Sensation versus perception
Your senses gather raw information, but your brain decides what it means.
Two different steps
Sensation is the detection of physical energy, such as light or sound waves, by sensory receptors. Transduction converts that energy into neural signals. Perception is the brain's organisation and interpretation of those signals into meaningful experiences, like recognising a friend's face or a song.
Thresholds
The absolute threshold is the minimum stimulus intensity a person can detect half the time. The difference threshold, or just noticeable difference, is the smallest change a person can notice. Weber's law says this difference is a constant proportion of the original stimulus: adding one candle to a dark room is noticeable, but not to a room with a hundred.
Attention and adaptation
Sensory adaptation is reduced sensitivity to an unchanging stimulus, which is why you stop noticing the feel of your clothes. Selective attention focuses on some information while filtering out the rest. In inattentional blindness, people miss something obvious, like a person in a gorilla suit, because their attention is elsewhere.
Flashcard
Converting physical energy into neural signals
Check your understanding
After a few minutes in a room, you no longer notice the hum of the air conditioner. This is: