AP Psychology Unit 1.6-Sensation

Sensation

The process by which our sensory receptors in our nervous system detect information in our environment

Perception

The process by which our brain interprets and processes sensory input

Transduction

The process by which sensory receptors convert physical energy or chemicals into a neural impulse to be interpreted by the brain

Absolute threshold

Occurs when a stimulus can be detected at least 50% of the time

Difference threshold

The degree to which stimuli needs to be different for the difference to be detected

Weber’s Law

In order to detect a change in a stimulus it must change by a constant minimum percentage

Sensory adaptation

Sensory receptors become less sensitive to constant stimuli

Sensory interaction

Taste and smell, and vision and hearing working in tandem

Synthestesia

An experience of sensation in one system is processed in another

Wavelenghts

Blue -

Light

A kind of energy that travels in waves

We can only see a few wavelengths that make up visible

Light Wavelengths

The distances between the peaks of light waves

Short-High frequency

Long-Low frequency

Short-Blue

Long-Red

Medium-Green

Structures of the eye

cornea, pupil, iris, lens, retina, fovea, optic nerve, blind spot

Cornea

Transparent, dome-shaped structure that covers the outer surface of the eye

Pupil

A small hole in the eye in the center of the iris

Iris

A muscle that contracts to change the size of the pupil depending on how much light there is in an environment

Lens

Flexible structure that focuses light by changing its shape.

Retina

Photosensitive surface at back of the eye.

Cells in this capture visual information that is transduced to the brain.

Optic/Visual Nerve

Carries electric signals to the occipital lobe of the brain

Fovea

Central point of vision

Contains rods and cones

Rods

Cells in the periphery of the eye that can detect shapes and movement

Cones

Photoreceptor cells located in the fovea that process color and detail

Blind spot

A spot where the nerve touches the retina

No visual ability

Accomodation

The process of the lens changing shape to see items at different distances

Nearsightedness

The ability to see items close up, but not far way.

Farsightedness

The ability to see items far away, but not close up

Refraction

Light rays bending as they pass through the cornea and lens

Images are flipped upside down and reversed left to right, but the brain flips it back over.

Color vision theories

Trichromatic theory

Opponent-Process Theory

Trichromatic theory

The theory that we have 3 cone photoreceptors that see different wavelengths of light

Opponent-process theory

The cones detect color and then signals are processed in pairs of opposing color channels by the ganglion cells.

White and black, blue and yellow, and red and green.

Afterimages

When you can still see an image but in opposite colors after looking away

Help prove the opponent-process theory

Result when certain ganglion cells are activated while others are not

Color vision deficiency

Damage or irregularities to cones or ganglion cells

Dichromatism or monochromatism

Dichromatism

A type of color vision deficiency when the person has 2 types of functioning cones

Monochromatism

A type of color vision deficiency when the person has 1 or no type of functioning cones

Visual processing disorders

Disorders linked to dysfunction in the brain

Prosopagnosia, blindsight

Prosopagnosia

Face blindness

Individuals have difficulty recognizing and interpreting differences between faces

Linked to disfunction in the fusiform gyrus

Blindsight

Eyes work, but the brain cannot process it.

Happens when a person has damage to the part of their brain that’s responsible for processing conscious visual information

Sound Waves

Amplitude determines loudness, while the wavelengths determine pitch

Short amplitude for quiet, short wavelength for a lower pitch.

Auditory sensory system

The system responsible for hearing

Pinna, ear canal, ear drum, hammer, anvil, and stirrup

Cochlea, basilar membrane, cilia, and auditory nerve.

Process of hearing

Vibrations travel through the pinna, which guides them into the ear canal. The ear canal amplifies the sound and brings it to a thin membrane called the eardrum. It vibrates and hits 3 tiny bones called the occiples. Then, they vibrate onto the cochlea. It creates waves that travel into the basilar membrane, and this bends the cilia. This movement of the cilia creates electrical signals that go to the auditory nerve, the thalamus, and finally, the temporal lobe.

Pitch theories

Place theory, volley theory, frequency theory.

Place theory

The theory that different parts of the cochlea respond to different pitches of sounds. High pitched sounds make the base vibrate more, but low pitched sounds make the tip vibrate more.

Volley theory

The theory that groups of neurons work together to send information about high-frequency auditory stimuli to the brain.

Frequency theory

The theory that the rate at which a neuron fires its signals matches the frequency of the sound waves.

Sound Localization

The ability to recognize where in our environment a sound coming from

Hearing loss

Results from aging and damage to auditory structures

Conduction deafness

Sensorineural deafness

Conduction deafness

The hearing loss that’s a result of damage to the outer and middle ear

Can occur after an ear infection

Sensorineural deafness

The hearing loss that’s a result of damage to the inner ear

Occurs due to damage to cilia hair cells

The 7 senses

Sight, hearing, smell, taste, touch, balance (Vestibular), body movement (kinesthetic)

Chemical senses

Olfactory system,pheromones

Processed by nose and mouth

Olfactory system

Responsible for our sense of smell

Inhale air, odor particles enter nasal cavity, dissolve in mucus lining that has olfactory receptor neurons. They change the signal into an electrical signal that travel to the olfactory bulb which then sends it to the olfactory cortex

Only sensation that bypasses the thalamus

Pheromones

Chemical signals released by animals that subconsciously affect states of others in the same species.

Detected by an organ in the nasal cavity

Gustation

Sense of taste

Sweet, sour, salty, bitter, umami, oleogustus

Gustatory system

Tongue, taste buds, and nerves

Taste buds pick up and detect taste, and convert them into electrical signals. Then they are sent to the brainstem, the thalamus, and to the frontal and temporal lobes.

Sensitivity to tasste

Supertasters, medium tasters, nontasters

Due to differing number of papillae (taste buds) on the tongue

Supertasters

People with higher sensitivity to taste

Finds bitter food extremely strong and unpleasant

Medium tasters

Average sensitivity to taste

Nontasters

Low sensitivity to taste

Finds many foods bland

Touch

Temperature, stretching, light touches, pain

Detected by skin, and sent to somatosensory cortex

Temperature

Detected by the sense of touch and thermoreceptors in skin

Pain

Detected by nociceptors in skin

Gate-Control theory

Explains how pain can be modulated in spinal cord before leading to the brain

Allows or blocks pain signals to brain

Phantom limb sensation

The sensation that occurs when people who have lost limbs feel pain or sensation where the limb used to be

Vestibular sense

Sense of balance detected by semicircular in the inner ear canals and structures in the brain. They make signals and send it to the cerebellum

Kinesthetic sense

Our awareness of movement and the position of our body. Detected by proprioceptors located in our muscles and joints. The signals are sent to the cerebellum and the somatosensory cortex.