“Deep Aphantasia: a Visual Brain With Minimal Influence from Priors or Inhibitory Feedback?”, 2024-01-04 ():
The authors are both self-described congenital aphantasics, who feel they have never been able to have volitional imagined visual experiences during their waking lives. In addition, Loren has atypical experiences of a number of visual phenomena that involve an extrapolation or integration of visual information across space.
In this perspective, we describe Loren’s atypical experiences of a number of visual phenomena, and we suggest these ensue because her visual experiences are not strongly shaped by inhibitory feedback or by prior expectations. We describe Loren as having Deep Aphantasia, and Derek as shallow aphantasia, as for both a paucity of feedback might prevent the generation of imagined visual experiences, but for Loren this additionally seems to disrupt activity at a sufficiently early locus to cause atypical experiences of actual visual inputs.
Our purpose in describing these subjective experiences is to alert others to the possibility of there being sub-classes of congenital aphantasia, one of which—Deep Aphantasia—would be characterized by atypical experiences of actual visual inputs.
Most people can generate images that they experience in their mind’s eye. We authors cannot, and do not believe we have ever been able to. We can be described as Congenital Aphantasics ( et al 2015). We each obtain the minimum possible score on the VVIQ2 questionnaire (1995), which measures the subjective intensity of imagined visual experiences. But there are large differences between our subjective imagined experiences. Derek can have detailed imagined audio experiences (hearing snippets of symphonies at will), and his dreamt audio and visual experiences seem fully realistic (like most Congenital Aphantasics, see et al 2015; et al 2020). Loren, however, reports that she cannot have imagined audio experiences, has no inner monolog, and she does not have audio or visual experiences while dreaming. Loren can experience imagined tastes and tactile sensations, Derek cannot.
…Loren does not, however, have typical subjective experiences of a number of visual phenomena that involve extrapolation or integration of visual information across space. Loren cannot discern 3D kaniza shapes (Van 2008). To Loren, the 3D cone depicted in Figure 2A looks like a weirdly shaped triangle. Loren can experience the corridor size illusion (1966, see Figure 2B), but only after a delay during which the depicted figures seem matched in size (people typically instantly experience these as very different in size). Loren does not seem to experience neon color spreading—she cannot see an illusory floating blue square in Figure 2C. Loren does not experience variants of long-range apparent motion either. When offset disks are flashed on and off in counterphase (see Anstis et al 198539ya), she tends to experience localized flashes—she does not experience a sense of movement in-between the flash positions—as is typical.
Loren does not have typical experiences of bi-stable visual phenomena. These typically promote intermittent switching between two mutually exclusive perceptual experiences. For instance, Rubin’s (1915109ya) vase (see Figure 2D) is typically experienced as either a pair of faces, or as a vase. However, Loren typically only sees the faces (and not the vase). Nor can Loren discern Necker’s (1832192ya) cube. To her this just resembles a jumble of 2D shapes (see Figure 2E), so she does not experience switching between seeing one of the cube’s faces as being positioned at the front or at the rear of a 3D object. As Loren does not experience long-range apparent motion, she does not experience bi-stable long-range apparent motion (with movement seeming to alternate between moving in orthogonal directions, see Knapen et al 201113ya).
When looking at kinetic silhouette illusions (see Troje & 2010), that cause most people to experience intermittent reversals in the perceived direction of rotation, Loren experiences an unchanging (clockwise) direction. Loren does not have typical experiences of binocular rivalry. Inputs that elicit binocular rivalry in most people, characterized by alternating periods where only one of two rivalrous monocular images can be seen at a time, are only ever experienced by Loren as a fusion of the two images (transparency) or as a patchwork of both images (piecemeal rivalry, see left side image within the head of Figure 2F; 2002). Loren does not experience periods of dominance (where only one of the two rivalrous images can be seen), even after protracted viewing.
Loren does not experience face pareidolia ( et al 2022). To her non-face objects look like non-face objects, even if they feature two horizontally separated dark regions and an underlying feature that most people could regard as a nose or mouth (see Figure 2G). Loren feels like she is probably boring to go cloud watching with, as to her clouds are… just clouds. She does not see whimsical impressions of form in them. Finally, Loren experiences broadband visual snow—constant dynamic black and white dots across her visual field (see Figure 1D), and she thinks these might be associated with slight headaches.
Loren is an accomplished artist. She can draw realistic portraits, but only if she can see the input (see Figure 1E). Like other Aphantasics ( et al 2021), Loren cannot draw from memory. Neither Loren nor Derek have a history of neurological trauma, or diagnosis of a cognitive disorder. Loren’s structural brain scan did not reveal any overt abnormalities.
…The VVIQ2: Given the prominence of the VVIQ2 (1995) in contemporary research, we believe a brief comment on it is warranted. We join others (eg. 2023; 2024) in arguing that the field needs a better means of identifying who is, and is not, aphantasic. The VVIQ2 is a subjective questionnaire, asking people to rate the vividness of their imagined visual experiences.
Highlighting our concerns about the ambiguity of this instrument to aphantasics, when Loren first completed the VVIQ2 (1995) her responses were stereotypical, as she was not then aware that other people could have imagined visual experiences. She misconstrued questions as relating to effort expended and success in remembering facts about visual experiences.
Researchers have reported on other potentially diagnostic tasks (eg. 2017; et al 2022), but these have only ever been validated by correlation with the VVIQ2 (1995). So, we have not really escaped reliance on identifying aphantasics via subjective report.
We highlight this as a persistent issue that needs to be addressed.
See Also:
Anauralia: The Silent Mind and Its Association With Aphantasia
What is the frequency and nature of visual hallucinations in non-clinical participants?
Leroy’s elusive little people: A systematic review on lilliputian hallucinations
Telling more than we can know: Verbal reports on mental processes
Shared understanding of color among sighted and blind adults
