The Synesthesia Tree: Spatial sequence synesthesia

Often abbreviated to SSS

Other, less-used, names for it are Sequence-spatial, Sequence-space and Visuo-spatial synesthesia

Image created by The_Flower_Garden in this post on the online debate platform Reddit/Synesthesia. 2022

Spatial sequence synesthesia consists of visualising certain sequences in physical space. There are different types, and a particular synesthete may have just one type or several at the same time. The types are:

1. Calendar synesthesia (time-space synesthesia)

2. Number form synesthesia

3. Letter form (or alphabet form) synesthesia

4. Spatial visualisation of other sequences (school subjects, books of the Bible and signs of the zodiac are a few examples).

The first type (calendar synesthesia) is more common than the others, while type no. 4 appears to be the least common. In any case, even though no exact figures are currently agreed on, spatial sequencing has a high prevalence within the synesthete population and is even often found among people who have no other types of synesthesia. In the early study What is the relationship between synaesthesia and visuo-spatial number forms? (2005), Noam Sagiv and other major researchers found that 71% of a group of 114 colour synesthetes and 29% of 311 non-synesthete controls had some manifestations of one or more of the first three types, suggesting that spatial sequencing is quite a common phenomenon among both synesthetes and (otherwise) non-synesthetes alike, opening the door to questioning whether it should perhaps be considered an overlapping phenomenon also experienced by non-synesthetes, or whether the synesthetic population is actually much larger than the 4% estimated up to now.

"Spatial sequencers" perceive the months, dates, numbers, letters or other elements in a sequence in the physical space around them or in front of them. Apart from spatial position, these elements may also have their own colour, texture and shape. Projectors (a minority) see their sequences literally outside their own body space, while associators see them in the mind’s eye but not physically. Although the exact spatial arrangement is different for each person, it is consistent and tends to remain the same throughout their lifetime. The visual configuration of the sequences can be relatively simple, highly complex or anything in between: the elements might be on a horizontal, vertical or diagonal plane, in a ring or spiralling out of sight, progressing from left to right or vice versa and sometimes with many sudden or gradual changes of direction. Typically, the subject’s viewpoint can vary and the perspective can shift when necessary, so the synesthete feels that they are standing in front of the current month of the year, for example, with the rest of the months positioned accordingly and some of them even behind them and out of sight.

MAIN TYPES OF SPATIAL SEQUENCE SYNESTHESIA:

(the title links go to a description of each type, with examples)

CALENDAR SYNESTHESIA (TIME-SPACE SYNESTHESIA)