Unit 4: Sensation and Perception

Rods and Cones

Rod and cone photoreceptors are found on the outermost layer of the retina;

Subliminal Messages

About subliminal messages A brief description. A signal or message designed to pass below (sub) the normal limits of perception. An inaudible to the conscious mind (but audible to the unconscious or deeper mind) An image transmitted briefly, unperceived consciously, yet perceived unconsciously.

Frequency Theory

According to the frequency theory of hearing, the frequency of the auditory nerve's impulses corresponds to the frequency of a tone, which allows us to detect its pitch. Sounds come into the ear as acoustical signals and are later transformed into nerve impulses by the cochlea.

Afterimages

An afterimage is a non-specific term that refers to an image continuing to appear in one's vision after the exposure to the original image has ceased.

Binocular Depth Cues

Binocular cues are visual information taken in by two eyes that enable us a sense of depth perception, or stereopsis. Retinal disparity, also known as binocular parallax, refers to the fact that each of our eyes sees the world from a slightly different angle.

Blind Spot

Blind spot, small portion of the visual field of each eye that corresponds to the position of the optic disk (also known as the optic nerve head) within the retina. There are no photoreceptors (i.e., rods or cones) in the optic disk, and, therefore, there is no image detection in this area.

Closure

Closure is a Gestalt principle of perceptual organization that explains how humans fill in visual gaps in order to perceive disconnected parts as a whole object. For example, can you tell what shape this elements make? [__] -- answer = square

Color Blindness

Color blindness, or color vision deficiency, is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions.

Conduction Deafness

Conductive hearing loss occurs when there is a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane (eardrum), or middle ear (ossicles). This type of hearing loss may occur in conjunction with sensorineural hearing loss (mixed hearing loss) or alone.

David Hubel

David Hunter Hubel was a Canadian neurophysiologist noted for his studies of the structure and function of the visual cortex.

Signal Detection Theory

Detection theory or signal detection theory is a means to quantify the ability to discern between information-bearing patterns (called stimulus in humans, signal in machines) and random patterns that distract from the information (called noise, consisting of background stimuli and random activity of the detection

Eleanor Gibson

Eleanor Jack Gibson was an American psychologist. Among her contributions to psychology, the most important are the study of perception in infants and toddlers.

Ernst Weber

Ernst Heinrich Weber was a German physician who is considered one of the founders of experimental psychology. Weber was an influential and important figure in the areas of physiology and psychology during his lifetime and beyond.

Feature Detectors

Feature detectors are individual neurons - or groups of neurons - in the brain which code for perceptually significant stimuli.

Frequency

Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency.

Gestalt Rules

Gestalt principles, or gestalt laws, are rules of the organization of perceptual scenes.

Gustav Fechner

Gustav Theodor Fechner, was a German philosopher, physicist and experimental psychologist. An early pioneer in experimental psychology and founder of psychophysics, he inspired many 20th century scientists and philosophers

Sensory Habituation

Habituation is the decrease of a response to a repeated eliciting stimulus that is not due to sensory adaption or motor fatigue.

Absolute Threshold

In neuroscience and psychophysics, an absolute threshold was originally defined as the lowest level of a stimulus —light, sound, touch, etc.—that an organism could detect.

Sound Waves

In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement,

Bottom-up Processing

In the bottom-up processing approach, perception starts at the sensory input, the stimulus. Thus, perception can be described as data-driven. For example, there is a flower at the center of a person's field.

Monocular Depth Cues

Monocular cues provide depth information when viewing a scene with one eye. Motion parallax. When an observer moves, the apparent relative motion of several stationary objects against a background gives hints about their relative distance.

Motion Parallax

Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

Pitch Theories

Pitch depends on cochlea transduction

Place Theory

Place theory is a theory of hearing which states that our perception of sound depends on where each component frequency produces vibrations along the basilar membrane.

Nerve Deafness

Sensorineural hearing loss (SNHL) occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain.

Sensory Adaptation

Sensory adaptation is the process in which changes in the sensitivity of sensory receptors occur in relation to the stimulus. All senses are believed to experience sensory adaptation. However, some experimental psychologists say that the sense of pain does not experience this phenomenon.

Cochlea

The cochlea is the sense organ that translates sound into nerve impulses to be sent to the brain. Each person has two cochlea, one for each ear. The cochlea is a fluid-filled, snail shaped cavern in the mastoid bone of your skull behind each ear.

Cocktail-party phenomenon

The cocktail party effect is the phenomenon of being able to focus one's auditory attention on a particular stimulus while filtering out a range of other stimuli

Lens

The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina.

Retina

The entire retina contains about 7 million cones and 75 to 150 million rods. The optic disc, a part of the retina sometimes called "the blind spot" because it lacks photoreceptors, is located at the optic papilla, a nasal zone where the optic-nerve fibres leave the eye.

Fovea

The fovea (arrow) is the center most part of the macula. This tiny area is responsible for our central, sharpest vision.

Gate-control Theory

The gate control theory of pain asserts that non-painful input closes the "gates" to painful input, which prevents pain sensation from traveling to the central nervous system. Therefore, stimulation by non-noxious input is able to suppress pain.

Occipital Lobe

The occiptial lobe is important to being able to correctly understand what your eyes are seeing. These lobes have to be very fast to process the rapid information that our eyes are sending. Similar to how the temporal lobe makes sense of auditory information, the occipital lobe makes sense of visual information so that we are able to understand it. If our occipital lobe was impaired, or injured we would not be able to correctly process visual signals, thus visual confusion would result.

Opponent-process Theory

The opponent-process theory was first developed by Ewald Hering. He noted that there are color combinations that we never see, such as reddish-green or yellowish-blue. Opponent-process theory suggests that color perception is controlled by the activity of three opponent systems.

Pupil

The pupil is the opening in the centre of the eye. Light enters through the pupil and goes through the lens, which focuses the image on the retina. The size of the pupil is controlled by muscles. When more light is needed, the pupil is made larger.

Constancy

The tendency to perceive objects as maintaining stable properties, such as size, shape, brightness, and color, despite differences in distance, viewing angle, and lighting

Vestibular Sense

The vestibular system, in most mammals, is the sensory system that provides the leading contribution about the sense of balance and spatial orientation for the purpose of coordinating movement with balance.

Kinesthetic Sense

The word kinesthesia or kinæsthesia (kinesthetic sense) strictly means movement sense, but has been used inconsistently to refer either to proprioception alone or to the brain's integration of proprioceptive and vestibular inputs.

Top-down Processing

Top-down processing refers to how our brains make use of information that has already been brought into the brain by one or more of the sensory systems. Top-down processing is a cognitive process that initiates with our thoughts, which flow down to lower-level functions, such as the senses.

Torsten Wiesal

Torsten Nils Wiesel is a Swedish neurophysiologist. Together with David H. Hubel, he received the 1981 Nobel Prize in Physiology or Medicine, for their discoveries concerning information processing

Trichromatic Theory

Trichromatic Theory of Color Vision. The trichromatic theory of color vision is based on the premise that there are three classes of cone receptors subserving color vision. This theory has a very long history dating back to the 18th century.

Visible Light

Visible light is a form of electromagnetic (EM) radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Generally, visible light is defined as the wavelengths that are visible to most human eyes

Weber's Law

Weber's law, also called Weber-Fechner law, historically important psychological law quantifying the perception of change in a given stimulus. The law states that the change in a stimulus that will be just noticeable is a constant ratio of the original stimulus.

Retina

a layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.

Transduction

any process by which a biological cell converts one kind of signal or stimulus into another

Touch

come so close to (an object) as to be or come into contact with it.

Chemical Senses

detection of something entering the body?

Optic Nerve

each of the second pair of cranial nerves, transmitting impulses to the brain from the retina at the back of the eye.

Proximity

nearness in space, time, or relationship. Close things are perceived the same

Energy Senses

sense that gives information about the enviroment

Hearing

the faculty of perceiving sounds.

Olfaction (smell)

the faculty or power of perceiving odors or scents by means of the organs in the nose.

Vision

the faculty or state of being able to see.

Amplitude

the maximum extent of a vibration or oscillation, measured from the position of equilibrium.

Sensation

the operation or function of the senses; perception or awareness of stimuli through the senses.

Gustation (Taste)

the sensation of flavor perceived in the mouth and throat on contact with a substance.

Perception

the state of being or process of becoming aware of something through the senses. "the perception of pain"

Similarity

the state or fact of being similar. Perceive similar things as same.

Cornea

the transparent layer forming the front of the eye.

Continuity

the unbroken and consistent existence or operation of something over a period of time. Continuing things are perceived to continue forever