Psychophysics Flashcards
What is perception?
A psychological process: the act of organizing and interpreting sensory experience.
What is sensory adaptation?
Process by which our sensitivity diminishes when an object constantly stimulates our senses.
What is transduction?
The conversion of physical info into neural info.
What is psychophysics?
The study of how people psychologically perceive physical stimuli (e.g. light, sound waves, touch).
What is absolute threshold?
The lowest intensity level of a stimulus a person can detect half of the time.
What is signal detection theory?
Viewpoint that both stimulus intensity and decision-making processes are involved in the detection of a stimulus.
What is difference threshold?
Smallest amount of change between two stimuli that a person can detect half of the time.
What is Weber’s law?
The finding that the size of a just noticeable difference is a constant fraction of the intensity of the stimulus.
What is bottom-up processing?
Assembling a perceptual experience from its basic elements.
What is top-down processing?
Perception of the whole based on our experience and expectations, which guide our perception of smaller elemental features of a stimulus.
What is perceptual set?
Effect of frame of mind on perception.
What is a cornea?
Clear hard covering that protects the lens of the eye.
What is a lens?
Structure behind the pupil; bends light rays that enter eye to focus images on retina.
What is a pupil?
Opening in the iris through which light enters eye.
What is an iris?
Muscle that forms coloured part of eye; adjusts pupil to regulate amount of light that enters eye.
What is a retina?
Thin layer of nerve tissue that lines back of eye.
What are photoreceptors?
Cells in retina (called rods and cones) that convert light energy into nerve energy; they are transducers.
What are ganglion cells?
Retinal cell that carries visual info from the eye to the brain; their axons make up optic nerve.
What are bipolar cells?
Retinal cell that links photoreceptors with ganglion cells.
What are horizontal cells?
Retinal cells responsible for modulating activity at photoreceptor-bipolar cell synapse.
What are amacrine cells?
Retinal cells responsible for modulating activity at bipolar-ganglion cell synapse.
What are rods?
Photoreceptors that function in low illumination and play key role in night vision.
What are cones?
Photoreceptors responsible for colour vision; most functional in bright light.
What is a fovea?
Spot on back of retina that contains highest concentration of cones; place of clearest vision.
What is rhodopsin?
Light-sensitive protein responsible for transduction in rods
What are photopsins?
Light-sensitive proteins responsible for transduction in cones.
What is the optic chiasm?
Point at which strands of optic nerve from half of each eye cross over to opposite side of brain.
What are Gestalt’s Laws of Grouping?
Similarity; continuity; proximity; closure.
What is the tympanic membrane?
The eardrum.
What makes up the middle ear, and what do they do?
Hammer, anvil, and stirrup. Amplify waves 20 times compared to when they entered ear.
What makes up the inner ear, and what do they do?
Semicircular canals - maintain balance.
Cochlea - bony tube; site of transduction in auditory system. Contains basilar membrane, which contains hair cells - transduce sound vibrations into neural impulses.
What is the range of human hearing?
20-20,000 Hz
What are bodily senses?
Senses based in skin, body, membrane surfaces.
What are mechanoreceptors?
Receptor cells in skin; sensitive to different tactile qualities such as shapes, vibrations, etc.
What are olfactory sensory neurons?
Sensory receptors for smell; reside high up inside nose.
What is the purpose of cilia in the nose?
Convert chemical info in odour molecules into neural impulses.
What is the olfactory bulb?
Forebrain structure that sends info either directly to smell-processing areas in cortex or indirectly to cortex by way of the thalamus.
Where are the olfactory cortexes located?
Primary in the temporal lobe; secondary in the frontal lobe.
What are taste buds?
Structures inside papillae that contain taste receptor cells (sensory receptors).
What are papillae?
Textured structures on surface of tongue that contain taste buds.
What is sensation?
A physical process: the stimulation of our sense organs by features of the outer world.
