Sight Hearing Smell Taste Touch Vestibular senses Physical

Sight Hearing Smell Taste Touch Vestibular senses

Physical change in external or internal environments triggers chemical, electrical and mechanical activity in sense receptors. Complex processing by nervous system Pattern of activity in part of brain

The initial electrical activity is is aa sensation: , a stimulus (colors, forms, sounds, smells, tastes, etc. ) that activates a receptor. A perception is: a series of organized sensory information that creates meaningful stimuli. + =

Transduction: sensory process that converts physical energy into the form of neural messages.

Transduction (smell example) Step 1: Transform one form of energy to another—detection by a sensory neuron of a physical stimulus Stimulus: food aroma Nose detects the stimulus (aroma)

Transduction Step 2: When the appropriate stimulus (aroma) reaches a sense organ (Niki’s nose), it activates specialized neurons called receptors

Transduction Step 3: Receptors convert their excitation into a nerve signal that travels along a sensory pathway to specialized sensory processing areas of the brain (in all but smell, the signal travels by way of the thalamus)

Stimulus = any aspect of or change in the environment to which an organism responds. Stimuli measured many ways: duration, intensity, wavelength

Sensations occur any time one stimulus activates a receptor. A combination of sensations plus your past experience=perception Absolute threshold --the minimum amount of physical energy required to produce a sensation

A candle flame can be seen 30 miles away on a dark, clear night The ticking of a watch can be heard 20 feet away under quiet conditions. Perfume can be detected when one drop is put in a three-room apartment.

--the minimum The difference threshold amount of physical energy change required to produce a change in sensation Weber’s Law --the larger or stronger a stimulus, the larger the change required for an observer to experience a noticeable difference.

The senses are most responsive to increases and decreases; to new events rather than ongoing, unchanging stimulation

Sensory Adaptation The senses adapt, or adjust, to constant levels of stimulation. Darkness Noisy streets Smelly rooms Let’s do the sensory adaptation Experiment On p. 212.

A person’s ability to detect a stimulus also depends on motivation. Individuals decide to receive stimuli, although that decision-making process is usually entirely unconscious, and is often based on feelings or expectations.

Signal Detection Theory Disputes absolute threshold No sharp boundary between stimuli that you can perceive and stimuli that you cannot perceive Detection thresholds involve recognizing some stimulus against a background of competing stimuli

Signal Detection Theory Processing stimuli Pre-attentive process—extracting information automatically and simultaneously when presented with stimuli Attentive process—considers only one part of the stimuli presented at a time

Signal Detection Theory The Stroop Interference Effect (Attentive) Step 1: name the colors in boxes at left rapidly Step 2: read words at right rapidly Step 3: name the colors at right rapidly

Actually more than 5 senses Basic Five: vision, hearing, taste, smell and touch Several skin senses Internal senses: vestibular and kinesthetic

Each type of sensory receptor takes some sort of external stimulus. . . and converts it into a chemicalelectrical message that can be understood by the brain. The process of transduction.

Vision

Vision Blind spot Lack of receptors at the spot where the optic nerve connects to the retina

Vision Most studied of all the senses Light enters via the pupil reaches the lens, a flexible structure that focuses light on the retina

Vision Retina contains two types of lightsensitive receptor cells: Rods and cones Those cells change light energy into neuronal impulses, which then travel via the optic nerve to the brain.

Vision Cones require more light than rods before they respond 75 -150 million rods; 6 -7 mil. cones Only cones are sensitive to color If all or some cones do not function properly: color deficiency 8% Amer. men; 1% Amer. women

We psychology teachers love experiments. So let’s do some about our eyes. Turn to p. 216 in the textbook. We all have blind spots Color deficiencies Negative afterimages

Vision Two eyes two images Combination of 2 images into one is called binocular fusion Images differ on each retina Retinal disparity

Hey-yo! Let’s do another experiment—this one is about retinal disparity. Pen or pencil Hold 12 -inches in front of face. Both eyes, then left eye closed, then right eye closed. What happens?

We look with our eyes, but see with our brain

Hearing If a tree falls in the forest, and no one is there to hear it, does it make a sound?

Hearing Depends on vibrations of the air, called sound waves Sound waves from the air pass through various bones and fluids to the inner ear

Hearing The inner ear contains tiny, hairlike cells that move back & forth Hair-like cells change sound vibrations into neuronal signals that travel, via the auditory nerve, to the brain.

Hearing Anvil Hammer Stirrup

Hearing Anvil Hammer Stirrup 1. Airborne sound waves must be relayed to the inner ear. In this initial transformation, vibrating waves of air enter the outer ear and strike the eardrum, or tympanic membrane. This tightly stretched sheet of tissue transmits the vibrations to three tiny bones: the hammer, anvil and stirrup

Hearing Anvil Hammer Stirrup 2. These bones pass vibrations on to the primary organ of hearing, the cochlea (in the inner ear) b. The cochlea focuses the vibrations on the basilar membrane

Hearing 3. The basilar membrane converts the vibrations into neural messages (the swaying of tiny hair cells on the vibrating basilar membrane stimulates sensory nerve endings connected to the hair cells. ) The excited neurons transform the mechanical vibrations of the basilar membrane into neural activity.

Hearing 4. Finally, the neural messages travel to the auditory cortex in the brain—neural signals leave the cochlea in a bundle of neurons called the auditory nerve. The neurons from the two ears meet in the brain stem, which passes the auditory information to both sides of the brain

Hearing Perception of loudness depends on amplitude of vibrations in the air. That amplitude, or sound-pressure energy, is measured in decibels. Softest Sounds 0 dbls. Loudest ear can detect: 140 dbl.

Hearing Any sound over 110 dbls can damage hearing. . . as can persistent sounds as low as 80 dbls

Hearing Timbre (pronounced tam-ber): “tone color” or the complex quality of the sound wave. Example: recognizing your company commander’s voice on the radio

Conduction deafness: Conduction conduction of vibrations has been negatively affected Nerve deafness: Damage to auditory nerve or one of higher auditory processing centers

Hearing Some hearing loss comes as a result of age, however. Mosquito Ring Tone (Teen Buzz) Presbycusis: aging ear; starting around age 20, the human ear loses its ability to hear tones in the highest human-range frequencies (18 -20 k. Hz) and as one ages it becomes more difficult to detect those sounds

Smell and Taste The chemical senses: their receptors are sensitive to chemical molecules rather than to light energy or sound waves Smell: molecules, via vapors, make contact with a special membrane in upper nasal passages where smell receptors are located.

You may recall that we used smell to describe Transduction Step 1: Transform one form of energy to another— detection by a sensory neuron of a physical stimulus Stimulus: food aroma Nose detects the stimulus (aroma)

Transduction Step 2: When the appropriate stimulus (aroma) reaches a sense organ (Niki’s nose), it activates specialized neurons called receptors

Transduction Step 3: Receptors convert their excitation into a nerve signal that travels along a sensory path-way, via the Thalamus, to specialized sensory processing areas of the brain

Smell and Taste Those receptors send messages about smells via the olfactory nerve to the brain. Taste: appropriate chemicals must stimulate receptors in the taste buds of your tongue

Sour, salty, Four primary sensory bitter experiences and make up taste: sweet Recent research: umami (Asian) Old theory re: smell: six qualities Flowery, fruity, spicy, resinous, putrid, and burned Several smell theories, no conclusions Smell and Taste

Smell and Taste Sensations of warmth, cold and pressure. . . affect taste Cold chili; hot soda pop; soggy chips

Smell and Taste is actually produced by smell

Please read from the top of p. 220 to the end of Section 2 on p. 222. This is a 5 minute exercise.

The Skin Senses Receptors in the skin provide the brain with four kinds of information about the environment: Pressure, warmth, cold, and pain

The Skin Senses Level of sensitivity varies on body Fingertips—densely populated with receptors: highly sensitive— 10 times more so than on backs or calves Back of calf—relatively few receptors: less sensitive

The Skin Senses Pressure sensations can serve as protection Some skin receptors are particularly sensitive to hot or cold stimuli. Warm water on warm vs. cold day

The Skin Senses Stimuli such as scratches, punctures, severe pressure, heat, and cold can produce pain. Pain is an emergency system that demands immediate action. It makes it possible to prevent damage to your body.

Balance Regulated by the vestibular system inside the inner ear. Three semicircular canals containing fluid Over stimulation cause dizziness or motion sickness

Vestibular Anvil Hammer Stirrup

Body Sensations Kinesthesis—sense of movement and body positions Cooperates with the vestibular and visual senses to maintain posture and balance Sensation of kinesthesis comes from receptors in/near muscles, etc.

It’s time for a full DAY of experiments. HOOAH!!! Rods & cones & peripheral vision The taste buds

Bitter Sour Sweet Salty Sour

It’s time for a full DAY of experiments. HOOAH!!! Rods & cones & peripheral vision The taste buds Taste controlled by smell Skin receptors—differences in density based on body parts

It’s time for a full DAY of experiments. HOOAH!!! Rods & cones & peripheral vision The taste buds Taste controlled by smell Vision

People do not merely have sensory experiences; we perceive objects.

Instructions: draw 9 evenly spaced dots on your paper as shown above. Without lifting your pencil from the paper, draw exactly 4 straight, connected lines that will go through all nine dots, but through each dot only once.

Brain receives information from the senses and interprets it into meaningful experiences—unconsciously. Process of perception

Brain continuously trying to build “wholes” out of the confusion of stimuli that bombards the senses. The “whole” experience that comes from organizing bits and pieces of information into meaningful objects and patterns is called Gestalt.

Gestalt: German term meaning shape or configuration Scientists try to identify principles brain uses in constructing perceptions Five principles: proximity, continuity, simplicity, closure and similarity

Proximity: perceive a number of similar objects as groups or sets

Proximity: perceive a number of similar objects as groups or sets Do you see a lawn or individual blades of grass? Do you see pine trees or individual needles?

Example: in music we do not hear individual notes as much as we hear melodies (notes in proximity to one another)

Continuity: we tend to see continuous patterns, not disrupted ones Baseball venue rather than various shapes (diamond infield, square bases, etc. )

Following a sound of a particular voice or instrument when many other sounds are occurring is due to similarity and continuity

Simplicity: we see the simplest shapes A possible; the law of bird Pragnanz in the hand Closure: when we see a familiar pattern or shape with some missing parts, we fill in the gaps.

Similarity: when similar and dissimilar objects are mingled, we see the similar objects as groups x o x Home team in red uniforms Visiting team in white uniforms x x x x o o o o x x

Gestalt principles of organization help to explain how we group our sensations and fill gaps in order to make sense of our world.

Types of Perception Figure-ground perception—ability to properly discriminate between figure and ground The fact that we can perceive a single pattern in more than one way shows that we are not passive receivers of stimuli

Often perceptions are not based entirely on current sensory information Hear a barking dog in the distance. . . assume it is a dog. Perceptual influence: phenomenon of filling in gaps in what senses tell us.

Perception is learned behavior Takes babies 7 -8 months to learn to recognize different people.

Hi students, often times subliminal messages affect our perceptions of things. Subliminal: from the Latin words sub (below) and limen (threshold. ) Subliminal messages are brief visual or auditory messages presented below the absolute threshold; there is a less than 50% chance they will be perceived.

Often when television or print ads appear, they incorporate certain subliminal advertising techniques. Name Calling: using negative labels to discredit a competitor Glittering generalities: broad statements that appeal to emotions

Here are some more subliminal advertising techniques. Card stacking—slanting facts Plain folks—using folksy language Transfer: connecting a product with someone or something that is admired Bandwagon: Appealing to people’s desire to “go with the crowd. ”

Now, form into groups and discuss each of the six subliminal advertising techniques. Think about examples of each: name calling, glittering generalities, card stacking, plain folks, transfer, and bandwagon. Be prepared to discuss your results with the class.

Now you will have a group activity so you can demonstrate what you have learned in this chapter. And this activity should be fun because we science people always have fun!

Television Commercial ü 30 -60 Seconds üDialog and action üAppeal to at least 1 sense üFactor in use of subliminals— Name calling, Glittering generalities Card stacking, Plain folks, Transfer Bandwagon

Illusions are created when perceptual cues are distorted so that our brains cannot correctly interpret space, size and depth cues. Many illusions are optical illusions. Sometimes our perceptions can be incorrect. Those situations are called illusions. To demonstrate, we shall now observe some optical illusions from the Internet.

Extrasensory Perception (ESP) Receiving information about the world through other than the normal senses. Paranormal experience—a sense beyond the basic 5 senses.

Experienced with thoughts, not body sensations—therefore very controversial Major types of ESP: Telepathy—ability to read another’s thoughts Clairvoyance—ability to “see” events or objects happening somewhere else Precognition—ability to see the future

Major types of ESP (continued) Retrocognition—ability to see into the distant past Mediumship—the ability to channel dead spirits Psychometry—ability to read information about a person or place by touching a physical object

Parapsychology: “Father: ” J. B. Rhine Zener Card Experiments— deck of 25 cards, each with one of 5 patterns +