Chapter 6: Sensation & Perception Section 1: Our Sensational Senses

PDN: Read Psychology in the News Pages 174-175

Sensation and Perception Sensation: The detection of physical energy emitted or reflected by physical objects it occurs when energy in the external environment or the body stimulates receptors in the sense organs. Produce an immediate awareness of sound, color, form, etc

Perception: The process by which the brain organizes & interprets sensory information. Foundation of learning, thinking, & acting An understanding can help us think more critically about our own experiences

Ambiguous Figure Colored surface can be either the outside front surface or the inside back surface Cannot simultaneously be both Brain can interpret the ambiguous cues two different ways After figure on p 150, from Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.

Our Sensational Senses Skin- touch, pressure, hot, cold, pain, itching, & tickling Ears- hearing & sense of balance

Measuring the Senses Absolute Threshold The smallest quantity of physical energy that can be reliably detected by an observer

Difference Threshold The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared also called Just Noticeable Difference (JND).

Absolute Sensory Thresholds Vision: A single candle flame from 30 miles on a dark, clear night Hearing: The tick of a watch from 20 feet in total quiet (measured in decibels) Smell: 1 drop of perfume in a 3-room apartment Touch: The wing of a bee on your cheek, dropped from 1 cm Taste: 1 tsp. Sugar in 2 gal. water

Despite our impressive sensory skills, our senses are tuned to a narrow band of physical energies. Other species can detect signals that we cannot.

Signal Detection Theory Holds that responses in a detection task depend on a sensory process & a decision process. These may vary with a person’s motivation, alertness, & expectations

Sensory Adaptations Senses are designed to respond to change & contrast in the environment Sensory Adaptation: The reduction or disappearance of sensory responsiveness that occurs when stimulation is unchanging or repetitious. Picture page 179

Useful because it spares us from having to respond to unimportant information Rarely adapt completely to visual stimuli

Sensory Deprivation: The absence of normal levels of sensory stimulation.

Sensory Overload Can lead to fatigue & mental confusion “Cocktail Party Phenomenon” A person typically focuses on just one conversation, ignoring other voices, music, laughter, etc

Selective Attention: The focusing of attention on selected aspects of the environment and the blocking out of others.