Synesthesia and Memory

I saw this interesting paper while closing browser tabs. It repeats a some very unlikely, anecdotal memory feats, but it’s still worth reading.

Conventionally, the stimulus triggering a synaesthetic experience is called the inducer and the elicited experience is called the concurrent (GrossenbacherandLovelace, 2001). A specific form of synaesthesia is usually indicated by first naming the inducer hyphenated with it sconcurrent (e.g., grapheme-colour synaesthesia). Accordingly, synaesthetic experiences are usually reported to be unidirectional (e.g., letters trigger colours, but not vice versa). However, on an implicit basis concurrents (e.g., colour information) can affect inducer related tasks (i.e., implicit bidirectionality; Bruggeretal., 2004; Cohen Kadosh and Henik, 2006; Meier and Rothen, 2007; Rothenetal., 2010). Synaesthesia has an early onset in life (Simneretal., 2009 a). It runs in families and hence, seems to have a genetic basis (Barnettetal., 2008a; Asheretal., 2009). Generally, about five percent of the general population are affected by one or several forms of synaesthesia. To date, the best studied form is grapheme-colour synaesthesia which is found in about onepercent of the general population (Simneretal., 2006). Another well studied form is sequence-space synaesthesia in which sequences as numbers, days of the week, and so on, are perceived in explicit and highly specific spatial arrangements. So far, memory studies on synaesthesia are limited to these two forms of synaesthesia.

There is a section about eidetic memory that cites some other resources that look interesting:

In the context of memory performance and imagery, it is also important to consider eidetic memory. It can be described as the persistence of a visual image after the according stimulus has been removed (Allport, 1924). It is to be differentiated from non-visual memory and afterimages. In contrast to afterimages, eye movements during stimulus inspection do no prevent eidetic images from occurring, additionally they are positive in colouration and do not shift with eye movements (Girayetal., 1976; Haber, 1979). Eidetic imagery is predominantly, but rarely, found in children from 6 to 12 years and virtually absent in adult populations (Girayetal., 1976). It is important to mention that eidetic imagery is not photographic and hence does not generally benefit memory performance (cf., Haber, 1979).

The PDF is online here:

I’ve only read half of it so far, but will finish it later tonight.