on the skin surface (e.g., edges, curvature, and texture) and proprioception of hand position and conformation. People can rapidly and accurately identify three-dimensional objects by touch. This involves exploratory procedures, such as moving the fingers over the outer surface of the object or holding the entire object in the hand. Haptic perception relies on the forces experienced during touch. Gibson defined the haptic system as "the sensibility of the individual to the world adjacent to his body by use of his body." Gibson and others emphasized the close link between body movement and haptic perception, where the latter is active exploration. The concept of haptic perception is related to the concept of extended physiological proprioception according to which, when using a tool such as a stick, perceptual experience is transparently transferred to the end of the tool. Taste Taste (formally known as gustation) is the ability to perceive the flavor of substances, including, but not limited to, food. Humans receive tastes through sensory organs concentrated on the upper surface of the tongue, called taste buds or gustatory calyculi. The human tongue has 100 to 150 taste receptor cells on each of its roughly-ten thousand taste buds. Traditionally, there have been four primary tastes: sweetness, bitterness, sourness, and saltiness. The recognition and awareness of umami, which is considered the fifth primary taste, is a relatively recent development in Western cuisine. Other tastes can be mimicked by combining these basic tastes, all of which contribute only partially to the sensation and flavor of food in the mouth. Other factors include smell, which is detected by the olfactory epithelium of the nose; texture, which is detected through a variety of mechanoreceptors, muscle nerves, etc.; and temperature, which is detected by thermoreceptors. All basic tastes are classified as either appetitive or aversive, depending upon whether the things they sense are harmful or beneficial. Smell Smell is the process of absorbing molecules through olfactory organs, which are absorbed by humans through the nose. These molecules diffuse through a thick layer of mucus; come into contact with one of thousands of cilia that are projected from sensory neurons; and are then absorbed into a receptor (one of 347 or so). It is this process that causes humans to understand the concept of smell from a physical standpoint. Smell is also a very interactive sense as scientists have begun to observe that olfaction comes into contact with