AP Psychology Unit 1 - Sensation

Sensation

The process of detecting information from the environment

Sensory Transduction

The process of converting physical stimuli into neural signals.

Absolute Threshold

The threshold that must be reached in order to experience a sensation

If the neurons don’t receive enough stimulation input, they won’t notice a sensation

Difference Threshold

The minimum change between two stimuli for an individual to detect change in one of them.

This is also known as the just noticeable difference (JND), which varies depending on the intensity of the original stimulus.

Weber-Fechner Law

To notice a difference between two stimuli, both must differ by a constant percent, not a constant amount

Example: Adding one cup of water into a bowl will be noticeable. But adding one cup of water into the sea will not be noticeable

Sensory Adaptation

When stimulus is continuous and unchanging, causing the individual to get used to it

Habituation

When there is a decrease in response to a stimulus after repeated presentations, allowing individuals to focus on more important stimuli.

Sensory Interaction

The principle that one sense may influence another, such as taste being affected by smell.

Synesthesia

A phenomenon or condition that is experienced with another

Example: Individual sees colors when hearing music, or tasting flavors when reading

Pupil

The part of the eye using lens to focus the light it intakes into the retina at the back of the eye

Retina

The light-sensitive layer of tissue at the back of the eye (photoreceptors) that converts light images into electrical signals for the brain.

Rods

The part of the eye that helps you see in dim lighting

Cones

The part of the eye that helps you see finer details

Optic Nerves

Where neural impulses travel from the eyes to process visual information

Trichromatic Theory

The theory that the human eye has three types of color receptors (cones) sensitive to red, green, and blue light, which combine to create the perception of all colors.

Opponent Processing Theory

A color vision theory that suggests colors are perceived in pairs, with neurons that are activated by one color and inhibited by its opponent color (red-green, blue-yellow, black-white).

After Image Phenomenon

A visual illusion that occurs after staring at an image, resulting in a reversed coloring of that image after looking away.

Achromatism

A condition in which individuals can only see black, white, and gray

Dichromatism

A condition in which individuals only have two cones and will be confused between sensing multiple colors

Monochromatism

A visual condition where individuals have only one type of cone, perceiving no color and seeing the world in shades of gray.

Accomodation

The process by which the eye adjusts its lens to focus on objects at different distances.

Myopia

A common vision condition where close objects appear clearly, but distant objects are blurred due to the eye being too long or the cornea being too curved.

Hyperopia

A common vision condition also known as farsightedness, where distant objects may be seen more clearly than close ones due to the eyeball being too short or the lens being too weak.

Prosopagnosia

A neurological condition characterized by an inability to recognize faces, also known as face blindness.

Blindsight

A phenomenon where individuals can respond to visual stimuli even without conscious perception, often due to damage in the primary visual cortex.

Sound Localization

The ability to determine the origin of a sound in the environment, relying on cues such as the intensity and timing differences of sound reaching each ear.

The Place Theory

The theory that certain hair cell placements in the ear respond to certain frequences

The Frequency Theory

The theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, allowing us to perceive pitch.

The Volley Theory

The theory that groups of auditory nerve fibers fire in succession, or "volley," to match the frequency of a sound wave, contributing to pitch perception.

Sensorineural Deafness

A type of hearing loss caused by damage to the inner ear or to the auditory nerve, affecting the ability to hear certain frequencies and leading to distortion of sound.

Conductive Deafness

A type of hearing loss caused by blockage with the ear canal, eardrum, or middle ear structures that prevent sound waves from being conducted to the inner ear.

Olfactory Receptors

Specialized sensory nerve cells in the nose that respond to odor molecules, playing a crucial role in the sense of smell.

Pheromones

Chemical signals detected by olfactory receptors that influence the behavior of other individuals, often related to social and reproductive behaviors.

Taste Receptors

Specialized sensory cells located on the tongue that respond to chemical substances in food, contributing to the sense of taste.

• Umami: Associated with savory, protein taste

• Bitter: Associated with toxins

• Sour: Associated with food gone bad

• Sweet: Associated with sugars

• Oleogustus: Associated with fats

Super tasters

People with more taste receptors and will experience tastes more intensely

Medium tasters

People with moderate amount of taste receptors and has balanced sensitivity

Nontasters

People with fewer taste receptors, and are less sensitive to certain tastes. They may prefer toods with stronger flavors

Epidermis

Also known as the skin. It serves as a barrier to protect a person from foreignn pathogens and gives individuals their skin color

Dermis

The layer of skin beneath the epidermis that registers touch and pain with nociceptors (pain receptors)

Hypodermis

The deepest layer of skin that contains fat and connective tissue, providing insulation and cushioning for the body.

Mechanoreceptors

Sensory receptors that respond to pressure

Thermoreceptors

Sensory receptors that respond to temperature

The Gate Control Theory

Theory that suggests the spinal cord contains a neurological "gate" that either blocks or allows pain signals to pass to the brain, influencing the perception of pain.

Pain requires attention

Phantom Limb Sensation

The phenomenon where individuals with an amputated limb continue to experience sensations, including pain, in the missing limb.

Proprioceptors

Sensory receptors located in various muscles and tendons that detect body position and movement.

Kinesthesis

The sensory system that detects the position and movement of body parts, allowing for coordination and balance.

Anosmia

A condition where an individual loses sense of smell

Hyposmia

A condition where an individual has reduced ability to smell

Hypogeusia

A condition where an individual has reduced ability to taste sweet, sour, bitter, or salty things

Congenital Insensitivity

A condition where a person is unable to feel physical pain

Weber’s Law

The principle that the just noticeable difference between two stimuli is a constant proportion of the original stimulus.

Law of Effect

The principle that behaviors followed by favorable consequences are more likely to recur, while those followed by unfavorable consequences are less likely to occur.

Yerkes-Dodson Law

The principle that optimal performance is achieved with a moderate level of arousal, while too little or too much arousal can hinder performance.

Olfactory Nerves

Where neural impulses travel to the nose to process smell

Oculormotor Nerve

Where neural impulses travel between brain, head, neck, and torso. This controls eye movement and focus

Trigeminal Nerve

Where neural impulses travel around the face to process sensation