Tag: eye

Posted in Psychology & Medicine

Watching You

Posted on by Jinavie

What drives our morality? Philosophers have argued and pondered for millennia where our sense of selflessness, altruism and honesty come from. Are we inherently good or evil? Do we only help others when it benefits us? How can we motivate people to act more morally?

One interesting research reveals a startling truth about our morality.

In 2006, psychologist Melissa Bateson published a research where she experimented with eyes. Their university tea room had an honour-based coffee and tea system, where you pay the price of the beverage into a box. Because there was no one keeping guard over the box, you could choose to cheat the system by taking a free drink without paying. Bateson wanted to see if she could influence how often people paid by making a simple alteration to the notice banner.

The notice banner had the prices for tea, coffee and milk. Bateson decided to add an image above the prices: a pair of eyes, or flowers. She would alternate the image used week by week, then recorded the total earnings and the number of drinks purchased. She would use different flowers and different eyes from various genders, ethnicities and expressions, but the eyes all had something in common: they stared directly at you.

The results were fascinating: on weeks where the notice banner included pictures of eyes, people paid 2.76 times as much compared to the flower weeks.

Turns out, seeing a depiction of eyes makes us more honest and cheat less. The same effect has been seen when using cartoons or drawings of eyes, resulting in less littering, more donations, less crime and overall more pro-social behaviours. This is called the watching-eye effect.

Why do harmless pictures of eyes make us want to do good?

The effect is likely to be an unconscious, automatic reaction. Our brains are remarkably sensitive to eyes and gaze – which is why we can easily spot people staring at us and why we are so good at reading emotions from eyes.

Furthermore, we are social animals and thus have evolved to show pro-social behaviours so that we fit into the group and live together harmoniously.

This means that when we see even a symbol of an eye, our brain automatically thinks that we are being watched by someone, pushing us to act morally to avoid punishment or embarrassment. This suggests that our desire to preserve our social reputation plays a significant role in our morality (but by no means the only factor).

The other thing to consider is that as we grow up, we are continuously taught that we are being watched, to dissuade us from bad behaviour. God will send you to hell, Santa Claus will put you on the naughty list and Big Brother will send you to prison. All of these stories and cultural beliefs fuel our subconscious paranoia of being watched and fear of consequences.

So if your lunch keeps getting stolen from the fridge, try sending a message by putting a photo of eyes on it to see if it deters your coworkers.

Posted in History & Literature

Night Vision

Posted on by Jinavie

During World War II, the British Royal Air Force boasted an impressive accuracy in intercepting Nazi German bombers despite the cover of darkness at night. The British air ministry reported that their fighter pilots ate a large amount of carrots to boost their night vision. Since then, it has become public knowledge that carrots help you see better in the dark.

Unfortunately, this is false. The British air force were not actually using carrots to help see better in the dark; they were using a revolutionary new technology called radar to spot enemy war planes from a far distance. The carrot propaganda was spread to hide this fact from the Germans.

The carrot myth sounds plausible as carrots contain a large amount of beta-carotene, which is converted into vitamin A in the body. Vitamin A is a key chemical required for vision, in the form of retinal. It is true that vitamin A deficiency can cause night blindness. However, the dose of vitamin A required to improve your night vision is so high that it cannot be achieved by simply eating a lot of carrots.

Posted in Psychology & Medicine

Tetrachromacy

Posted on by Jinavie

They say that human imagination is infinite and limitless. But consider this: can you imagine a colour outside of the visible spectrum? Most likely, you are incapable of thinking of a new colour that cannot be mapped on a standard colour chart. Interestingly, a small proportion of people can see and understand colours beyond the range that the majority of us can see.

The physiology of vision is rather complex, but essentially boils down to the retina (inside lining of the eyeball) acting as a film for the image that you see. Cells known as photoreceptors convert the visual image into electrical signals that are transmitted to the occipital lobe of the brain via the optic nerve. There are two types of photoreceptors: rod cells, which sense movement, and cone cells, which sense colour and provide sharp images (visual acuity). Human beings typically see colour by combining three primary colours: red, green and blue (known as the RGB system). There are cone cells for each primary colour. The brain processes the signals sent by each cone cells and figures out what “colour” you are seeing. Therefore, you can only perceive colours made from a combination of red, green and blue. It is easy to visualise this by playing with colour palettes on computer programs such as Photoshop.

In recent years, it has been speculated that a certain percentage of women have an extra type of cone cell that senses a different wavelength of light. Ergo, they can theoretically sense a greater range of colours compared to someone who has three types of cone cells. This condition is called tetrachromacy (“four colours”). Tetrachromacy is the opposite to colour blindness, which is caused by a deficiency or fault in one or two types of cone cells. To these people, the average person (a trichromat) will appear “colour blind”.

According to one estimate, as many as 12% of women are tetrachromats. Although there are many theoretical barriers to true tetrachromacy, there have been several documented cases of women who perceive colour in much more depth.

The ability to see an extra primary colour is more significant than just a 25% increase in the person’s colour range. An average person can see about 1 million different hues (shades of colours), while a true tetrachromat can see 100 million hues – a hundred-fold increase in the range of colours they can see. One can only wonder what kind of amazing sights a tetrachromat sees when she gazes upon a field of flowers or even a rainbow. Unfortunately, even if a tetrachromat tried to explain the colours she saw to us, we would not be able to grasp the colours as our minds would be incapable of visualising the colours, much like how describing the colour red to a blind person is impossible.

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Posted in Science & Nature

Vision

Posted on by Jinavie

Consider this: if you see something that is not there, or not see something correctly, is that due to a problem in your eyes or your brain? An interesting anatomical fact is that the eyes are part of the brain. They originally evolved from the brain and drifted further and further forwards, connected to the brain by the optic nerves. If you lift a brain out from the skull, the eyes would be pulled backwards too. But technically speaking, eyes are distinct organs by themselves that have merely originated from a portion of the brain. It does not think or make decisions by itself. Just like a camera, an eye records things as it sees it and transmits it to the brain via the optic nerve via electrical signals. The brain then processes the signals in the occipital lobe, located at the back of the head (this is why you “see stars” when you bang the back of your head).

This means that vision can be altered anywhere along the pathway. If you have cataracts, where the lens of the eye becomes clouded, you lose portions of your visual field. If you have a large pituitary gland tumour, it presses on the optic nerve and causes double vision (diplopia) or vision loss. If you have a stroke in the occipital lobe, you can lose your vision. The brain’s role in producing vision can easily be demonstrated in the form of optical illusions. The eye merely records and transmits what it sees, but the brain becomes confused by what information it receives and tries to make sense of it. In the process, we experience bizarre illusions such as static images moving by themselves.

Because of this intricate pathway, some pathologies present with fascinating symptoms. A condition called Anton’s blindness (or Anton-Babinski syndrome) causes a patient to “see” despite being blind. Patients with Anton’s blindness are adamant that they can see perfectly clearly, and will even describe what they are seeing. However, what they “see” is completely different to what the object actually looks like. For example, if the patient looked at a blonde woman wearing a yellow blouse and a red skirt, they may describe her as a brunette woman wearing a blue shirt and black jeans.

The reason for their blindness is that their occipital lobe was damaged (usually by a stroke), leading to an inability to process the information from the eyes. Although the eyes are pristine and record what they see in perfect detail, the brain is incapable of interpreting the signals. The brain then goes on to confabulate, where the brain fills the gap by conjuring up false information. This makes Anton’s blindness quite hard to pick up on as the patient will not complain of it. It is only found when someone pays close attention to the patient and notices subtle cues like the patient bumping into furniture or talking in the direction where they think a person is at (even after they move). Ergo, the patient adamantly believes that they can see as their brain thinks it is seeing things (even though it is not receiving the information from the eyes properly).

Seeing is not believing. You see what you believe.

Posted in Psychology & Medicine

Scrubs

Posted on by Jinavie

Scrubs is the uniform that surgeons, anaesthetists, emergency department doctors and nurses wear for the freedom and mobility required in activities such as surgery and CPR. Also, since it is owned and washed by the hospital instead of being privately owned, it is more hygienic and helps prevents infections. A noticeable trait of scrubs (and also surgical gowns) is that almost every hospital uses a shade of blue or green instead of white. Why is this?

The reason being, looking at a surgical scene for a long period of time can cause eye fatigue and afterimages due to the redness of blood and organs. Afterimage is a phenomenon that occurs when the retina becomes insensitive to a strong colour and instead making the complementary colour stand out more. Ergo, a surgeon looking at blood and organs for too long will see afterimages of a blue shade, which may cause accidents to happen as it overlaps on white surfaces or the surgical field. Clothing of blue or green colour neutralises the afterimage and is much easier on the eyes, reducing the fatigue. Lastly, blue-green colours have a calming psychological effect, which helps in a high-tension, stressful environment such as in an operating theatre.

Posted in Science & Nature

Complementary Colours

Posted on by Jinavie

Red, green, blue, white… There are many colours that we can see and there are even more different combinations of colours possible. It is common knowledge that some colours clash with each other while some synergise very well. A common example of a “good combination” is when you use complementary colours. Complementary colours are two colours that oppose each other on the colour wheel, creating an effect where they brighten each other. This makes it very eye-catching and attracts people’s attention. For example, blue and orange make a bright contrast making them a popular colour choice for movie posters. Red and green, and yellow and purple are also examples of complementary colours. Complementary colours are an important concept in art and design as it helps the product stand out.

Complementary colours have an interesting relationship with our sense of sight. If you stare at a colour for a while then quickly look at a blank, white surface, you will see an afterimage of the complementary colour. A good example is when you have your eyes closed under bright sunshine and upon opening your eyes the world seems a blue hue (the blood vessels in your eyelid make the light appear orange as it reaches your eyes). This is because the retinas try to negate the intense colour by downregulating the nervous signals corresponding to that colour, which makes the complementary colour stand out. Furthermore, the photoreceptors in the retina become fatigued after stimulation, causing a reduction in the signals sent for that colour.

Knowing about complementary colours is very useful when designing a sign or poster that easily attracts people.

(Image source: http://bonka-chan.deviantart.com/art/Color-Wheel-136855103?q=boost%3Apopular%20color%20wheel&qo=3)

Posted in Philosophy

Perfection

Posted on by Jinavie

화룡점정 (Hwa Ryong Jum Jung) – 畵 그림 화 (painting). 龍 용 룡 (dragon). 點 점 찍을 점 (spot). 睛 눈동자 정 (pupil).

During the Liang Dynasty (modern day China), there lived a famous painter called Zhang Sengyao. It is said that he was such a skilled artist that his paintings were lifelike and almost like a photograph. 

One day, a monk asked him to paint a mural of dragons on the wall of his temple. Zhang accepted and proceeded to draw four dragons rising through black clouds. The fluid motion of the body, armour-like scales, the ferocious and vivacious look of the dragons… the sheer scale and detail of the painting astounded everyone who gazed upon the painting. However, people noted that none of the dragons had eyes drawn in.

When asked why, Zhang simply replied: “If I draw in the eyes, the dragon will immediately burst out of the wall and fly off.” No one believed him and laughed at such an insane comment. After constant pressure from the people to do it, Zhang reluctantly lifted his brush and plotted a single black dot where the eye was to be. 
Suddenly, lightning flashed and thunderclaps boomed out of the painting, from where a dragon emerged and proceeded to flash off into the sky. The people were speechless. The painting (minus the one dragon) still exists to this day.

To seek perfection is arrogance. This is a common mistake found in modern society, where people are too obsessed with becoming perfect and not see the beauty of imperfection.

Posted in History & Literature

Darkness

Posted on by Jinavie

When you close your eyes, what do you see? When you look into the night sky, what do you see? Most people describe darkness as pitch black, but this is not quite true.
The colour that we see in perfect darkness is not black, but more of a dark grey colour. This colour has a special term called eigengrau, which is German for “intrinsic grey”. Similarly, when you look into the night sky the actual colour is a deep navy.

The reason for this is that the brain uses relative contrast to determine true black rather than the absolute brightness. So when you see darkness, the optic nerve still fires off some signals that the brain interprets as eigengrau. When you see a black object, the brain compares it to the surrounding to cancel this effect out to see true black.

The night sky is lit with stars and the moon, giving it a darker colour than eigengrau due to contrast, while retaining the blue hue produced by the dust diffracting light in a particular manner. Because of this, ninjas actually wore dark navy clothes instead of the black that we associate with them in the present.

An interesting point regarding darkness is that people often see it as a symbol of the negative side (e.g. The Dark Side). However, darkness is technically the opposite of light. It is in fact defined by the absence of light, which in other words suggests it is the default state.

The default state of the universe is nothing.

Posted in Psychology & Medicine

Cranial Nerves

Posted on by Jinavie

Nerves can be divided broadly as spinal nerves and cranial nerves: the latter which is directly from the brain. There are 12 pairs of cranial nerves:

  1. CN I – Olfactory nerve (smell)
  2. CN II – Optic nerve (sight)
  3. CN III – Oculomotor nerve (eye movements, control of pupil and lens)
  4. CN IV – Trochlear nerve (eye movements)
  5. CN V – Trigeminal nerve (sensory information from face and mouth, chewing)
  6. CN VI – Abducens nerve (eye movements)
  7. CN VII – Facial nerve (taste, tear and salivary glands secretion, facial expressions)
  8. CN VIII – Vestibulocochlear nerve (hearing and sense of balance)
  9. CN IX – Glossopharyngeal nerve (taste, swallowing, parotid gland secretion, sensory information from oral cavity, information about blood)
  10. CN X – Vagus nerve (sensory and motor signals to and from many internal organs, glands and muscles)
  11. CN XI – Accessory nerve (movement of SCM and trapezius, which are neck/shoulder muscles)
  12. CN XII – Hypoglossal nerve (tongue movements)

As there are so many nerves and the names are all varied, there is a simple (yet very obscene) mnemonic to help medical students remember the names and order of nerves:

Oh, Oh, Oh, To Touch And Feel Virgin Girls’ Vaginas And Hymens
or
Oh, Oh, Oh, To Touch And Feel A Girl’s Very Soft Hands
(where vestibulocochlear -> auditory)

It is also worth noting the mnemonic for the types of nerves is:

Some Say Marry Money, But My Brother Says Big Boobs Matter More

Perhaps the only way to survive medical school is through humour.