Psych 11

WEARENOWHERE

 knowledge of the world depends on: vision, hearing, taste, smell, position, movement, balance, and touch  eyes and ears pick up stimuli such as light and sound waves and send neural signals to the brain

 sensation = physical energy from objects in the world or in the body stimulates the sense organs  Perception = happens when the brain organizes and interprets sensory information

 Cutting yourself example – it is in you, and you will remember the pain when you see the knife (near you, near others-same neurons stimulated, evidence of learning, genetic predisposition of neurons to connect – visual to pain receptors)  Histamine  Pain sensations are processed and altered by mechanisms within the spinal cord.  Endorphins relieve pain by inhibiting pain perception

 Gate-control theory -pain signals traveling from the body to the brain must go through a gate in the spinal cord  If the gate is closed, pain signals can’t reach the brain  -not really a gate -a pattern of neural activity that either stops pain signals or allows them to pass  Signals from the brain can open or shut the gate

 The neural pathways for emotional and physical pain cross  The brain cannot distinguish  Pain can be controlled by a number of therapies including, drugs, surgery, acupuncture, exercise, hypnosis, and even thought distraction.

 Transduction  Sensory organs contain receptors that transduce sensory energy into nerve impulses that are carried to the brain

External light falls on receptors within the eye to generate the visual message Light = electromagnetic radiation Wavelength of light determines color

 Accommodation refers to automatic adjustments of the eye, which occurs when muscles change the shape of the lens so that it focuses light on the retina from objects at different distances.  Nearsightedness  Farsightedness

Three Types of Processing: 1. Transduction: converts sensory stimuli into neural impulses that are sent on to the brain 2. Sensory Reduction: filters and analyzes incoming sensations before sending on to the brain 3. Coding: converts particular sensory input into a specific sensation sent to differing parts of the brain

Humans are able to discriminate 7 million different hues Colors convey important information: Ripeness of food Danger signals Trichromatic theory Eye contains 3 different color sensitive elements Blue, green or red elements Trichromatic theory accounts for color mixing of lights.

Optic nerves connect to the thalamus in the middle of the brain, and the thalamus connects to the visual cortex

Genetic disorder in which people are blind to green or red colors. This supports the Trichromatic theory. Ishihara Test

Gaze at the middle of the flag for about 30 Seconds. When it disappears, stare at the dot and report whether or not you see Britain's flag.

 Psychophysics is the study of how the physical properties of stimuli relate to people’s experience of stimuli  Questions the acuity of the senses

 Close your left eye, and fixate your right eye on the black dot. Move the page towards your eye and away from your eye. At some point the car on the right will disappear due to a blind spot

 Psychologists assess the acuity of the senses in three ways:  Measuring the absolute threshold  Measuring the difference threshold  Applying signal detection theory

 The absolute threshold is the minimum amount of stimulation required for a person to detect the stimulus 50 percent of the time  difference threshold is the smallest difference in stimulation that can be detected 50 percent of the time-just noticeable difference (jnd), depends on the strength of the stimulus.

Activation of retinal cells by light results in action potentials that travel along neurons that project to the occipital cortex

Wavelength (distance between peaks) - determines frequency - perceived as pitch - some wavelengths cannot be perceived Amplitude (height of wave) - perceived as loudness Mixture of Wavelengths; Complex Sounds - perceived as timbre / tone saturation

Cochlea: Coiled, bony, fluid- filled tube in the inner ear that transforms sound vibrations to auditory signals.

Place Theory of Pitch Perception  location of stimulation is important  only explains perception of high frequencies Frequency Theory of Pitch Perception  frequency of nerve firing ▪ limitations of neuronal firing rate  volley principle ▪ cell clusters can exceed limitations of firing rate

 Receptors are embedded in a mucus-coated membrane called the olfactory epithelium  When chemical molecules in the air pass through the nose, the receptors initiate a neural impulse which travels to the olfactory bulb, where most olfactory information is interpreted  =Olfaction

 The sense of smell is closely connected with memory  Most people have had the experience of smelling something, maybe a certain perfume or spice, and suddenly experiencing a strong emotional memory  Researchers don’t know exactly why this happens, but they theorize that smell and memory trigger each other because they are processed in neighboring regions of the brain.

 Taste receptors are located on the tongue and are sensitive to five major tastes: salty, sweet, sour, bitter and umami.  Taste receptors respond differentially to the varying shapes of food and liquid molecules.  =Gustation

 The sense of touch is a mix of four distinct skin senses—pressure, warmth, cold, and pain.

 Skin Senses: there are three basic skin sensations: touch, temperature, and pain.  Vestibular Sense: sense of body orientation with respect to gravity and three-dimensional space  The semicircular canals provide the brain with balance information.  Kinesthetic Sense: sensory system for body posture, orientation and movement  Kinsethetic receptors are found throughout the muscles, joints, and tendons of the body.

 Perceptual processes include:  Selection refers to choosing which of many stimuli that will be processed.  Organization involves collecting the information into some pattern.  Interpretation involves understanding the pattern

 Selective attention: filtering out and attending only to important sensory messages.  Feature detectors: specialized cells in the brain that respond only to certain sensory information  Habituation: tendency of the brain to ignore environmental factors that remain const

 Gestaltists proposed laws of organization that specify how people perceive form.  Figure and ground are basic organizational themes for perception.  Figure is perceived as distinct from the background.  Figure is closer to the viewer than the background.

 Perceptual Constancy is the tendency for the environment to be perceived as remaining the same even with changes in sensory input.  Size constancy  Shape constancy  Color constancy  Brightness constancy

 Depth perception is the ability to perceive three-dimensional space and to accurately judge distance.  Binocular cues include retinal disparity and convergence. (fingers in, 1inch-5inch)  Monocular cues include linear perspective, interposition, relative size, texture gradient, aerial perspective, light and shadow, accommodation and motion parallax.

 Interpretation is influenced by: perceptual adaptation perceptual set individual motivation frame of reference

 Subliminal stimuli are stimuli presented below the threshold of awareness; the effect on behavior is uncertain

 ESP refers to the ability to perceive stimuli that are outside the 5 senses  Telepathy: the ability to read minds  Clairvoyance: the ability to perceive objects or events  Precognition: the ability to predict the future  Psychokinesis: the ability to move objects