Unit 3 Flashcards
Sensation and Perception
Sensation
Information you take in. Sensory receptors (eyes, ears…) and the nervous system receive stimuli from the environment.
Senses
Sense organs transform physical stimulation into neural impulses that give us sensations. Light waves give us light and dark sensations.
Bottom-Up Processing
Body response. See, smell, touch, hear. Analysis that emphasizes the characteristics of the stimuli rather than our concepts or expectations.
Perception
How you interpret the information (sensation). Process of organizing and interpreting sensory information.
Top-Down Processing
Emotional response. Looks pretty/ugly, smells gross, feels rough, sounds loud. Analysis the emphasizes the perceiver’s expectations, concept memories, and other cognitive factors, rather than individual characteristics.
Psychophysics
Relationship between physical stimuli and our psychological experiences to them.
Absolute Threshold
Weakest amount of a stimulus required to produce a sensation.
Difference Threshold
Smallest difference in stimulation that can be detected. A just noticeable difference.
Weber’s Law
The noticeable difference of the stimulus is large when the intensity is high and vice versa.
Sensory Adaptation
Getting used to a level of stimulus. Sense organs are change detectors. Diminishing responsiveness of our sensory systems to prolonged stimulation. Unless it is intense or painful, stimulation that persists without change shifts to the background of our awareness.
Signal Detection Theory
The detection of a stimulus depends on the intensity of the stimulus and the physical and psychological state of the individual.
Sesory Overload
Over stimulating the senses.
Selective Attention
Focusing attention on selected aspects of the environment.
Divided Attention
Focusing attention on several aspects of the environment.
Cocktail Party Effect
You can hear your name across the room in another conversation.
Transduction
Process of stimuli changing from physical to neural. Converts energy such as light into neural messages. Begins with sensory neurons detecting physical stimuli. When stimuli reaches sense organ, activates receptors. Receptors convert excitation into a nerve signal.
Cornea
Protective outer layer.
Iris
Colored part of the eye. Muscle that constricts pupil.
Pupil
Opening in the iris. Changes shape in light and dark.
Lens
Changes shape to send best image to back of the eye. Flips the image upside down. Is an “accessory structure” in the body- modifies stimulus before transduction.
Retina
Back of the eye. Contains rods and cones. Transduction occurs here.
Photoreceptors
Light sensitive cells (neurons) that convert light energy to neural energy. Rods- black and white (125 mil/eye) vision. Cones- color vision (7 mil/eye)
Fovea
Area of sharpest vision. Highest concentration of cones.
Distal and Proximal Stimuli
Distal: what you see- exists in the real world
Proximal: inverted image the retina sends to the brain- image formed in the mind
Optic Nerve
Carries impulses from the retina to the brain. Bundles of neurons/fibers.
Blind Spot
Area in the retina (called the optic disk) without photoreceptors- where the optic nerve exits the eye. Any stimulus in this area cannot be seen.
Visual Cortex
Brain region where neural impluses are transformed into visual sensations of color, form, boundary, and movement. Through parallel processing- the simultaneous processing of several aspects of a stimulus.
Feature Detectors
Specific cells that see lines, motion, curves, and other features. Work of Hubel and Wiesel- cats have special feature detectors for edges. Evolutionarily helpful to see objects and other critters.
Light Energy, Wavelength, and Intensity
Light energy: visible spectrum.
Wavelength: distance from the peak of one light wave to the peak of the next (the distance determines the hue (color) that we perceive). Short- blues. Long- reds.
Intensity: Amount of energy in a light wave. Determined by height of the wave (amplitude). The higher the wave, the more intense the light.
Color Blindness
True color blindness: see only black and white. Must have a color deficiency.
Inherited: most common in males, worsens over time.
Partial: affects some colors- trouble distinguishing between some colors.
Trichromatic Theory
Realized any color can be created by combining the light waves of 3 primary colors- red, green, and blue. Guessed that there are three types of receptor cells in our eyes. Together they pick up 7 million color variations. Most color-blind people lack cone receptor cells for one or more of these primary colors.
Depth Perception: Binocular Fusion and Monocular Cues
The ability to see objects in three dimensions although the images that strike the retina are two dimensional. Allows us to judge distance.
Retinal Disparity
Differences between images you see in each eye.
Accommodation
Tension of the muscle that changes the focal length of the lens of the eye. Brings into focus objects at different distances. This depth cue is weak- effective only at short viewing distances.