Sensation

Sensation: your window to the world

Perception: interpreting what comes in your window

Sensation

The process by which our sensory receptors and nervous system receive stimulus from the environment

Bottom-up v. Top-Down Processing

Bottom Up: begins with the sensory receptors and nervous system receive stimulus from the environment

Top-Down: information processing guided by higher level mental processes

Absolute Threshold: the minimum stimulation needed to detect a stimulus 50% of the time

Difference Threshold: the minimum difference that a person can detect between two stimuli

- Also known as Just Noticeable Difference

Weber's Law: the idea that, to perceive a difference between two stimuli, they must differ by a constant percentage not a constant amount

Signal Detection Theory: predict how we detect a stimulus amid other stimuli

Sensory Adaptation: decreased responsiveness to stimuli due to constant stimulation

Selective Attention: the focusing of conscious awareness on a particular stimulus

Cocktail-party phenomenon: The cocktail party effect describes the ability to focus one's listening attention on a single talker among a mixture of conversations and background noises, ignoring other conversations
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Vision

Vision: our most dominating sense

Gathering Light

• Short Wavelength = High frequency (bluish colors, high-pitched sounds)
• Long Wavelength = Low frequency (reddish colors, low-pitched sounds)

 Transduction: Transforming signals into neural impulses
-Information goes from the senses to the thalamus then to the various areas in the brain

Conversion of one form of energy to another
Stimulus energies to neural impulse

• Light energy rto vision
• Chemical energy to smell and taste
• Sound waves to sound



Color Vision:

Two Major Theories

Young-Helenholtz Trichromatic (three color) Theory

Three types of cones: - Red -Blue - Green

-These three types of cones can make million of combinations of colors

Opponent-Process Theory: the sensory receptors comes in pairs

• Red/Green
• Yellow/Blue
• Black/White

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Hearing

Hearing: The height of the wave gives us the amplitude of the sound

-The frequency of the wave gives us the pitch of the sound



Transduction of the ear

Sound waves hit the eardrum then anvil then hammer then stirrup then anvil window

-Everything is just vibrating

-Then the cochlea vibrates

-The cochlea is lined with mucus called basilar membrane

-In basilar membrane there are hair cells

-When the hair cells vibrate they turn vibrations into neural impulses which are called organ of corti

-Sent then to thalamus to auditory nerve

Pitch Theories:

Place Theory: different hairs vibrate in the cochlea when thre are different pitches

-So some hairs vibrate when they hear high pitches and other vibraet when they hear low pitches

Frequency Theory: all the hairs vibrate but at different speeds

Deafness

Conduction Deafness: Something goes wrong with the sound and the vibration on the way to the cochlea

-You can replace the bones or get a hearing aid to help

Nerve Deafness: The hair cells in the cochlea get damaged

-Loud noises can cause this deafness

-NO WAY to replace the hairs

-Cochlea implant is possible

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Taste

Taste: We have bumps on our tongue called papillae

-Taste buds are located on the papillae

-Sweet, salty, sour, and bitter

 Umami: flavorable meaty favory taste

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Touch

Touch: Receptors located in our skin

-Gate Control Theory of Pain

Gate Contril Theory of Pain: Where the spinal cord controls a neurological gate that blocks pain signals or allows them to pass on the brain

Vestibular Sense: Tells us where our body is oriented in space

-Our sense of balance

Kinesthetic Sense: Tells us where our body parts are

-Receptors located in our muscles and joints