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.
We selectively attend to, and process, a very limited portion of incoming information, blocking out much and often shifting the spotlight of our attention from one thing to another.
Focused intently on one task, we often display inattentional blindness (including change blindness) to other events and changes around us.
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.
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 minimum stimulus difference we can discern 50 percent of the time. Weber’s law states that two stimuli must differ by a constant percentage (not a constant amount) to be perceived as different.
Priming shows that we can be affected by stimuli so weak that we don’t consciously notice them, and we can evaluate a stimulus even when we’re not consciously aware of it.
While we can be primed by subliminal stimuli, however, research indicates that such stimuli cannot persuade us or change our behavior.
Sensory adaptation (our diminished sensitivity to constant odors, sights, sounds, and touches) focuses our attention on informative changes in our environment.
Multiple-Choice Questions
As she looks at a face, Jamie is able to recognize it as the face of her mother. Which of the following explains why she can recognize her mother’s face?
Selective attention
Transduction
Bottom-up processing
Top-down processing
Signal detection theory
Charles and his wife are at a loud baseball game, yet are able to have a conversation with each other in spite of all the noise around them. Which principle best explains this scenario?
Bottom-up processing
Weber’s law
The cocktail party effect
Top-down processing
Sensory adaptation
As Jeff reads his psychology textbook he is able to convert the light waves into signals that his brain can interpret due to the concept of
transduction.
perception.
priming.
signal detection theory.
threshold.
Natalia is washing her hands, and she adjusts the faucet handle until the water feels just slightly hotter than it did before. Natalia’s adjustment until she feels the change in temperature is an example of
a subliminal stimulus.
an absolute threshold.
a difference threshold.
signal detection.
perceptual constancy.
Tyshane went swimming with friends who did not want to get into the pool because the water felt cold. Tyshane jumped in and after a few minutes declared, “It was cold when I first got in, but now it’s fine. Come on in!” Tyshane’s body became accustomed to the water temperature due to
priming.
absolute threshold.
difference threshold.
selective attention.
sensory adaptation.
Practice FRQs
Marisol is planning a ski trip for winter break. Explain how each of the following might play a role in her perception of the winter weather she will experience: