AP Psych Sensation & Perspective

Sensation

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

Perception

The process of organizing and interpreting sensory information to make sense of the world around us.

Transduction

The conversion of sensory stimuli into neural impulses that can be understood by the brain.

Absolute Threshold

The minimum amount of stimulation required for a stimulus to be detected by a sensory system. It represents the point at which a stimulus becomes noticeable to an individual at least 50% of the time.

Just-Noticeable Difference (JND)

The smallest change in a stimulus that can be detected by an individual. It's the minimal difference needed for a person to perceive that a change has occurred.

Weber's Law

The perceived difference in a stimulus must be proportional to the original intensity of the stimulus

Sensory Adaptation

The process by which sensory receptors become less responsive to constant stimuli over time.

Synesthesia

A condition in which stimulation of one sensory pathway leads to automatic, involuntary experiences in another sensory pathway.

Transduction in the eye

occurs in the retina, where photoreceptor cells (rods and cones) convert light into electrical signals that can be processed by the brain.

Retina

The light-sensitive inner surface of the eye containing photoreceptor cells that convert light into neural signals.

Rods

Photoreceptor cells in the retina responsible for vision in low light conditions and detecting motion. They provide black-and-white vision and are highly sensitive to light, allowing us to see in dim environments.

Cones

Photoreceptor cells in the retina responsible for color vision and detail in bright light. They enable us to perceive colors and fine visual details, such as reading text or distinguishing between different hues.

Fovea

Central area of the retina responsible for sharp central vision. It contains a high concentration of cone cells (no rods), enabling detailed and color vision

Blind Spot

Area on the retina where the optic nerve exits the eye, lacking photoreceptor cells. It's a spot where vision is absent, as there are no light-sensitive cells to detect visual stimuli.

Ganglion Cells

Neurons in the retina that receive visual information from bipolar cells and transmit it to the brain via the optic nerve. They play a crucial role in processing visual signals and relaying them to the brain for further interpretation.

Lens

Transparent structure in the eye that focuses light onto the retina. It adjusts its shape to help the eye properly refract light, enabling clear vision at different distances.

Accommodation

The process by which the lens of the eye changes its shape to focus on objects at different distances. It allows for clear vision of both nearby and distant objects by adjusting the curvature of the lens.

Trichromatic Theory

A theory proposing that color vision is based on three types of cone receptors, each sensitive to different wavelengths of light (red, green, and blue). The brain combines signals from these cones to create the perception of a wide range of colors

Opponent-Process Theory

A theory proposing that color vision is based on pairs of opposing color processes (red-green, blue-yellow, and black-white).

Afterimages

Visual sensations that persist after a stimulus is removed. They occur due to temporary overstimulation of cone cells in the retina, resulting in a brief perception of an inverted or complementary image.

Dichromatism

A type of color vision deficiency where an individual has only two types of functioning cone cells instead of the normal three. This condition typically results in difficulty distinguishing between certain colors, especially reds and greens.

Monochromatism

A rare form of color blindness where an individual has only one type of functioning cone cell, or none at all. This results in the inability to perceive colors, seeing the world in shades of gray.

Blindsight

A phenomenon where individuals with damage to their visual cortex can respond to visual stimuli without consciously perceiving them. It suggests that some visual processing can occur unconsciously, bypassing traditional pathways in the brain.

Prosopagnosia

A neurological condition characterized by the inability to recognize familiar faces, including one's own face, despite intact vision and intellect. It's often referred to as face blindness.

Transduction in the ear

occurs in the cochlea, where hair cells convert sound vibrations into electrical signals that are sent to the brain.

Wavelength

The distance between sound wave peaks. Shorter wavelengths mean higher-pitched sounds, while longer wavelengths mean lower-pitched sounds.

Amplitude

The measure of the intensity or loudness of a sound wave, represented by the height of its peaks. Greater amplitude corresponds to louder sounds, while lower amplitude indicates softer sounds.

Pitch Perception

The brain's interpretation of the frequency of sound waves, determining whether a sound is high or low in tone. Higher frequencies are perceived as higher pitches, while lower frequencies are perceived as lower pitches.

Place Theory

Idea that different parts of the inner ear detect different sound frequencies. High pitches are sensed near the entrance, low pitches near the end.

Frequency Theory

A theory of pitch perception proposing that the frequency of a sound wave directly corresponds to the rate at which auditory nerve fibers fire. Higher frequency sounds lead to faster firing rates, resulting in higher perceived pitches.

Volley Theory

A theory of pitch perception proposing that groups of auditory neurons fire in rapid succession, or "volleys", to encode the frequency of sounds above 1000 Hz. This allows the brain to perceive pitches that exceed the firing rate of individual neurons.

Sound Localization

The brain's ability to determine the location of a sound source in space. It relies on cues such as differences in arrival time and intensity between the ears, as well as spectral cues, to accurately locate sounds.

Conduction Deafness

Hearing impairment caused by problems with the outer or middle ear, such as damage to the ear canal, eardrum, or middle ear bones. It typically results in difficulty hearing soft sounds and can often be treated medically or surgically (temporary).

Sensorineural Deafness

Hearing loss caused by damage to the inner ear or auditory nerve. It results in difficulty hearing soft sounds and understanding speech, and is often permanent. Common causes include aging, exposure to loud noise, and certain medical conditions.

Sensory Interaction

The principle that one sense can influence another, such as when smell affects taste. It demonstrates how our senses work together to create our overall perception of the world.

Olfactory Systems

Responsible for smell. Special receptors in the nose detect smells and send signals to the brain via the olfactory nerve. The thalamus helps process this information, allowing us to identify different odors.

Pheromones

Chemical substances released by animals, including humans, that trigger social or behavioral responses in others of the same species. They play a role in communication, mating, and territorial marking.

Gustation

The sense of taste, involving receptors on the tongue that detect different flavors.

Taste Receptors

Specialized cells located on the tongue and in the mouth that detect different tastes.

Warm/Cold Receptors

Specialized sensory neurons in the skin that detect changes in temperature. Warm receptors respond to increases in temperature, while cold receptors respond to decreases. They help us perceive and regulate our body's temperature.

Pain

Is a more difficult concept than others. It is in fact not a sensation but an emotional response to stimuli.

Gate Control Theory

A theory proposing that the experience of pain is modulated by a neural "gate" in the spinal cord. This gate can open to allow pain signals to be transmitted to the brain or close to block them.

Phantom Limb

Sensation of pain or other feelings in a missing limb. It occurs due to the brain's continued perception of the limb, even though it's no longer there.

Vestibular Sense

The sense of body orientation and movement, including balance and spatial awareness. It relies on receptors in the inner ear that detect changes in head position and movement, helping to maintain stability and coordinate bodily movements

Semicircular Canals

Fluid-filled structures in the inner ear that detect rotational movements of the head. They play a crucial role in the vestibular sense, helping to maintain balance and coordination by sending signals to the brain about changes in head position and movement.

Kinesthesis

The sense of body movement and position, including the awareness of muscle and joint sensations. It allows us to perceive and control our body's movements, providing feedback to the brain about the position and orientation of body parts.

Bottom-Up Processing "Details to Big Picture"

our brain makes sense of information by starting with the small details and then building up to a complete perception. BU: Build Up from the details.

Top-Down Processing "Big Picture to Details"

involves interpreting sensory information based on the larger context, prior knowledge, and expectations.

Think Down from the big picture.

Selective Attention

the process of focusing on a specific aspect of information while ignoring others.

Cocktail Party Effect

our ability to focus on a single conversation in a noisy environment, like a crowded party, while tuning out other stimuli.

Inattentional Blindness

an individual fails to notice an unexpected stimulus in their visual field when their attention is focused on something else.

Change Blindness

the failure to notice large changes in one's environment when the change occurs simultaneously with a visual disruption.

. Perceptual Organization (Gestalt Principles)

The brain tends to organize stimuli into coherent groups.

Figure-Ground:

Distinguishing an object (figure) from its surroundings (ground).

Proximity:

Grouping nearby figures together

Similarity:

Grouping similar elements together

Continuity

Perceiving smooth, continuous patterns.

Closure

Filling in gaps to create a complete object.

Binocular Cues:

Retinal disparity: The brain compares images from both eyes to judge depth.

Convergence: The inward angle of the eyes increases with closer objects.

Monocular Cues

Depth cues available to one eye (e.g., linear perspective, relative size, interposition, light and shadow, motion parallax).

Perceptual Constancy

Perceiving objects as unchanging despite variations in sensory input.

Size Constancy

Object size is perceived as constant even if distance changes.

Shape Constancy

Object shape is perceived as constant despite changes in viewing angle.

Color and Brightness Constancy

Perceived color/brightness remains stable under varying lighting conditions.

Perceptual Set

A mental predisposition to perceive one thing and not another, shaped by expectations, context, emotions, and culture. Example: Interpreting ambiguous images differently based on prior experience.

Context Effects

The environment or situation influences perception. Example: A figure may appear larger or smaller depending on surrounding objects.

Cultural and Emotional Influences

Cultural background and emotional state can alter how stimuli are perceived. Example: Facial expressions are recognized differently across cultures.

Extrasensory Perception (ESP):

Claimed ability to perceive beyond sensory input (telepathy, clairvoyance, precognition).

Parapsychology

The study of paranormal phenomena—lacks empirical support.