Researchers have long suspected that grapheme-color synaesthesia is useful, but research on its utility has so far focused primarily on episodic memory and perceptual discrimination. Here we ask whether it can be harnessed during rule-based Category learning. Participants learned through trial and error to classify grapheme pairs that were organized into categories on the basis of their associa...

Synesthesia, the conscious, idiosyncratic, repeatable, and involuntary sensation of one sensory modality in response to another, is a condition that has puzzled both researchers and philosophers for centuries. Much time has been spent proving the condition's existence as well as investigating its etiology, but what can be learned from synesthesia remains a poorly discussed topic. Here, synaesth...

We describe a study of 11-year-old twin sisters who are physically identical in appearance but who have considerably different conscious experiences. One twin appears to be a synaesthete in that she states that she has specific colour experiences (i.e. photisms) whenever she views, hears or thinks of digits. The other twin does not report such conscious experiences when viewing, hearing or thin...

The visual content of out-of-body experiences (OBEs) has received little attention but a number of theories of OBEs include implicit predictions regarding the determinants of this phenomenological feature. Hypnagogic imagery and unusual sleep experiences, weak synaesthesia and preference for employing object and spatial visual imagic cognitive styles were psychometrically measured along with th...

In many cultures, one of the earliest representations of number to be learned is a fingercounting system. Although most children stop using their fingers to count as they grow more confident with number, traces of this system can still be seen in adulthood. For example, an individual’s finger-counting habits appear to affect the ways in which numbers are implicitly associated with certain areas...

It has been suggested that individuals with synaesthesia may show heightened creativity as a result of being able to form meaningful associations between disparate stimuli (e.g. colour, sound). In this study, a large sample (N=82) of people with various kinds of synaesthesia were given two psychometric tests of creativity (Remote Associates Test, Alternate Uses Test) and were also asked about t...

Figure 1. Induction of mirror-touch synaesthesia by transcranial electrical stimulation. (A) An incongruent visuo-tactile (VT) trial of the Hand task. The task (~6 min) was to report the site of the actual touch on the hand, while ignoring the viewed touch at the same (Congruent VT) or opposite location (Incongruent VT). In counterbalanced sessions, anodal or sham tDCS (1.5 mA, ~16 min) to S1 o...

Judgments about personalities and social traits can be made by relatively brief exposure to animate living things. Here we show that unusual architecture in the microstructure of the human brain is related to atypical mental projections of personality and social structure onto things that are neither living nor animate. Our participants experience automatic, life-long and consistent crossmodal ...