Bell Work When there is a conflict between bits of information received by two or more senses, which sense tends to dominate the others? hearing vision smell touch taste

Test: Monday Vocab: Eye/Ear Anatomy and Transduction

FRQ You have been asked to paint a picture that includes buildings, fields, a river, and a mountain. Describe how you would use at least three monocular/binocular cues to give your painting a sense of depth (e.g., interposition, relative height, relative size, texture gradient, linear perspective, and shadow.) Define and give an example.

Signal Detection Theory Signal detection theory is the theory which predicts how and when we detect the presence of a faint stimulus amidst background stimulation. Assuming that there is no single absolute threshold and the detection depends partly on a person’s experience, expectations, motivation and level of fatigue. A person’s heightened attention decreases after 30 minutes. Ego Strength Age plus 7 More false alarms are detected in heightened responsiveness The Difference Threshold (just noticeable difference or jnd) is the lowest difference you can detect between the two stimuli 50% of the time.  For example, you are just able to notice the difference between 1kg and 1.02kg half the time .

Priming is an acuteness to stimuli because of exposure to a certain event or experience. For example, an individual who has just purchased a new car may now start to notice with more frequency other people driving her same make and model. This person has been primed to recognize more readily a car like hers because of the experience she has driving and owning one. Sensory Adaptation- lowered sensitivity due to constant exposure from stimulus. For example, when you go into someone’s house you notice an odor…but this only lasts for a little while because sensory adaptation allows you to focus your attention on changing environment. This adaptation allows the person to focus on informative changes, leaving out uninformative, constant stimulations. It helps people pay attention to new stimuli over the old

Vision Transduction refers to Sensory energy being convert (transformed) into Neural energy/impulses.  Light is composed of electromagnetic waves with Wavelengths (distance from one peak to another peak on a wave)and Amplitudes (height of the wave) Wavelength  determines hue  and pitch determines the frequency  in sound.  Amplitude  determines intensity  and  loudness in sound.  External Light entering the eye first travels through the Cornea (protective layer) Pupil  (an adjustable opening) is controlled by Iris (muscle around the pupil) Lens (an oval transparency) that changes shape to focus light by a process called accommodation

Retina Johannes Kepler revealed that the retinas did receive upside-down images. Researchers later revealed that the retina does not read the image as a whole, receptor cells convert light energy into neural impulses The Retina has 2 types of receptor cells : Rods and Cones.  Cells connecting these detectors activate the bipolar cells that activate the ganglion cells and then form the Optic Nerve that sends the impulses to brain. Rods are receptor cells in the retina responsible for night vision and perception of darkness. Cones allow detail an color Cones allow one to perceive color. In the dark, the cone is ineffective. The rods are not affected by the dim light and many rods will focus their energy into one bipolar cell.  Everyone has a Blind Spot, a small region in the visual field where nothing could be seen.  This is because there are no receptor cells where the optic nerve leaves the eye in the retina.  Normally, we don’t witness this effect because we have two eyes that compensate for each other’s blind spot, and the fact that our eyes are constantly moving. Fovea is the region in the retina where light is centrally focused.  The fovea has no rods, only cones.

Visual Information Processing The retina is brain tissue that floats to the eye during early fetal development There are three levels in which visual information is received. First, the retina processes information before sending it via the thalamus to the brain’s cortex. The retina also analyzes the sensory information Information from the retina is received and transmitted ganglion cells. Nobel prize winners Hubel and Wiesel discovered Feature Detectors in the brain cortex that are sensitive to specific features in what we see ,like shape, color, depth, movement, and form. Perret identified nerve cells that specialize in responding to a specific gaze, head angle, posture.

Color Processing Young and von Helmholtz revealed that color can be created by combining the light waves of blue, red and green colors. They inferred that the eye must have three types of color receptors.  Color processing is described in 2 stages : 1)  Young-Helmholtz trichromatic (three-color) theory – Light is detected by 3 types of cones each specifically sensitive to Red, Blue, or Green. Combinations of them produce intermediate colors (yellow, cyan, purple) 2)  Opponent-Process theory – Color is then processed by their opponent colors (red-green, blue-yellow, black-white). Some cells are excited by blue and inhibited by yellow, vice versa. Thus, you cannot see a bluish-yellow.

Hearing Hearing is highly adaptable Hearing Frequency (Pitch) is the number of waves travelling through a point in one second, relates to how fast a wave travels.  Sound travels through the 3 sections of the ear to the brain :  Outer ear :  Auditory Canal  Middle ear: Ear drum (tight membrane) . Concentrates the vibrations of the eardrum on the cochlea’s oval window  Inner ear :   contains the Cochlea (coiled, fluid-filled tube) that contains the Basilar Membrane, which is lined with hair cells that vibrates to excite nerve fibers.  The fibers form the Auditory Canal connecting to the brain. Loudness is determined by number of activated hair cells. Harder to hear sounds are amplified more than loud sounds

Hearing Loss Conduction Deafness – loss of hearing due to damage of eardrum, and/or the tiny bones in middle ear. (Could be fixed by hearing aid) Sensorineural hearing loss- damage to the cochlea’s receptors. Destroys the receptors Cochlear Implants are the only way to restore hearing for people with nerve deafness These implants are wired to many sites on the auditory nerve, which allows them to transmit electrical impulses to the brain Most effective when the child is very young Critical period

Touch Touch is composed of 4 senses : Warmth, Pain, Cold, and Pressure Only pressure has specific receptors No specialized receptors for pain Pressure and Cold = wet Cold and warm = hot Pressure and Pain = tickling itch Gate Control Theory of the spinal cord has “gates” that opens/closes to transmit pain impulses.   Pain can be stopped before it gets to brain so we don’t feel it (shock, adrenaline, etc.)  Pain is merely a physical and psychological interpretation.  Distraction methods, where attention is focused elsewhere, can ease the felt pain.  Acupuncture (may affect gate-control), electrical stimulation, exercise can also relieve pain.

Pain The Gate-Control Theory states that the spinal cord has “gates” that opens/closes to transmit pain impulses.   Small fibers open Gate = pain. Large fibers close Gate = no pain  Pain is merely a physical and psychological interpretation.  Distraction methods, where attention is focused elsewhere, can ease the felt pain.  Acupuncture (may affect gate-control), electrical stimulation, exercise can also relieve pain.

Taste Taste is a Chemical Sense composed of 4 basic senses : Sweet, Sour, Salty, and Bitter Taste receptors (taste buds) regenerate every 1 or 2 weeks, but age, smoking, and alcohol will lower taste bud number and sensitivity. Taste buds on top and sides of the tongue and in the back and on the roof of the mouth contain taste receptor cells. The taste receptor cells send information to an area of the temporal lobe

Smell    Smell or  Olfaction  is also a  Chemical Sense that  directly transmits information from nose to the temporal lobe. The only sense that doesn’t first relay impulses to the Thalamus.

Body Position and Movement Kinesthesis (using sensors in muscles, tendons, and joints)-where our body/parts are  Vestibular sense (using fluids in semicircular canal, cochlea, and vestibular sacs in inner ear)-balance Both sense our position, movement, and balance.