Sensory reception

Perception of the environment is essentially a matter of converting energy--light, heat, sound, electricity, gravity, magnetism, chemical bonding--into an electrical signal in the nervous system. Conversion of one energy form to another is called transduction, and sensory receptors are transducers. Transducers are a familiar aspect of human life; a speaker transduces electrical energy into sound, the head on a tape recorder transduces recorded magnetic patterns into electrical impulses, and a light bulb transduces electricity into light.

Sensory organs usually include structures for gathering energy from the environment. Examples of this are the lens part of the eye, and the outer portion (called the pinnae in vertebrates) of the ear. The stimulus is then focused or channeled to specialized nerve cells, which make the actual conversion from environmental energy to a signal n the nervous system.

For the animal behaviorist, the most important aspects of sensory systems are those which facilitate or limit how animals perceive the environment and how they can communicate.

The most significant limitation an animal can have is the inability to perceive a particular kind of stimulus. Humans, for example, cannot perceive polarization of light; some other animals, such as honeybees, use polarization to gain important information for navigation. One of the most important goals of sensory biology is to develop a picture of the sensory capabilities of different species. In the study of animal behavior, it is very important not to assume that animals suffer the same limitations, or have the same sensory abilities, as humans.

Precise perceptual mechanisms are specific to the sensory modality:

Sound

Vision (light)

Chemical (odor)

Tactile

Electrical

Magnetic