Chapter 4 Flashcards
Sensation
the stimulation of sensory receptors and the transmission of sensory information to the central nervous system
i. Sense receptors are the specialized neural cells in sense organs that respond to stimuli and change physical energy into neural impulses
ii. The process of stimulus info being converted into a neural impulse that the brain can interpret is called transduction
iii. Sensation is mechanical… it just happens
transduction
The process of stimulus info being converted into a neural impulse that the brain can interpret is called
Perception
the process by which sensations are organized into an inner representation of the world by the brain
i. Perception is not mechanical - involves more than sensations; it reflects learning and expectations and organization of information
Perception and sensation flow continuously - broken down into bottom up and top down processing
Schema
Your personal reality, based on concepts and prior knowledge
i. Your body detects some form of energy -> the energy is transduced into neural activity -> the brain interprets the info and produces perception of the sense
Bottom - up processing
i. Is basic sensory processing and works up to higher levels of processing (how we process when we have no prior knowledge); external content
Top - down processing
i. Constructs perceptions from this sensory input by drawing on your culture, experiences, and expectations (how we process if we have prior knowledge); internal factors
Attention
an interaction of sensation and perception that is affected by internal and external processes
Selective attention
the focusing of conscious awareness on a particular stimulus
Cocktail Party Effect
our ability to attend to mentions of our name or specific topics in loud, distracting environments
Inattention
failing to perceive when our attention is directed elsewhere
i. It is a by-product of what we are really good at: focusing our attention on some part of our environment
Change blindness
failing to notice changes in the environment (a form of inattention)
Absolute Threshold
minimum amount of stimulus that must be present to produce a sensation 50% of the time
Signal-detection theory
idea that the perception of stimuli involves not only the strength of the stimuli, but also the interaction of physical, biological, and psychological factors
Just Noticeable difference
minimal amount of difference in intensity between two stimuli so that they will be perceived as being different; aka Differences threshold
i. Example: Take two cans of same red paint. Add drops of white to the point at which the difference between the paints is first barely detectable
Weber’s Law
the minimal percentage by which a source of physical energy must be increased or decreased so that a difference in intensity will be perceived… it is a constant proportion to initial stimulus
Sensory Adaptation
sensory change in response to environmental stimuli (i.e.… becoming more/less sensitive to stimuli); tends to be physiological
Perceptual set
a mental predisposition to perceive one thing and not another
Synesthesia
a condition in which one sense is simultaneously perceived as if by once or more additional senses
i. Just about any combination of senses is possible, and no two people really experience it the same way
Synesthesia Diagnosis
i. It just happens - not something that has to be thought about to perceive
ii. Must be the same experience every time
Vision
○ Your brain makes sense of colors, shapes, symbols, depth, and movement by putting the information together like a jigsaw puzzle – into something coherent
○ Optical illusions work by exploiting the mind’s tendency to try to find order in patterns (tapping into it’s stored information)
Light
stuff that triggers visual sensations; described in terms of wavelengths
○ The hue (color) we perceive in light depends on its wavelength, while its intensity (brightness) depends on the light wave’s amplitude
Cornea
transparent tissue forming outer surface of eyeball; light 1st passes through this into your fluid-filled eye
Iris
colored part of the eye; muscle that determines amount of light that passes through pupil
Pupil
the black opening in the iris; size adjusts automatically to the amount of light; is also sensitive to emotional responses
Lens
transparent body behind the iris/pupil that focuses an image on the retina; adjusts to an image by changing its thickness
i. When people squint to focus near or far, they are adjusting the thickness of the lens (accommodation)
ii. Nearsightedness - when the lens focusses objects in front of the retina
iii. Farsightedness - when the lens focusses objects behind the retina
Retina
light-sensitive photoreceptor cells and layers of neurons that begin processing visual information
Fovea
area of central focus in the retina; just above optic nerve; cones cluster in and around it (makes peripheral vision a poor judge of color)
optic nerve
a bundle of axons from a specific type of cells called ganglion cells
Millions of retinal photoreceptor cells convert light energy into neural impulses which are sent to the brain via the **
Blind spot
point where eye is insensitive to visual stimulation; where optic nerve exits to the brain
Rods
photoreceptors sensitive only to intensity of light; allow us to see only in black, grey, and white
Cones
photoreceptors that provide color vision and detect fine detail
Dark Adaptation
the process of adjusting to conditions of lower lighting by increasing the sensitivity of rods and cones
Light Adaptation
the adjustment of the visual system to perform best based on overall lighting conditions (i.e. attempts to keep rods from over-saturating as lighting increases)
Trichromatic theory
theory that the retina contains three types of color receptors; when stimulated in combination, they can produce the perception of any color
Color Blindness
(Color Vision Deficiency)
i. CVD is caused by damage or irregularities to various cones or ganglion cells
ii. Trichromatic - normal color vision
iii. Monochromatic - sensitive to light and dark only; total colorblindness
iv. Dichromatic - discriminate only 2 colors - blues & yellows or reds & greens; partial colorblindness; the color one is deficient in is seen as a muted grey or brown