4 research outputs found
Recommended from our members
A clinical, neuropsychological, and forensic investigation of congenital aphantasia
Congenital aphantasia is a neurodevelopmental condition characterised by markedly impaired visual imagery determined from birth. For example, when asked to imagine a sunset, most people can ‘see’ an image of the scene within their mind’s eye. People with aphantasia do not experience an internal image, despite knowing what a sunset looks like. Aphantasia only entered mainstream science in recent years, meaning our understanding of the condition is relatively limited. Through four experimental studies, this thesis will enhance our understanding of aphantasia from a clinical, neuropsychological, and forensic perspective. Chapter 2 asks how often aphantasia occurs in the general population, providing a reliable prevalence estimate. Chapter 3 examines how aphantasia intersects with the clinical condition of autism, and the neuropsychological condition of synaesthesia – both traits themselves characterised by imagery differences. Here, I show that aphantasics tend to experience high levels of autistic traits, and have an unusual profile of (certain types of) synaesthesia. Chapter 4 examines the broader sensory/imagery profile of aphantasia. Here, I show that aphantasia is often tied to low imagery beyond the visual domain (weak auditory imagery, olfactory imagery, etc.), and I coin the term dysikonesia to characterise multi-sensory imagery weakness (where aphantasia is the visual subtype). I also show that aphantasics tend to experience lower levels of sensory sensitivity (i.e., differences in responsivity to incoming sensation) across multiple senses. These findings demonstrate for the first time that mental imagery and sensory sensitivity are linked. Finally, Chapter 5 explores the forensic question of whether imagery influences face processing. I show that aphantasia is linked to weak face recognition and perception, but intact abilities when constructing face composites. Overall, this thesis shows that aphantasia is linked to a distinct psychological profile, with clinical, neuropsychological, and forensic implications. Together, this body of work serves to enhance our understanding of aphantasia, and mental imagery more broadly
Recommended from our members
What is the link between mental imagery and sensory sensitivity? Insights from aphantasia
People with aphantasia have impoverished visual imagery so struggle to form mental pictures in the mind's eye. By testing people with and without aphantasia, we investigate the relationship between sensory imagery and sensory sensitivity (i.e., hyper- or hypo-reactivity to incoming signals through the sense organs). In Experiment 1 we first show that people with aphantasia report impaired imagery across multiple domains (e.g., olfactory, gustatory etc.) rather than simply vision. Importantly, we also show that imagery is related to sensory sensitivity: aphantasics reported not only lower imagery, but also lower sensory sensitivity. In Experiment 2, we showed a similar relationship between imagery and sensitivity in the general population. Finally, in Experiment 3 we found behavioural corroboration in a Pattern Glare Task, in which aphantasics experienced less visual discomfort and fewer visual distortions typically associated with sensory sensitivity. Our results suggest for the very first time that sensory imagery and sensory sensitivity are related, and that aphantasics are characterised by both lower imagery, and lower sensitivity. Our results also suggest that aphantasia (absence of visual imagery) may be more accurately defined as a subtype of a broader imagery deficit we name dysikonesia, in which weak or absent imagery occurs across multiple senses
Recommended from our members
Mental imagery and visual attentional templates: a dissociation
There is a growing interest in the relationship between mental images and attentional templates as
both are considered pictorial representations that involve similar neural mechanisms. Here, we
investigated the role of mental imagery in the automatic implementation of attentional templates
and their effect on involuntary attention. We developed a novel version of the contingent capture
paradigm designed to encourage the generation of a new template on each trial and measure
contingent spatial capture by a template-matching visual feature (color). Participants were required
to search at four different locations for a specific object indicated at the start of each trial.
Immediately prior to the search display, color cues were presented surrounding the potential target
locations, one of which matched the target color (e.g., red for strawberry).
Across three experiments, our task induced a robust contingent capture effect, reflected by
faster responses when the target appeared in the location previously occupied by the targetmatching
cue. Contrary to our predictions, this effect remained consistent regardless of self-reported
individual differences in visual mental imagery (Experiment 1, N = 216) or trial-by-trial variation of
voluntary imagery vividness (Experiment 2, N = 121). Moreover, contingent capture was observed
even among aphantasic participants, who report no imagery (Experiment 3, N = 91). The magnitude
of the effect was not reduced in aphantasics compared to a control sample of non-aphantasics,
although the two groups reported substantial differences in their search strategy and exhibited
differences in overall speed and accuracy. Our results hence establish a dissociation between the
generation and implementation of attentional templates for a visual feature (color) and subjectively
experienced imagery.</p
Mental imagery and visual attentional templates: a dissociation
There is a growing interest in the relationship between mental images and attentional templates as
both are considered pictorial representations that involve similar neural mechanisms. Here, we
investigated the role of mental imagery in the automatic implementation of attentional templates
and their effect on involuntary attention. We developed a novel version of the contingent capture
paradigm designed to encourage the generation of a new template on each trial and measure
contingent spatial capture by a template-matching visual feature (color). Participants were required
to search at four different locations for a specific object indicated at the start of each trial.
Immediately prior to the search display, color cues were presented surrounding the potential target
locations, one of which matched the target color (e.g., red for strawberry).
Across three experiments, our task induced a robust contingent capture effect, reflected by
faster responses when the target appeared in the location previously occupied by the targetmatching
cue. Contrary to our predictions, this effect remained consistent regardless of self-reported
individual differences in visual mental imagery (Experiment 1, N = 216) or trial-by-trial variation of
voluntary imagery vividness (Experiment 2, N = 121). Moreover, contingent capture was observed
even among aphantasic participants, who report no imagery (Experiment 3, N = 91). The magnitude
of the effect was not reduced in aphantasics compared to a control sample of non-aphantasics,
although the two groups reported substantial differences in their search strategy and exhibited
differences in overall speed and accuracy. Our results hence establish a dissociation between the
generation and implementation of attentional templates for a visual feature (color) and subjectively
experienced imagery.</p