Individual differences in perceptual experiences: Exploring associations between imagery vividness, sensory (processing) sensitivity, synaesthesia, and (subclinical) psychiatric traits

Mental imagery, perceptual processing not directly triggered by sensory input (Nanay, 2021), is a top-down process that can be used as a proxy of top-down influences on perception during perceptual inference (Konigsmark et al., 2021; Pearson, 2019; Salge et al., 2021). Sensory (processing) sensitivity is a trait described as a heightened sensitivity to sensory information, with or without an increased depth of information processing, emotional reactivity, and empathic reactivity (Aron et al., 2012; Greven et al., 2019; Greven et al., 2025), that is theorized to be indicative of bottom-up influences on perception during perceptual inference (Greven et al., 2025). According to the predictive processing theory of perception (Clark, 2013; Friston, 2005; Walsh et al., 2020), typical perception depends on a balance between top-down and bottom-up processes. In this study, we aim to leverage individual differences in mental imagery vividness and sensory (processing) sensitivity to understand more about top-down and bottom-up influences in divergent perception in the general, non-clinical, population.
It has been proposed that in divergent perception the balance between top-down and bottom-up influences during perceptual inference is altered, for instance in the case of divergent perceptual experiences in psychosis (Corlett et al., 2019; Friston, 2005; Sterzer et al., 2018), neurodevelopmental conditions such as autism (Lawson et al., 2014; Van de Cruys et al., 2014; van Leeuwen et al., 2020), and in synaesthesia (Seth, 2014; van Leeuwen et al., 2020). For example, psychotic experiences (e.g., delusions, hallucinations) have been associated with weak, imprecise priors (e.g., priors fail to suppress inner speech, resulting in delusions) as well as strong, overly precise priors (e.g., perception relying more strongly on internally generated beliefs than on bottom-up sensory input, resulting in hallucinations) (Goodwin et al., 2026; Sterzer et al., 2018).
To study how divergent perception can arise from a disbalance in bottom-up and top-down influences on perception in the general, non-clinical, population, we turn to individual differences in mental imagery and sensory (processing) sensitivity, and specifically the extremes of these traits. At the extreme ends of imagery vividness (1-3% of individuals; Zeman, 2024) are individuals with aphantasia (complete lack of mental imagery) or hyperphantasia (extremely vivid mental imagery). Additionally, 20-30% of people qualify as highly sensitive (e.g., Lionetti et al., 2018). If imagery vividness and sensory (processing) sensitivity are regarded as a proxy of top-down and bottom-up influences on perception, respectively, extremes in imagery vividness and sensory (processing) sensitivity could be leveraged to help understand mechanisms through which divergent perception occurs. Following this logic, lower extremes in imagery vividness (proxy of top-down processing) should be associated with lower extremes in sensory (processing) sensitivity (proxy of bottom-up processing), such that an individual’s position on the “top-down-scale” is equal to their position on the “bottom-up-scale”. Indeed, diminished sensory sensitivity has been shown in people with aphantasia (Dance et al., 2021), even though in general there does not seem to be a correlation between imagery vividness and sensory sensitivity (Taylor et al., 2026).
Building on this, perceptual extremes (aphantasia, hyperphantasia, high sensory (processing) sensitivity) should be associated with divergent perceptual experiences (e.g., hallucinations, synaesthesia, divergent perceptual characteristics of autism, see Reeder et al., 2024), especially in the case of an imbalance between extremes (e.g., high imagery vividness combined with low sensory (processing) sensitivity). Previous studies confirm that imagery vividness is indeed higher in synaesthesia (e.g., Spiller et al., 2019; Spiller et al., 2015) and schizophrenia (e.g., Böcker et al., 2000). Similarly, sensory sensitivity is enhanced in synaesthesia (van Leeuwen et al., 2019; Ward et al., 2017), altered in autism (Tomchek & Dunn, 2007) and affected in schizophrenia (e.g., Doniger et al., 2001). However, to our knowledge, no previous studies have looked at individual differences in both imagery vividness and sensory (processing) sensitivity in the context of divergent perception.
In the current study, we examine how these individual differences relate to each other and to (clusters of) sub-clinical psychiatric traits. Specifically, we hypothesize that an imbalance in imagery vividness and sensory (processing) sensitivity will be associated with elevated levels of synaesthesia and subclinical psychiatric traits. For example, extremes in imagery vividness in combination with sensory hyposensitivity are thought to be associated with psychosis-like divergent perception, and extremes in imagery vividness in combination with sensory hypersensitivity with synaesthesia-like divergent perception (cf. Reeder et al., 2024). Furthermore, we hypothesize that imagery vividness predicts the sensory richness of psychosis (i.e., hallucinations versus delusions), synaesthesia (i.e., likeliness to experience concurrents as sensory versus abstract), and autistic traits (cf. Reeder et al., 2024).
Pilot data (Mak et al., 2024) from 476 participants on a subset of questionnaires showed that imagery vividness and sensory (processing) sensitivity are indeed positively correlated. Additionally, both imagery vividness and sensory processing sensitivity) appeared to be associated with divergent perception. Principal Component Analysis suggested that imagery vividness and positive aspects of sensory processing sensitivity (e.g., aesthetic sensitivity, social-affective sensitivity) were associated with psychotic-like experiences (i.e., hallucination and delusion proneness), whereas hypersensitivity and negative aspects of sensory processing sensitivity (e.g., tendency to get overwhelmed by sensory stimuli) were associated with multiple subclinical psychiatric traits (such as generalized anxiety, depression, and autistic traits). However, due to the nature of the pilot data (i.e., low N aphantasics and hyperphantasics), we were unable to specifically test our hypotheses regarding perceptual extremes (in imagery vividness and sensory (processing) sensitivity).
Therefore, we are currently finishing data collection (N = 672 completed) of a large data set overrepresenting participants at the extremes of the mental imagery vividness-continuum, synaesthesia, and sensory (processing) sensitivity (currently 82 aphantasic, 128 hyperphantasic, 129 synaesthetic and 134 high SPS participants, as well as control participants). Data from this cohort will enable us to test for associations between imagery vividness, sensory (processing) sensitivity and subclinical psychiatric traits in people with extreme perceptual experiences. At the IRCA conference, we will present the results from this study, shedding light on the associations between perceptual extremes (in mental imagery, sensory (processing) sensitivity), and divergent perception.