Sensation and perception Chapter 4

Sensation Sensation: stimulation of sensory receptors followed by transmission of the information to the CNS Results from light, sound, taste, smell, hearing

threshold Absolute Threshold: the minimal amount of energy that can produce a sensation Vision: a candle from ~30 miles on a clear, dark night Hearing: a watch ticking from ~20 feet away in a quiet room Taste: 1 tsp of sugar in 2 gallons of water Smell: 1 drop of perfume in a small house Touch: the pressure of a wing of a fly falling on your cheek from ~1/2 inch Difference Threshold: the minimal difference in intensity required to notice a difference (How much is it going to take in order for you to notice a difference?) Example: If you are holding 100 pounds, you would not notice if you added 1 pound, but you could tell a difference if you added 2. (That is the threshold for weight).

Signal Detection Theory People are influence by psychological factors. (We sometimes hear what we want to hear.) We attempt to focus on what we want to and block out the rest. Signal-detection theory: the view that the perception of sensory stimuli involves the interaction of physical, biological, psychological factors: Training, motivation, alertness Intensity of the signal Background noise

Sensory Deprivation A state in which stimulation of the senses is greatly reduced. Short periods of deprivation can be relaxing. Extended periods of deprivation can result in anxiety, hallucinations, depression, and antisocial behavior

Sensory Adaptation Sensory Adaptation: the process by which we become more sensitive to stimuli of low magnitude and less sensitive to stimuli that remain the same Sensitization: becoming more sensitive Desensitization: becoming less sensitive

perception Perception: the process by which sensations are organized Begins with sensation Also reflects our experiences and expectations

Selective attention Focusing on a particular object in the environment for a certain amount of time