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• sensation

  the process of receiving stimulus from the external environment & transforming those energies into neural energy. When a receptor cell registers a sensation, it converts it to electrochemical impulse, or action potential that relays information about the stimulus through the nervous system to the brain. The biological processing & process of encountering stimuli
• perception

  the process of organizing & interpreting sensory information so that it makes sense. The experience of processes in action & is the brain providing meaning to those encounters.
• bottom up processing

  sensory receptors register information about the external environment & then sends it to the brain for interpretation.

  It means to take in information & make it sense of it. It begins

  with an external world.
• top down processing

  it starts with cognitive processing in the brain. There is some sense of what is happening & is applied to framework to incoming information from the world.
• sensory receptors

  All sensation begins with these. They are specialized cells that detect stimulus information & transmit it to sensory (afferent) nerves and the brain. They are the openings through which the brain & nervous system expenience the world.
• absolute threshold

  The minimum amount of stimulus energy a person can detect.
• difference threshold

  The degree of dilference that must

  exist between two stimuli before the difference is detected.
• signal detection theory

  focuses on decision making about stimuli under conditions of uncertainty. depends on a variety of factors like fatigue, expectations, the urgency of

  the moment.
• selective attention

  The act of focusing on a specific aspect of experience while ignoring others.
• perceptual set

  A predisposition or readiness to perceive something in a particular way. They act as the psychological filters in processing information about the environment.
• sensory adaptation

  A change in responsiveness of the sensory system based on the average level of surrounding

  stimulation.
• retina

  The multilayered light sensitive surface in the eye that records electromagnetic energy & converts it to neural impulses for processing in the brain. It is the primary mechanism for sight.
• rods

  The receptor cells in the retina that are sensitive to light but not very useful for color vision. Rods function well when there is little light (at night)
• cones


  The receptors cells in the retina that allow for color perception. Cones are light sensitive, but they require a lot more light to respond, so they work best during daylight or under high illumination.
• visual cortex

  It is located in the occipital lobe at the back of the brain & is part of the cerebral cortex involved in vision. Most visual information travels to the primary visual cortex where it’s processed before moving to other visual areas for further analysis.
• feature detectors

  Neurons in the brains visual system that respond to particular features in a stimulus. They pick up edges, shapes, colurs, & contours of a stimuli.
• trichromatic theory

  The theory that states color perception is produced by 3 types of cone receptors in the retina that are particularly sensitive to diferent, but overlapping ranges of wavelengths.
• opponent process theory

  the theory that states that cells in the visual system respond to complementary pairs of red-green & blue-yellow colors; a given cell might be excited by red & inhibited by green, whereas another cell might be excited by yellow & inhibited by blue.
• figure ground relationship

  The principle by which we organize the perceptual Field into stimuli that stand out (figure) and those that are left over (ground).
• Gestalt Psychology


  A school of thought interested in how people naturally organize their perceptions according to certain patterns.
• Depth Perception


  The ability to perceive objects 3-dimensionally.
• Binocular Cues

  Depth cues that depend on the combination of the images in the left & right eyes & on the way the two eyes work together.
• Monocular Cues

  Powerful depth cues available from the image in one eye, either the right or left.
• Perceptual Constancy

  The recognition that objects are constant and unchanging even though sensory input about them is changing.
• Size Constancy


  The recognition that an object remains the same size even though the retinal image of the object changes.
• Shape Constancy


  the recognition that an object remains the same shape even though it’s orientation towards you changes.
• Color Constancy

  the recognition that an object retains the same color even though different amounts of light fall on it.
• Cochlea

  The spiral structure consisting of fluid filled canals.
• Kinesthetic Sense

  senses that provide information about movement. posture, & orientation.
• Vestibular Sense

  senses that provide information about balance & movement.