Basic concepts of Sensation and Perception

Weber's Law

The size of the difference threshold is greater for heavier objects than for lighter ones. This BEST illustrates:

Psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

Perception

the top-down process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Sensory adaptation

Barbara stubbed her toe last night. It hurts and all day today she has been aware of her toe. She says, "This is so weird. I usually don't think about my toe." Barbara is describing:

signal detection theory

Dennis, a nurse, notes that some parents of asthmatic children respond to very small changes in their children's breathing and seek care accordingly. However, other parents do not notice the same small changes. This type of difference in reaction to stimuli is BEST explained by:

top down processing

Interpreting new sensory information within the framework of a past memory illustrates:

perceptual set

Once John learned of Sara's past history of being an abuse victim, he began to view her cautious behavior around men as more self-protective rather than rude. This BEST illustrates the impact of:

signal detection theory

Two Transportation Security Administration officers are scanning bags at the airport. One of the officers lets a bag go through, but the other officer yells, "Wait, didn't you see that?" Why one officer saw a weapon and the other did not is BEST explained by

perceptual set

When people look at a photograph of an adult-child pair and are told that the two individuals are parent and child, the people tend to say the pair looks more alike than people who are told the pair is unrelated. This is MOST likely due to:

perceptual set

a mental predisposition to perceive one thing and not another

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain's integration of sensory information

subliminal stimulation

below one's absolute threshold for conscious awareness

Transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

sensory receptors

sensory nerve endings that respond to stimuli by developing action potentials

Sensation

the bottom-up process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time.

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time

Weber's Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)