Different types of synaesthesia trigger different types of extraordinary experiences. For instance, letters and numbers are associated with specific colours in grapheme-colour synaesthesia, and days of the week and months of the year are associated with specific spatial positions in sequence-space synaesthesia. The project requires us to rethink conditions like synaesthesia as not just representing extraordinary experiences, but that the changes in the brains of synaesthetes support a distinct cognitive profile. For instance, a decade of group studies on memory in grapheme-colour synaesthesia is providing increasing evidence for a specific profile of enhanced memory which cannot be explained by means of conventional memory strategies but is rather supported by representational views of perception and memory, according to which the memory advantage in grapheme-colour synaesthesia reflects the structural and functional divisions of the human visual system.
The primary goal of this project is to further develop theories on the relationship between perceptual ability and memory performance. We will use a systematic experimental approach with different special populations (e.g., different types of synaesthetes and first degree non-synaesthetic relatives of genuine synaesthetes) to further inform on the relationship between perception and memory.
The primary aim of this project is to advance theoretical understanding of the relationship between perceptual ability and memory performance. Synaesthesia is a perceptual phenomenon experienced by otherwise healthy individuals, in which particular stimuli automatically and consistently evoke additional perceptual experiences. For example, individuals with grapheme-colour synaesthesia associate letters and numbers with specific colours, whereas individuals with sequence-space synaesthesia experience ordered sequences, such as days of the week or months of the year, as occupying specific spatial locations.
This project moves beyond the conceptualization of synaesthesia as representing extraordinary experiences. Instead, it proposes that the neural and cognitive characteristics associated with synaesthesia may give rise to a broader and distinctive cognitive profile. For instance, more than a decade of group-level research on memory in grapheme-colour synaesthesia is providing increasing evidence for a specific profile of enhanced memory performance which cannot be explained by means of conventional mnemonic strategies but is rather supported by representational views of perception and memory.
This project proposes a systematic experimental approach, based on double dissociations, to inform theories of individual differences in human cognition from a healthy special-populations perspective. Specifically, this project argues that research should focus not only on the presence or absence of synaesthesia, but also on cognitive profiles similar to synaesthesia which can be found in varying degrees in the general population without synaesthesia. Accordingly, the project will examine three groups: 1) individuals with different forms of synaesthesia, including grapheme-colour and sequence-space synaesthesia; 2) non-synaesthetic individuals whose visual perceptual abilities resemble those associated with particular forms of synaesthesia; and 3) non-synaesthetic first-degree relatives of individuals with genuine synaesthesia. These different groups of participants will complete assessments of visual perceptual ability and memory performance. This design will allow an investigation of whether domain-specific perceptual advantages are associated with corresponding benefits in memory. The use of a double-dissociation approach will also address longstanding methodological concerns regarding previous studies of synaesthesia, including the possibility that observed group differences may reflect variation in motivation, familiarity with research procedures, or recruitment from established participant databases rather than genuine cognitive differences.
It is predicted that, 1) grapheme-colour synaesthetes will demonstrate enhanced perception and memory for colour information, whereas sequence-space synaesthetes will demonstrate enhanced perception and memory for spatial information, in comparison to each other and non-synesthetic controls; 2) non-synaesthetic individuals with similar perceptual profiles as synaesthetes, will resemble these synaethestes in memory performance; and 3) non-synaesthetic first-degree relatives of synaesthetes will show perceptual and memory profiles similar to those of their synaesthetic relatives and will outperform non-synaesthetic individuals without a first-degree family history of synaesthesia.
Using this systematic approach, the project will contribute to theories of the relationship between perceptual ability and memory performance while addressing a longstanding question in synaesthesia research: what can unusual perceptual experiences reveal about the organisation of the human mind? More broadly, the project aims to establish a framework for investigating individual differences in cognition through the study of healthy special populations, thereby extending its theoretical relevance beyond synaesthesia itself.
Stage 1 Accepted Manuscripts (Registered Reports)
How perceptual ability shapes memory: An investigation in healthy special populations.
Lien : https://osf.io/zm3k8/files/mxdwe
Synaesthesia as a model for assessing individual differences in visual perception and memory performance.
Lien : https://osf.io/ej3gb/files/d8ujk
