PSY 101 Chp.4-7

2/4/25

Chapter 4: Sensation & Perception

Sensation: The process of receiving, converting, and transmitting raw sensory info from the external and internal environment to the brain. (Occurs in sensory organs ie. eyes)

Perception: Making sense of sensory info by selecting, organizing, and interpreting it. (Occurs in the brain

What are the Human Sensory Processes

• Audition (Hearing)

• Vision

• Olfaction (Smell)

• Gustation (Taste)

• Somatosenses:

Tactile Sense (touch)

Vestibular (balance)

Kinesthesis (movement)

How do sensory organs communicate w/ the CNS?

• Transduction: THe process by which sensory receptors convert stimulus into neural impulses (Specific receptors stimulate specific neurons in the CNS)

• The brain decodes this info by the frequency of neuron firing, the type of neuron being stimulated, and the physical location of the neuron being stimulated.

*Sense of smell and taste can activate the amygdala and hippocampus, which is involved in memory recall, allowing us to attach certain sensory input to memories.

*In the case of reflexes we’ll have a motor response before the third step of making sense of the info occurs.

Absolute Threshold: Minimum amount of a stimulus that an observer can reliably detect. Ex. One teaspoon of sugar in 2 gallons of water or the tick of an old-fashioned watch at 20 feet.

Difference Threshold: The minimum difference required to notice a stimulus change; aka “just noticeable difference”. Asks the question of at what point do we notice there’s been a change? Ex. A room smells like perfume. At what point will you notice if the smell is stronger or weaker than before?

Reducing Sensory Info (Brain-Based)

Sensory Reduction:

• Analyze and filter incoming sensations before sending a neural message to the cortex.

• Reduction done by the reticular formation (decides if the stimulus is high enough in priority to be brought to the attention of the conscious part of the brain).

Selective Attention:

• Attending only to important sensory info by filtering out said info that is interpreted to be unimportant.

• This is done by the frontal lobe

Sensory Adaptation (aka Neural Adaptation):

• Repeated or constant stimuli decreases the number of sensory messages sent to the brain causing decreasing sensation, (Ex. After a while you don’t notice the clothes you’re wearing on your body.)

• The stimuli entering sensory organs remains the same amount, but the number of messages sent to the CNS decreases.

• Occurs in parts of the brain responsible for interpreting these stimuli.

Reducing Sensory Info (Sensory-Organ Based)

Habituation:

• Pattern of decreased response to stimuli after frequent, repeated exposure.\

• Reduced response to something that used to elicit a stronger response.

• Occurs in the body at the location of the sensory organ.

• Ex. The more often you eat spicy foods, the less spicy some things are to you, therefore increasing your spice tolerance.

Vision

Stimulus: Light Waves

• We see only a small part of the light spectrum (visible spectrum ROYGBIV).

• The color we see depends on the wavelength (long=red short=blue and vice-versa w/ frequency).

• Wave amplitude = the color’s brightness. (Higher amplitude = brighter color)

• Complexity = Purity of color (seeing primary vs. secondary colors)

(Can People In Lansing Rely On Foot Doctors)

• Lens: Elastic structure behind the pupil that thins to see farther structures and thickens to see closer structures. It’ll focus the image onto the retina. (It’ll reverse the image left to right and bottom to top, the brain will put it back into its original orientation.)

• Retina: Contains light-sensitive photoreceptors (rods and cones). 

• Optic Nerve: The collection of photoreceptors.

• Fovea: Contain only cones.

• Optic Disk: The location in the retina where the optic nerve exits the eyeball producing a blind spot. (The brain will create or “fill in” that blind spot/ignore it.)

Cones;

• Transduce info about color and fine delta, and are concentrated in the center of the fovea.

• A type of photoreceptor cell.

Rods:

• Transduce info about black, white, and gray and are the periphery/line the outer circle of the fovea.

• A type of photoreceptor cell.

How do feature detectors work?

• Groups of cells/specialized neurons in the brain that only respond/are stimulated by specific features.

• Three elements processed first form info from the retina. The form, motion, and color of what’s in front of us.

• Other parts of the cortex reconstruct the visual image from this info.

• Retina —>Thalamus—> Occipital Lobes and associated structures.

Trichromatic Theory:

States that there are three types of cone receptors (red, blue, and green) in the retina that are sensitive to different but overlapping wavelengths of light.

Audition (Hearing)

• The auditory system transduces the physical air changes to hear sounds.

Outer Ear: Consists of the pina (ear lobe), auditory canal, and tympanic membrane (eardrum).

Middle Ear: Ossicles (hammer, anvil, and stirrup) are tiny bones that amplify the vibrations from the tympanic membrane.

Inner Ear: 

• Senses sound and where our head is positioned in space

• Consists of the cochlea (little hair cells that are the receptors to the vibrations) and the auditory nerves (relays stimulus to thalamus then auditory cortex in temporal lobe.)

Sound Localization:

We know where sounds are coming from based on which ear the sound hits first. Ex. If a dog barks on our left we know it’s on our left because the sound is louder in our left ear than our right. (Sound Shadow) (We have trouble placing sound directly above, behind, or in front of us because it hits our ears at the same time with the same intensity.)\

How Do We Perceive Pitch?

Place Theory

Different locations on the cochlea(certain hairs) are stimulated by different pitches.

Frequency Theory

Pitch is sensed based on the firing rate of the auditory nerve. (Higher pitch = higher firing rate and vice-versa)

• Frequency theory is true for lower pitches/low frequency sounds and the Place theory is true for higher frequency sounds.

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How do we perceive info?

Bottom-Up Processing:

Taking sensory info and then assembling and integrating it. 

Top-Down Processing:

Using models, ideas, and expectations to interpret sensory info. 

• Priming; Means that prior info will alter what we expect to perceive. Ex. If I sing Old Mcdonald had a farm and ask you for a three letter word that begins with C you’ll think of cow.

• Demonstrating the context in which we receive info also changes what we perceive.

*Conscious perception of info uses both bottom-up and top-down processing to coordinate our understanding of sensory info.

Gestalt Principles of Organization

Perceptual Parsing

• Our visual system divides everything we see into components, a process called perceptual parsing.

• The most important aspect of this is dividing what we see into the figure and ground theory.  A principle that describes how we separate figures from their background.

Forms of Perceptual Grouping

Proximity: Elements that are near each other tend to be perceived as part of the same configuration

Similarity: When parts of a configuration are perceived to be similar, they will be perceived as belonging together

Closure: People perceive objects as being whole when they aren’t complete.

Continuity: People link elements together that form a continuous pattern that makes sense.

Critical Visual Features for Perception

1. Depth Perception

• Allows us to see things in three-dimensions.

• Depth perception is primarily learned through experience.

• Monocular Cues: Visual input from one eye allowing us to see depth or distance using lights and shadows, linear perspectives(vanishing point in distance w/ lines), and motion parallax (observer is moving and object is stationary), 

• Binocular Cues: Visual input from both eyes allowing us to see depth or distance using retinal disparity (difference in image seen from one eye to the next) and convergence (eyes drawing closer/crossing for close images and farther for images further away).

2. Constancy

• The ability to retain an unchanging perception of an object despite the sensory input that is being received.

• Despite the sensory input we tend to perceive constancy of size, shape, and brightness. Ex. When I think of an orange I know it’s the same size, shape, and color hue in front of me as it is 20ft away from me.

3. Motion

2/11/25

Chapter 5: States of Consciousness

Consciousness: an individual’s awareness of external events and internal sensations under a condition of arousal, including awareness of the self and thoughts about one’s experiences. (An organism’s awareness of its own self and surroundings). 

• It’s critical for having varying levels of consciousness because if we had to do everything with the same level of attention and thinking the productivity and effectiveness of the task would lower. (Ex. Riding a bike. Initially learning it was very hard, but now you can ride one without thinking which allows you to notice more the scenery around you.)

Arousal: Is a physiological state of being engaged with the environment. (Uses the reticular formation, brain stem, medulla, and thalamus to determine state of arousal or wakefulness.)

Altered Consciousness: Mental states that aren’t waking that can be found during sleep/dreaming, hypnosis, drugs, or some mental disorders.

Subconscious Awareness: Occurs when we have low levels of consciousness of the outside world. Involves waking, incubation (the idea our brain works on a problem after we’re no longer consciously thinking about it to find a solution), parallel processings, sleep, and dreams. Basically processes that occur that do not interfere with our awareness.

No Awareness: Unconscious processes such as associative learning. (***Freud believes we have unconscious thoughts that direct our behavior.***)

Circadian Rhythms

• Are daily biological cycles that are about 24 hours long. This is regulated by the suprachiasmatic nuclei (SCN).

• Effected by day-night cycle, metabolism, what we eat, jet lag, irregular schedules, etc.

• Examples of circadian rhythms are sleep, menstrual cycle, body warmth, and eating.

Example of SCN role in melatonin cycle to regulate how awake/sleepy we are.

Sleep

• A state marked by low physical activity and a reduced sense of awareness.

• Controlled by the thalamus and hypothalamus (slow-wave sleep) and the pons (REM).

• Sleep is associated with secretion and regulation such as melatonin. FSH, luteinizing hormone, growth hormones, and cortisol.

• Induces paradoxical paralysis, which means our body is in a state where it’s relatively paralyzed so we don’t act out our dreams in our sleep.

(Come back and list role of each structure in sleep)

Why Do We Sleep?

Evolutionary Theory: Occurred to conserve energy and as a protection from predators.

Growth/Development Theory: Sleep is correlated with physical development.

Repair/Restoration Theory: Sleep allows us to repair or replenish key factors.

Learning/Memory Theory: It’s important for learning and consolidation, enhances synaptic connections, and maintenance of memory.

We do have evidence to suggest all of these theories are correct to a degree.

Stages of Sleep

1. REM (Rapid Eye Movement)

• Marked by REM, high-frequency brain waves, paralysis of large muscles, and dreaming.

• Important for learning and memory consolidation.

2. NREM (Non-REM)

• Stages 1-4 of sleep.

• NREM needs to occur before REM.

*This cycle repeats for the duration of sleep

*Sleep needs change as we age, generally in the pattern of we need less hours the older we are.

Freud

Manifest Content: The surface level appearance of a dream. Symbols

Latent Content: The actual meaning of the dream or hidden content.

2/18/25

Chapter 6: Learning

Types of Learning:

1. Associative Learning

• Classical Conditioning

• Operational Conditioning

2. Observational Learning

Learning: A systematic, relatively permanent change in behavior or mental processes that occurs through experience. 

What is learned can be unlearned

Classical Conditioning

Definition: A learning process in which a neutral stimulus becomes associated with an innately meaningful stimulus (ex. food) and eventually the neutral stimulus elicits the same response as the innately meaningful stimulus even if the innately meaningful stimulus is not present.

Phenomena:

• Acquisition: The initial learning/pairing of the unconditioned stimulus(US) with the neutral/conditioned stimulus(CS).

• Extinction: Occurs when the CS is presented enough times without the US resulting in the gradual loss of the conditioned response (CR) (over time).

• Spontaneous Recovery: Reappearance of previously extinguished response.

• Generalization: When a stimulus similar to the in some way elicits a similar CR. (Ex. A tone was used to elicit the salivation of Pavlov’s dogs. If the dogs also salivated to the tone/ding of a bell then that is an example of generalization.)

• Discrimination: CR occurs for one stimulus but not another. (Ex. The dogs salivate for the tone of a bell, but not for the sound of a text.)

• Renewal: Recovery of the CR when the organism is placed in a novel context.

Notable Figures

Ivan Pavlov (Classical Conditioning)

BF Skinner

• Believed that to understand behavior we should only look at observable, external, or environmental stimuli and responses. Does not consider what the organism feels or wants.

• According to Skinner organisms act/operate on the environment.

Operational Conditioning

Definition: A form of associative learning in which behavior is influenced by consequences (occur after the behavior and could be an award or punishment)  to influence the probability of the behavior’s recurrence (making the behavior more or less in the future).

Thorndike’s Law of Effect

1. Reinforced acts are strengthened and increase in intensity or frequency.

2. Punished acts are weakened and decrease in intensity or frequency.

Shaping: Reinforcing or rewarding successive approximations towards a complex desired action.(Ex. With Skinner’s box the rat may be rewarded for getting closer and closer to the pedal and then only rewarded when it hits the lever/pedal.)

Schedules of Reinforcement

Once a behavior is acquired, reinforcement can be applied in a variety of ways which can be used to promote learning and behavior.

1. Fixed Ratio: Reinforcement given after a fixed number of responses.

2. Variable Ratio: Reinforcement is given after a variable number of correct responses, usually centered around an average.

3. Fixed Interval: Reinforcement given after a fixed amount of time since last response.

4. Variable Interval: Reinforcement is given after a variable amount of time since the last response, usually centered around an average.

Observational Learning

Means learning a behavior/how to do something by watching someone else do it first

Steps.

1. Paying attention to someone performing the behavior

2. Retaining the behavior performed

3. Physically try to replicate the behavior

4. Motivate to display the behavior through reinforcement

2/25/25

Chapter 7: Memory

What Do We Study with Memory?

• How do we process and store information?

• Are there different types of memory?

• How do we remember?

• Why do we forget?

Memory: Is the retention of information and experience over time. A process to encode, store, and retrieve information over different periods of time.

Steps to making a memory:

1. Encoding - The input of information into the memory system.

2. Storage - The retention of the encoded information in different places of the brain.

3. Retrieval - The process of getting information out of storage and bringing it to awareness. AKA remembering something.

Encoding

Definition: When the brain receives info from the environment and tries to process it by labelling it, organizing with other similar info, and connecting the new concepts to ones that already exist in our brain.

Types of Encoding Processing:

Automatic Processing - Encoding details like time, space, frequency, and meaning of words. Usually done without conscious awareness. (Ex. Knowing when you last studied.)

Effortful Processing - Encoding of details that takes time and effort. Usually done with conscious awareness. (Ex. Knowing what you last studied.)

Contributing Factors:

Attention mainly affects what and when something is encoded and the type of attention affects this even more.

Selective Attention - The person chooses what they pay attention to. Paying more or less attention to something will affect it being encoded. (Ex. If in class you pay more attention to your phone than you’re less likely to encode the content of the lecture and vice-versa.)

Divided Attention - Often occurs when people are multi-tasking. Typically leads to worse performance on all tasks than doing them one at a time.

Sustained Attention - Means paying great attention to one thing for an extended period of time (vigilance). Highly likely what is being focused on will be encoded.

Types of Encoding:

1. Semantic Encoding 

• The encoding of words and their meaning.

• Involves a deeper level of processing.

• Attaching meaning to information makes it easier to recall later.

2. Visual Encoding

• Words that create a mental image aka concrete words (Ex. car or banana) are easier to recall later than abstract words (Ex. truth or value) because there’s an image and word associated with it providing two access points for retrieval instead of just one when you only have words.

3. Acoustic Encoding

• Encoding of sounds.

Notes:

• Memory is a constructive process (meaning it’s made up of different things that were significant to you in that moment, resulting in memory not being like a video camera.)

• Memory is highly fallible.

• Self-Reference Effect: The tendency of an individual to have better memory for info related to themselves than to material that has less personal relevance.

Storage: Atkinson-Shiffrin Model of Memory

Storage: The retention over time and how this info is represented in memory.

Atkinson-Shiffrin Model:

• Memory passes through three distinct stages in order for it to be stored in long-term memory.

• Based on the belief the memory is processed in the same way that computers process info.

Types of Memory

1. Sensory Memory

• Sub-divided into iconic and echoic memory.

• Iconic Memory: Stores visuals for up to 1 second

• Echoic Memory: Stores sounds for up to 4 seconds.

• Stroop Effect:

2. Short-Term Memory

• Temporary storage system that processes incoming sensory memory that last 20-30 seconds and remembers 7 +/- 2 bits of info.

• Working Memory: Combines short-term and attention, allowing people to hold info temporarily as they perform cognitive tasks.

• After 20-30 seconds these memories are either discarded or move into long-term. Memory consolidation is the transfer of short-term memories to long-term ones.

• Rehearsal: The conscious repetition of info to be remembered in short-term memory. (Mostly done by repeating something aloud.)

3. Long-Term Memory

Explicit (Declarative) Memory: The conscious recollection of info, such as facts or events. It has two sub categories.

1. Semantic Memory: Everyday knowledge about the world (Ex. We drive on the right in the US.) This memory is independent of where or when the individual learned it.

2. Episodic Memory: Retains info on where, when, and what’s happening for life events. (Ex. How you celebrated your 10th birthday). AKA autobiographical memory.

Implicit (Non-declarative) Memory: Memory in which behavior is affected by prior experience without a conscious recollection of that experience. Has three sub-types.

1. Procedural: Memory for skills (Ex. Riding a bike or how to tie your shoes.)

2. Classical Conditioning: CR to CS.

3. Priming: The activation of info people already have in storage to help them remember new info better and fast. (Connects previous knowledge in order to learn new concepts.)

Retrieval

Definition: The memory process that occurs when info that was retained in memory comes out of storage.

Ways to Retrieve Info

1. Recall: Being able to access information without cues. (Ex. Answering essay questions.)

2. Recognition: Being able to ID info that you’ve learned previously after you’ve encountered it again. (Ex. Answering a multiple-choice question.)

3. Relearning: Learning info you’ve previously learned again. (Ex. You learned Spanish in highschool and haven’t used it in years. When you go to relearn it though you’ll learn it faster than the first time.)

Primacy/Recency Effect: People remember info better that they hear first and last. Therefore the middle of the list is often forgotten. (*Recency effect is diminished if there’s a delay such as a 30 second pause between when info is learned and when participant is asked to recall.)

Chunking: We can hold more info than the usual 7 +/- 2 if we group or “chunk” the smaller bits of info together into larger more meaningful pieces. (Changing 21 pieces of info into 7 or 8.)

Depth of Processing: The deeper you process something the more likely you are to remember. Ex. You’re more likely to remember a word you wrote in a sentence (deep processing) than if you were just asked how many letters were in the word (shallow processing).

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Brain Structures & Memory

Amygdala: Enhances the formation of a memory by associating it with a strong emotional experience.

Basal Ganglia & Cerebellum: Creation and storage of basic memory and implicit memory (skills).

Hippocampus & Surrounding Area: Holds explicit and implicit LTM and the sequences of events. It activates the areas of the brain associated with a memory

Thalamus: Formation of new, spatial, working, explicit, and implicit memory

Cerebral Cortex: Responsible for the encoding, storage, and retrieval of explicit and implicit memories.

Learning and memory modifies and changes our neural networks and brain structures.

Long-Term Potentiation (LTP)

Definition: A biological mechanism for learning and memory that is a long-lasting increase in neural excitability (ability to activate neuron) . This change in neural excitability happens in one of two ways.

1. Repeated Stimulation of a Synapse

Repeated stimulation causes a neuron to grow more spines on dendrites therefore creating more sites/receptors for it to uptake neurotransmitters and therefore the neuron is more sensitive to the amount of neurotransmitters.

2. Change in the Amount of Neurotransmitter Released

More neurotransmitters are released for the same signal than previously, resulting in increased message transmission efficiency.

Neurotransmitters Involved in Memory

• Acetylcholine

• Epinephrine

• Serotonin

• Dopamine

Arousal Theory: Stronger emotions trigger the formation of stronger memories (stronger emotions release more neurotransmitters strengthening memories) and weaker emotional experiences form weaker memories.

Forgetting & Amnesia

Can occur by encoding failure or failure to retrieve information.

Forgetting Types:

1. Transience - Info fades away from LTM over time if it’s not accessed frequently. (Ebbinghaus forgetting curve.)

2. Absentmindedness - Forgetting caused by lapses in attention

3. Blocking - Access to info is temporarily blocked (tip-of-tongue phenomenon)

Bias Affecting Memory (Dr. Shacter)

Your feelings and/or view of the world can distort your memory of past events.

Stereotypical Bias: Involves racial and gender bias

Egocentric Bias: Involves enhancing memories of the past (viewing yourself in a way that makes you look better)

Hindsight Bias: The tendency to think an outcome was inevitable after the fact

***All of these biases distort our memory of past events according to our beliefs, demonstrating again that memory is constructive.***

Interference

The failure to retrieve information

Proactive Interference: Info you’ve learned previously makes it harder to recall info you’ve learned recently.

Retroactive Interference: Info you’ve learned recently makes it hard to recall info you’ve learned previously.

Amnesia

The loss of LTM due to physical trauma, emotional trauma, or disease.

Anterograde Amnesia: Inability to remember new information after the point of trauma occurrence. (Won’t remember things from after an accident, but you would know your life from before it.)

Retrograde Amnesia: The loss of memory (partially or completely) for events that occurred before the point of trauma.