MCATTSocial/Behavioral

• B.F SKINNER'S OPERANT CONDITIONING LEARNING
• Neuropsychology is the study of the connection between the nervous system and behavior. It most often focuses on the functions of various brain regions.
• The brain has three subdivisions: The hindbrain contains the cerebellum (motor task), medulla oblongata, and reticular formation. The midbrain contains the inferior and superior colliculi. The forebrain contains the thalamus, hypothalamus, basal ganglia, limbic system, and cerebral cortex.
• Methods of studying the brain include studying humans and animals with lesions, electrical stimulation and activity recording (including electroencephalography [EEG]), and regional cerebral blood flow.
• The cerebral cortex is divided into four lobes: The frontal lobe controls executive function, impulse control, long-term planning, motor function, and speech production. The parietal lobe controls sensations of touch, pressure, temperature, and pain; spatial processing; orientation; and manipulation. The occipital lobe controls visual processing. The temporal lobe controls sound processing, speech perception, memory, and emotion.
• The brain is divided into two cerebral hemispheres, left and right. In most individuals, the left hemisphere is the dominant hemisphere for language. The dominant hemisphere (usually the left) is primarily analytic in function, making it well-suited for managing details. For instance, language, logic, and math skills are all located in the dominant hemisphere. The nondominant hemisphere (usually the right) is associated with intuition, creativity, music cognition, and spatial processing
• Neurotransmitters are released by neurons to carry a signal to another neuron or effector (a muscle fiber or a gland). Acetylcholine is used by the somatic nervous system (to move muscles), the parasympathetic nervous system, and the central nervous system (for alertness). Dopamine maintains smooth movements and steady posture. Endorphins and enkephalins act as natural painkillers. Epinephrine and norepinephrine maintain wakefulness and alertness and mediate fight-or-flight responses. Epinephrine tends to act as a hormone, and norepinephrine tends to act more classically as a ne...
• The endocrine system is tied to the nervous system through the hypothalamus and the anterior pituitary, along with a few other hormones. Cortisol: stress hormone released by the adrenal cortex. Testosterone and estrogen mediate libido; testosterone also increases aggressive behavior. Both are released by the adrenal cortex. The testes also produce testosterone. The ovaries also produce estrogen. Epinephrine and norepinephrine are released by the adrenal medulla and cause physiological changes associated with the sympathetic nervous system.
• The nervous system develops through neurulation, in which the notochord stimulates overlying ectoderm to fold over, creating a neural tube topped with neural crest cells. The neural tube becomes the central nervous system (CNS). The neural crest cells spread out throughout the body, differentiating into many different tissues (PNS).
• (Primitive reflexes) The rooting reflex: the infant turns her head toward anything that brushes the cheek. In the Moro reflex, the infant extends the arms, then retracts them and cries due to a sensation of falling. In the Babinski reflex, the big toe is extended and the rest fan in response to the brushing of the sole of the foot. In the grasping reflex, the infant grabs anything put into their hand.
• Developmental milestones give an indication of what skills and abilities a child should have at a given age. Gross and fine motor abilities progress head to toe and core to periphery. Social skills shift from parent-oriented to self-oriented to other-oriented. Language skills become increasingly complex.
• Sensation is the conversion of physical, electromagnetic, auditory, and other information from the internal and external environment into electrical signals in the nervous system. Sensory receptors: nerves that respond to stimuli and trigger electrical signals. Sensory ganglia: collections of cell bodies outside the central nervous system. Sensory stimuli are transmitted to projection areas in the brain, which further analyze the sensory input. E.g., photoreceptors, nociceptors. Perception is the processing of sensory information.
• A threshold is the minimum stimulus that causes a change in signal transduction. The absolute threshold is the minimum of stimulus energy that is needed to activate a sensory system. The threshold of conscious perception is the minimum of stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness. The difference threshold or just-noticeable difference (jnd) is the minimum difference in magnitude between two stimuli before one can perceive this difference.
• Signal detection theory refers to the effects of nonsensory factors, such as experiences, motives, and expectations, on perception of stimuli. Signal detection experiments allow us to look at response bias. In a signal detection experiment, a stimulus may or may not be given, and the subject is asked to state whether or not the stimulus was given. There are four possible outcomes: hits, misses, false alarms, or correct negatives.
• The visual pathway starts from the eye, then travels through the optic nerves, optic chiasm, optic tracts, lateral geniculate nucleus (LGN) of the thalamus, and visual radiations to get to the visual cortex. The optic chiasm contains fibers crossing from the nasal side of the retina (temporal visual fields) of both eyes. The visual radiations run through the temporal and parietal lobes. The visual cortex is in the occipital lobe.
• Vision is processed through parallel processing: the ability to simultaneously analyze and combine information regarding color, shape, and motion. Color is detected by cones. Shape is detected by parvocellular cells, with high spatial resolution and low temporal resolution. Motion is detected by magnocellular cells, with low spatial resolution and high temporal resolution.
• The ear is divided into the outer, middle, and inner ear. The outer ear consists of the pinna (auricle), external auditory canal, and tympanic membrane.
• The auditory pathway starts from the cochlea and travels through the vestibulocochlear nerve and medial geniculate nucleus (MGN) of the thalamus to get to the auditory cortex in the temporal lobe. Sound information also projects to the superior olive, which localizes the sound, and the inferior colliculus, which is involved in the startle reflex. Sound wave-induced vibration of hair cells generates tension within the cell membrane that directly activate ion channels responsible for auditory signaling. This is a mechanically-gated channel: it creates a depolarizing current within the cell.
• Smell is the detection of volatile or aerosolized chemicals by the olfactory chemoreceptors (olfactory nerves) in the olfactory epithelium. The olfactory pathway starts from the olfactory nerves and travels through the olfactory bulb and olfactory tract to get to higher-order brain areas, such as the limbic system. Pheromones are chemicals given off by animals that have an effect on social, foraging, and sexual behavior in other members of that species.
• Taste is the detection of dissolved compounds by taste buds in papillae. It comes in five modalities: sweet, sour, salty, bitter, and umami (savory).
• Somatosensation refers to the four touch modalities: pressure, vibration, pain, and temperature. Pacinian corpuscles: respond to deep pressure and vibration. Meissner corpuscles: respond to light touch. Merkel cells: respond to deep pressure and texture. Ruffini endings: respond to stretch. Free nerve endings: respond to pain and temperature. Nociceptors are responsible for pain perception.
• Kinesthetic sense (proprioception) refers to the ability to tell where one’s body is in three-dimensional space.
• Bottom-up (data-driven) processing refers to recognition of objects by parallel processing and feature detection. It is slower, but less prone to mistakes. Top-down (conceptually driven) processing refers to recognition of an object by memories and expectations, with little attention to detail. It is faster, but more prone to mistakes. Perceptual organization refers to our synthesis of stimuli to make sense of the world, including integration of depth, form, motion, and constancy.
• Gestalt principles are ways that the brain can infer missing parts of a picture when a picture is incomplete. The law of proximity: elements close to one another tend to be perceived as a unit. The law of similarity: objects that are similar appear to be grouped together. The law of good continuation: elements that appear to follow the same pathway tend to be grouped together. Subjective contours refer to the perception of nonexistent edges in figures, based on surrounding visual cues. The law of closure: when a space is enclosed by a group of lines, it's perceived as complete.
• To a psychologist, learning refers specifically to the way in which we acquire new behaviors. Habituation is the process of becoming used to a stimulus. Dishabituation can occur when a second stimulus intervenes, causing a resensitization to the original stimulus. Associative learning is a way of pairing together stimuli and responses, or behaviors and consequences.
• In classical conditioning (IVAN PAVLOV), an unconditioned stimulus that produces an instinctive, unconditioned response is paired with a neutral stimulus (signaling stimuli). With repetition, the neutral stimulus becomes a conditioned stimulus that produces a conditioned response. Acquisition: refers to the period when the stimulus comes to evoke the conditioned response. Extinction: If the conditioned stimulus is presented without the unconditioned stimulus enough times, the organism can become habituated to the conditioned stimulus. Spontaneous Recove...
• In operant conditioning (B.F. SKINNER), behavior is changed through the use of consequences. Reinforcement increases the likelihood of a behavior. Negative reinforcers can be subdivided into escape learning and avoidance learning; differ in the timing of the unpleasant stimulus. Escape Learning: the role of the behavior is to reduce the unpleasantness of something that already exists. Avoidance learning: meant to prevent the unpleasantness of something that has yet to happen. Punishment decreases the likelihood of a behavior; positive vs negative punishment.
• Encoding is the process of putting new information into memory. It can be automatic or effortful (controlled). There are a few different ways that we encode the meaning of information that requires controlled processing. We can visualize it (visual encoding), store the way it sounds (acoustic encoding), or put it into a meaningful context (semantic encoding). Semantic encoding is stronger than both acoustic and visual encoding. Self-Reference Effect: putting information against the context of our lives.
• The brain organizes ideas into a semantic network, in which concepts are linked together based on similar meaning, like an online encyclopedia wherein each page includes links for similar topics. When one node of our semantic network is activated, such as seeing the word red on a sign, the other linked concepts around it are also unconsciously activated; spreading activation. Spreading activation is at the heart of a retrieval cue known as priming, in which recall is aided by first being presented with a word or phrase that is close to the desired semantic memory.
• Source-monitoring error involves confusion between semantic and episodic memory: a person remembers the details of an event, but confuses the context under which those details were gained.
• Both learning and memory rely on changes in brain chemistry and physiology, the extent of which depends on neuroplasticity, which decreases as we age.
• Long-term potentiation, responsible for the conversion of short-term to long-term memory, is the strengthening of neuronal connections resulting from increased neurotransmitter release and adding of receptor sites.
• COGNITION Thought is more than just that of which we are conscious. The brain processes and makes decisions about the importance of various stimuli below the level of conscious awareness.
• The information processing model states that the brain encodes, stores, and retrieves information much like a computer. Paivio's Dual-Coding Theory: states that both verbal association and visual images are used to process and store information. The information processing model has four key components, or pillars: Thinking requires sensation, encoding, and storage of stimuli. Stimuli must be analyzed by the brain (rather than responded to automatically) to be useful in decision making. Decisions made in one situation can be extrapolated and adjusted to help solve n...
• COGNITIVE DEVELOPMENT Cognitive development is the development of one’s ability to think and solve problems across the life span. The ability to think abstractly develops over the life span. Early cognitive development is limited by brain maturation. Culture, genes, and environment also influence cognitive development. Lev Vygotsky: proposed that the engine driving cognitive development is the child’s internalization of his or her culture, including interpersonal and societal rules, symbols, and language.
• Piaget’s stages of cognitive development are sensorimotor, preoperational, concrete operational, and formal operational. 0-2 years: The sensorimotor stage focuses on manipulating the environment to meet physical needs through circular reactions. Object permanence ends this stage: the understanding that objects continue to exist even when out of view. Object permanence marks the beginning of representational thought: the child has begun to create mental representations of external objects and events. 2-7 years: The preoperational stage focuses on symbolic...
• Aging brings many changes in cognition. Reaction time increases steadily in early adulthood, and time-based prospective memory—the ability to remember to perform a task at a specific time in the future—also declines with age. A mild level of cognitive decline while aging is normal; significant changes in cognition may signify an underlying disorder. Fluid intelligence consists of problem solving skills, while crystallized intelligence is more related to use of learned skills and knowledge. Biological factors that affect cognition include brain disorders, gene...
• Problem solving requires identification and understanding of the problem, generation of potential solutions, testing of potential solutions, and evaluation of results. A mental set is a pattern of approach for a given problem. An inappropriate mental set may negatively impact problem solving. Functional fixedness is the tendency to use objects only in the way they are normally utilized, which may create barriers to problem solving.
• Trial-and-error: less sophisticated type of problem solving; various solutions are tried until one that works is found.. An algorithm: a formula or procedure for solving a certain type of problem, mathematical or a set of instructions, designed to automatically produce the desired solution. Deductive (top-down) reasoning: starts from a set of general rules and draws conclusions from the information given; e.g., a logic puzzle. Inductive (bottom-up) reasoning: seeks to create a theory via generalizations. This type of reasoning starts with specific instances, and then d...
• Heuristics are shortcuts used to make decisions. Availability heuristic: when we try to decide how likely something is. Representativeness heuristic: categorizing items on the basis of whether they fit the prototypical, stereotypical, or representative image of the category. Base Rate Fallacy: Using prototypical or stereotypical factors while ignoring numerical information. Biases exist when a decision maker is unable to objectively evaluate information. Confirmation bias: the tendency to focus on information that fits an individual’s beliefs, while re...