Psychology

Sensation

Detecting a stimulus from the environment, data the body notices.

Transduction

Process of transforming one form of energy into another; transformation of stimulus energies into neurochemical messages.

Absolute threshold

Minimum stimulation needed to detect a stimulus 50% of the time.

Difference threshold / Just noticeable difference (JND)

The smallest difference between two stimuli to notice a difference, must also be detected 50% of the time.

Weber’s Law

It is easier to detect a change between stimuli when they are less intense due to the proportional nature of the JND.

Sensory adaptation

Diminishing sensations as a result of constant stimulation; sensory receptors respond less to unchanging stimuli.

Retina

A photosensitive surface at the back of the eye containing photoreceptor cells that perform transduction.

Rods

Photoreceptor cells that detect shapes and movement but not color; work in dim environments.

Cones

Photoreceptor cells that process color and detail; they only work in bright light.

Trichromatic Theory

Theory stating that three cone types (RGB) are sensitive to long, medium, and short wavelengths to see specific colors.

Opponent-process theory

Theory that suggests optic nerve cells process complementary colors from the cones in pairs.

Afterimages

Visual sensations that remain after a sensation is removed, caused by fatigue in specific color sensors.

Audition

The biological process where ears process sound waves.

Place Theory

Theory suggesting that higher and lower pitches excite different areas of the cochlea.

Conductive Hearing Loss

Condition where there is poor transfer of sounds from the tympanic membrane to the inner ear.

Olfaction

The sense of smell, which begins with receptors in the mucus membrane in the upper nasal cavity.

Gustation

The sense of taste, transduced by taste bud receptors called papillae.

Gate-Control Theory

Theory suggesting that different pain messages pass through the same gate in the spinal cord.

Vestibular sense

Sense that helps with balance, primarily detected by the semicircular canals.

Kinesthesis

The sense of body position and movement, sensed by receptors in muscles, tendons, and ligaments.

Transduction in Vision

Changes electromagnetic light waves into neural signals that our brain can understand.

Cornea

Protects the eye and directs light to the center of the eyeball.

Iris

The colored part of the eye; a muscle that controls the amount of light entering the eye by relaxing in bright light and contracting in dim light.

Lens

Located behind the pupil, it directs light and focuses visual stimuli onto the retina.

Retina

A photosensitive surface at the back of the eye containing photoreceptor cells that perform transduction.

Optic Nerve

Sends nerve impulses from the eye to the brain.

Accommodation

The process by which the eye adjusts its output to focus on objects at different distances, potentially leading to nearsightedness (myopia) or farsightedness (hyperopia).

Visual Pathway

The sequence from Retina → Ganglion Cells → Bipolar Cells → Rods and Cones.

Rods

Photoreceptors that detect shapes and movement but not color; they work in dim environments and play a role in light/dark adaptation.

Cones

Photoreceptors that process color and detail; sensitive to red, green, and blue light, and only function in bright light.

Fovea

The center of the retina where cones cluster, providing the best vision quality.

Blind Spot

The area where the optic nerve leaves the eye, resulting in a lack of vision in that spot.

Trichromatic Theory

Theory stating that three cone types (RGB) are sensitive to long, medium, and short wavelengths, allowing us to see specific colors by comparing the responses of these cone types.

Opponent-process theory

A theory suggesting that optic nerve cells process complementary colors in pairs, where one color in the pair is excited while its counterpart is inhibited.

Afterimages

Visual sensations that persist after a stimulus is removed, caused by fatigue in specific color sensors.

Color Vision Deficiencies

Commonly known as color blindness, resulting from a malfunction in the cone cells.

Place Theory

Different pitches stimulate distinct areas of the cochlea; 'hair cells' bend differently based on pitch location.

Volley Theory

Neurons work in groups to achieve a more precise perception of pitch by firing slightly out of phase with one another.

Frequency Theory

The brain perceives pitches by tracking the frequency of neural impulses traveling along the auditory nerve; as pitch increases, the entire cochlea membrane vibrates accordingly.

Sound Localization

The process of determining the origin of sounds in our environment, based on sound intensity and timing; may involve moving the head.

Conductive Hearing Loss

A condition characterized by poor sound transfer from the tympanic membrane to the inner ear, often occurring with aging or ear bone damage.

Sensorineural Hearing Loss

Results from damage to the inner ear or auditory processing regions of the brain; can involve congenital abnormalities in 'hair cells' or loss due to infection, trauma, or aging.

Gustation

The sense of taste, which is transduced by receptors in taste buds known as papillae.

Taste Signal Pathway

Signals from taste buds are transmitted to the thalamus and then to the cerebral cortex.

Taste Receptors

The number of taste receptors on the tongue correlates with taste sensitivity.

Supertasters

Individuals with a heightened sensitivity to taste due to a higher density of taste buds.

Medium Tasters

Individuals with an average sensitivity to tastes.

Non-tasters

Individuals with a lower sensitivity to taste due to fewer taste buds.

Sweet Taste

A taste that is a good source of glucose, providing energy.

Sour Taste

A taste that is potentially toxic or acidic in nature.

Salty Taste

A taste that indicates high sodium content, essential for mental functions.

Bitter Taste

A taste that can indicate potential poisons, often found in plants.

Umami Taste

A taste that signals high protein content, important for tissue growth and repair.

Oleogustus

A taste associated with fat, which can be prevalent in spoiled or rancid foods.

Chemical Senses

Taste and smell are known as chemical senses, which interact to create the perception of flavor.

Impact of Smell on Taste

Without the sense of smell, taste sensations are diminished or not fully experienced.

Senses of Touch

Our sense of touch comprises a combination of four distinct skin senses: pressure, warmth, cold, and pain.

Temperature Perception

Warm and cold receptors located on the skin enable us to comprehend temperature changes.

Pain

Pain sensations are processed in both the body and the brain.

Gate-Control Theory of Pain

This theory posits that pain messages from various nerve fibers pass through the same gate in the spinal cord; if one pain message closes the gate, others cannot pass through.

Cognitive Influences on Pain Perception

Cognitive factors can affect how we perceive pain, as distractions are a possible method to help regulate it.

Phantom Limb Sensation

This phenomenon occurs when individuals who have lost limbs report sensations or pain in the area where the limb once was.

Vestibular Sense

The sense that aids in maintaining balance, which is primarily detected by the semicircular canals located above the cochlea.

Kinesthesis

The sense that provides awareness of body position and movement, relying on receptors found in muscles, tendons, and ligaments to sense muscle force and joint position.

Sensory Integration and Conflict

While sensory systems typically work in collaboration, there are instances where they conflict; discrepancies between visual input and vestibular or kinesthetic feedback can result in motion sickness.