A.P Psychology Chapter 4 Study Guide Sensation and Perception

1. What is Sensation? the process of sensing our environment through touch, taste, sight, sound, and

smell.

2. What is Perception? the way we interpret signals or sensations and make sense of everything around us.

3. Define and give an example of the process of Transduction. Stimuli from the environment are

transformed into neural impulses.

ex) the brain receiving the sensory stimulus of smelling smoke. Because the brain smells smoke, it may

begin to perceive that something nearby is burning.

4. Explain the difference between Sensory Adaptation and Sensory Habituation. Sensory adaptation is a

decreasing responsiveness to stimuli due to constant stimulation, while sensory habituation - our

perception of senses is partially due to how focused we are on them.

5. List and define the functions of the different parts of the eye (~10 main terms).

- Cornea: controls and focuses light entering the eye.

- Pupil: regulates the amount of light entering the eye by adjusting its size.

- Iris: controls the size of the pupil to adjust light intake.

- Lens: focuses light onto the retina by changing shape.

- Retina: converts light into electrical signals via photoreceptors.

- Rods: detect low light levels and enable black-and-white vision.

- Cones: detect color and fine details in bright light.

- Fovea: provides the highest visual acuity for sharp focus.

- Optic Nerve: transmits visual information from the retina to the brain for interpretation.

- Vitreous Humor: maintains the eye’s shape and allows light to pass to the retina.

6. What are the two main theories of color vision? List and define them. Which one of them best explains

color blindness? Why?

-Trichromatic theory- 3 types of cones in our retina, cones that detect blue, red, and green, and that

different activation combinations of the cones produces all the colors we see

-Opponent Process Theory- sensory receptors in the retina come in pairs: red/green, yellow/blue,

black/white. If one sensor is stimulated, its pair is inhibited from firing. This is the theory that explainsA.P Psychology Chapter 4

color blindness; if one of your colors is limited, then the

“

pair

”

of that color is also limited.

7. How do we hear? Describe in detail the process by which we process sound.

1. Sound waves enter the outer ear.

2. Sound waves cause the eardrum to vibrate.

3. Three tiny bones: stapes, incus, and malleus, in our middle ear amplify the vibrations and send them to

the inner ear.

4. Vibrations hit the cochlea which is lined with hair cells that move and trigger the release of

neurotransmitters.

5. Electrical signals sent by the auditory nerve travel to the brain.

8. What are the two main theories of hearing we learned in class? List and describe them in detail.

a) Place Theory - the different hair cells in the cochlea respond to different frequencies of sound

based on where they are located in the cochlea. We sense pitch because the hair cells move in

different places in the cochlea.

i) Research demonstrates that place theory accurately describes how hair cells sense the

upper range of pitches but not in the lower tomes.

b) Frequency Theory - lower tones are sensed by the rate at which hair cells fire. We sense lower

ranges of pitch because the hair cells fire at different frequencies in the cochlea.

9. Where is our center of balance? How does it maintain our balance? How and why do we “lose

balance”? (Which ‘sense’) V estibular Sense - responsible for how our body is oriented in space. Three

semicircular canals in the inner ear that are filled with fluid that moves and activates hair cells, causing

nerve cells to fire, telling the brain about spatial orientation. We can lose our sense of balance, when the

liquid in our ear moves around and isn't where it is supposed to be.

10. What are the different types of taste we learned about? Taste buds are located on the papillae, which

are bumps on your tongue ( some are also located on the roof of your mouth and cheeks).

ex) types of taste: sweet, salty, sour, bitter, savory.

11. What is olfaction? What system of the brain do olfactory receptors connect to? What other

functions is olfaction closely associated with? Odor, scents, and smells make their way up to the

olfactory bulb where the smell is processed by olfactory receptor cells. Olfactory receptors connect

to parts of the limbic system like the amygdala and hippocampus, parts of the brain responsible for

emotion and memory.A.P Psychology Chapter 4

12. What is Gate Control Theory? explains that some pain messages have a higher priority than others.

When a higher priority message is sent, the “gate” swings open for it and shuts off lower priority

messages. Not actually a gate, just an analogy.

13. What is our Kinesthetic sense? Gives feedback about the position and orientation of specific body

parts. Receptors in our muscles and joints send information to the brain about limbs.

14. Define Absolute Threshold and provide an example. The smallest amount of a stimulus that we can

detect (for any of the senses).

○ Stimuli below the absolute threshold are said to be subliminal.

○ ex) hearing the faintest sound a person can hear, such as the ticking of a watch 20 feet

away in a quiet room.

15. Define Difference Threshold (“just noticeable difference”) and provide an example. How

much a stimulus has to change before we notice a difference. ex) If you are holding a bag that

weighs 10 pounds, and someone adds 1 pound, you will notice it. But if the bag weighs 50

pounds, you might need an additional 5 pounds to notice.

16. What are False Positives and False Negatives? False Positive: when a stimulus that is not

there is perceived. False Negative: when a stimulus that is there is not perceived.

17. Explain how Top-Down Processing works. Occurs when you use your previously acquired knowledge

to fill in gaps in what you perceive. Quicker but more prone to errors.

18. What is a schema? A schema or schemata is a cognitive framework or concept that helps organize and

interpret information.

19. Explain how Bottom-Up Processing works. The opposite of top down processing. Analysis of the

stimulus begins with sense receptors and works up to the level of the brain and mind. Occurs when we

encounter something new or unfamiliar like analyzing a new language. Feature analysis - we analyze the

lines, curves, motion, and our brain builds a picture from the bottom up. More accurate, but takes up a

longer amount of time.

20. List and describe all of the Gestalt principles we went over in class.

● Proximity - objects that are close together are more likely to be perceived

as belonging in a group.

● Similarity - objects that are similar in appearance are more likely to be perceived as belonging in

a group.

● Continuity - objects that form a continuous form are likely to be perceived as a continuous thing.A.P Psychology Chapter 4

● Closure - objects that make up a recognizable image are more likely to be perceived as in the

same group.

● Connectedness - objects that are connected to each other using colors, lines, frames, or other

shapes are perceived as a single unit when compared with other elements that are not linked in the

same manner.

21. What is Perceived Motion?

● Stroboscopic Effect: Images in a series of still pictures presented at a certain speed will appear to

be moving.

● Phi-phenomenon - a series of lights flashed on an off at a particular rate will appear to be moving

light.

● Autokinetic Effect - If a spot light is projected steadily onto the same place on a wall of a dark

room and people are asked to stare at it, they will report seeing it move even though it isn’t.

22. Monocular Cues:

● Linear Perspective - a type of perspective used by artists in which the relative size, shape, and

position of objects are determined by drawn or imagined lines converging at a point on the

horizon.

● Relative Size Cue - the relative size of an object serves as an important monocular cue for depth

perception. The size difference can make the larger object appear closer and the smaller objects

appear farther away.

● Interposition Cue - objects that block the view of other objects must be closer to us.

● Texture Gradient - a change in the appearance of the grain or microstructure of a surface. Objects

closest in the picture have detail, while things far off fade in appearance.

● Shadowing - shading implies where the light source is coming from.

23. What is Binocular Disparity? How does it work? The difference in image location of an object seen by

the left and right eyes, resulting from the eyes’ horizontal separation. The brain uses binocular disparity to

extract depth information from the 2-D retinal images.