Biology, Sensation/Perception, and Consciousness Domain Two Biology, Sensation/Perception, and Consciousness

Biology

The Nervous System Two main parts Central Nervous System: the brain and the spinal cord

The Nervous System Two main parts Peripheral Nervous System: contains nerve cells; has two divisions Somatic Nervous System: activated by touch, pain, and temp Automatic Nervous System: regulates the body’s vital functions (like our heartbeat)

The Brain

Parts of the Brain There are some sections listed on our Zombie article! Pons: help regulate sleep Limbic System: involved in learning, memory, emotion, hunger, sex, and aggression Cerebrum/Cerebral Cortex: the part that does the thinking

The Two Halves Connected by the corpus callosum Information received by one side of the body is transmitted to the opposite hemisphere of the brain Don’t act independently, but some think… Right brained people are creative Left brained people are logical

The Endocrine System Contains the glands that release hormones into our bloodstream Pituitary Gland: releases growth hormones Thyroid Gland: controls our metabolism Adrenal Glands: help us with stressful situations Testes/Ovaries: important for reproduction

Heredity: Our Genetic Background Heredity: passing along traits from parents to offspring Nature-Nurture Debate: How did we develop who we are? Through Nature: our genetic make-up Through Nurture: from our environment

Kinship Studies Explore the Nature-Nurture Debate Twin Studies: look at identical and fraternal twins Adoptee Studies: look at siblings not raised together Twins Reared Apart: combines Twin Studies and Adoptee Studies

Alone or with a partner… Find a kinship study. Describe their question, summarize the experiment, and share the results. Which side of the Nature-Nurture Debate are you on? Are you who you are from genetics or your environment?

Sensation & Perception

Sensation is basically what the senses take in. Perception is how we organize and give meaning to what we sense.

Affected by… Absolute Threshold: the weakest amount of stimulus that can be sensed Example: some of us see better than others Difference Threshold: our ability to detect small differences between stimuli Example: can you tell when the radio is turned up

Affected by… Signal-Detection Theory: not only the stimulus, but our mood and attitudes impact perception Example: motivation can effect whether we excel at an event Sensory Adaptation: we can get used to stimuli Example: eyes adjust in a dark theater

Vision

The Eye The Pupil The black part of the eye Allows light to enter the eye Large pupil = more light Also opens more when we’re afraid! The Iris: the color of your eye The Sclera: the white of your eye

More on the Eye The Lens: adjusts its thickness to help with distance Retina: holds the picture of what we’ve seen Photoreceptors: neurons in the retina Our blind spot is where the optic nerve leaves the eye

Visual Acuity The sharpness of vision Measured by the Snellen Vision Chart Nearsighted—can see near, not far away Farsighted—need glasses for reading

Color Vision The Color Circle Complimentary colors are across from one another Cones enable us to see colors

Color Blindness Most do not see shades of red or green Total loss is very rare You should see a 58, 18, E, and 17

Afterimage The afterimage of a color is its complimentary color When you look at the image for 30 seconds and look at a white paper—you’ll see the complimentary colors!

Hearing

Parts of the Ear The part outside is the outer ear The eardrum is the “door” from the outer to the middle ear Three bones in the middle ear: hammer, anvil, and stirrup In the inner ear, the cochlea moves and sends info to the brain via the auditory nerve

How We Hear Sounds travel in waves Each sound has its own Pitch: how high or low the sound is; determined by the length of the wave Loudness: how loud or quiet the sound is; determined by the height of the wave Measured in decibels About 2 million Americans have no hearing

Other Senses

Smell and Taste Without smell, we wouldn’t be able to taste Odors are detected by receptor neurons in the nose Send info to the brain via the olfactory nerve Tastes are detected by receptor neurons on the tongue

Skin Senses (also called touch) Pressure Sensory receptors near the roots of the hair on our bodies give us this sense Some parts are more sensitive than others (fingertips and lips) Temperature Neurons beneath the skin sense temps It’s all relative to our temp—usually 98.6 degrees Pain The more pain receptors, the more sensitive to pain

Perception

We have certain rules for perception Closure: we can fill in the blanks Figure-Ground Perception: we can focus on an object or the background Perception of Movement: we judge our movement relative to other objects

Consciousness

Truth or Fiction If it were not for cues such as the sunrise and sunset, people would act as if a day were 25 hours long. The only time people dream is just before they wake up. It is possible to hypnotize any person at any time. People who are drunk always know that they are drunk. TRUTH FICTION

The Study of Consciousness

Meanings of Consciousness Consciousness as Sensory Awareness: we are aware of the items we see, smell, taste, hear, and feel We can be unaware of sensory stimulation We are more aware of unusual stimuli or intense stimuli

Meanings of Consciousness Consciousness as Direct Inner Awareness: we are aware of things within ourselves (memories, past experiences, etc.) Consciousness as Sense of Self: we are aware that we are unique individuals, separate from other people and their surroundings

Levels of Consciousness Total Consciousness: we are aware of our awareness The Preconscious Level: we can answer a question about something by recalling it, even if we aren’t presently thinking about it; we simply direct our attention to it Ex: What did you have for dinner last night?

The Unconscious Level: also called the subconscious; this information is hidden from us and is unavailable Freud says we “hide” painful memories and certain unacceptable impulses—like aggression We protect ourselves from feelings of anxiety, guilt, or shame The Non-conscious Level: includes some basic biological functions Our fingernails grow, our pupils dilate, we breathe

Altered States of Consciousness A person’s sense of self or senses of the world changes Examples: sleep, drugs, and medications

Sleep and Dreams

We sleep about one-third of our lives Circadian Rhythms: biological clocks, govern how we function; include a sequence of bodily changes (body temperature, blood pressure, and sleep patterns) that occur on a 24-hour schedule

Sample Circadian Rhythm

The Stages of Sleep Defined in terms of brain wave patterns measured by EEGs Four brain wave patterns: alpha, beta, theta, and delta waves Awake/Alert to Drowsiness We emit beta waves—short and quick waves As we relax, we emit alpha waves—a little slower; we may experience flashes of color or feelings of falling

The Stages of Sleep Defined in terms of brain wave patterns measured by EEGs Four brain wave patterns: alpha, beta, theta, and delta waves

Stage One The lightest stage of sleep Brain waves move from alpha to the slower rhythm of theta waves Includes brief images, similar to photographs We will remember these images if we awake from stage one sleep Lasts no more than 30-40 minutes

Stages Two to Four We move from stage two to three to four Stages 3 and 4 are the deepest stages and we emit the slowest brain waves—delta waves We have the hardest time waking from stage four sleep After 50 minutes, we move to stage four and back through the stages to stage one again

Rapid Eye Movement / REM Sleep We breathe more irregularly, our blood pressure rises, and the heart beats faster; our brain wave patterns are similar to stage one (theta waves) Beneath our closed eyelids, our eyes move quickly REM sleep becomes longer as we approach morning REM sleep may help brain development in infants and may exercise brain cells in adults During 8 hours of sleep, we may go through five sleep cycles (1 to 2 to 3 to 4 to 3 to 2 to 1 to REM to 1 to 2, etc.)

Why do we sleep? For our health: to revive our tired bodies, to build up resistance to infection, we can help recover from stress When we go without sleep… Randy Gardner’s study in 1964 found people became irrational We become irritable, our eyes do not focus, we have speech difficulties and memory lapses When deprived of only REM sleep, we experience longer REM sleep when we’re able to reach this stage

Dreams Characteristics May be in color or black and white May be realistic or totally disorganized Sometimes we dream in “real time,” a ten minute dream takes ten minutes for us to dream it Most dreams are extensions of our daily activities We often don’t remember dreams because we are unable to hold on to information from one state of consciousness to another

Freud’s View Our dreams reflect our unconscious wishes/urges Unacceptable and painful wishes may appear in symbolic form

The Bio-psychological Approach Dreams begin when neurons stimulate the section of the brain that controls movement and vision The brain responds to these random stimuli by creating stories—whatever is stimulated is the basis for our dream Ex: if the part of our brain that controls running is stimulated, our dream would center on running in some way

Sleep Problems

Insomnia Definition: the inability to sleep, usually the inability to fall asleep at bedtime Racing minds at bedtime Becomes worse when we try to fall asleep—increases tension Solution? Sleeping pills or a variety of techniques (tense/relax muscles, avoid worrying in bed, stick to a routine, relax with daydreams/pleasant images)

Nightmares/Night Terrors Definition: dreams that frighten us Usually affect people who are anxious or depressed Night terrors: more severe than nightmares, memories may be vague, our hearts race and we gasp for air; tend to occur during deep sleep (stages 3 and 4) and closer to the beginning of sleep May be due to immature nervous systems; common with children

Sleepwalking Definition: roaming around during sleep Little Sleepwalker

Sleep Apnea Definition: breathing interruptions during sleep May result in being tired in the morning Caused by blocked air passages May be linked to SIDS

Narcolepsy Definition: falling asleep at any time in any place Very rare Go straight to REM sleep Treated with medication and frequent naps

Altered States When We're Awake

Meditation Definition: narrowing our consciousness Techniques: focus on a peaceful, repetitive stimulus Looking into a candle or oil lamp Looking at intricate/detailed drawings Repeating mantras (pleasing sounds like “om”) and focusing on the sounds Important in some religions (Buddhism)

Hypnosis Definition: a “sleep-like” state in which people respond to suggestions and/or answer questions Uses To help people relax, reduce anxiety, manage pain, or overcome fears As an anesthetic in surgery Can only occur if the patient is willing! Effectiveness Post-hypnotic Suggestion: technique in which behavior changes after hypnosis Some people have stopped smoking after hypnosis

Déjà Vu A feeling of re-experiencing a specific situation Can be used to relive the experiences of past lives Some epileptics experience déjà vu prior to having a seizure

Lucid Dreaming A dream in which the dreamer is aware he/she is dreaming Can happen naturally Through training, people are able to place themselves into dreams Used to relax and relieve stress Is different from dream control in which the dreamer directs his/her dreams

Drugs and Consciousness

Depressants Definition: drugs that slow down the nervous system (breathing, movement, etc.); may make people feel relaxed

Examples of Depressants Alcohol Small doses may make people feel relaxed, but large doses can up a person to sleep Narcotics: addictive depressants used to relieve pain and induce sleep Includes: morphine, heroin, and codeine Users may suffer withdrawal symptoms (tremors, chills, cramps, rapid heartbeat, insomnia, vomiting, and diarrhea)

Stimulants Definition: drugs that increase the activity of the nervous system Examples Nicotine Spurs the release of adrenaline, which increases the user’s heart rate Reduces the appetite and increases metabolism Is addictive; quitters suffer from withdrawal Can cause serious health risks and thus the surgeon general’s warnings

Another Example Amphetamines (speed) Known for helping people stay awake and reducing one’s appetite High doses can produce feelings of pleasure and highs, but the users usually “crash” or come down quickly and become depressed Can lead to hallucinations (people see/hear things that aren’t real—seeing/feeling bugs crawling all over you) and delusions (a false idea that seems real—thinking you can fly)

Hallucinogens Definition: a drug that produces hallucinations; may produce feelings of pleasure, but may also induce panic Examples Marijuana: leads to relaxation and very mild hallucinations Can impair perception, coordination, memory, and learning Used to treat minor aches and pains over 100 years ago (like Tylenol and aspirin today)

Another Example LSD/Acid: much stronger than marijuana, produces strong hallucinations Users claim they become extremely creative, but may forget when the effects wear off Effects are not predictable Long or continuous use can lead to flashbacks

Drug Abuse Treatments Detoxification: remove the drug from the body Maintenance Programs: participants are given controlled amounts of the drug or a less addictive substitute Example: nicotine gum to help quit smoking Counseling: individually or in groups Support Groups: include several people who share similar experiences, concerns, or problems; useful to provide emotional and moral support Example: Alcoholics Anonymous