Psychology Module 18 Review

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

priming

the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference (or jnd).

absolute threshold

the minimum stimulus energy 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).

sensation

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

perception

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

psychophysics

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

How do absolute thresholds and difference thresholds differ, and what effect, if any, do stimuli below the absolute threshold have on us?

Our absolute threshold for any stimulus is the minimum stimulation necessary for us to be consciously aware of it 50 percent of the time. Signal detection theory predicts how and when we will detect a faint stimulus amid background noise. Individual absolute thresholds vary, depending on the strength of the signal and also on our experience, expectations, motivation, and alertness. Our difference threshold (also called just noticeable difference, or jnd) is the difference we can discern between two stimuli 50 percent of the time. Weber's law states that two stimuli must differ by a constant minimum percentage (not a constant amount) to be perceived as different. Priming (the often unconscious activation of certain associations that may predispose one's perception, memory, or response)shows that we process some information from stimuli below our absolute threshold for conscious awareness.

Does subliminal sensation enable subliminal persuasion?

Subliminal stimuli are those that are too weak to detect 50 percent of the time. While subliminal sensation is a fact, such sensations are too fleeting to enable exploitation with subliminal messages: There is no powerful, enduring effect.

subliminal

below one's absolute threshold for conscious awareness

perceptual set

a mental predisposition to perceive one thing and not another

What three steps are basic to all our sensory systems?

Our senses (1) receive sensory stimulation (often using specialized receptor cells); (2) transform that stimulation into neural impulses; and (3) deliver the neural information to the brain. Transduction is the process of converting one form of energy into another. Researchers in psychophysics study the relationships between stimuli's physical characteristics and our psychological experience of them.

How do our expectations, contexts, motivation, and emotions influence our perceptions?

Perceptual set is a mental predisposition that functions as a lens through which we perceive the world. Our learned concepts (schemas) prime us to organize and interpret ambiguous stimuli in certain ways. Our physical and emotional context, as well as our motivation, can create expectations and color our interpretation of events and behaviors.

What are sensation and perception? What do we mean by bottom-up processing and top-down processing?

Sensation is the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. Perception is the process of organizing and interpreting this information, enabling recognition of meaningful events. Sensation and perception are actually parts of one continuous process. Bottom-up processing is sensory analysis that begins at the entry level, with information flowing from the sensory receptors to the brain. Top-down processing is information processing guided by high-level mental processes, as when we construct perceptions by filtering information through our experience and expectations.

What is the function of sensory adaptation?

Sensory adaptation (our diminished sensitivity to constant or routine odors, sounds, and touches) focuses our attention on informative changes in our environment.

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 beings with the sensory receptors and works up to the brain's integration of sensory information

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 brain can interpret