PSY 110 1st Edition Lecture 4 Outline of Last Lecture I. CerebrumII. Lobes of the BrainIII. Age, Gender, and the BrainIV. Beyond the Nervous SystemV. HeredityOutline of Current Lecture I. The Process of SensationII. VisionIII. The EyeCurrent LectureThe Process of SensationSensation: The process through which the senses pick up visual, auditory, and other sensory stimuli and transmits them to the brain.Perception: The process by which the brain actively organizes and interprets sensory information.**cannot have one without the other (sensation without perception or vice-versa)Absolute Threshold: Minimum amount of sensory stimulation that can be detected 50% of the time.Difference Threshold: A measure of the smallest increase/decrease in a physical stimulus that isrequired to produce the Just Noticeable Difference.Just Noticeable Difference (JND): The smallest change in sensation that a person is able to detect 50% of the time.Weber’s Law: Law stating that the JND for all the senses depends on a proportion or percentageof change in a stimulus rather than on a fixed amount of change (proportion/percentage varies depending on the sense)**JND is NOT the same for everyone (varies from person to person)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Sensory Receptors: Highly specialized cells in sense organs that detect and respond to one type of sensory stimulus and transduce (convert) the stimuli into neural impulses.**provides link between physical sensory world and brainTransduction: Process through which sensory receptors convert the sensory stimulation into neural impulses.Sensory Adaptation: Process where sensory receptors grow accustomed to constant, unchanging levels of stimuli over time. Not likely to occur in presence of very strong stimulus.EX) ammonia, baby crying, etc.Vision**most studied senseVisible Spectrum: Narrow band of light waves that are visible to the human eye.**eyes only respond to visible light wavesWavelength: A measure of the distance from the peak of a light wave to the peak of the next.**electromagnetic waves measured in wavelengths The EyeCornea: Tough, transparent, protective layer that covers the front of the eye and bends light rays inward through the pupil. Performs the first step.Iris: Contracts and dilates the pupil to regulate amount of light entering the eye.Lens: Transparent disk-shaped structure behind iris and pupil that changes shape as it focuses on objects at varying distances.- Accommodation: The flattening and bulging action of the lens as it focuses images of objects on the retina- Presbyopia: Age-related loss of lens’ ability to change shape- Nearsightedness: Can only see close up, cannot see far away- Farsightedness: Can only see far away, cannot see close upRetina: Layer of tissue located on the inner surface of the eyeball and contains the sensory receptors for vision.- Rods: The light-sensitive receptor cells in the retina that look like slender cylinders and allow the eye to respond to as few as five photons of light- Cones: The light-sensitive receptor cells in the retina that enable humans to see color and fine detail in adequate light but do not function in very dim light- Fovea: Small area at the center of the retina that provides the clearest and sharpest vision because it has the largest concentration of cones- Blind Spot: The point in each retina where there are no rods or cones because the cable of ganglion cells is extending through the retinal wall- Optic Nerve: Nerve that carries visual info from each retina to both sides of the brainOptic Chiasm: Point where some optic nerve fibers cross to opposite sides of the brain.Primary Visual Cortex: Enables us to see integrated images and interpret what we’re seeing.**Nerve fibers extend from optic chiasm to the thalamus  transmits impulses to primary visual cortexFeature Detectors:- Neurons of the primary visual cortex- Respond only to specific visual patternsEX) lines, angles- Coded at birth to make unique responseHue: The specific color perceivedSaturation: The purity of a colorBrightness: The intensity of the light energy perceived as color**brightness can be considered as how much black or white is in the colorTrichromatic Theory: There are 3 types of cones in the retina and each is sensitive to one of three colors: blue (shorter wavelengths), green (medium wavelengths), or red (longer wavelengths).Opponent-Process Theory: Cells respond by increasing or decreasing their rate of firing when different colors are present.- red/green cells: increases with red, decreases with green- yellow/blue cells: increases with yellow, decreases with blue- white/black cells: increases with white, decreases with black- Antichromatic: black and white cells- Chromatic: red, greend, yellow, and blue cells- Afterimage: visual sensation that remains after stimulus is withdrawn (brain will give sensation of opposite