The body has five main senses that it uses to detect the world around it: feel, hearing, sight, smell, and taste. The signals that your body gets from the respective organs are what it uses to determine what kind of environment it's in, and as a result, it these senses play a huge role in your perspective of what's going on.
For example, if your mind likes the taste of something that you see, you'll be inclined to eat more of whatever looks like it. In the case of, for example, a Snickers bar, if you like the way it tastes, you'll try to eat more Snickers bars.
In this experiment, the goal is to trick the senses of the body into thinking something is happening when it's really not. You'll see these guys trick the senses of touch, taste, and even sight into sensing things that the brain really wants to sense, but doesn't.
It's considered a "tricked" sense, because the body isn't really sensing what it expects to sense.