What is the difference between sensation and perception?
Sensation is the transduction of physical energy into neural signals; perception is the interpretation of those signals to form a meaningful representation.
Why is perception considered an active process?
Because the brain makes inferences, groups patterns, segments figure–ground, and constructs structure from incomplete input.
Why is the problem of perception difficult?
The brain must interpret ambiguous sensory input and can make systematic errors, as shown by illusions.
What are qualia?
The subjective qualities of experience, such as redness or sweetness.
What does the labelled-line theory propose?
Each sensory neuron sends information to a dedicated brain region, letting the brain identify the stimulus type.
How does synesthesia relate to labelled lines?
It occurs when sensory “lines” cross, causing mixed experiences like seeing colours for sounds or letters.
Why are illusions important for understanding perception?
They show perception is not a direct copy of reality but a constructive process using assumptions.
What do illusions reveal about the brain’s processing?
The brain fills in contours, adapts, flips figure-ground, and perceives motion where none exists.
What biological signals do sweet tastes represent?
Energy-rich nutrients.
What does salty taste signal?
Electrolyte balance.
What does sour taste signal?
Acidity or potential spoilage.
What does bitter taste signal?
Possible toxins.
What does umami taste signal?
Amino acids/protein sources.
Why is taste an example of dimensionality reduction?
Millions of chemical stimuli are compressed into just five taste receptor types.
Why is smell more complex than taste?
Humans can detect up to a trillion odours using only ~400 receptors.
What is the leading theory of smell?
Shape-pattern theory: odours are identified by patterns of receptor activation.
Why does olfactory adaptation happen quickly?
The system rapidly reduces sensitivity to continuous odours (e.g., your own scent).
What is the difference between taste, smell, and flavour?
Taste is from taste buds, smell is airborne chemicals, and flavour is the combination of both plus temperature and trigeminal input.
Why does food taste bland when you have a blocked nose?
Most of flavour comes from olfaction.
What is exteroception?
Senses of touch, pressure, vibration, temperature, and pain.
What is proprioception?
Sensing body position and movement.
What is interoception?
Sensing internal organ states like heart or gut activity.
What do Meissner corpuscles detect?
Low-frequency vibration and grip control.
What do Pacinian corpuscles detect?
High-frequency vibration and deep pressure.
