Chapter 6

What is sensation?

Sensation is the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

What are the rods in the eyes?

The rods are retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond.

Explain how context and culture shape someone's perception.

A given stimulus may trigger radically different perceptions, partly because of our differing perceptual set, but also because of the immediate context.

What is absolute threshold?

Absolute threshold is the minimum stimulation needed to detect a particular stimulus 50 percent of the time.

What is bottom-up processing?

Bottom-up processing is analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.

What is conduction hearing loss?

Conduction hearing loss is hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

What is difference threshold?

Difference threshold is the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference or jnd.

Explain the gate-control theory of pain.

Gate-control theory is the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in large fibers or by information coming from the brain.

Why is sensory adaptation beneficial for humans?

It is important because it gives freedom to focus on informative changes in our environment without being distracted by background chatter.

What is perception?

Perception is the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

How do motivation and emotion affect perception?

Perceptions are influenced, top-down, by our motivation and emotions. Desired objects seem closer. This perceptual bias energizes our going for it. Our motives direct our perception of ambiguous images.

What are the psychological and social-cultural influences of pain perception?

Psychological: Distraction, such as during intense athletic competition, can limit the experience of pain. Memories of pain focus on peak moments more than duration. Tapered pain is recalled as less painful than abruptly-ended pain. Social cultural: Social contagion : We feel more pain if other people are experiencing pain. This occurs either out of empathy/mirroring, or a shared belief that an experience is painful. Cultural influences: We may not pay attention as much to pain if we see a high level of pain endurance as the norm for our family, peer group, or culture.

What is the sensorineural hearing loss?

Sensorineural hearing loss is the hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness.

What is sensory adaptation?

Sensory adaptation is the diminished sensitivity as a consequence of constant stimulation.

What is signal detection theory?

Signal detection theory is a theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

What is the blind spot in the eye ?

The blind spot is the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there.

What is the cochlea structure?

The cochlea is a coiled, bony, fluid filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses.

What are the cones in the eyes?

The cones are retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.

What is the fovea in the eye?

The fovea is the central focal point in the retina, around which the eye's cones cluster.

What is the inner ear structure?

The inner ear is the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

What is the middle ear structure?

The middle ear structure is the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrates the vibrations of the eardrum on the cochlea's oval window.

What is the opponent process theory?

The opponent process theory is the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.

What is the optic nerve in the eyes?

The optic nerve is the nerve that carries neural impulses from the eye to the brain.

What is the retina?

The retina is the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.

What is the trichromatic color theory?

The trichromatic theory is the theory that the retina contains three different color receptors, one most sensitive to red, one to green, one to blue, which, when stimulated in combination, can produce the perception of any color.

What is top-down processing?

Top-down processing is information processing guided by high-level mental processes, as when we conduct perceptions drawing on our experience and expectations.

What is transduction?

Transduction is the conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret.