Tag: hand

Posted in Psychology & Medicine

Rubber Hand Illusion

Posted on by Jinavie

The five senses are something we take for granted as we never even give a thought as to how complex the way we receive sensory information about the world we live in. As incredible the science behind all the senses may be, it is also interesting to see such intricate mechanisms being fooled by sensory illusions. An experiment that highlights how intricate the senses can be is that of the rubber hand illusion.

In this experiment, researchers made participants look at a dummy rubber hand, while obscuring their real hand from view. They then applied exactly the same stimulus to the real hand as the rubber hand, such as stroking it with a brush or feather. Within a short amount of time, the participants reported that they were convinced that the rubber hand was their real hand, confusing the visual sensation of seeing the rubber hand with the tactile sensation of their real hand being brushed.

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Because the brain is so good at piecing together things to come up with explanations, it links the two sensations and thus concludes that the rubber hand must be part of the body. The association is so strong that some participants would even feel pain when the rubber hand was attacked, pulling away their real arm.

One of the lesser known senses of the body is proprioception – the sensation of knowing where your body lies in three-dimensional space. This sensation is what lets you do things with your eyes closed, while also being responsible for the feeling of embarrassing yourself with a fall when someone pulls the chair out from under you. Proprioception is based on a delicate “body map” your brain draws out from various sensory information such as your joint position and touch sensation from your muscle and skin. It then adds more information such as vision and spatial orientation information from your inner ears to accurately predict how you will interact in your environment. In the case of the rubber hand illusion, the brain is fooled into remapping the body map to accommodate the rubber hand.

The application of this phenomenon, known as multisensory integration, extends from out-of-body experiences to phantom limb pain, where amputees feel pain and sensation from an amputated limb. There are also anecdotal evidence of men with penile prostheses being able to achieve orgasms, most likely thanks to the rubber hand illusion.

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Posted in Psychology & Medicine

Left-handedness

Posted on by Jinavie

Phones, golf clubs, scissors, forks and knives, the order of writing… Almost everything in this world is made for the convenience of right-handed people. Because of this, there is a hypothesis that left-handed people have a relatively shorter life expectancy compared to right-handed people.

Dr. Diane F. Halpern of California State University conducted a research comparing the life expectancy of right-handed people versus left-handed people. The results were astounding; the mean life expectancy of right-handed people was 75, while left-handed people only lived 66 years on average. Dr. Halpern posited that this was due to left-handed people becoming stressed living in a right-handed world, shortening their life expectancy. Of course, there were debates about whether the results were reliable or not and there was heavy opposition from the left-handed community. But if the left-handed people are enraged about being discriminated against by society, this would stress them out and actually shorten their life, so it might not be best not to debate about the issue.

Left-handedness has historically been associated with evil. The word right also means “good”, while left-handedness is formally known as sinistrality, which shares its etymological origin with sinister. The word for right is associated with good things throughout the world, while left is associated with bad things. In Korea, 오른 (oreun, right) has the same pronunciation as 옳은 (orlheun, true)“. The Chinese character for left (左) is also used to mean “improper”. In medieval Europe, left-handed people were thought to be associated with the devil or witches and were often executed. Left-handed people have been unjustly hated throughout time and space.

Posted in History & Literature

Wedding Ring

Posted on by Jinavie

The practice of wearing jewellery to signify the sacred bonds of marriage dates back to ancient Egypt, where chains and bracelets were worn. This eventually evolved into wearing a ring, where the circle symbolised endless love while the open centre represented the doorway to an unknown future. This practice spread to the ancient Greeks, then the ancient Romans, where it became a commonplace tradition around the 2nd century. The Romans called the wedding ring annulus pronubis and it was tradition for a man to give a ring to a woman at the betrothal ceremony to symbolise his eternal devotion.

A wedding ring is most often worn on the fourth finger of the left hand, so-called the “ring finger”. It is uncertain when this tradition arose, as various cultures chose different fingers on different hands for the wedding ring. One theory suggests that the tradition arose from the ancient Romans believing that the fourth finger contained a vein called the vena amoris – a vein that connects directly from the finger to the heart. As the heart is a symbol of love, placing a ring on this finger symbolised eternal love. However, this is a false belief for two reasons. Firstly, every vein, by definition, returns to the heart. Thus, it makes no sense that the fourth finger is special. Secondly, there is no such thing as the vena amoris, with all the veins in each finger having an identical structure (common palmar digital veins). As the circulatory system was not known during ancient times, it is likely that this story is a myth that arose sometime after the Middle Ages when a romantic story was matched with the tradition. It is also likely that jewellery companies marketed such a story to promote wedding ring sales (much like the marketing of the diamond engagement rings).

Posted in Science & Nature

Rock-Paper-Scissors

Posted on by Jinavie

Rock-paper-scissors is a game with a long history. The earliest example of the game is a Chinese game called huoquan, which follows a cyclic rule where the frog eats the slug, the slug dissolves the snake and the snake eats the frog. The reason why rock-paper-scissors has been saved throughout history is because of the uncertainty it contains. Any hand you choose, the chance of winning is the same. Ergo, there is no single best choice and there is no move that will always win. But this is still a game played by people. It is not a game played by emotionless machines, meaning that you can use human psychology, the surfacing of emotion and specific signs and movements to help deduce your opponent’s hand. Mentalist Derren Brown can read tiny flickering of muscles in the opponent and microexpressions to pull off his “undefeatable rock-paper-scissors trick”, but this is near impossible for a normal person to try. However, you can use the following strategies to improve your odds.

  1. Use paper on a beginner: Statistically, people prefer using rock. Males especially have a strong tendency to play rock.
  2. Use scissors on an experienced player: People who know the first trick can be defeated by going one step further.
  3. Use a hand that loses to the hand your opponent played: This uses the psychology of the opponent wanting to mix up hands and wanting to beat the hand you last played (which is the same as theirs as you drew).
  4. Say what you will play and play that hand: In a competitive situation like rock-paper-scissors, people tend not to trust others. Thus, if you say you will play a certain hand, they will think is a trap and not play the hand that defeats that hand. For example, if you said you will play scissors, the opponent will play paper or scissors and you will either win or draw.
  5. Do not give the opponent a chance to think: People have a subconscious tendency to play a hand that beats the hand that they played before. Without time to think, the subconscious takes action meaning that you can predict their move. If you do the same as strategy 3 and play a hand that loses against the opponent’s previous hand, you will win.
  6. Suggest a certain hand: This is a form of hypnosis where you suggest something to the opponent’s subconscious. To use this trick, pretend to go over the rules by saying “rock, paper, scissors” then play a certain hand. The opponent will likely play the hand that the subconscious last saw.
  7. If you keep drawing, use paper: This is the same as strategy 1.

Unfortunately, rock-paper-scissors has an equal probability of a win and a draw, meaning draws are rather common. Thus, a computer engineer called Samuel Kass devised a game where two additional hands are added: rock-paper-scissors-lizard-Spock. Lizard is played by making your hand into the shape of an animal’s head, while Spock is played using the Vulcan Salute from the science fiction show Star Trek, where you make a V-shape with two fingers on each side. The rules are as follows.

Scissors cut paper. Paper covers rock. Rock crushes lizard. Lizard poisons Spock. Spock smashes scissors. Scissors decapitate lizard. Lizard eats paper. Paper disproves Spock. Spock vaporizes rock. Rock crushes scissors.

As each hand has two ways of winning, the odds of winning is 10/25, or 2/5 and the odds of drawing is 5/25, or 1/5. As you can see, you have double the chance of winning compared to drawing, making the game much faster to play than the original game.

Posted in Psychology & Medicine

Open Hand

Posted on by Jinavie

90% of human communication is non-verbal. This shows how facial expressions and body language have a powerful effect on our subconscious. Even the position of the hand can send a clear signal.

An open hand suggests peace, love and openness. Because of this, if the other person has his or her palm showing, you will feel more comfortable talking with them and view them in a more positive light. Jesus is often pictured in a pose with his arms stretched and palms showing, sending the message: “I would like to embrace you”. The same signal is used to initiate a hug.

On the other hand, a closed hand sends a cold message of strictness and professionalism. Therefore, people who are debating or negotiating often have their hands flat on a table or their lap to symbolise their resolution and defiance.

From this analysis, we can tell that an open hand is a good way to gain the affection of another person. Furthermore, this body language can manipulate the other person’s subconscious.

From my experiments, I found that when given the choice between a closed fist facing up and another fist facing down, the subject would choose the fist with the palms facing up about 90% of the time. Although it is a crude test, it definitely beat the 50:50 statistics that is expected.
This experiment was probably affected by other factors. Especially because people will usually choose the unusual choice due to curiosity (as when told to pick a hand, the person will usually have both fists facing down) and due to the psychology of “the unusual fist will probably contain something more interesting”. Also, most people who chose the downward-facing fist later said that they “deliberately chose the other fist because they felt they were supposed to choose the upwards-facing fist”. Thus, they too were first attracted to the unusual fist.

This test must be done suddenly to bypass the logical conscious mind and have an effect on the subconscious mind. If you take too long to explain the test, the results become skewed. 
Bypassing the conscious mind to suggest an acceptable choice to the subconscious mind – this test shows the basic principles of hypnosis.