PSY 105 Chapter Notes - Chapter 4: Sclera, Electromagnetic Spectrum, Wavelength
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ex. Photoreceptor, pressure, waves, chemical molecules, mecanoreceptors, thermal
receptors
•Perception: Process by which the brain organizes and interprets sensory
information.
•Sensory problems (e.g.,cataracts)
•Perceptual problems (e.g., phantom limb pain, prosopagnosia)
Psychophysics :
•Studies the relationship between the physical nature of stimuli (amplitude,
frequency, intensity, chemicals that generate a scent,…) and the sensory responses
from the organism.
•Signal detection: Not only the intensity of the stimulus, but a lot of psychological
factors may have an impact: past experiences, expectations, motivations, fatigue,
environnemental factors (noises)
e.g. Haunted house
Psychophysics : Relation between the physical nature of stimuli and the sensory
reactions in response to those stimuli.
• Tries to create a bridge between the exterior physical environment and the internal
psychological world.
Sensory Detection:
•Difference threshold ≠ fixed. It’s proportional to the initial stimulus value.
•Weber’s Law : Law that states that the just noticeable difference is a consistent
proportion of the intensity of the initial stimulus.
Note : Threshold: The minimal intensity needed to just barley detect stimulus
e.g. Two lights --8%
Two weights --2%100-102…1,000--1020
Two tones --0.3%
Two prices--10%$0.85 = $0.94
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