiment reported color-graphemic synesthesia is a phenomenon that may be triggered by automatic co activation of different independent brain areas which are responsible for processing the color as well as symbols.  Even though the researchers manipulated different physical colors displays for alphanumeric characters, interpretation of incongruent color words written in different print color usually takes longer for the participants having color-graphemic synesthesia compared to the control adults (Mattingley et al., 2001). Similar result executed in a second experiment where participants were able to name the physical color of the alphanumeric stimuli presented in the computer display (Lupiáñez &Callejas , 2006).  . This research has high implications in the clinical field and emerging literature because synesthetic colors cannot be suppressed consciously.  This is a significant issue because cognitive interference is first when there is a conflict between actual physical color and synesthetic colors. The only way to succeed in such experiences is to mask the induced Trigger.

Discussion of the experimental research

On the other hand, the findings of second research suggested that the participants having synesthesia exhibit significant to effect while naming the colors as well as naming the photisms. It is the automatic response rather than learnt response colors and specific graphemes It means in presence of stimuli it cannot be dismissed (Lupiáñez &Callejas , 2006). What was not included in the first research result is that it is specifically memorable because experience of connecting colors with letters enable individuals to repeat similar experience and it is emotional because senses are involved. Even though both our studies fail to consider the specific brain region responsible for such experience, the literature evidence suggested that higher levels of communication between sensory regions in the parietal and frontal lobe are responsible for such experience (Levy, Dixon & Soliman, 2017).

The major resemblance of two papers is that both the papers used Stroop test. Stroop Task is one of the best-known psychological experiments named after John Ridley Stroop. This experiment provides a clear illustration of people’s capacity for selective attention and the ability of some stimuli to escape attentional control (Shichel & Tzelgov, 2018). On the other hand, despite the different procedures followed in that experiment, both studies focus on the ability of Synesthetes to have synesthetic experiences by comparing synesthetes and non-synesthetic controls (Mattingley et al., 2001). In both cases control served as the baseline data so that was purchased and compared the level of control those experimental participants have and appropriate phenomena associated with psychological concept of Synesthesia. The first research article conducted two research simultaneously by comparing controls and experimental group while the second research article conducted to research separately for gaining similar results. In the second research, additionally, NP paradigm is used to study the capacity of the attentional system (Lupiáñez &Callejas , 2006). Both researchers used to use Stroop test to suggest Stroop effect that different print color usually takes longer for synesthetes participants compared to non-synesthetic controls. Hence, all of these can be used for assisting future researchers to focus on cognitive marker that influence   Synesthesia and diagnosis criteria for assessing Synesthesia.

Conclusion:

On a concluding note, it can be said that Synesthesia is a neurological condition which causes a blending of the senses and able to connect touch to vision and smell and taste to music.    However, the previous researchers unable to frame appropriate research method, especially experimental study that can provide comprehensive and clear knowledge of the phenomena and cognitive marker of the research. In this case, both the papers used Stroop test.  Both studies focus on the ability of Synesthetes to have synesthetic experiences by comparing synesthetes and non-synesthetic controls The findings reported that color-graphemic synesthesia is a phenomenon that may be triggered by automatic co activation of different independent brain areas which are responsible for processing the color as well as symbols.  While these studies fail to consider the specific brain region responsible for such experience, the literature evidence suggested that higher levels of communication between sensory regions in the parietal and frontal lobe are responsible for such experience. The future research must focus on cognitive marker that influence   Synesthesia and diagnosis criteria for assessing Synesthesia.

References:

APA (2022). Everyday fantasia: The world of synesthesia. Retrieved 24 March 2022 fromhttps://www.apa.org/monitor/mar01/synesthesia#:~:text=Research%20suggests%20that%20about%20one,some%20variation%20of%20the%20condition.

Levy, A. M., Dixon, M. J., & Soliman, S. (2017). Isolating automatic photism generation from strategic photism use in grapheme-colour synaesthesia. Consciousness and Cognition, 56, 165-177. https://www.sciencedirect.com/science/article/abs/pii/S1053810017304129

Lupiáñez, J., & Callejas, A. (2006). Automatic perception and synaesthesia: Evidence from colour and photism naming in a stroop-negative priming task. Cortex, 42(2), 204-212. https://www.sciencedirect.com/science/article/abs/pii/S0010945208703459

Mattingley, J. B., Rich, A. N., Yelland, G., & Bradshaw, J. L. (2001). Unconscious priming eliminates automatic binding of colour and alphanumeric form in synaesthesia. Nature, 410(6828), 580-582. https://www.nature.com/articles/35069062

Nanay, B. (2020). Synesthesia as (multimodal) mental imagery. Multisensory Research, 34(3), 281-296. https://brill.com/view/journals/msr/34/3/article-p281_4.xml

Scarpina, F., & Tagini, S. (2017). The stroop color and word test. Frontiers in psychology, 8, 557. https://www.frontiersin.org/articles/10.3389/fpsyg.2017.00557/full

Shichel, I., & Tzelgov, J. (2018). Modulation of conflicts in the Stroop effect. Acta Psychologica, 189, 93-102. https://www.sciencedirect.com/science/article/abs/pii/S1053810017304129

Spiller, M. J., Harkry, L., McCullagh, F., Thoma, V., & Jonas, C. (2019). Exploring the relationship between grapheme colour-picking consistency and mental imagery. Philosophical Transactions of the Royal Society B, 374(1787), 20190023. https://royalsocietypublishing.org/doi/full/10.1098/rstb.2019.0023

Van Leeuwen, T. (2017). A social semiotic theory of synesthesia?-A discussion paper. Hermes-Journal of Language and Communication in Business, (55), 105-119.https://tidsskrift.dk/her/article/view/24292

Weiss, F., Greenlee, M. W., & Volberg, G. (2018). Gray bananas and a red letter A—From synesthetic sensation to memory colors. i-Perception, 9(3), 2041669518777515. https://journals.sagepub.com/doi/full/10.1177/2041669518777515