The Five Senses and Beyond: The Encyclopedia of Perception - Jennifer L. Hellier 2017

Spatial Sequence Synesthesia

Synesthesia is the cross-integration of two or more sensory systems at the same time. There are two main categories used to classify synesthesia: perceptual, which is triggered by sensory stimuli such as sights and sounds, and conceptual, which involves abstract concepts such as time and calendars. The most prevalent conceptual form of synesthesia is spatial sequence synesthesia, which involves the synesthetes seeing units of time or mathematical concepts as shapes in their extrapersonal space or their mind’s eye. These shapes can include being surrounded by the months of the year as a flat ribbon, each unit of time having a distinct shape and arranged like a Ferris wheel, or seeing the days of the week like a spiral staircase directly in front of you. It is estimated that approximately 20 percent of synesthetes experience spatial sequence synesthesia.

Synesthetic Experience

As with other forms of synesthesia, spatial sequence synesthesia is individual, consistent over time, idiosyncratic, and can evolve. There is a rich variety of detailed visual content that can be experienced by an individual with spatial sequence synesthesia such as associated visual images, color, texture, and written text. This variation reflects a distinction between spatial imagery and visual imagery. Spatial imagery can take the form of a spatial map with flexible viewpoints and is detailed and complex. Visual imagery represents visual surface properties and depicts visual appearance. The majority of synesthetes with spatial sequence synesthesia experience both spatial and visual images as opposed to experiencing only one of the two. Spatial sequence synesthetes typically experience numerical sequences as floating in the space around them. This can include visualizing the months of the year in some pattern in space. One suggested idea is that this is part of the reasoning behind visualizing the calendar from left to right. This is based on a directional bias for reading in Western nations. Some synesthetes describe what they experience as having a mental map of sequences within their head.

Spatial Sequence Synesthesia and Memory

Spatial sequence synesthetes have also been shown to have superior memories over their nonsynesthete counterparts. This is in stark contrast to the historical viewpoint that all forms of synesthesia are a product of overactive imaginations or a sign of mental illness. Spatial sequence synesthetes have an automatic, built-in mnemonic reference that helps them to remember a sequence and as such they do not have to create one for themselves. Recently spatial sequence synesthesia has been linked to a superior ability to form memories. This type of synesthesia has also been linked to hyperthymestic syndrome where individuals can recall events with perfect clarity from any point in their lives. Scientists are now looking at the possible benefits of synesthesia. Does it improve memory or help in learning a musical instrument or in composing music? Research has indicated that synesthetes show a marked tendency to spend more time engaging in creative disciplines. It is believed that certain aspects of synesthesia could be taught. This is an exciting possibility that has far-reaching benefits for augmenting memory and working with some mental health disorders such as autism, dyslexia, and attention deficit hyperactivity disorder (ADHD).

Carolyn Johnson Atwater

See also: Auditory-Tactile Synesthesia; Grapheme-Color Synesthesia; Lexical-Gustatory Synesthesia; Mirror-Touch Synesthesia; Proprioception; Synesthesia

Further Reading

Jonas, Clare N., & Mark C. Price. (2014). Not all synesthetes are alike: Spatial vs. visual dimensions of sequence-space synesthesia. Frontiers in Psychology, 5, 1171. http://dx.doi.org/10.3389/fpsyg.2014.01171. Retrieved from http://journal.frontiersin.org/article/10.3389/fpsyg.2014.01171/full

Rothen, Nicolas, Kristin Jünemann, Andy D. Mealor, Vera Burckhardt, & Jamie Ward. (2015). The sensitivity and specificity of a diagnostic test of sequence-space synesthesia. Behavioral Research. http://dx.doi.org/10.3758/s13428-015-0656-2

Simner, Julia, Neil Mayo, & Mary-Jane Spiller. (2009). A foundation for savantism? Visuo-spatial synaesthetes present with cognitive benefits. Cortex, 45(10), 1246—1260.