Psych Chap 4

Sensation

Detection of physical energy from the environment by sensory receptors.

Perception

Organization and interpretation of sensory information by the brain.

Sensation vs. perception

Sensation detects sensory input; perception interprets what that input means.

Sensory receptor

Specialized cell that responds to a particular form of physical energy.

Transduction

Conversion of physical sensory energy into neural signals.

Why can't humans sense all physical energy?

Sensory receptors respond only to particular ranges and types of energy.

Sensory deprivation

A condition in which normal sensory stimulation is greatly reduced.

Effect of prolonged sensory deprivation

Reduced sensory input can alter perception, cognition, and behavior.

Subliminal stimulus

A stimulus presented below the level of conscious awareness.

Subliminal perception

Processing of sensory information without conscious awareness of the stimulus.

Can subliminal information influence behavior?

Yes; stimuli outside conscious awareness can sometimes influence judgments or behavior.

Subliminal odor experiment

Unconsciously detected pleasant or unpleasant odors influenced participants' ratings of faces.

What did the subliminal odor experiment demonstrate?

Sensory information can affect judgments without entering conscious awareness.

Priming

Exposure to one stimulus influences the response to a later stimulus.

What does priming demonstrate?

Information can influence later perception or behavior without deliberate conscious thought.

Electromagnetic spectrum

The full range of electromagnetic energy wavelengths.

Visible spectrum

The small portion of electromagnetic energy that humans can see.

Can humans see the entire electromagnetic spectrum?

No. The human visual system detects only a very narrow range.

Wavelength

Distance between successive peaks of an electromagnetic wave.

Wavelength and color

Different wavelengths of visible light are perceived as different colors.

Iris

Colored muscular structure of the eye that regulates how much light enters.

Pupil

Opening in the center of the iris through which light enters the eye.

How does the iris regulate light?

It changes pupil size, controlling the amount of light entering the eye.

Retina

Light-sensitive tissue at the back of the eye containing visual sensory receptors.

Main function of the retina

Transduces light energy into neural signals.

Photoreceptors

Light-sensitive receptor cells located in the retina.

Two types of photoreceptors

Rods and cones.

Rods

Retinal receptors especially sensitive to dim light.

Cones

Retinal receptors important for color vision and detailed vision.

Rods vs. cones

Rods specialize in dim-light vision; cones specialize in color and fine detail.

Fovea

Central retinal region containing a high concentration of cones and supporting sharp vision.

Blind spot

Retinal location where the optic nerve exits; it contains no photoreceptors.

Optic nerve

Carries visual information from the retina toward the brain.

Basic visual transduction sequence

Light → retinal photoreceptors → neural signals → brain.

Why is vision both sensation and perception?

The eye detects/transduces light, while the brain interprets the resulting neural information.