Tag Archives: Vision

Does this explain that visual experience?

“OUR sight is sharpest at dawn and dusk – and now we may know why. It is not a result of changes within our eyes, but of how the brain processes visual signals.”

Clare Wilson Our eyesight is sharpest at twilight – and now we may know why. New Scientist. 10 April 2018.


This could be the solution to a mystery in sensory psychology that I’ve been wondering about for many years. I noticed a subtle effect in which my sense of sight without warning occassionally seems to improve, but not in any way that is obvious such as sharper focus or altered colour perception, resulting in a somewhat blissful effect that lasts a few seconds. I had noted that it seems to happen around the time of sunset, and I’d theorised that it is something to do with the visual system in my brain being able to readjust to a more optimal or fine-grained level of functioning as the result of a reduced level of light, similar to the effect of one’s eyes taking up to 20 minutes to adjust to the dark when one enters a dark cave during the day.

The Brain documentary series reaches Australia

I’ve started watching the TV series The Brain featuring the accomplished American neuroscientist Dr David Eagleman, who has made major contributions to synaesthesia research and many more areas of neuroscience. Face recognition and synaesthesia are some of the many topics mentioned in the first episode, which has already been broadcast on SBS.


Colour-blindness a variation in visual perception ability possibly endowing advantages relevant to work performance, rather than simply a disability

Payne, Rob Colour-blindness may aid in search and rescue effort. Science Network. November 11th 2015.

The idea that colour-blindness can be advantagous is not new to me, as last year I watched with great interest a story on ABC24’s News Breakfast in which the colour-blind presenter Michael Rowland explained his advantage over people with normal colour vision in visually detecting camouflaged items. Unfortunately the clip of this story is no longer available to view.

Vision scientist explains colour blindness. ABC News Breakfast. 7 Apr 2014.



If you couldn’t see properly, would you be the last one to know?

I think it is fair to say that they average person believes that seeing and vision is all about the eyes. In actual fact, a person could be blind but still possess perfectly functioning eyes. the eyes don’t see. It is the brain, or the person who’s consciousness is produced by their brain, which does the seeing, more specifically, the parts of the brain that are responsible for visual processing. I think they are mostly at the back of the brain.

Vision is the result of the operation of the eyes and also the brain, and neuroscience is more and more becoming aware that there is a great amount of normal and also unhealthy variation among brains. The brains of dyslexics don’t handle reading well. The brains of left-handed people are definitley different to those of most of us, but not in one uniform way. Some people’s brains are damaged or derailed in development even before their untra-uterine development is completed and they are born, because their mother smoked during pregnancy or drank alcohol or had some misfortune such as catching one of the many infectious diseases that can harm a foetus. The genes that we all inherit or mutate can affect they way our brains work in profound ways, including visual processing. Prosopagnosia or face-blindness can be inherited and can run in families.

Your brain is different to my brain in countless ways that have an impact on the way our minds work. I often experience music as a coloured form of entertainment. You probably don’t. I can’t help but remember the faces of people that I meet, even if they are people who play very minor roles in my life and are not expected to be met ever again. Here’s an example. I took one of our kids to the Royal Show recently. One of the attendants at one of the animal pavillions was kind enough to let my child collect an egg that one of the prize-winning special-breed chickens had laid in it’s cage. He was a nice person, but there was nothing particularly memorable or different about his face or appearance, and I never expected to meet him again. Some hours later I involuntarily spotted his face among the teeming crowd of scores of show visitors surging down one of the streets in the showgrounds. As is usual, I consciously avoided looking like I had recognized him, lest I be seen as some kind of stalker weirdo. Is this kind of experience a common one? A rare one? Who could know for sure? One thing that I do know is that it was a complete surprise when on a whim I found the Cambridge Face Memory Test online and did the test and found that I had gotten a perfect score. At the same website for the first time I saw the term “super-recognizer”. What is a super-recognizer, I thought? Could I possibly be a super-recognizer? I’ll Google it!

It appears that I have some kind of visual gift, but I had no idea. People who have the opposite level of ability in face recognition also sometimes have little awareness that they are different from the norm. I recall seeing one of the prosopagnosics who were interviewed on the US version of 60 Minutes saying that before her diagnosis she had thought she was just not good with people. That’s a very vague idea of what the issue is. That is a remarkable lack of insight into what was going on in her life, but of course, I’m not blaming her. If you are looking for examples of visual or sensory processing disabilities that people can have but be unaware of, there are clearer examples to find than prosopagnosia. I’ve read that stroke patients can be unaware of a loss of vision in half of the visual field of one or both eyes (hemianopsia) or can be unaware of a loss of awareness of one side of space (Hemispatial neglect). People who have one form of colour-blindness, Anomalous trichromacy, can be unaware that their visual perception is different. Doctors even have a term for a lack of awareness of disability or deficit; Anosognosia. Psychologists have a term that seems to cover similar ground, plus some; the Dunning-Kruger Effect. In the Dunning-Kruger Effect people who lack skill in some area may mistakenly believe they are skilled or even above average, while people whose skills are excellent may lack the appropriate self-confidence to go with their high ability or expertise, because they mistakenly or unknowingly assume that everyone is operating at their level and they are just average. In my experience, the Dunning-Kruger Effect applies to visual processing ability. I’ve seen people time and time again mis-identify things such as plants, vehicles or animals with confidence, and time and time again, I get told that I’ve got a great eye for detail. Sometimes it seems to me that it is instead the case that I’m inexplicably surrounded by people who are borderline cases of cortical blindness, or are way overdue for an appointment with an optometrist. If you couldn’t see properly, would you be the last one to know?

Unusual experiences that perhaps do not have proper names

Wakewisdom – If you wake up “feeling” a particular opinion about some question or matter in your life, do consider it very seriously, because it is a message from your unconscious mind which is more coldly objective than one’s daytime mind, which has a dangerous bias towards optimism and self-delusion. The one single thought sitting inside your head when you wake up is well worth noting, should you wake with one.

Midmorningkeynote – Whatever one is thinking, feeling, experiencing, doing or listening to at 10 o’clock in the morning sets the tone for the whole day, and might reverberate through one’s thoughts at later times of the day. Music enjoyed at this time of day could develop into an earworm.

Drowsyloudness – Do sounds suddenly sound louder and somehow closer or interior when you feel tired, drowsy or are half-asleep? Does a sense of the timing of sounds disappear, making sounds seem somehow isolated or freed in time? Does it feel as though some barrier between you and sounds around you fails when you are sleepy? No? That’s a pity, because it can be quite a trippy thing if you choose to listen to an epic piece of music while half asleep, and there’s no need to dabble in dangerous and expensive drugs. Might I suggest listening to “A Canyon” by Philip Glass when you are half-way to the land of nod? Thank me later.

Necksqueak – Being able to hear the sounds of the internal workings of one’s body, like the squeak of tendons rubbing when I move my neck, or the sound of blood pulsing through small blood vessels inside ears, is a bad thing for me, because for me it means a bad headache is on the way.

Sightbliss – I suspect that this one is also associated with headaches. It doesn’t happen often. Hard to describe and subtle. Yesterday I experienced a brief moment of it (and it is typically an effect that lasts only moments) while we were walking back from the beach just after sunset. I had a bit of a headache at the time, but not severe. The trigger seems to be an abrupt decrease in outdoor light levels, as typically happens after sunset, and could possibly be triggered by the addition of cloud-cover. I can’t point to any way in which the eyesight clearly alters, it is more like an awareness of seeing or an openness to visual stimuli abruptly increases. Sometimes it feels like the eyes are suddenly flooded with vision, and in hindsight it seems as though eyesight was previously inferior by comparison. My theory is that it is an unknown adaptation to night-time vision, or a point of abrupt transition between a more neurologically-guarded mode for daytime vision, to a less defensive and more sensitive mode of nocturnal visual processing. I don’t think it is as simple as an opening of the pupils, because the openness of the pupils changes all the time, but this experience is quite rare.

Earwormmessages – Next time you have a piece of music that won’t stop going round and round in your mind, consider the lyrics or the title of the piece of music. Is it a wise reflection on things that are currently happening in your life, or is it just a very catchy tune, or both? I’d like to make it clear that this is not “hearing voices”. It is the involuntary experience of having a tune in one’s head which just happens to have lyrics that seem to be a commentary on the current events in one’s life.