Chapter 4: Sensation & Perception Flashcards
Sensation
process of receiving stimulus energies from the external environment
Perception
process of organizing and interpreting sensory information
Bottom-up Processing
is initiated by sensory input, the influence of the outside world on perception
Top-Down Processing
is initiated by cognitive processing, the influence of the internal/mental world on perception
(expectations and prior understanding)
Sensory Receptors
specialized cells that selectively detect and transmit sensory information to the brain, these signals are sent through distinct neural pathways
3 Categories of Receptors
Photoreception - vision, detection of light
Mechanoreception - touch/hearing, detection of pressure, vibration, & movement
Chemoreception - smell/taste, detection of chemical stimuli
Absolute Threshold
minimum amount of stimulus an organism can detect 50% of the time
ex: a candle flame at 30 miles on a dark, clear night
Difference Threshold/JND
amount of stimulus change needed for detection, weber’s law states that it is not necessarily about amount of change but more about proportion of change
Signal Detection Theory
how we notice things, “did I detect something?”
4 outcomes =
- Hit -> a stimulus is present and is detected
- Miss -> a stimulus is present but not detected
- False Alarm -> false detection of stimulus
- Correct Rejection -> no stimulus present and no detection
Attention
focusing awareness on a narrowed aspect of the environment
Cocktail Party Phenomenon
Selectively paying attention within a loud setting (certain things in the environment grab attention more than others)
Stroop Effect
mixed sensory signals confuse perception
Sensory Adaptation
our brain cells become less sensitive to to constant stimuli that is detected by our senses
ex: our eyesight
adjusting to darkness
Retina
consists of rods and cones, converts light that enters our eye into signals sent to the brain
Rods
are sensitive to dim light, but not color. function well in low illumination, humans have about 120 million