AP Psychology 1.6A

Absolute Threshold

The minimum amount of stimulation needed for a person to detect a stimulus 50% of the time. Example: the softest sound you can hear.

Just Noticeable Difference (JND) / Difference Threshold

The smallest change in a stimulus that a person can detect 50% of the time. Example: noticing when the TV volume goes from 20 to 21.

Perception

The process of organizing and interpreting sensory information so we can recognize meaningful objects and events.

Sensation

The process by which our sensory receptors and nervous system receive and detect stimulus energies from the environment.

Sensory Adaptation

Decreased sensitivity to a constant or unchanging stimulus over time. Example: no longer noticing a strong perfume after a few minutes.

Sensory Interaction

The principle that one sense may influence another. Example: taste is affected by smell.

Synesthesia

A condition where stimulation of one sense leads to involuntary experiences in another. Example: seeing colors when hearing music.

Transduction

The process of converting physical energy from stimuli (like light waves or sound waves) into neural signals that the brain can interpret.

Weber’s Law

The principle that the JND is proportional to the intensity of the stimulus. In other words, bigger stimuli require larger differences to notice a change.