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IB Psychology - Biological Level of Analysis
Transcript of IB Psychology - Biological Level of Analysis
What is the Biological Level of Analysis? (BLOA?)
The Biological Level
The BLOA is the branch of psychology that is concerned with trying to explain behavior on a biological basis.
It is important in helping us understand how the brain influences the way we think and act, as well as understanding the structure of the brain and the nervous system.
At the core of the way we think, feel and act is the nervous system.
Nervous system: The physiological network of intercommunicating nerve cells that form the basis of our ability to perceive, adapt to, and interact with the world.
The nervous system is divided into two main parts, the central nervous system and the peripheral nervous system.
Central nervous system: Consists of the brain and the spinal cord, both of which are protected from shocks and minor traumas by the cerebrospinal fluid that circulates through them. The CNS controls our senses, motor abilities, reflexes, and mental activity.
Peripheral nervous system: Comprised of all the neurons in the body except the neurons of the brain and the spinal cord. The PNS assists the CNS, but PNS neurons are external to the CNS.
The job of the PNS is to relay information between the CNS and the afferents (sensory) and efferents (motor) lying outside of the CNS. The PNS connects with afferents in external sensory organs and our internal body parts.
The PNS is divided into two parts:
The somatic nervous system
The autonomic nervous system
Somatic nervous system (part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles): In charge of quick and conscious movements of our skeletal muscles, which are muscles that are directly attached to our bones and allow us to move.
Autonomic nervous system: Controls movement of our non- skeletal muscles, which include the cardiac muscles and the smooth muscles, which are the muscles of our blood vessels and organs.
Fun Fact: autonomic means “self-regulating”
The autonomic nervous system is divided into two parts:
Sympathetic nervous system: Concerned primarily with the metabolic processes in our that use energy and other resources from the reserves in our body.
Parasympathetic nervous system: Concerned with the metabolic processes in our body that store energy.
The nervous system uses of two kinds of neurons:
1. Sensory afferents, which receive electrochemical sensory information from the outlying neurons of the body (eyes, ears, skin, etc.) and send that information back to the brain.
2. Motor efferents, which send motor information (movements of muscles) either from the brain to the spinal cord to the muscles or directly from the spinal cord to the muscles (reflexes.) Motor efferents control bodily responses.
The nervous system is composed of billions of cells, the most essential being the nerve cells (neurons).
Parts of the Neuron
There are three different types of neurons:
1. SENSORY NEURONS receive information from the environment and connect with receptor cells that detect physical or chemical changes in the skin, ears, tongue, eyes, nose, muscles, joints, and organs. They carry information away from the receptor cells and to the spinal cord or brain.
2. MOTOR NEURONS carry information away from the spinal cord or brain and to the body parts that are supposed to respond to the information.
3. INTERNEURONS receive signals from sensory neurons or interneurons, and send those signals to other interneurons or motor neurons. They are the “messengers.”
The SOMA is the body of the neuron and is responsible for the life of the cell. Contains the nucleus which performs reproductive functions for the cell.
The DENDRITES are the branch-like parts at the end of the soma that receive communications from other cells through the receptors on their external membranes.
The AXON is a long, thin tube that can divide and branch many times at its end. It responds to the information received by the dendrites and soma, and sends the information through the neuron until it reaches somewhere where it can be sent to other neurons. A bundle of axons is called a NERVE.
The axon is surrounded by a MYELIN SHEATH, which insulates and protects the axon from electrochemical interference from other neurons. It also speeds up information along the axon.
The TERMINAL BUTTONS are small knobby structures at the ends of the branches of the axon, which send messages across the synaptic gap to be received by other neurons.
Communication between neurons is a chemical process; one neuron sends out chemicals known as neurotransmitters, and other neurons pick up the chemicals and may or may not send the message on.
For one neuron to send a message to the other, the terminal buttons of the neuron sending the message must release a neurotransmitter across the SYNAPSE, which is the gap between the terminal buttons of one neuron and the dendrites of another.
Acetylcholine (Ach): enables muscle action, learning, and memory. Alzheimer’s disease deteriorates the production of Ach.
Dopamine: functions in movement, learning, attention, and emotion. Excess amounts of dopamine lead to Schizophrenia and decreased amounts lead to Parkinson’s disease.
Serotonin: functions in mood, hunger, sleep, and arousal. Antidepressants can affect serotonin levels.
Norepinephrine: helps control alertness and arousal. An undersupply of this can depress mood.
The brain is the organ in our bodies that directly controls our thoughts, emotions, motivations, and motor responses. It responds to information that it receives from other places in the body (organs, etc.). It is the control center of our body.
PARTS OF THE BRAIN
MEDULLA OBLONGATA- An elongated interior structure of the brain that keeps us alive by controlling heart rate, breathing, swallowing, and digestion.
PONS- Serve as a relay station, containing neurons that pass signals from one part of the brain to the other.
CEREBELLUM- Controls bodily coordination, balance, and muscle tone. If the cerebellum is damaged, movement becomes jerky and disjointed.
BRAIN STEM- Connects the brain to the spinal cord. Sends sensory information from the body up to the brain, and motor information from the brain down through the body.
RETICULAR ACTIVATING SYSTEM (RAS)- A network of neurons essential to the regulation of consciousness, heart rate, and breathing.
THALAMUS- The primary relay station for sensory information coming into the brain. It sends information to areas of the cortex.
HYPOTHALAMUS- Controls the endocrine system, the autonomic nervous system, appetite, internal temperature regulation, and thirst. It also plays a role in controlling consciousness, and is involved in emotions, sexual response, pain, and pleasure.
THE NERVOUS SYSTEM
The Limbic System
A system of brain structures important to emotion, motivation, and learning.
HIPPOCAMPUS- Plays an extremely important role in memory function.
AMYGDALA- Plays a role in anger and aggression
SEPTUM- Plays a role in anger and fear.
The Cerebral Cortex
The outer layer of the brain that is responsible for our being able to plan, coordinate thoughts and actions, perceive visual and sound patterns, use language, and think.
The LEFT hemisphere processes information logically and sequentially, and deals with language, while the RIGHT hemisphere deals with more visual information and processes things randomly, intuitively, and holistically.
CORPUS CALLOSUM- Dense body of nerve fibers that connects the two hemispheres of the brain.
The FRONTAL LOBE deals with higher thought processes, reasoning, planning, parts of speech, emotions, problem solving, and social and sexual behavior. It contains the PRIMARY MOTOR CORTEX, which specializes in planning, control, and execution of movement.
The PARIETAL LOBE is associated with movement, orientation, recognition and perception of stimuli. It contains the PRIMARY SOMATOSENSORY CORTEX, which receives information from the senses about pressure, texture, temperature, and pain.
The OCCIPITAL LOBE is associated with visual processing.
The TEMPORAL LOBE is associated with perception and recognition of auditory stimuli, memory, and speech.
BROCA'S AREA- Located in the left frontal lobe, it is the part of the cortex that controls speech and language recognition (language outputs.)
WERNICKE'S AREA- Located in the left temporal lobe, it is involved in understanding language (language inputs.)
Visual information that we see through our left eye is processed in our right hemisphere, while information we see in our right eye is processed in our left hemisphere. Neural fibers from the eyes cross over the OPTIC CHIASMA and go to the opposite hemisphere of the brain.
In an ELECTROENCEPHALOGRAM, or EEG, electrodes establish contact between the brain and a device that sums the effects of brain activity over large areas containing many neurons. Most often, electrodes are attached directly to the scalp. The patterns of electrical waves indicate different levels of brain activity.
ANGIOGRAMS are X-rays that are enhanced to provide visual contrast by injecting special dyes into the blood vessels of the head. They are used to assess diseases of the blood vessels, locate brain tumors, and to indicate which parts of the brain are active when people perform different tasks such as listening, speaking, or moving.
A COMPUTERIZED AXIAL TOMOGRAM, or CAT scan, uses radiation to show a cross-sectional slice of the brain, and is used to detect blood clots, tumors, and other brain diseases. They are also used to show how certain locations of brain damage can affect people’s behavior.
MAGNETIC RESONANCE IMAGING, or MRI, is very similar to a CAT scan except that it uses no radiation, and the pictures are clearer. A FUNCTIONAL MRI, or fMRI, measures changes in the magnetic state of the blood as a function of the blood’s degree of oxygenation. It shows what parts of the brain are active during certain processes.
In POSITRON EMISSION TOMOGRAPHY, or PET scans, we can see the brain in action. Mildly radioactive glucose is inserted into a patient and absorbed by the cells, and the amount of glucose absorbed by the brain indicates the activeness of an area of the brain.
Measuring Electrical Activity in the Brain
The Endocrine System
The endocrine system is a physiological communication network that complements the nervous system. It is operated by glands, groups of cells which secrete hormones directly into the bloodstream.
Hormones are the chemical substances that foster the growth of cells. Hormones play an extremely important role in growth and development, especially sexual development. Hormones are released reflexively without our conscious control. A stimulus from inside or outside the body brings a change in neural activity, triggering the release of hormones.
The ADRENAL GLANDS are just above the kidneys, and secrete epinephrine (adrenaline) and norepinephrine (noradrenaline), which in the nervous system are also neurotransmitters.
The THYROID GLAND, located at the front of the throat, regulates the metabolic rate of cells. It releases thyroxine, which increases metabolic rate.
The PITUITARY GLAND, or the “master gland,” is very important in that it controls many other endocrine glands. The pituitary is controlled by the hypothalamus, and is located underneath the hypothalamus.
Characteristics and traits that we inherit from our ancestors are largely responsible for the way we think and behave. Inside the cells, our GENES provide the basic physiological building blocks for the hereditary transmission of our BIOLOGICAL TRAITS- the distinctive characteristics or behavior patterns that are determined by our genes. The degree to which our genes influence behavior is a constantly debated by psychologists.
CHROMOSOMES are rod shaped bodies that contain many genes. Each human has 23 chromosome pairs, for a total of 46 chromosomes. Chromosomes are partly composed of DEOXYRIBONUCLEIC ACID, or DNA, our genetic makeup.
The DOMINANT TRAIT is the stronger genetic trait in our genotype which will appear as a quality in our phenotype, while the RECESSIVE TRAIT does not appear.
Our GENOTYPE is the pair of genes on a given chromosome pair, and our PHENOTYPE is the expression of an inherited trait, based on the dominant trait in the genotype.
HERITABILITY refers to the proportion of variation among individuals that is due to genetic causes.
DOWN SYNDROME- A set of mental and physical symptoms that result from having an extra copy of Chromosome 21. Symptoms include a flat face with an upward slant to the eye, short neck, and abnormally shaped ears. Mental development and physical development are slower in people with Down syndrome than in others.
"THE SPLIT BRAIN IN MAN” BY MICHAEL GAZZANIGA (1967)
Gazzaniga studied split-brain patients, that is, patients who had a severed corpus callosum, and whose right and left hemispheres were not connected. Although Roger Sperry is said to be the founder of split brain research, Gazzaniga worked with human patients while Sperry worked mostly with animals. Gazzaniga wanted to explore the extent to which the two halves of the brain are able to function independently, as well as whether they have separate and unique abilities. Three different tests were developed to explore a wide range of capabilities:
1. A visual test that in which a picture of an object, a word, or parts of words were sent to the visual area of either the right or left hemisphere, but not to both.
2. A tactile test in which participants could feel, but not see, an object, block letter, or block words.
3. An auditory test in which common objects were placed into a cloth bag, and the participant was asked to find a certain item by touch.
Results: The results demonstrated that the two halves of the brain have many specialized skills and functions. The left hemisphere is “better” with speaking, writing, mathematical calculation, and reading, and is the primary center for language. The right hemisphere has capabilities for recognizing faces, solving problems involving spatial relationships, symbolic reasoning, and artistic activities.
The founder of split-brain research
Sperry conducted split-brain experiments in cats and monkeys, noticing how the hemispheres of their brains aren’t specialized like the human brain.
His split-brain work lead him to win the Nobel Prize.
David Hubel and Torsten Wiesel
They experimented with deprivation of visual experiences during the critical period of life in kittens, primates, and humans.
Their studies showed that in humans and other animals, there is a critical period for the development of the sense of sight.
“BRAIN CHANGES IN RESPONSE TO EXPERIENCE” BY MARK ROSENZWEIG (1972)
Rosenzweig experimented on lab rats to see whether certain experiences produce physical changes in the brain. He believed that animals raised in highly stimulating environments will show differences in brain growth when compared with animals raised with little or no stimulation.
Three male rats were chosen from each litter and then randomly assigned to one of three conditions:
A standard laboratory cage with several rats in adequate space with food and water always available
The impoverished environment was a slightly smaller cage isolated in a separate room in which the rat was placed alone with adequate food and water
In the enriched environment, six to eight rats lived in a large cage with a variety of objects with which they could “play.” New playthings were placed in the cage every day.
Results: The brains of the enriched rats were different from the impoverished rats in many ways. Their cerebral cortexes were heavier and thicker, greater activity of the nervous system was found in the brain tissue of the enriched rats.
HOW DOES THIS RELATE TO THE CLOA AND SCLOA?
The way we think and percieve is dependent on the functions of our brain and nervous system
If we have any sort of genetic disorder or damage to the brain, it could drastically change the way we percieve ourselves and the others around us.
Drugs and medications that influence our bodies could also change the way we think and percieve
For instance, when smoking marijuana, chemicals such as delta-9-tetrahydrocannabinol, or THC, are sent to our brain, giving us a "high." While we are "high," we expereince distorted perceptions, impaired coordination, difficulty with thinking and problem solving, and problems with learning and memory.
Genetic diseases, personality disorders, and other clinical disorders that are rooted in genes change the way we behave in social situations.
Some inherited and biological disoders inhibit the way we make relationships and communicate with others
For instance, some symptoms of Schizophrenia, a chronic brain disorder, are losing interest in everyday activities, and feeling out of touch with other people, family, or friends.
Some, but not all, familiar brain disorders include:
Dyslexia- Involves difficulty in learning to read or interpret words, letters, and other symbols
Aphasia- Loss of ability to understand or express speech
Agraphia- The inability to write
Anomia- The inability to identify or recall words
Adrenaline- in the adrenal glands, functions in fight or flight responses and arousal
Cortisol- in the adrenal glands, functions in arousal, stress, and memory
Melatonin- in the pineal gland, it helps to regulate sleep
Oxytocin- in the pituitary gland and hypothalamus, this is important in forming mother-child attachment (is released from skin-to-skin contact)
Testosterone/Estr0gen- in the gonad gland, it is important in physical and emotional development
Psychout: IB Psychology at Seoul Foreign School. (2012). Retrieved March 10, 2012, from Andreas Viklund website: http://psychout50.edublogs.org/the-biological-level-of-analysis/
Boeree, C. G. (2003-2009). General Psychology: The Neuron. Retrieved March 10, 2012, from Dr. C. George Boeree website: http://webspace.ship.edu/cgboer/theneuron.html
Brain Structures and their Functions. (2005, June 3). Retrieved March 10, 2012, from Serendip website:
Templeton, M. (2012, March 19). Differences Between Right and Left Hemisphere. Retrieved March 10, 2012, from Mark Templeton, Ph.D website: http://frank.mtsu.edu/~studskl/hd/hemis.html
The Split Brain Experiments. (2012, March 19). Retrieved March 10, 2012, from Nobel Media AB website: http://www.nobelprize.org/educational/medicine/split-brain/background.html
InfoFacts: Marijuana. (2010, November). Retrieved March 10, 2012, from NIDA: National Institute on Drug Abuse website: http://www.drugabuse.gov/publications/infofacts/marijuana