Saylor URL: http://www.saylor.org/books Saylor.org
KEY TAKEAWAYS
- Sensation is the process of receiving information from the environment through our sensory organs. Perception is the
process of interpreting and organizing the incoming information in order that we can understand it and react
accordingly. - Transduction is the conversion of stimuli detected by receptor cells to electrical impulses that are transported to the
brain. - Although our experiences of the world are rich and complex, humans—like all species—have their own adapted
sensory strengths and sensory limitations. - Sensation and perception work together in a fluid, continuous process.
- Our judgments in detection tasks are influenced by both the absolute threshold of the signal as well as our current
motivations and experiences. Signal detection analysis is used to differentiate sensitivity from response biases. - The difference threshold, or just noticeable difference, is the ability to detect the smallest change in a stimulus about
50% of the time. According to Weber’s law, the just noticeable difference increases in proportion to the total intensity
of the stimulus. - Research has found that stimuli can influence behavior even when they are presented below the absolute threshold
(i.e., subliminally). The effectiveness of subliminal advertising, however, has not been shown to be of large magnitude.
EXERCISES AND CRITICAL THINKING
- The accidental shooting of one’s own soldiers (friendly fire) frequently occurs in wars. Based on what you have
learned about sensation, perception, and psychophysics, why do you think soldiers might mistakenly fire on their own
soldiers? - If we pick up two letters, one that weighs 1 ounce and one that weighs 2 ounces, we can notice the difference. But if
we pick up two packages, one that weighs 3 pounds 1 ounce and one that weighs 3 pounds 2 ounces, we can’t tell the
difference. Why? - Take a moment and lie down quietly in your bedroom. Notice the variety and levels of what you can see, hear, and
feel. Does this experience help you understand the idea of the absolute threshold?
[1] Stoffregen, T. A., & Bardy, B. G. (2001). On specification and the senses. Behavioral and Brain Sciences, 24(2), 195–261.
[2] Galanter, E. (1962). Contemporary Psychophysics. In R. Brown, E. Galanter, E. H. Hess, & G. Mandler (Eds.), New directions in
psychology. New York, NY: Holt, Rinehart and Winston.