Sensation and PerceptionSensation and Perception

Chapter 3Chapter 3

Sensation and PerceptionSensation and Perception

• Detection and interpretation of stimuli so that we can understand and adapt to the world

• Essential to thinking, emotions, and behavior

• Imagine if you had NO senses

SENSESSENSES

• Detect and analyze stimuli through SENSORY RECEPTORS

• These are specialized neurons that transform stimuli into neural responses

• This is called transduction (see p. 90)

SENSORY THRESHOLDSSENSORY THRESHOLDS

• Absolute Threshold: Smallest strength of a stimulus you can detect 50% of the time

• Examples: candle flame 30 miles away on a dark night, one drop of perfume in a 3-room apartment

SENSORY THRESHOLDSSENSORY THRESHOLDS

• Difference Threshold: smallest possible difference between 2 stimuli that can be noticed 50% of the time

• AKA “Just noticeable difference”• Varies depending on the relation to original

stimulus—it is in constant proportion to the size of the original stimulus

• If the original stimulus was very intense, it will take more of a new stimulus to notice a difference

SENSORY ADAPTATIONSENSORY ADAPTATION

• Senses get used to a prolonged stimulus—they become less responsive to a constant stimulus

• Experience of sensation is relative to the duration of the exposure

• Sensory receptors are best at responding to new and different stimuli—so that we can quickly notice new or changing stimuli and react to it

PERCEPTIONPERCEPTION

• Your interpretation and organization of the world: making sense of the sensations

• Perception depends on sensations, but also on psychological activities like memories, expectations, familiarity, etc.

What do you see?What do you see?

What do you see?What do you see?

Who is tallest?Who is tallest?

Can you see the faces?Can you see the faces?