Sensory Perception Flashcards
binocular cues
- retinal disparity - eyes are 2.5 inches apart, allowing you to see different angles
- convergence - things far away, eyes relax; things close up, eyes contract
monocular cues
- relative size - see the relative size of 2 objects and infer their proximity to us
- interposition - rectangle in front of oval means it’s closer to us
- Relative height - perceive higher things to be further away
- shading and contour
- motion parallax - cars further away move slower - gives you an idea of how far away objects are
- Constancy - a. size - two women appear to be different sizes based on how far away they are even though they’re basically the same; b. shape; c. color
sensory adaptation
- Hearing - inner ear muscle contracts in response to increased noise; 2. Touch - sensory nerves can become saturated and thus you adapt to hand being in cold water; 3. Smell - sensory receptors get desensitized; 4. Proprioception - goggles that change orientation of objects - eventually your brain adjusts; 5. Sight - pupils dilate and rods/cones adjust to adapt to bright vs. dark environments
Weber’s Law
K (constant) = (delta I)/I
You need a larger change in stimulus to notice the change if your background intensity is higher. Ex: notice difference between 2 lbs vs. 2.2 lbs but not 5 lbs vs 5.2 lbs. You need 5 lbs vs. 5.5 lbs for larger initial stimulus.
Absolute threshold of sensation
the minimum intensity stimulus needed to detect a difference 50% of the time. The JND is the minimum DIFFERENCE between two stimuli that can be detected, while the absolute threshold is the minimum intensity stimulus that can be detected 50% of the time.
Factors that influence absolute threshold of sensation
expectations, experience, motivation, alertness
subliminal stimuli
stimuli below the absolute threshold
Vestibular system
controls balance and spatial orientation. comes from receptors in our inner ear
semi-circular canals
there are 3 of these in our inner ear and they’re all at right angles to each other (x, y, and z axes)
endolymph
fluid that fills semi-circular canals. The way the fluid moves in the canals allows us to detect the direction and intensity of movement
Otolithic organs
help us detect linear acceleration and head positioning. Two otolithic organs are the utricle and sacule. Calcium crystals attach to hair in ear - when head moves, crystals move b/c they’re heavier than hair - sends an action potential (signal) to the brain
Somatosensation - sensations
- temperature - thermoception
- pressure - mechanoception
- pain - nocieception
- position - proprioception
intensity of sensation
determined by how quickly neurons fire
timing
when does the sensation start or stop? (1) non-adapting - no change in firing rate of neuron the whole time the stimulus is being applied (2) slow-adapting neuron - starts firing really fast and then slows down; (3) fast-adapting - fires a lot at the beginning of the stimulus and then stops and fires again when stimulus stops
bottom up processing
stimulus influences our perception. data driven
top down processing
background influences perception (e.g. where’s Waldo?); theory driven
Gestalt principles
- similarity –> items that are similar are grouped together (e.g. your brain recognizes pattern of squares and circles)
- Pragnanz –> reality reduced to its simplest form (e.g. 5 circles juxtaposed on top of one another instead of tons of different shapes and lines)
- Proximity –> objects closer together we group together
- continuity –> lines are seen as following smoothest path
- closure –> objects grouped together are seen as a whole
sensation vs. perception
–Sensation refers to the process of sensing our environment through touch, taste, sight, sound, and smell. This information is sent to our brains in raw form where perception comes into play. Perception is the way we interpret these sensations and therefore make sense of everything around us.
perception
–the process by which sensory information and prior knowledge are integrated to form a representation of the environment
bottom-up vs. top-down processing
- -There are two general processes involved in sensation and perception. Bottom-up processing refers to processing sensory information as it is coming in. … Top-down processing, on the other hand, refers to perception that is driven by cognition.
- -Top-down processing requires exerting cognitive control over sensation, while bottom-up means sensation drives things
