This episode is also on Bilibili too.
There’s a very simple way to trigger a powerful hallucination of having six fingers (and you can even control the length of the ‘phantom finger’).
Props
1. A mirror roughly 30-40cm wide and 30-40cm tall;
2. A good buddy who can touch your fingers.
Setting Up
As shown in the picture below:
1. Sit beside the mirror, with the mirror facing the side of your right hand, and lean your body slightly to the right.
2. Place both palms face down on the table, with your right hand in front of the mirror and your left hand behind it (as shown in the picture). Adjust the position of the mirror and your body to make sure you can see only your right hand and its reflection in the mirror, but not your left hand.
3. Keep your eyes fixed on your right hand’s reflection in the mirror.
4. Your good buddy sits across from you and uses the index fingers of both hands to stroke your fingers according to the procedure below.
Inducing the Hallucination
As shown in the picture below:
First, stroke your thumbs (number 1 in the picture above). Your good buddy lightly touches the back of each thumb, stroking from the base to the tip and then back to the base, twice. The stroking movements on the left and right must be synchronized, and the speed must remain consistent.
Starting with both thumbs, move in sequence to both index fingers, middle fingers, and ring fingers. Stroke each finger back and forth twice, keeping the left and right sides synchronized (numbers 2-4 in the picture above).
Finally, move on to the little fingers. The way you stroke them is the crucial part, and it has two steps:
First, your good buddy strokes the back of your right little finger using the same technique as above. At the same time, he synchronously strokes the side of your left little finger that faces your ring finger (number 5 in the picture above). This time, there are more strokes: 20 synchronized strokes on both sides.
And now, it’s time to witness the miracle:
In the final step, your good buddy strokes the tabletop beside your right little finger using the same technique, while simultaneously stroking the side of your left little finger facing away from your ring finger (number 6 in the picture above).
At this point, there’s a very good chance you’ll suddenly experience a remarkably powerful illusion: you’ll feel that what’s being stroked behind the mirror is a sixth finger beyond your little finger!
The hallucination is so intense that in the actual experiment (see the references), some participants were startled enough to cry out.
Manipulating the Length of the Phantom Finger
More interestingly, we can also manipulate the length of the ‘sixth finger.’
If you want to grow a short ‘sixth finger,’ here’s what you do:
In the final step above (number 6 in the picture), when your good buddy strokes the tabletop on the right, shorten the ‘stroke path’ (as shown in the picture below), while still making sure the two sides remain synchronized. (When the right side moves from the base toward the tip, the stroking direction along the outer side of the left little finger must also run from the base toward the tip.) To do this, stroke the side of the left little finger facing away from the ring finger slightly faster than the right side. As shown below:
With this adjustment, you’ll feel that what has grown beside your left little finger is a relatively short stub of a finger.
If you want to grow a long ‘sixth finger,’ do the opposite:
In the final step above (number 6 in the picture), when your good buddy strokes the tabletop on the right, lengthen the ‘stroke path’ (as shown in the picture below), while still making sure the two sides remain synchronized. (When the right side moves from the base toward the tip, the stroking direction along the outer side of the left little finger must also run from the base toward the tip.) To do this, stroke the side of the left little finger facing away from the ring finger slightly slower than the right side. As shown below:
With this adjustment, you’ll feel that what has grown beside your left little finger is a relatively long finger.
By: Zhichao Wei
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