Visual memories and sensory experiences

It seems people who lose vision use information that transfers between the senses to retrieve visual memories. And that their visual memories decay when they have reached a certain level of experience in the other senses. (See our blog for the scientific approach, the crossmodal correspondences between the senses, and Decay and maintenance of sensory memories). But what happens when people who are born blind gain vision and then lose it again?


I have invited P.B. to share his experiences of visual memories and sensory information when going from blind to partially sighted and back to being blind again. P.B. was born blind with some light perception in one eye. After surgery and other medical treatments, he had gained about 7% vision in the other eye at three and a half years old. P.B. does not remember this shift from being blind to being partially sighted. Then, in his early twenties, P.B. had an accident that rendered him totally blind in both eyes. P.B. thinks of himself as a sighted person who happens not to see. He visualises when making plans. And his dreams are always visual. P.B. approved this text before we posted it on our blog.


P.B. has several visual memories from when he was little. From the house he grew up in, for example, he remembers the light from a chandelier hanging over the coffee table in the living room, the patterned wallpaper in his room, and the countries on the world map hanging on the wall. And he remembers the colours on the outside walls, the doors, and the window frames.


Today, when he has no new visual input, P.B. creates visual images based on his memories and knowledge. For example, that of a White Swiss Shepherd Dog working as a guide dog from his memories of both the white colour and the German Shepherd Dog. As well as his knowledge of guide dogs.


His visual memories are typically triggered by somebody describing how something looks, like a bright red sunset – not by information from the other senses.


P.B.’s visual memories “flash up almost like the flavour when eating or drinking”.


He has to decide not to focus on visual memories and images when talking to people: the memories are now 20 years old and people have changed. And his created visual images of what new people look like may be very wrong.


P.B. has to actively suppress his urge to retrieve visual memories or create visual images of people based on their voices.


He describes not having visual memories and images of spatial relations and distances. P.B. rather remembers them through his body. He walks around in the city centre with no vision, a podcast or some music in his ears, and shoes with a thick curved sole (which makes it difficult to feel the surfaces on pavements, streets, steps, floors, etc.). He does not count steps or any of that and pauses the podcast or music in his ears only when he feels he might get lost.


For P.B., sensory experiences include a variety of simultaneous sensations as well as visual memories and created images – they are multisensory. The forest, for example, is the sound of wind and trees, the texture of surfaces under his feet, scents, and the memories of colours. He zooms in on whatever attracts his attention: indeed, not on one piece of sensory information after the other in a certain order. For example, zooming in on a sudden shift from soft to hard texture under his feet.


An interesting sensory experience, according to P.B., is that of new flavours, the texture of the food, and the sound of crunch when chewing, He describes a cloudberry cream dessert as “not very sweet, but also not sour, light orange colour, and creamy texture”. But a redcurrant jelly only as “something wobbling on the plate”. He does not describe the flavour, scent, and/or feel in his mouth – merely how the jelly looks on the plate.


Was he not able to suppress his visual memories of jelly – did they take over?


When P.B. is sensory tired, he relaxes his senses by listening to “concentration music, like opera or prog rock where I can immerse myself and get absorbed by a different universe”.


It seems P.B. can maintain his visual memories and ability to create visual images through people’s descriptions of what something looks like. But, at the same time, these memories and images are distracting him from focusing on sensory information that is more relevant to him today with no vision, for example, people’s voices and the feel of wobbling jelly in his mouth, So is this, in fact, a negative spiral – that maintaining visual memories prevents experiences in the other senses, which in turn helps nurture the visual memories?


See our blog for Activities; especially 49-51.

How anxious individuals perceive odours

The brain processes sensory information through a network of crossmodal correspondences. And, it integrates multiple sensations too. (See our blog for the scientific approach, the crossmodal correspondences between the senses, Crossmodal brain plasticity and empowering of sensory abilities, and Multisensory processing.) But what it actually perceives and later processes is affected by emotions. Which in turn affects the emotions, for example, the feeling of anxiety.


This time Michal Pieniak, Institute of Psychology, University of Wroclaw, and Professor Thomas Hummel, Smell & Taste Clinic, Department of Otorhinolaryngology, Universitätsklinik Dresden, demonstrate how anxiety affects the sense of smell. In his research, Michal Pieniak focuses on connections between olfaction and both cognitive and emotional functioning, and Professor Thomas Hummel on the diagnostics and treatment of olfactory / gustatory loss, the mechanisms involved in irritation of the upper airways, the olfaction in neurodegenerative disorders, and the interactions between the olfactory, trigeminal, and gustatory systems. Between them, they have more than 800 scientific publications. And have received several scholarships and awards (e.g., the 32nd edition of the START program, Foundation of Polish Science, and the European Chemoreception Research Organization (ECRO) for “Excellence in Chemosensory Research”).


The sense of smell helps humans detect dangers in their environment. For example, the smell of smoke or natural gas warns us about potential threats to our safety. If someone can’t smell these odors, they might have more accidents or injuries at home. This is a common problem for people who have lost their sense of smell1. Therefore, being able to accurately detect odors is crucial for our safety and health.


People who experience anxiety, such as generalized anxiety, tend to focus more on things that might be threatening2. This attention to threats can apply to many types of dangers, but sometimes it is more specific. For example, people with social anxiety pay extra attention to faces showing negative emotions3. However, it is not well understood how anxious people perceive smells and if their attention to threats extends from visual objects to odors.


Recently, we teamed up with a research group from Macquarie University in Sydney, led by Prof. Mem Mahmut, to investigate this question. We tested 127 university students who reported their levels of social and generalized anxiety symptoms. They participated in tasks measuring their sense of smell accuracy and perception of odors. Some odors were general, like rose, turpentine, and motor oil, while others were socially relevant, like perfumes, artificial flatulence, and unpleasant body odor. We found that students with higher levels of generalized anxiety were better at detecting subtle differences in intensity of general odors than those with lower anxiety levels.


Increased symptoms of social anxiety > Socially relevant odors perceived as more threatening > Improved ability to detect subtle differences in odor concentration
Figure 1: How anxious individuals perceive odours (Pieniak & Hummel)

Similarly, students with social anxiety were better at sorting socially relevant odors according to their intensity, what was related to the perceived threat of these odors. This suggests that socially anxious individuals see socially related odors as more threatening, which helps them notice subtle differences in odor concentration.


Since our study was correlational, we cannot say for sure whether anxiety causes heightened smell sensitivity or if heightened smell sensitivity leads to anxiety. Additional research, including neuroimaging studies, will help us better understand the relationship between smell and anxiety disorders.


Considering previous findings and results of our study we can conclude that:

– Our sense of smell is essential for detecting environmental dangers and maintaining safety.

– Anxiety can affect how people perceive and respond to odors, with those experiencing anxiety perceiving odors as more threatening and being more sensitive to certain smells4.


See our blog for Activities; especially 43-45.


Some suggestions for further listening, reading, and watching:

Anxiety and Sensory Processing Disorder – Which Comes first?

How Anxiety Affects the Mind and Body

How anxiety warps your perception

Sensory Anxiety: Not Your Ordinary Anxiety

Sensory Problems Caused by Anxiety

What the nose knows

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1Santos, D. V., Reiter, E. R., DiNardo, L. J., & Costanzo, R. M. (2004). Hazardous Events Associated With Impaired Olfactory Function. Archives of Otolaryngol-Head & Neck Surgery, 130(3), 317-319. DOI: 10.1001/archotol.130.3.317

2Mogg, K., & Bradley, B. P. (2005). Attentional Bias in Generalized Anxiety Disorder Versus Depressive Disorder. Cognitive Therapy and Research, 29(1), 29-45. DOI: 10.1007/s10608-005-1646-y

3Lee, H.-J., & Telch, M. J. (2008) Attentional biases in social anxiety: An investigation using the inattentional blindness paradigm. Behaviour Research and Therapy. 46(7), 819-835. DOI:  10.1016/j.brat.2008.04.001

4This research was funded by the National Science Centre in Poland (grant 2022/45/HS6/00651).