chapter 5 Sensation & Perception

Being made and is known as webers fraction eg the jnd

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Unformatted text preview: rabsolutethresholdanddoesnotregisterinour consciousmind;ithassomeeffectonourconsciousattitudes TheDifferenceThreshold - The difference threshold is the smallest difference between two stimuli that a person can detect 50% of the time Aka just noticeable difference (jnd) - Weber's law: difference threshold is directly proportional to the magnitude of the stimulus with which the comparison is being made and is known as weber's fraction Eg. The jnd value for weight is 1/50; this means that there has to be a difference of Psych 1000 My Notes Page 29 Eg. The jnd value for weight is 1/50; this means that there has to be a difference of 1/50 of the original weight for a difference to be noticed; for a 50g weight, an increase or decrease of 1g is required for the difference to be detectable Weber's law does not work at very low or very high intensities Smaller Weber's fraction = more sensitivity SensoryAdaptation - Our sensory system is tuned to detect changes in stimulation, and the diminishing sensitivity to unchanging stimulus is called sensory adaptation Eg. Not feeling a watch on the wrist after a long time If it weren't for small retina movements, even vision would vanish - Sensory adaptation is adaptive because it frees our senses from constant mundane pick up of information TheSensorySystems Vision - Human can only sensitive of wavelengths between 700nm (red) to 400nm (blue ­violet); bees can detect x ­rays and snakes can detect infrared energy Thehumaneye - Light enters the eye through the cornea, a transparent protective structure - Then it passes by the pupil, which can dilate or constrict to control the amount of light entering The size of the pupil is controlled by the colored iris that surrounds the pupil - Behind the pupil is the lens which can get thicker or thinner to focus the light on the retina, at the rear wall of the fluid filled eyeball - The original image is flipped left to right and up to down, but the brain reconstructs the input - Myopia (near sightedness) causes eyeball to become longer; and the lens is too close to the image - Hyperopia (far sightedness) The image is...
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This document was uploaded on 02/26/2014 for the course PSYCHO 1000 at UWO.

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