Neurophilosophy has an excellent piece on ‘time-space’ synaesthesia where affected individuals experience units of time – such as hours, days, or months – as occupying specific locations in space relative to their own body.
The image on the right is taken from a BBC News article on time-space synaesthesia and was drawn by one lady to illustrate how days of the week appear to her.
However, Neurophilosophy piece covers two new studies, one on a person with synaesthesia who experiences months in the space around her body in the form of a ‘7’ shape:
Michelle Jarick of the Synaesthesia Research Group at the University of Waterloo in Ontario and her colleagues describe the case of an individual whose time-space synaesthesia has a previously undescribed feature. Like other time-space synaesthetes, the 21-year-old individual, known as L, experiences the time of day and the months of the year as being represented in the space around her body. She experiences the hours of the day in the form of a large “clock face”, and her mental calender consists of a giant number “7”, which extends for approximately 1 meter around her waist, and on which the months of the year are arranged.
Both of the studies covered in the article demonstrate a crucial technique in synaesthesia research – in part, a demonstration that the effect is a genuine cross-over of the senses.
The general technique is the same no matter what form of synaesthesia you’re testing. It involves finding a task which will be changed by the triggered sense but not (or not so much) by the original perception.
For example, with the lady who drew the layout of her months in the image above, October appears on her right and July appears on her left.
So if you did a reaction task that involved indicating what side a word appeared on, you’d expect someone with this form of synaesthesia to do worse when October appeared on the left and July appeared on the right, owing to the confusion caused by the unfamiliar associations, or better when they appeared on the expected sides.
This form of study, where synaesthesia can be shown to improve or worsen performance on other tasks related mostly to the triggered perception is the basis of much research in this area, and the Neurophilosophy piece outlines how these two new studies have shown how time-space fusion is associated with better abilities in understanding time and space.
Link to Neurophilosophy on ‘The cognitive benefits of time-space synaesthesia’.
Link to BBC News on time-space synaesthesia.
Mind Hacks 
When I was a kid I went to Montessori school where visual learning was emphasized. A calendar circled the room with a season on each wall. I will always associate summer with the east wall, fall with the south, etc.
I guess I have this – and its also heavily influenced by visual cue. For example, I visualise numbers in blocks of ten with the same font as the book I learnt maths tables from. My calendar is similarly to that above, but my perspective is tethered to the current date (I currently see the rest of the year as a loop whilst standing in November)
I tend to imagine everything, especially dates and figures visually. It is so key to how I solve problems such as calculations (numbers float and arrange) I have no idea how non-synthestes do so. Huh.
Time-Space synaesthesia is no big deal. A parlor trick in a sense. May give you a slight advantage on multiple choice history exams (I did get a perfect score on the GRE) but is otherwise of no value or advantage. Had it all my life. It’s entirely automatic and requires no energy or effort. It’s just there. Like an in-house pop-up screen on a computer. Except it’s in your head. Anyone mention anything with a time dimension (history, evolution, etc.), well then your internal screen pops up with everything you know plastered across it. Rather like having six toes on one foot, in a sense. Interesting to brain scientists but not otherwise.