Sensation and perception

Sensation

The study of how our senses first detect incoming stimuli and process it through the brain and nervous system.

Perception

The process of organizing and interpreting raw sensory data and creating meaningful patterns.

Bottom-up processing

The way sensation works.

Top-down processing

The way perception works.

Absolute threshold

Weakest level of a stimulus that can be accurately detected at least 50% of the time.

Signal detection theory

A theory that helps us understand how quickly we can notice and interpret incoming stimuli.

Difference threshold (just noticeable difference)

The smallest detectable change in a stimulus.

Sensory adaptation

The diminishing of sensitivity to an unchanging stimulus.

Parallel processing

The processing of several elements of a problem simultaneously.

Transduction

The process in which sensory information is converted into neural energy/messages.

Retina

The most important part of the eye where the transduction of light energy into nerve impulses occurs.

Fovea

The area in the retina where cones are most heavily concentrated and our best vision is found.

Blind spot

The area where the optic nerve exits the retina, lacking rods and cones.

Accomodation

The process by which the eye’s lens changes shape to focus on far or near objects.

Blindsight

Visual processing without conscious awareness due to damage to the visual cortex.

Young-Helmholtz theory of color vision

Proposes there are 3 different types of color-sensitive cones (red, green, blue) and explains additive color mixing.

Opponent-process theory of color vision

Suggests that certain color-processing neurons oppose each other, and colors cannot be seen simultaneously.

Trichromats

People who have normal color vision.

Dichromats

People who are blind to either yellow-blue or red-green.

Monochromats

People who are totally color blind.

Sound localization

The ability to determine the source of a sound based on the time-lag between left and right auditory stimulation.

Cochlea

Contains the auditory receptors and triggers neural impulses that are sent to the auditory cortex.

Place theory (Helmholtz)

The theory which states that pitch is related to the exact spot where the cochlea's basilar membrane is stimulated.

Frequency Theory

The theory that states the entire basilar membrane vibrates in response to sound frequencies.

Taste buds

Taste receptors that reproduce themselves every week and allow us to perceive flavors like sweet, salty, sour, and bitter.

Smell

Processed by the olfactory bulb with receptors recognizing individual odors; chemical-based sense.

Gate-control theory of pain

The theory that proposes a functional gate in the nervous system can let pain impulses travel to the brain or block them.

Kinesthetic sense

The sense of body movement and the position of body parts.

Vestibular sense

The body's sense of orientation and balance.