Understanding grapheme personification: A social synaesthesia?

Abstract

Much of synaesthesia research focused on colour, but not all cross-domain correspondences reported by synaesthetes are strictly sensory. For example, some synaesthetes personify letters and numbers, in additional to visualising them in colour. First reported in the 1890's, the phenomenon has been largely ignored by scientists for more than a century with the exception of a few single case reports. In the present study, we collected detailed self reports on grapheme personification using a questionnaire, providing us with a comprehensive description of the phenomenology of grapheme personification. Next, we documented the behavioural consequences of personifying graphemes using a congruity paradigm involving a gender judgement task; we also examined whether personification is associated with heightened empathy as measured using Empathy Quotient (EQ) and found substantial individual differences within our sample. Lastly, we present the first neuroimaging case study of personification, indicating that the precuneus activation previously seen in other synaesthesia studies may be implicated in the process. We propose that frameworks for understanding synaesthesia could be extended into other domains of cognition and that grapheme personification shares more in common with normal cognition than may be readily apparent. This benign form of hyper-mentalising may provide a unique point of view on one of the most central problems in human cognition -understanding others' state of mind.

Social responsiveness to inanimate entities: Altered white matter in a ‘social synaesthesia’

“…It may be that differences in imagery are common across a range of synaesthesia (and indeed this certainly seems to be the case in behavioural terms; see Barnett & Newell, 2008;Simner, Mayo & Spiller, 2009;Rizza & Price, 2012;Havlik, Carmichael, & Simner, 2015). If imagery differences are at the root of the current findings in the corona radiata and body of the corpus callosum, these would join a third region --the cuneus --also implicated in imagery differences in sequence-personality synaesthesia in an fMRI study by Amin and colleagues (Amin et al, 2011).…”

“…Candidate regions in this latter regard might be somatosensory cortices and inferior parietal and frontal regions, all implicated in social responsiveness (Adolphs, 2003;see Discussion for further details). We may also find the involvement of more widely distributed regions e.g., Whitake et al, i pli ated pe haps i pa ietal i di g p o esses see 'ou & " holte, 2007) or self-reflection/ imagery (e.g., Amin et al, 2011). Key however are likely to be regions that reflect the primarily personality/social mappings that are inherent in the OLP/ sequence-personality experience.…”

“…There has been just one previous imaging study in this area, by Amin et al (2011) who presented functional rather than structural data, and tested a single synaesthete. Amin et al performed functional magnetic resonance imaging (fMRI) of a case-study with a relatively restricted form of sequence-personality synaesthesia in which just letters --and only a subset of the alphabet in particular--triggered personifications, and these personifications were limited to genders only (e.g., A might be, say, female).…”

“…Contemporary interest in OLP has reemerged sporadically in the last decade (Amin et al, 2011;Simner, Gartner, & Mills, 2011;Simner & Hubbard, 2006;Simner & Holenstein, 2007) but despite behavioural studies validating the consistency and automaticity of these associations (e.g., Simner & Holenstein, 2007) very little progress has been made understanding the neural architecture driving them. This architecture does not appear to involve regions tied to empathy for example, since, despite their unusual personality attributions, people with OLP score no higher than average on questionnaire such as the Empathy quotient (Baron-Cohen & Wheelwright, 2004).…”

“…Like more typical synaesthesias, OLP automatically and developmentally pairs two otherwise unrelated modalities, and is triggered by the most common triggers for synaesthesia in general (i.e., ordered sequences; see . It has therefore been suggested that OLP is a og iti e o so ial variant of synaesthesia (e.g., Simner & Holenstien, 2007;Amin et al, 2011) which we label henceforth as se ue e-pe so alit s aesthesia . He e e p ese t a st u tu al i agi g stud of a g oup of individuals with this form of OLP/ sequence-personality synaesthesia, to determine whether they show similar changes in brain structure that have been found in other variants of synaesthesia more broadly.…”