Sensation and Perception Flashcards
What is sensation?
the process of detecting stimulus from the environment and converting it into neural signals
What is perception?
the process by which we select, organize and interpret our sensations
What is Attention
the taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought
What is bottom up processing
analysis of the stimulus that begins with the sense receptors and works up to the level of the brain and mind
What is top down processing
info processing that is guided by higher level mental processes as we construct perceptions, drawing on our experience and expectation
what is interactive processing?
a combo of top down and bottom up processing
What is psychoPhysics?
the study of how physical stimuli (sensations) are translated into psychological experiences (perception)
What is absolute threshold
the minimum amount of stimulation that an organism can detect
What is subliminal Perception?
perception that occurs in response to a stimulus presented below the threshold of awareness (might be described as unconscious perception)
What is sensory adaptation?
- diminished sensitivity to a stimulus as a consequence of constant stimulation by that stimulus.
- nerve cells fire less frequently
What is desensitization?
reduced sensitivity to a stimulus as a result of paying less attention to it
What does wavelength determine in light?
Color/hue
What does amplitude determine about light?
Intensity/brightness
What is the absolute threshold method?
using limits (descending an ascending) have the subject say whether a stimulus was presented or not
What is difference threshold method?
present 2 stimuli and the subject has to decide whether the 2 stimuli were the same or different
What is Weber’s law?
to perceive a difference between 2 stimuli the 2 stimuli must differ by some relative amount
What is Signal Detection Theory?
- ability to identify messages in a noisy system
- helps understand how experience, expectations and other factors influence our absolute and difference thresholds.
What is the lens?
the transparent structure that focuses the light rays onto the retina
What is the pupil?
The opening in the centre of the iris that helps regulate the amount of light passing into the rear chamber of the eye
What is the retina?
the neural tissue lining the inside back surface of the eye; it absorbs light, processes images, and sends visual info to the brain
What is the optic disk?
a hole in the reina where the optic nerve fibres exit the eye; blind spot
What are cones?
visual cells that play a key role in daylight vision and colour vision
What is the fovea?
the tiny spot in the centre of the retina that contains only cones; visual acuity is greatest in this spot
What are rods?
visual cells that play a key role in night vision and peripheral vision
What is accommodation?
the process by which the eye’s lens changes shape to help focus near or far objects on the retina
What is dark adaptation?
process where eyes become more sensitive to light in low illumination
What is light adaptation?
process where the eyes become less sensitive to light in high illumination
What is the receptive field?
the receptive field of a visual cell is the retinal area that, when stimulated, affects the firing of that specific cell
What does the trichromic theory say and what is the problem with this theory?
- 3 kinds of cones in the eye respond mostly to light in either red, blue or green range of wavelengths
- Problem: doesn’t explain color after effects
What is the opponent process theory of color vision say?
color perception depends on receptors that make antagonistic responses to three pairs of colors. This theory explains color after images.
What is a color after image?
complementary colors (yellow and blue, green and red) that you see when you look at one color and then a blank paper.
What is color blindness?
Genetic disorder in which people are blind to some colors (X chromosome linked)
