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The Biological Perspective
NERVOUS SYSTEM
SOMATIC NERVOUS SYSTEM
● Soma = body
Somatic nervous
system
Division of the PNS consisting of nerves that carry information from the senses to the CNS and from the CNS to the voluntary muscles of the body.
Sensory
pathway
Nerves coming from the sensory organs to the CNS consisting of sensory neurons. ● sight (vision) ● sound (hearing) ● smell (olfaction) ● taste (gustation) ● touch (tactile perception)
Motor pathway Nerves coming from the CNS to
the voluntary muscles, consisting of motor neurons.
PEEKING INSIDE THE BRAIN
CLINICAL STUDIES
● Deep lesioning - insertion of a thin, insulated wire into the brain through which an electrical current is sent that destroys the brain cells at the tip of the wire. ● Electrical stimulation of the brain (ESB) - milder electrical current that causes neurons to react as if they had received a message. HUMAN BRAIN DAMAGE ● Electroencephalography (EEG) - machine designed to record the brain wave patterns produced by the electrical activity of the surface of the brain. ● Computed tomography (CT) - brain-imaging method using computer controlled x-rays of the brain. ● Magnetic resonance imaging (MRI) - brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain. ● Functional MRI (fMRI) - computer makes a sort of “movie” of changes in the activity of the brain using images from different time periods. PARTS OF CORTEX CONTROLLING SENSES AND MOVEMENTS NAV | 1
The Biological Perspective
CEREBRAL HEMISPHERE
● Cerebral Hemisphere - two sections of the cortex on the left and right side of the brain. ● Corpus Callosum - thick band of neurons that connects the right and left cerebral hemisphere. MAJOR STRUCTURES OF THE BRAIN ● Pituitary gland - Regulates other endocrine glands ● Cerebral cortex - Controls complex thought processes Temporal lobes Areas of the cortex located just behind the temples containing the neurons responsible for the sense of hearing and meaningful speech. ● Primary auditory cortex - processes auditory information from the ears. ● Auditory association cortex- identifies and makes sense of auditory information Frontal lobes Areas of the cortex located in the front and top of the brain, responsible for higher mental processes and decision making as well as the production of fluent speech. ● Motor cortex - section of the frontal lobe located at the back, responsible for sending motor commands to the muscles of the somatic nervous system. Occipital lobe Section of the brain located at the rear and bottom of each cerebral hemisphere containing the visual centers of the brain. ● Primary visual cortex- processes visual information from the eyes. ● Visual association cortex - identifies and makes sense of visual information. Parietal lobes Sections of the brain located at the top and back of each cerebral hemisphere containing the centers for touch, taste, and temperature sensations. ● Somatosensory cortex - area of neurons running down the front of the parietal lobes responsible for processing information from the skin and internal body position, and possibly taste.
The Biological Perspective
STRUCTURES UNDER THE CORTEX
● Limbic System - A group of several brain
structures located under the cortex and involved in learning,emotion, memory, and motivation.
Thalamus
Part of the limbic system located in the center of the brain, this structure relays sensory informations from the lower part of the brain to the proper areas of the cortex and processes some sensory information before sending it to its proper area.
Olfactory bulbs
Two projections just under the front of the brain that receive information from the receptors in the nose located just below.
Hypothalamus
Small structure in the brain located below the thalamus and directly above the pituitary gland, responsible for motivational behavior such as sleep, hunger, thirst, and sex. ● Sits above and controls the pituitary gland (master endocrine gland)
Hippocampus
Curved structure located within each temporal lobe, responsible for the formation of long-term memories and the storage of memory for locations of object.
Amygdala Brain structure^ located near the
hippocampus, responsible for fear responses and memory of fear
The Nervous System
THE CENTRAL NERVOUS SYSTEM The Brain The Spinal Cord 2 Major parts of the CNS ● The Brain ● The Spinal Cord 6 Main Sections ● Cerebrum ○ Divided into 2 hemispheres, right and left hemispheres. ○ Further divided into Four Lobes: ○ Frontal - reasoning and thought. ○ Parietal - Integrates sensory information ○ Temporal - processes auditory information from the ears. ○ Occipital - processing visual information from the eyes. ● Cerebellum ○ Located below the cerebrum and above the 1st cervical of the neck. ○ Responsible for: Muscle Coordination , Balance P Posture, Muscle Tone ● Diencephalon ○ Located between the cerebrum and the mid brain and contains two structures ○ Thalamus - directs sensory impulses to the Cerebrum ○ Hypothalamus - control and regulates temperature, appetite, water balance, sleep, and blood vessel constriction and dilation. ○ Also plays a role in emotion such as: Anger, Fear, Pleasure, Pain, and Affection ● Midbrain ○ Located below Cerebrum at the top of the brain stem ○ Responsible for eye and auditory reflexes ● Pons ○ Located below the midbrain (in Brainstem) ○ Responsible for certain reflex action ● Medulla Oblongata ( The Center for Respiration) ○ Located at the bottom of the brainstem ○ Connects to the spinal cord ○ Regulates heart and blood vessel function, digestion, respiration, swallowing, coughing, sneezing, and blood pressure. ○ The link between the brain and the nerves in the rest of the body. 4 Regions ● Cervical ● Thoracic ● Lumbar ● Spinal Nerves ○ Afferent: carries information from the body to the brain ○ Efferent: carries information from the brain to the body ● Peripheral Nervous System ○ Somatic Nervous System- responsible for carrying motor and sensory information to and from CNS.
- It is made up of nerves that connect to skin, sensory organs, and skeletal muscles
- Is responsible for nearly all voluntary **muscle movements
- Processes** sensory information from external stimuli. (Hearing, Touch, and Sight) ● Afferent neurons take information from the nerves to the CNS ● Efferent neurons take information from the CNS to the muscle fibers throughout the body The Autonomic Nervous System Sympathetic Nervous System Parasympathetic Nervous System “Fight or Flight” revs up the body to either defend yourself or escape the threat Brings all systems of the body back to normal
The Memory
DETERMINING THE ABSOLUTE THRESHOLDS ● When a stimulus has less energy than absolute thresholds, we cannot detect its presence, more energy, we can. (ex: wrist watch that ticks [ 20ft at 50% of the time; 25ft at 38% of the time) ● People have different thresholds because people have better hearing than others and some have better vision than others. SUBLIMINAL SENSATION ● Subliminal stimuli - stimuli that are below the level of conscious awareness. ○ Just strong enough to activate the sensory receptors but not strong enough for people to be consciously aware of them. ● Limin - “threshold” ● Sublimin - “below the threshold” ● Subliminal perception - process by why subliminal stimuli act upon the unconscious mind, influencing behavior. HABITUATION AND SENSORY ADAPTATION ● Habituation or stimulus boredom - tendency of the brain to stop attending to constant, unchanging information. (ex. unpleasant stimuli - rotting garbage/superb taste of gourmet) ● Sensory adaptation - tendency of sensory receptors cells to become less responsive/less sensitive to a stimulus that is unchanging. PERCEPTION AND CONSTANCIES ● Perception - the method by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion. ● Size constancy - the tendency to interpret an object as always being the same actual size, regardless of its distance. ● Shape constancy - the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina. ● Brightness constancy - the tendency to perceive the apparent brightness of an object as the same even the light conditions change. GESTALT PRINCIPLES ● Figure ground - the tendency to perceive objects, or figures, as existing on a background. ● Reversible figures - visual illusions in which the figure and ground can be reversed. ● Similarity - the tendency to perceive things that look similar to each other as being part of the same group. ● Proximity - the tendency to perceive objects that are close to each other as part of the same grouping. ● Closure - the tendency to complete figures that are incomplete. ● Continuity - the tendency to perceive things as simply as possible with a continuous pattern rather than with a complex, broken-up pattern. ● Contiguity - the tendency to perceive two things that can happen together in time as being related. ● Depth perception - the ability to perceive the world in three dimensions.
The Memory
PERCEPTUAL ILLUSIONS ● Müller-Lyer illusion - illusion of line length that is distorted by inward-turning or outward-turning corners on the ends of the lines, causing lines of equal length to appear to be different. ● Moon illusion - the moon on the horizon appears to be larger than the moon in the sky. ○ Apparent distance hypothesis ● Illusions of Motion: ○ Autokinetic effect - a small, stationary light in a darkened room will appear to move or drift because there are no surrounding cues to indicate that the light is not moving. ○ Stroboscopic motion - seen in motion pictures , in which a rapid series of still pictures will appear to be in motion. FACTORS THAT INFLUENCE PERCEPTION ● Perceptual set (perceptual expectancy) - the tendency to perceive things a certain way because previous experiences or expectations influence those perceptions. ● Top-down processing - the use of pre-existing knowledge to organize individual features into a unified whole. ● Bottom-up processing - the analysis of the smaller features to build up to a complete perception. FACTORS THAT INFLUENCE PERCEPTION APPLYING PSYCHOLOGY ● Extrasensory perception (ESP) - claim of perception that occurs without the use of normal sensory channels is such as sight, hearing, touch, taste or smell. ○ Telepathy - claimed ability to read another person’s thoughts, or mind reading ○ Clairvoyance - supposed ability to “see” things that are not actually present. ○ Precognition - supposed ability to know something in advance of its occurrence or to predict a future event ● Parapsychology - the study of ESP, ghosts, and other subjects that do not normally fall into the realm of ordinary psychology. ATKINSON-SHIFFRIN MODEL OF MEMORY THREE STAGES OF MEMORY
- Sensory Memory
- Short-term Memory (STM)
- Long-term Memory (LTM) ● Stages determine whether and how long information is stored RETRIEVAL ● Locating information and returning it to consciousness ● Retrieval relies on cues
The Memory
SERIAL POSITION EFFECT
● Tendency to recall the first and last items in a series
- May be more attention to first and last items
- May rehearse first item more often and last most recently CHUNKING ● A grouping of stimuli that is perceived as a discrete piece of information ● Number of items held in STM -
- Seven ( plus or minus two)
- Chunking stimuli allows for semantic coding LEVELS OF PROCESSING MODEL OF MEMORY ● Memories endure when processed deeply
- Attention, encoding, strong, retrieval all involved FLASHBULB MEMORIES ● Tend to remember events that are important and emotionally string
- Memories are more distinctive
- Increased networks of association
- Elaborative rehearsal
- Secretion of stress hormones
