Sensory and Perception: Visual, Touch, and Pain Processes

What is sensation?

The detection of physical stimuli and transmission of that information to the brain.

What is perception?

The brain's further processing, organization, and interpretation of sensory information.

What is bottom-up processing?

Processing based on the physical features of the stimulus, building up to a perception.

What is top-down processing?

How knowledge, expectations, or past experiences shape the interpretation of sensory information.

What is transduction in sensory systems?

The process of translating physical properties of stimuli into patterns of neural impulses.

What are sensory receptors?

Specialized cells in the sense organs that receive stimulation.

What is the absolute threshold?

The minimum intensity of stimulation that must occur before you experience a sensation.

What is the difference threshold?

The smallest difference between two stimuli that you can notice.

What does Weber's law state?

The just noticeable difference between two stimuli is based on a proportion of the original stimulus.

What is sensory adaptation?

A decrease in sensitivity to a constant level of stimulation.

What is synesthesia?

An unusual combination of sensations, where one sense is involuntarily linked to another.

What is the function of the cornea?

The eye's thick, transparent outer layer that focuses incoming light.

What is the role of the retina?

Contains sensory receptors that transduce light into neural signals.

What is the function of the pupil?

A small opening that determines how much light enters the eye.

What are rods and cones?

Rods respond to low light levels and are responsible for night vision; cones are responsible for color and detail in brighter conditions.

What happens at the optic chiasm?

Half the axons in the optic nerve cross, projecting information from the left visual field to the right hemisphere.

What is presbyopia?

A condition where the lens hardens with age, making it difficult to focus on close images.

How many rods and cones are in each retina?

Each retina has approximately 120 million rods and 6 million cones.

What is the fovea?

The area in the retina where cones are densely packed, responsible for sharp central vision.

What is a blind spot?

The area at the back of the retina where the optic nerve exits, containing no photoreceptors.

What are the two main pathways for visual processing?

The ventral stream (what pathway) and the dorsal stream (where pathway).

What is object agnosia?

A condition where a person cannot recognize objects, as seen in the case of D.F. after carbon monoxide poisoning.

What is the wavelength range of visible light?

400-700 nanometers.

What does the Trichromatic Theory of color vision propose?

Color vision results from activity in three types of cones sensitive to different wavelengths: S (blue-violet), M (yellow-green), and L (red-orange).

What is the Opponent-Process Theory?

It describes how colors are perceived in opposing pairs, such as red-green and blue-yellow, and explains afterimages.

What are the three dimensions of color?

Hue, saturation, and lightness.

What is the Gestalt principle of proximity?

We tend to group figures that are close to each other as part of the same object.

What does the principle of closure in Gestalt psychology refer to?

The tendency to complete figures that have gaps.

What is object constancy?

The perception of objects as unchanging despite changes in sensory data.

What is prosopagnosia?

A condition where individuals cannot recognize faces, which can be present from birth or result from brain injury.

What is the significance of turning a face upside down?

It impairs face perception more than turning other objects upside down, indicating the brain's specialized processing for faces.

What are binocular depth cues?

Depth cues that require both eyes and provide information about distance based on the slightly different views from each eye.

What is motion parallax?

A depth cue that arises from the relative speed with which objects move across the retina as a person moves.

What are the two types of nerve fibers identified for pain?

Fast fibers for sharp, immediate pain and slow fibers for chronic, dull pain.

What is the Gate Control Theory of pain?

It posits that pain is experienced when pain receptors are activated, and a neural gate in the spinal cord can allow or block pain signals.

What is the role of haptic receptors?

They are sensory neurons in the skin that respond to temperature and pressure, contributing to the sense of touch.

What is the primary somatosensory cortex responsible for?

Processing touch information received from the skin.

What is the relationship between touch and pain according to the Gate Control Theory?

Touch information can close the pain gates, reducing the perception of pain.

What is the expertise hypothesis regarding face perception?

It suggests that faces are special because they are objects we interact with extensively, not due to inherent properties.

What is the difference between monocular and binocular depth cues?

Monocular cues are available from one eye alone, while binocular cues require both eyes.

How does the brain perceive distance using convergence?

By knowing how much the eye muscles turn inward when viewing nearby objects.

What does saturation refer to in color perception?

The purity of the color, with pastels being less pure due to mixtures of wavelengths.

What is lightness constancy?

The perception of an object's color as constant despite changes in lighting conditions.

What is the significance of figure and ground in visual perception?

It helps us distinguish objects from their backgrounds to simplify the visual world.

What is the role of experience in identifying figures?

Experience can inform how we identify figures and distinguish them from the background.

What are the implications of having specialized brain regions for face processing?

It suggests that face recognition is a distinct cognitive process due to our extensive experience with faces.

What is the effect of worrying on pain perception?

Worrying can open pain gates wider, increasing the perception of pain.