An eye for fashion

blueblackdress

Image source: swiked.tumblr.com/

This is the most famous dress on the internet today. More famous even than any hundred-thousand dollar dress worn to the Oscars last week.

Do you see it as ‘blue and black’ or ‘white and gold’? Whatever you see, you probably can’t imagine how anyone could see it differently.

This dress is a reminder that our perception of the world around us is not necessarily a perfect mirror of reality. Most of us have three groups of colour-sensitive cells that can detect ‘red’, ‘green’, and ‘blue’ light and convert this information into signals that our brains can interpret as colour. However, the colour that we perceive also depends on other factors such as the brightness of the image and the contrast with its surroundings. Together with innate differences in colour perception, this has divided us into two camps: those who see the dress as blue/black and those who see it as white/gold. Personally, I’ve tried looking at the dress in a variety of different lighting conditions, and I just can’t see the white and gold version. (FYI, apparently the dress is actually blue).

Do we all see the same colours anyway? Maybe we call them the same name, but is my ‘blue’ the same as your ‘blue’? Sure, you learnt what ‘blue’ was as a child, but if you could look through someone else’s eyes, perhaps you would see a sky of gold. Maybe that’s difficult to imagine, but then again, so is a white and gold dress…

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The Reality of Reaction Times

Photo credit: Richard Masoner

Photo credit: Richard Masoner

With the summer road toll climbing, we’re hearing constant reminders for Kiwi drivers to watch their speed and following distances.

The New Zealand Road Code recommends a 2 second following distance during normal conditions. Next time you’re on the motorway, check out how many drivers actually follow this recommendation. We’ve all seen tail-gaters travelling at 100km/hr with only 5 metres of stopping distance between the car in front.

Perhaps what gives some drivers such little disregard for their own and others safety is an over-estimation of the capabilities of their own brain. If the driver in the car ahead can brake suddenly, then why can’t they?

The time it takes you to respond to an emergency road incident is based on many external factors, including the weather conditions, and the responsiveness of your vehicle. The recent example of the 100+ car pile up in Michigan during icy weather conditions is an unfortunate example. There are also biological factors that influence your reaction time. You attentiveness, age, and neurological disorders can all slow your ability to react to a hazardous situation.

But no matter how ‘lightning fast’ you think your reflexes are, there’s no beating basic brain biology. The light rays that hit your eyes are coded into electrical signals that travel along the length of your neurons, diffusing across the gaps between neurons, until they reach the visual areas of the brain. In fact, it can take around 80 milliseconds before a visual stimulus in front of you reaches your conscious perception – about the blink of an eye. This doesn’t sound like much time, but if you are tail-gating someone at 100km/hr, then at least 2.2 metres of following distance are wasted before reality catches up with you.

For those drivers who disregard the recommended following distances, don’t forget that your reality of your brain biology!

If you have some time on your hands, check out how fast your reaction times are.

 

Free diving: a brain sport

DivingSealDid you find yourself holding your breath in anticipation whilst watching Kiwi free diver William Trubridge attempt to break his own world record

If you are hoping to increase your breath-holding record, then you’re more likely to achieve that underwater than you are on land. Humans and other mammals have evolved some important ‘dive reflexes‘ that allow us to conserve enough oxygen to survive for short periods underwater. Jump into a cold pool, and you will reflexively stop breathing, your heart rate slows down, and blood is redirected to your organs at the expense of your limbs. This is thanks to control centres in the brain stem that detect a decrease in oxygen and the sensation of water on the face. While our dive reflexes cannot compete with those of a seal, even dunking your face in a bowl of cold water is enough to experience a mild form of this reflex. 

Your brain is your most expensive organ, requiring up to 20% of your total oxygen consumption. William managed 4 minutes and 9 seconds underwater, by encouraging a relaxed mental state to decrease the brain’s oxygen requirements. 

But free diving to 100 metres provides the brain with more bodily challenges than oxygen deprivation alone. As William felt the pressure of the world on his shoulders as thousands of New Zealanders watched his record attempt, so did he feel the pressure of the water on his body. This change in pressure can cause ‘barotraumas’, such a rupturing of the inner ear and sinuses. At extreme depths, the pressure is so high that the concentration of gases in your body (such as nitrogen) are much higher than they normally are. This can lead ‘narcosis‘ that can impair your ability to think and coordinate your muscles – a similar feeling to alcohol intoxication. The jury is still out, but there’s even some evidence that repeated free dives can lead to early signs of brain damage.

But I think perhaps most remarkable of all, is the brain’s ability to overcome panic and fear as it descends into the darkness. Under that kind of pressure, it really is sink or swim (or sink first, then swim?) William didn’t make a new record, this time, but his brain certainly survived an epic challenge.