David Molnar October 18, 2011
Psychology 1000 - Sensation, Perceiving, and Consciousness
2. The Senses
4. Perceptual Stability
Extrasensory Perception: set of phenomena called “PSI”, divided into ESP and
psychokinesis. ESP divided into telepathy, clairvoyance and precognition. Psychokinesis
is the ability to make things happen in the environment. (P. 232-)
- The fact that different species have different reactions to stimulation. and the fact that
different organisms within species have different reactions to stimulation, make it difficult
for us to make general statements about sensory efficiency or capacity and sensory
- We are woefully poor at describing our sensations.
- “Its sort of like a toothache in my stomach”
- The sub science of psychophysics is what we use to deal with these problems. (P.
- Psychophysics: the sensory consequences of controlled physical stimulation. “We
hope to be able to compare and make statements about humans senses.”
- Threshold: the minimum detectable stimulus intensity.
- Absolute Threshold: stimulus intensity detectable on 50% of its presentations. Not a
constant value but changes from person to person and situation to situation.
- Difference Threshold: What is the smallest difference between stimuli that we can
detect. The minimum detectable change in stimulus intensity. The “just noticeable
Weber’s Law (1843): [delta]I/I = K (Weber’s Constant) For every stimulus, there is some
constant percentage of stimulus intensity that must b