AP Psych Unit 3 Test

Sensation

-How our sense organs detect information from the environment

-Your eyes, ears, nose, tongue, and skin receive information

-Transduction: Turning stimulus energy into electrical signals (neural impulses) that the brain can understand

Perception

-How your brain organizes and interprets sensory information

-Ex. Your brain recognizes that the sound you hear is your favorite song

Stimulus Energy (Something happens in your environment) —> Sensory Receptors (Your sense organs detect it) —> Neural Impulses (Transduction turns energy into electrical signals) —> Brain (Processes the information) —> Perception (You interpret what you sensed)

Psychophysics

-The study of how physical stimuli relate to what we experience through our senses

-Ex. How loud a sound is compared to how loud it seems to you

Absolute Threshold

-The smallest amount of stimulation you can detect 50% of the time

-The weakest stimulus you can notice

-Ex. Turning music on at a very low volume. The absolute threshold is the lowest volume you can hear about half the time.

Signal Detection Theory

-Explains how we decide whether or not we detect a stimulus

Hit- You detect a signal that is actually there

Ex. You hear your phone ring.

Miss- You don’t detect a signal that is there

Ex. Your phone rings, but you don’t hear it.

False Alarm- You think there’s a signal, but there isn’t

Ex. You think your phone rang, but it didn’t.

Correct Rejection- You correctly recognize there is no signal

Ex. You know your phone isn’t ringing

Just Noticeable Difference (JND)

-Also called Difference Threshold

-The smallest change in a stimulus that you can detect 50% of the time

-The smallest difference you can notice between two things

-Ex. Listening to music at volume 10. Someone changes it to volume 11. You notice the volume changed.

Weber’s Law

-The larger the original stimulus, the bigger the change needs to be for you to notice a difference

-Ex. If you put a pencil on a paper plate, adding another pencil might make a noticeable difference in weight. But if you put a pencil on top of a heavy textbook, adding another pencil might not make a noticeable difference.

Sensory Adaptation

-When your senses become less sensitive to an unchanging stimulus over time

-Getting used to something

-Ex. You walk into a room that smells strongly of perfume. At first, you notice the smell. After being there for a while, you barely notice it anymore.

-Happens with your eyes too (Saccadic Movements)

-Saccadic Movements: Quick movements your eyes make to look at different things

Retina

-The part at the back of your eye that contains photoreceptors (light-sensitive cells)

-There are two types of photoreceptors —> Rods and Cones

Rods

-Long and thin

-Very sensitive to light

-Help you see in the dark or dim lighting

-Mostly located around the edges (periphery) of your retina

-Helps you see shades of gray, not color

Cones

-Short and thick

-Work best in bright light

-Help you see colors

-Mostly concentrated in the center of your retina

-Provide sharp, detailed vision

Parts of the Human Eye

Cornea- Clear outer covering that bends light into the eye

Pupil- Opening that allows light to enter the eye

Iris- Colored part of the eye that controls the size of the pupil

Lens- Focuses light onto the retina

Retina- Contains rods and cones that detect light

Optic Nerve: Carries visual information from the eye to the brain

Fovea- Small area of the retina responsible for the sharpest, clearest vision

Visual Pathway (Eye to Brain)

1. Optic Nerve: Carries visual signals from the eye to the brain.

2. Thalamus: Sorts and relays visual information to the visual cortex.

3. Primary Visual Cortex (Located in the Occipital Lobe): Processes visual information so you can understand what you’re seeing.

Feature Detector Cells

-Special cells in the brain that respond to specific visual features

-Simple cells: Respond to lines and their direction

-Complex cells: Respond to movement

-Hypercomplex cells: Respond to specific line lengths, angles, and edges

Trichromatic Theory

-The eye has three types of color receptors that detect red, green, and blue

-These three colors combine to create all the other colors we see

Ishihara Test

-A test that checks for color blindness or color vision deficiencies

-Uses colored dots that form numbers or patterns

-People with certain color vision deficiencies may have difficulty seeing the numbers

Opponent-Process Theory

-Color vision works through three pairs of opposing colors:

-Red vs. Green

-Blue vs. Yellow

-Black vs. White

-When one color in a pair is activated, the opposite color is suppressed

-Helps explain afterimages

-Afterimage: Seeing a different color after starting at one color for a while

-Ex. Stare at the American flag for a while. Look at a white surface. You may see an afterimage with opposite colors.

Diagram of the Human Ear

Cochlea Diagram

Auditory Localization

-The ability to tell where a sound is coming from

-Sounds coming from different directions reach your left and right ears differently

Place Theory

-Different parts of the cochlea respond to different sound pitches

-Different areas of the basilar membrane respond most strongly to different pitches

-High and low pitches activate different locations

-Where you hear the sound (location)

Frequency Theory

-The rate at which the basilar membrane vibrates matches the frequency (pitch) of the sound

-The faster it vibrates, the higher the pitch

-Individual nerves cannot fire fast enough to match very high frequencies

-How fast it vibrates