In this video, we lay the groundwork for future videos on sensation and perception (that is, how we sense and perceive using our eyes, ears, nose, and so on). We focus specifically on the difference between sensation and perception as well as on foundational principles that guide our ability to sense.

Sensation: The detection of physical energy (e.g., mechanical energy, light particles, sound waves) by our sense organs (e.g., ears, eyes, nose, skin, tongue), which relay this information to the brain; turning the signal to an electrical, neuronal signal.

Perception: The brain’s interpretation of sensation information; turning the electrical signal into a meaningful experience.

Transduction: The process of converting external energy or substance into electrical activity in the neurons using a sense receptor (e.g., cells in the back of the eye that transduce light, cells in part of the ear that transduce sound).

Sensory Adaptation: For all senses, activation is greatest when we first detect a stimulus; after the initial detection of the stimulus, activation decreases.

Absolute Threshold: The lowest level of a stimulus we can detect 50% of the time when no other stimuli are present.

Just Noticeable Difference: The smallest change in the intensity of a stimulus that we can detect.

Weber’s Law: The stronger the stimulus, the bigger the change needed for a change in stimulus intensity to be noticeable.

Multimodality: The principle which states that, given the right circumstances, sensory systems do not always stick to one sense.

Synesthesia: A rare condition, and an example of multimodality, in which people can “hear” or “taste” colors, “see” different numbers in different colors, and so on.