exam 2 Flashcards
Sensation
is the detection of physical stimuli and transmission of that information to the brain (ex. light, sound, molecules of food, temperature, etc)
Perception
is the brains further processing, organization, and interpretation of the sensory information.
What is the difference between sensation and perception?
Sensation is only detection while perception makes sense of the the detection. (ex. if you get splashed in the face w/ rootbeer, sensation tells you the smell and taste while perception identifies it with rootbeer.)
Bottom-up processing
Based on the physical features of the stimulus. Each piece of sensory input builds up to perception. Getting splashed in the face and then recognizing that it is root beer.
Top-down processing
Using knowledge, expectations, and past experiences to shape interpretation of sensory input. If we see an apple shaped object that is blue, we know it’s not a real apple because they aren’t usually blue.
Transduction
Translation of stimuli. Stimuli is translated into signals that the brain can understand through the use of sensory receptors.
Sensory receptors
Specialized cells in sense organs that pass physical stimulation like touch and vision or chemical stimulation like taste and smell to the brain via neural impulses.
What is different about transducing smell than the rest of the senses?
Smell bypasses the thalamus and goes straight to the cortex.
Stimuli, receptors, and pathway to brain for vision?
Stimuli: Light waves
Receptors: Rods and cones
Pathway to brain: Optic nerve
Stimuli, receptors, and pathway to brain for hearing?
Stimuli: Sound waves
Receptors: Hair cells in cochlea in inner ear
Pathway to brain: Auditory nerve
Stimuli, receptors, and pathway to brain for taste?
Stimuli: Molecules from dissolved food or drink.
Receptors: Cells in taste buds
Pathway to brain: Portions of facial, glossopharyngeal, and vagus nerves
Stimuli, receptors, and pathway to brain for smell?
Stimuli: Molecules from dissolved fluid on membranes of the nose
Receptors: Sensitive ends of olfactory mucous neurons in the mucous membranes
Pathway to brain: Olfactory nerve
Stimuli, receptors, and pathway to brain for touch?
Stimuli: Pressure on skin
Receptors: Sensitive ends of touch neurons in skin
Pathway to brain: cranial nerves for above the neck and spinal nerves for touch elsewhere.
How do neurons respond to qualitative information?
By firing different combinations of neurons.
How do neurons respond to quantitative information?
By firing neurons at different rates.
Absolute threshold
Minimum intensity of stimulation that must occur before you experience a sensation. (Stimulus intensity you would detect 50% of the time)
Difference threshold
Smallest difference between two stimuli that you can notice (ex. friend is watching a TV show and you are reading and a commercial comes on and it is louder, you look up because you can tell that something is different, the difference threshold is the minimum difference in volume that you notice)
Signal detection theory
Detecting a stimulus is not an objective process. It is subjective to two components: 1) sensitivity to the stimulus in the presence of noise and 2) the criteria used to make the judgement from ambiguous information (ex. a doctor may be influenced to see a faint line on an exam based on the knowledge they know about the patient or based on the level of consequences)
Response bias
a participants tendency to report or not report detecting a signal if it is ambiguous.
Sensory adaptation
a decrease in sensitivity due to a level of constant stimulation (ex. you don’t notice the sound of the air conditioner in your house because you hear it all the time, but your friend does hear it)
Rods
Low levels of light, responsible for night vision. No color, little fine detail.
Cones
Responsible for vision under brighter conditions, color and details.
Fovea
Where the cones are packed in the center of the retina.
Trichromatic theory
color vision results from activity in three types of cones that are sensitive to different wavelengths.
