Somatosensation (the “body senses”), the subject of this chapter, is really a conglomeration of four to eight (depending on how you count them) different sensory systems, responsible for:
- Detecting damage or potential damage to our bodily tissues (sensing pain)
- Determining the position of our body parts (proprioception) and how our muscles are moving (kinesthesis)
- Sensing temperature changes
- Feeling deformations, low- and high-frequency vibrations, and sustained pressure on our skin, the sensations most commonly referred to by the generic word touch
The activities and essays in this chapter will explore various aspects of somatosensation. Do you like to touch products while making a decision whether to buy them or not? The first activity in this chapter measures your Need for Touch (Activity 13.1). The next two activities cover two important physiological features of touch perception: the Somatosensory Receptors (Activity 13.2) and The Sensory Homunculus (Activity 13.3).
The Rubber Hand Illusion activity (Activity 13.4) demonstrates how our minds can be tricked into creating inaccurate body images, resulting in out-of-body experiences. In the Two-Point Touch Thresholds activity (Activity 13.5), you’ll map out how sensitive your various body parts are to detecting fine details of objects touching your skin. The Haptic Object Recognition activity (Activity 13.6) discusses how we use touch to identify objects (see also the essay on Lego Blocks Front and Back [Essay 13.4]). The essay on Body Image (Essay 13.2) explores our sense of our body’s position in space, while the essays on Living without Kinesthesis (Essay 13.1) and Phantom Limbs (Essay 13.3) discuss some intriguing consequences of damage to the somatosensory system.