Sensation and Perception

A Sense- a system that transmits specific types of information to the brain

A Perception- the way in which we organize, interpret, and give meaning to the raw, neural impulses

Sensation:

Sensory Receptors- specialized cells that respond to particular types of energy

• Photoreceptors (rods and cones in eyes)

• Chemoreceptors

• Mechanoreceptors

Absolute Threshold- the minimum intensity possible of a stimulus that still registers. This is defined as the point in which a very weak signal could be detected 50% of the time.

Just Noticeable Difference- the ability to detect subtle changes in the strength of a stimulus. Defined as the smallest change in a stimulus that a person can detect 50% of the time

Weber’s Law- the size of the JND is a constant proportion of the original stimulus

• ex. Lifting 100lbs and JND is achieved at 102lbs JND= 2lbs or 20%

• 1000lbs would have to increase by 20lbs to reach 20% JND

Parts of the Eye:

• Cornea- covers the eye and bends light into the iris (covers the eye)

• Iris- colored part of the eye that consists of muscles that open and close the pupil

• Pupil- dark center of the iris

• Lens- behind the iris, focuses image onto the retina

• Retina- round screen at back of the eye, contains photoreceptors (rods and cones)

• Rods- do not interpret color, but give night vision, peripheal vision, and detect motion

• Cones- interpret color and are concentrated at the center of the retina, work best in high levels of light

• Optic Nerve- transmits electrical impulses from the eye to the brain

How do we see color? Two theories

Trichromatic Theory- 3 color theory, we see all color as a mixture of red, blue, and green.There are 3 types of cones in the eye, each responding to one of the cones

Opponent/Process Theory- addresses the idea of “after images.” This theory suggests that in addition to the 3 color, we see activity through 2 opponent systems which cause more or less excitement in the neurons (blue/yellow system and red/green system)

Parts of the Ear:

• Ear Drum- thin skin tight membrane, vibrates when hit by sound waves

• Ossicles- malleus, incus, and stape- magnify vibrations and transmit to inner ear

• Cochlea- snail-shaped, fluid filled structure that connects to the auditory nerve\

• Auditory Nerve- carries auditory sensory information from the cochlea to the brain

Smell:

Olefactory Epithelium and olefactory receptors attach to the olefactory nerve which leads to the brain.

• Olefactory Epithelium- membrane at the roof of nasal cavity

• Olefactory Receptors- receptors to various chemicals

Taste:

As much as 75% of what we experience as taste actually comes from smell.

Taste Receptors/Gustatory Cells- located in the taste buds. Specialized and respond to a single taste. Sweet, salty, sour, bitter.

Touch:

Cutaneous Receptors- respond to touch: pressure, shape, texture, movement, temperature

Nociceptors- register pain

Perception:

• Kinesthetic System- part of human physiology that provides each person with sensory awareness of the position and movements of his or her body

• Vestibular System- provides the sense of balance and the information about body position that allows rapid compensatory movements in response to both self-induced and externally generated forces

• Bottom Up Processing- sensory information is gathered by the neurons, sorted and organized along the pathway before getting to the brain

• Top Down Processing- one of the sensory information is received in the Cerebral Cortex, the “higher level” processes, then take that info and combine with past experience, expectations, and emotional states to further process information

• Figure-Ground Processing- when we observe a scene, the parts we pay attention to are the “figure” the rest is the “ground”

• Gestalt (whole) Processing- grouping of the whole to better understand: proximity, similarity, continuity, common fate, closure

• Extrasensory Perception- said to be the ability to perceive outside of the 5 senses

• Paranormal Psychology- study of any phenomena that is not replicable, impossible, not explainable, beyond normal range of experience

Factors in Perception:

• Depth Perception- images on the retina are 2D, but we understand the world in 3D based on various cues

  Monocular Cues- we use physical characteristics of a scene to interpret depth, which includes convergence of parallel lines, relative size, light, and shadow

  Binocular Cues- the shape of our eyes changes when focusing on things close to us or far from eyes that information is relayed to the brain

• Movement- we use cues of movement to help us understand depth and interpret 3D images

• Personal Factors- your worldview affects your perceptions

Motivation and Emotion

Motivation:

An inner state and process that arouses, directs, maintains, and terminates behavior

• Intrinsic- a force from within us

• Extrinsic- a force from outside us

Biological Motivation:

• Instincts- automatic, involuntary, unlearned patterns of behavior that are triggered by particular stimuli

• Drive Reduction Theory- biological needs are the primary motivator to maintain homeostasis (Drives- unpleasant states that spur us into action, the psychological motivator of human behavior)

• Arousal Theory- we are driven to achieve our optimal state of arousal, explains why we do things that aren’t needs ex. people playing sports, climbing mountains, reading books, etc.

Emotions:

• Emotions- experience of emotions are characterized by two components, subjective feelings and physiological responses

• Paul Ekman’s 6 basic emotions- anger, fear, surprise, happy, sad, disgust

• Cognitive Theories of Emotion- emotion is a function of the psychologic response and our interpretation of that response

Stress:

• Stress- a generalized response to a non-specific threat. Can impact psychologically, emotionally, physiologically, and behaviorally.

• Social Readjustment Rating Scale- created by Holmes and Rahe, measures and ranks stress based on “life change units.” Explains the cumulative effect of stress

Learning and Memory

What is Learning?

• Learning- the mental process leading to a relatively permanent change in behavior. There are many theories, but none fully explain how we learn

Behavioral Theory of Learning:

• Classical Conditioning- unconditioned stimulus (UCS) gets an unconditioned response (UCR). When Neutral Stimulus (NS) is paired with UCS, NS becomes a Conditioned Stimulus (CS) that gets a Conditioned Response (CR). Ivan Pavlov

• Classical Conditioning Examples-

  1. A WARM AND NURTURING TEACHER MOTIVATES STUDENTS

  A warm and nurturing teacher (US) makes students feel connected (UR). Students associate going to school (CS) with the teacher. Therefore, students learn to enjoy going to school (CR)​

  2. A HARSH AND STRICT TEACHER DEMOTIVATES STUDENTS

  A harsh and strict teacher (US) makes students feel bad (UR). Students associate going to school (CS) with the harsh teacher and learn to feel bad about going to school (CR).

• Acquisition- the process of learning the Conditioned Response

• Extinction- the reverse of the Acquisition

• Operant Conditionining- B.F. Skinner

Law of Effect- any behavior followed by pleasant consequences tends to be repeated and any behavior followed by unpleasant consequences tends to not be repeated (Edward Thorndike)

Shaping- behavior by reinforcing “successive approximations” of desired behavior

Reinforcement- a consequence of a behavior that increases the likelihood it will occur again

Cognitive Theory of Learning:

• Latent Learning- acquiring new knowledge that is not yet needed and hasn’t been reinforced or punished

• Tolman and Honzik- study of rats and response time going through mazes. Rats with no reward but then who received a reward later, were the fastest

Social Theory of Learning:

We learn from one another through observation, imitation, and modeling

Memory:

• Memory- the process by which information is acquired, encoded,stored, retrieved, and forgotten

• Amnesia- the inability to form or recall memories as result of brain injury or trauma

• Anterograde Amnesia- unable to form memories of events after the brain injury or trauma

• Retrograde Amnesia- inability to retrieve memories of events prior to trauma

• Recall- the retrieval of presently stored information

• Recognition- comparing new information with information stored previously

• Memory Decay- refers to the fading of memories over time

Sensory Memory:

• Located in the brain and receives the input from the sensory neurons

• Holds a large amount of information for a very brief period of time

• Most pieces of information are “forgotten” in less than one second

• Selective Attention- we pay attention to certain sensory info and ignore the rest. Sensory overload is caused by problems with how to select important info and ignore other info.

Short Term Memory

• Often called Primary Memory

• Limited Capacity- only 5-9 “chunks” of info at a time

• Lasts only a few seconds

• The lengths of time can be extended by “rehearsing” information

Long Term Memory:

• Essentially consists of everything you know about the world

• Unlimited capacity and lasts a lifetime unless affected by illness or injury

• Declaritive/Explicit Memory- for facts, figures, dates, and requires conscious effort to encode and retrieve

• Procedural/Implicit Memory- for skills, abilities, routines, and requires practice and repetition to encode, but not to retrieve

• Episodic Memory- memories of single events and are stored in a mental autobiography

• Semantic Memories- memories of concepts, context, and meaning which includes language, your worldview, and understanding of personal relationships

• How Accurate is Long Term Memory?- “memories are mental representations, not reproductions.” Memories are subject to personal factors and environmental influence

• Mis-attribution and Memory Source Confusion- information learned after an event becomes part of the memory of the event