Sensations vs Perception

Sensation

a process by which our sensory receptors and nervous system receive and represent stimulus energy

Perception

a process of organizing and interpreting sensory information

What is bottom-up processing?

Interpretation of sensory information is unaffected by knowledge and expectations. Info processed til a “match“ in longterm memory is found

what is top-down processing?

Sensory information is interpreted differently depending on knowledge and expectations

What is the stroop effect? (1, 2, 3)

1. You look at a word spelling out a color, it is written in a different color than the word spells

2. Your brain prioritizes the meaning more than the ink color

3. Inference — slowing down reading the word — occurs when you pay attention to only the ink color

What are the three principles of sensation and perception?

1. There is not a 1 to 1 correspondence between physical and psychological reality

2. Sensations and perceptions are active processes

3. Sensations and perceptions are adaptive

What is sensory adaptation

Diminished sensitivity with constant stimulation

Whats transduction?

Sensory receptors translate physical stimulation into neural signals

What does the sensory threshold mean?

Sensory systems are sensitive to change in stimulation, the threshold is each system’s minimum amount of energy required to activate the system

What is absolute threshold? (not actually absolute)

The minimum stimulation needed to detect a particular stimulus. Defined as the stimulus needed for detection 50% of the time

What are subliminal stimuli?

Stimuli that are detected less than 50% of the time

Is subliminal messaging in music a thing?

No. The “messages” can only be heard when music is playing backward and typically need lyrics

difference threshold

Minimum difference between two stimuli that a subject can detect 50% of the time

Weber’s law

to perceive a difference between two stimuli, they must differ by a constant proportion

What are the 5 senses? (One is different)

Vision, hearing, taste, smell, body orientation

What is vision accommodation?

Change the shape of lens, focus near objects

What is the retina?

inner surface of eye, light sensitive, contains rods and cones

What are the cones in the retina’s receptor cells?

fine detail and color vision, used in daylight or well-lit conditions. Near center of retina on the fovea, aka area of central fovus

What are the rods in the retina’s receptor cells?

Peripheral of the retina, detects black white and grey. Used in twilight or low light conditions

Why are there a lot more rods than cones?

to help us see in the dark but there is less clarity and color

What is retina’s reaction to light?

blind spot, there are no receptor cells located there

What is trichromatic theory

the three color theory that gives us color vision, that there are 3 different retinal color receptors (red, green, blue). It allows us to see 1 million colors

What is the opponent-process theory

3 types of color opponent cells: white-black, red-green, blue-yellow

If one color is stimulated, the other is inhibited

What does opponent process cells explain?

1. After images

   1. visual illusion in which retinal impressions persist after the removal of a stimulus

   2. Fatigued cells can no longer inhibit, so other color comes through

2. Color deficient vision

   1. Red+Green=Yellow

   2. Red and green opponent cells are defective so you cant detect those colors

      1. But the yellow opponent cell works so you can see it

How does color vision work?

Opponent cells located in the retina and thalamus. Color vision is based on both the trichromatic and opponent process theory

What is tetrachromats

person with 4 types of cones (R, G, B, plus orange). Sees 10 colors in the rainbow instead of 7, sees 100 million colors

What is audition? what are the highest and lowest frequencies we can hear?

when sound waves interact with the structures of the ear.

Highest: 20,000 Hz

Lowest: 20 Hz

(Audition) what is place theory?

pitch is linked with the place where the cochlea’s membrane is stimulated

Works at high frequencies = 5,000 - 20,000 Hz

(Audition) what is frequency theory?

the rate of nerve impulses traveling up the auditory nerve matches the frequency of the tone

Works at low frequencies = <100 Hz

(Audition) what is volley theory?

Set of neurons fire at highest rate slightly out of sync

100 - 5,000 Hz

The volley adds up to overall Hz

Why do we sound different on tape than in person?

1. Air conduction (tape)

   1. Sound travels to sensory receptors via air

vs

2. Bone conduction (listening to self talk in person and tape)

   1. Sound travels to sensory receptors via bone

5 Taste sensations (+1)

Sweet

Sour

Salty

Bitter

Umami

• Savory

What structure help us taste? Where is it located? What was a common misconception until recently?

1. Papillae (tiny bumps on tongue)

   • Contain taste buds

     • Each bud has 50-100 cells

   • 10k taste buds on the tongue

Located on the roof of mouth, throat and esophagus

Once thought different types of taste buds concentrated in different regions, not true: they are equally distributed

Whats the reasoning behind different taste sensitivity?

The more papillae = greater taste sensitivity

What are the different types of tasters? What happens to taste with age?

Types of tasters:

1. Non tasters

   • <15 papillae

2. Normal Tasters

   • 15-30 papillae

3. Super taster

   • >30 papillae

   • Super tasters have nearly 6x the amount of taste buds as normal tasters

   • More likely to be sensitive to spicy foods

   • 1 in 4 people are super tasters

With ago, taste sensitivity decreases

What is the science behind spicy food?

No taste buds for spiciness of food

Capsaicin binds to a receptor in the mouth lining which is the same receptor that registers pain from heat, resulting in a burning feeling

4 Facts about smell

~1000 different types of olfactory receptor cells

10-20 million cells in total

detects 10,000 different odors

Connected to limbic system

Can humans track sent? How?

Yes, by blocking all other sensory clues

What is sensory interaction?

the principle that one sense may influence another

What is kinethesis?

The system for sensing the position and movement of individual body parts

Sensors in the joins and muscles send signals that coordinate with signals from the skin, eyes, and ears

What is vestibular sense (equalibrium)?

Sense of body movement and position relative to gravity. Including sense of balance

What are the 5 perceptual groupings (gestalt)?

1. Proximity: group nearby figures together

2. Similarity: group figures that are similar

3. Continuity: perceive continuous patters

4. Closure: fill in gaps (----)

5. Connectedness: spots and lines are seen as unit when connected

What is binocular cues (depth)?

Cues involving comparing images from both eyes

Retinal disparity

• Images from eyes differ

• gives 3D vision

• Closer the object is, larger the disparity

Convergence

• gives depth

• Neuromuscular vision

• Two eyes moving inward for near objects

How do we see a 3-D world using 2-D retinal images?

Retinal disparity

• brain combines different images to make 3-D

• 3D movies work on same principle

What are monocular cues? (Main point plus 5 and explainations for each)

Cues to figure out the depth of something requiring only one eye

• interposition

  • Closer objects block distant objects

• Relative size

  • smaller image is more distant

• linear perspective

  • parallel lines converge with distance

• relative height

  • Object closer to the horizon is perceived as father away

• texture gradient

  • change from coarse to smooth texture indicates increasing distance

How does the role of experience effect our depth perception? (term and definition)

Perceptual set: a mental predisposition to perceive one thing and not another

What is extrasensory perception (ESP) (answer, 4 examples and their definitions)

claim that perception can occur without sensory input

• telepathy

  • Mind to mind communication

• Clairvoyance

  • Perceive remote current events

• Precognition

  • perceive future events

• Psychokinesis

  • Direct mental influence over physical objects

What are paraphsychologists?

study the para normal phenomena,. beyond the scope of normal scientific understanding

Why do people believe in ESP?

• people ignore the laws of probability

• want to have a magical experience

• people are too trusting and don’t think others could lie