Perception and the Visual System-AP Psych

Sensation

Sensation

The raw data collected by our senses, like seeing an apple or feeling the warmth of the sun.

Perception

The brain's interpretation and organization of sensory information to recognize objects, like distinguishing an apple from a tomato.

Bottom-up processing

Starting with basic sensory input and building up to complex perceptions, such as recognizing letters, then words, then sentences.

Top-down processing

Perception guided by expectations or past experiences, like interpreting a vague shape as a person.

Selective attention

Focusing on one thing while ignoring others, such as concentrating on a conversation at a noisy party.

Inattentional blindness

Missing something obvious due to intense focus on something else, like not noticing a gorilla in a basketball game.

Change blindness

Failing to notice changes in the environment due to diverted attention, like overlooking a small detail change in a familiar room.

Transduction

Conversion of sensory stimuli into neural signals for the brain to interpret, like turning light waves into vision signals.

Psychophysics

Studying the relationship between physical stimuli and psychological experiences, such as brightness or loudness perception.

Parapsychology

Exploring phenomena beyond normal scientific understanding, like telepathy or clairvoyance.

Absolute threshold

Minimum stimulation needed to detect a stimulus at least 50% of the time, like the faintest sound or dimmest light.

Difference threshold

Smallest change in a stimulus detectable, like noticing weight change when sugar is added to coffee.

Subliminal

Stimuli below conscious awareness that can influence thoughts or behaviors, like hidden messages in ads.

Sensory adaptation

Sensory receptors becoming less sensitive to unchanging stimuli, like not noticing a constant smell.

Signal Detection Theory

Understanding decision-making in detecting uncertain stimuli against noise, like identifying a faint light.

Weber's Law

States the relationship between stimulus magnitude and difference threshold, meaning bigger stimuli require bigger changes to notice.

Perceptual set

Mental filter influencing perception, like expecting to see a cat and misinterpreting a shadow as one.

Priming

Preparing the brain to interpret information based on past experiences, like noticing yellow things after hearing the word "yellow."

Schema

Mental framework organizing information, like having a schema for a typical classroom.

Extrasensory perception (ESP)

Perceiving information without physical senses, like seeing future events in dreams.

Wavelength, hue, intensity

Wavelength is wave peak distance, hue is perceived color, and intensity is wave brightness.

Iris, lens, retina

Iris regulates light, lens focuses light, and retina converts light to neural signals.

Accommodation

Lens changing shape to focus on objects at different distances, like adjusting a camera lens.

Rods and Cones

Rods for low light and night vision, cones for color vision and detail in bright light.

Optic nerve, blind spot, fovea

Optic nerve carries visual info, blind spot lacks photoreceptors, fovea has high cone concentration.

Feature detectors and parallel processing

Neurons responding to specific features and brain processing multiple aspects of a stimulus simultaneously.

Young-Helmholtz trichromatic theory

Three types of cones sensitive to different light wavelengths, forming all colors.

Opponent-process theory

Color perception in opposing pairs, where activation of one inhibits the other.

3 opposing pairs:

blue versus yellow

red versus green

black versus white