Ch. 4 Sensation
Q: What is sensation?
A: The process of detecting external stimuli through sensory organs and converting it into neural signals.
Q: What is perception?
A: The process by which the brain organizes, interprets, and gives meaning to sensory information.
Q: What is transduction?
A: The conversion of sensory stimuli (like light, sound) into electrical neural impulses sent to the brain.
Q: What is the absolute threshold?
A: The minimum amount of stimulation needed to detect a stimulus 50% of the time.
Q: What is the difference threshold (Just Noticeable Difference)?
A: The smallest difference between two stimuli that can be detected 50% of the time.
Q: What is Weber’s Law?
A: The principle that the JND is a constant proportion of the original stimulus intensity, not a fixed amount.
Q: What is sensory adaptation?
A: A decrease in sensitivity to a constant level of stimulation over time.
👁 Vision
Q: What is the pathway of light through the eye?
A: Cornea → Pupil → Lens → Retina.
Q: What does the cornea do?
A: Bends light waves to help focus them.
Q: What controls the size of the pupil?
A: The iris.
Q: What does the lens do?
A: Changes shape to focus light onto the retina (accommodation).
Q: What is the retina?
A: The light-sensitive inner surface of the eye containing photoreceptors (rods & cones).
Q: What are rods responsible for?
A: Night vision, peripheral vision, detecting black and white.
Q: What are cones responsible for?
A: Color vision and detailed vision, work best in bright light.
Q: What is the optic nerve?
A: Carries neural signals from the retina to the brain’s visual cortex.
Q: What is the blind spot?
A: The point where the optic nerve exits the eye; no photoreceptors are present there.
🎵 Hearing (Audition)
Q: What are the main parts of the ear?
A: Outer ear (pinna, ear canal), middle ear (ossicles: hammer, anvil, stirrup), inner ear (cochlea).
Q: What does the cochlea do?
A: Contains fluid and hair cells that transduce sound waves into neural signals.
Q: What is the auditory nerve?
A: Carries sound information from the cochlea to the brain.
👅 Taste (Gustation)
Q: What are the five basic tastes?
A: Sweet, salty, sour, bitter, umami (savory).
Q: Where are taste receptors located?
A: In the taste buds on the tongue.
👃 Smell (Olfaction)
Q: What detects smell?
A: Olfactory receptors in the nose.
Q: Where are smell signals processed?
A: In the olfactory bulb and then sent to the brain, directly linked to areas processing emotion and memory.
✋ Touch and Body Senses
Q: What are the somesthetic senses?
A: Touch, temperature, pain, pressure.
Q: What is the vestibular sense?
A: The sense of balance and spatial orientation, located in the inner ear’s semicircular canals.
Q: What is the kinesthetic sense?
A: Sense of body movement and position of limbs.
🧠 Perception
Q: What is top-down processing?
A: Perception driven by prior knowledge, experiences, and expectations.
Q: What is bottom-up processing?
A: Perception starting from raw sensory input, building up to a full perception.
Q: What are Gestalt principles?
A: Psychological principles that describe how we organize visual information into wholes:
Proximity: Close objects are grouped together.
Similarity: Similar items are grouped.
Closure: We fill in gaps to complete a shape.
Continuity: We perceive smooth, continuous patterns.
Figure-ground: Distinguishing an object (figure) from its background.
Q: What is depth perception?
A: The ability to perceive the world in 3D and judge distance.
Q: What is perceptual constancy?
A: Recognizing that objects remain the same even when their appearance changes (like size, shape, color).