Psych Notes - Midterm 2 Review

Sensation:

-       way our nervous system detects/represents stimulus energies from the environment. Ex a bird detects the mag field

Perception:

-       organization/interpretation of sensory info, one thing to detect changes in light vs a sunset on a beach, separates humans from cameras, Ex see/recognise faces as all unique

Bottom-up process:

-       move from external world inward, from most basic sensory info to more complex, detect specific stimulus features, combine them and then recognise stimulus

Top-down process:

-      our knowledge/expectations shape the way we see the world; humans have strong top down. Ex walks into a class for the first time, we shape what we look for when we walk in, like we know what to expect based off of past experience, like confirmation bias, ex the info we use to judge colour always changing, organized by nervous system

What is psychophysics?

-       Study relation between physical energies/world and our psychological experiences

Individual absolute threshold:

-       how strong a stimulus has to be for an individual to detect the stimulus >50% of the time. Changes based on environmental factors

Signal detection theory discovery:

     Signal detection theory discovery: ability to detect a stimulus that’s very faint, ex a quiet sound, the ambient noise in the world or the just detecting the noise in the brain, ability to detect stimulus changes depending on factors

Priming:

-       activation of associations in the mind, even when stimulus doesn’t reach conscious awareness, may still have an effect, priming stuff in the mind.

Subliminal:

-       to detect it less< 50% of the time, so not reaching consciousness majority of cases, ex FedEx arrow

Subliminal stimuli and sensation

-       Subliminal stimuli: too weak to detect more than 50% of time

-       Subliminal sensation: stimuli is brief/fast so don’t detect/reach consciousness, ex film clip

Subliminal persuasion:

-       how much can the subliminal influence us? Can’t be persuaded by subliminal persuasion. A lot of info reaches nervous system but not much effect/subdued, minor, ex priming a face with brief photo of cute kitten/scary monster and tracking how people rate the faces differently.

Difference threshold:

the minimum difference between 2 stimuli that a person can detect, the noticeable difference, not an absolute value, it’s a ratio

Weber’s Law:

-       this ratio, ex 10g vs 20 g, need stimuli to differ by a minimum difference, not linear relationships, ex something 2X as many photons as bright is not necessarily felt/perceived that way, need many more photons striking the eye to perceive the light as being twice as bright

Sensory adaptation:

-       wearing socks all day, but ignore that fact, instead see useful things about the world, nervous system ignores absolute values/constant stimuli that provides no new info so removes non useful info, influences how the world is perceived in a personally useful way, ex blind spot, brain sees as filled in, ignores it. Increasing focus by reducing background chatter, and decreasing sensitivity to constant stimuli

Emotional adaptation:

-       ex faces influence, change expectations, ex upset face, once seeing full picture, knowledge influences how we perceive the world, (top-down)

Perceptual set:

-       predisposition of ability to notice some aspects/ignore others from sensory info. Determines our perceptual set: Schemas (the way we organize in our brains/mental representations), Context effects (ex, culture), motives, emotions

Vision

-       Vision: part of electromagnetic energy/spectrum, visible light is only small range of this spectrum

-       Humans have 3 colour receptors

-       Wavelength, understand colour through differences in wavelength, increased wavelengths give red, smaller wavelengths give blues,

Hue/colour:

-       a psychological phenomenon, top-down influence

Intensity:

-       smaller amplitude, dimmer and bigger amplitude, brighter

Frequency:

-       smaller wavelength, bigger freq. and bigger wavelength, smaller freq.

Light travels

-       Light waves hit the eyes(they collect info from both right and left sides), arranges info on sensory area, goes past cornea (hard outer lens which changes the angle of the light, through the pupil, to the second lens(soft flexible and contracts and changes angle of the light before it travels to the receptor cells in the retina(inside back of eye). Before reaching the retina though, light passes through fluid, cells/axons, blood vessels. Everything that lands on retina is backwards.

Specialized cells in retina

-       In the retina, the specialized cells are rods (1 type, sensitive to faint light) and cones (3 types, sensitive to detail and perceive colour):

Accommodation:

-       Accommodation: changes angle that the light strikes.

Visual info processing:

collection/analysis of sensory info

fundamental understanding of how the brain interprets this visual information,

-       Ganglion cells have long axons that project to brain, and optic nerve comes out to brain

-       Blind spot: where the axon is

-       Sensory info goes to thalamus (the sensory relay station) and then to the primary cortex

-       Visual info is also contralaterally organized (visual info from right side of world is processed on left hemisphere of brain and vice versa)

-       Processing in occipital lobe

Colour processing:

-       1. Every colour can be produced through combos of red, blue and green, seen as white when equal amounts, Young-Hemoltz trichromatic theory, 3 types of cones sensitive to different wavelengths of light, through activation we see colour. 2. Hering’s opponent process theory: boxes of colours, opposites, perceive this way since brain is wired to see them as compared signals

Feature/shape detection:

-       specialized processing at certain aspects of environment

Parallel processing

-       info arrives and spreads to many different regions in the brain at same time to be processed faster. (motion, form, depth, colour),

Hubel and Wiesel: Occipital lobe reassembles/enhances visual images 

Specialized processing for different perceptual info:

-       dorsal pathway(where), ventral pathway(what), these happen simultaneously yet are complex.

Visual organization:

-       we organize/interpret shapes/colours to create meaningful perceptions, ex Necker cube, Gestalt: we tend to organize pieces of info into an organized whole, ex recognizing a friend from strangers.

Grouping:

-       seeing gestalts, human minds use grouping strategies to see patterns/objects. (Proximity-group things that are close together, continuity-smooth ongoing patterns are one thing, closure-fit/fill in parts to close a gap, meaningfully grouping, perceptual constancy, depth perception

Depth perception:

-       ability to perceive/understand world as being 3D, ex predators have good depth perception, use depth cue, ex babies on cliff that stop

Binocular cues (2 eyes):

-       better perception of depth, retinal disparity: different on one retina vs the other, more disparity for closer objects, less for further, brain calculates distance by comparing images form 2 eyes.

Monocular cues (1 eye):

-       depth cue available to either eye alone, light and shadow, relative motion (driving car and road is moving but mountains are fixed), relative size(perceive smaller person as further), relative height(higher as further in scene), linear perspective(linear lines converge, ex train tracks), interposition(the thing covered is further).

Motion perception:

-       humans imperfect of motion perception, susceptible to it, ex still images that aren’t moving but appear to be, ex stop motion-Phi phenomenon/beta movement, illusions of movement

What is perceptual constancy?

-       See as consistent/same thing even though stimulus is changing, perception of object changes

-       Top-down process

-       Ex a door opening, a piece of paper being moved,

-       Colour constancy: light conditions

-       Size constancy: rotating door

-       Relative luminance: checkerboard with shadow, identical colours yet don’t perceive as identical, due to pattern and shadow,

-       we are not passively seeing the world, our knowledge of the world shapes what we perceive, weirddd

Experience & visual perception:

-       perceptual interpretation, need early stimulus for eye to work, cant develop later, theres a critical period for normal sensory and perceptual development

Perceptual adaptation:

-       ability to adjust to changed sensory input, including artificially displaced/inverted visual field, so some flexibility later too.

What is the physical stimulus that becomes the mental phenomenon of sound? How does

this physical stimulus gets transformed into sound?

-       Hearing: perceiving changes in air pressure

-       Hair cells: sensory cells in inner ear that convert mechanical vibrations into electrical signals

-       Sound waves go from environment into the brain, bands of compressed and expanded air of higher and lower density

-       We interpret characteristics of air pressure waves as characteristics of sound.

-       We’re good at hearing in the range of the plane, not above/below.

 

Describe the organs and brain areas related to sound.

-       Sound waves hit eardrum (compressing/expanding and flaps) is attached to 3 bones(move and cause vibrations) on the cochlea(using fluid to move amplifies) and cause hair cells to move(triggers impulses) to thalamus to main auditory cortex(in temporal lobe) and the sound is interpreted.

-       Cochlea: long membrane with hair cells, wide and flexible end(respond more to low freq, effects base of cochlea), narrow and rigid end(stimulates hair cells, hear as higher freq, affects the apex)

 

Describe how pitch (e.g. high versus low) is discriminated.

-       Pitch is related to wavelength, as wavelength increases, pitch sound increases

-       Place hearing theory: explains high pitches best

-       Frequency theory: explains low pitches best, fewer action potentials, hear lower frequency and more action potentials, hear higher frequency

-       Combinations of places and frequency theories, handles medium pitches

-       2 ears better than 1 to locate sounds

-       Psycho acoustics, sound arrives at 1 ear before the 2^nd ear, this delay allows us to know where sound is coming from,

-       the head is a barrier, low freq travels better through barriers,

-       high freq is blocked more: sound shadow, ear on other side hears less high freq content

 

Consciousness

=represents awareness and experiences such as thoughts, memories, actions, perceptions

What is consciousness? Why is it difficult to define? Why is it difficult to study?

Consciousness is the awareness of thoughts, memories, and perceptions that is subjective and challenging to define and study. It can't be measured easily, requiring objective variables for assessment. Using bistable stimuli like the Necker cube helps illustrate this complexity, while various states of consciousness, such as dreaming, further complicate understanding.

Subjectivity

Personal experience, not shareable with others.

Brain and Consciousness Relationship:

Consciousness is linked to brain activity in the cerebral cortex and thalamus. Cognitive neuroscientists can map these areas through techniques like fMRI, which shows that conscious experiences are based on synchronized brain activity. Even 'vegetative' patients may possess consciousness that they cannot express.

Anterograde amnesia

Inability to form new memories while remaining conscious, living only in the present.

What is attention?

Attention is the cognitive process of selectively focusing on important stimuli in the environment while filtering out less relevant information. It allows us to manage our limited cognitive resources effectively.

How is attention related to memory?

-       Attention controls info that reaches short term memory

-       Strongly influences what ends up stored in long term memory

-       Not all info unattended is lost – implicit memory

Selective attention

Focus on particular stimuli while shifting consciousness; limits awareness of other stimuli, leading to inattentional and change blindness. Multi-tasking decreases performance. Models include filter theory (disproven) and attenuation model (unattended info can break through). Performance improves with directed attention.

Nervous System Divisions

Divided into Central Nervous System (brain & spinal cord, processes sensory info) and Peripheral Nervous System (sensory and motor neurons). Peripheral splits into somatic (voluntary control) and autonomic (involuntary control). Autonomic includes sympathetic (activates fight or flight) and parasympathetic (conserves energy), both controlling the same organs oppositely.

Major Divisions of the Brain

• Interacts with the endocrine system via the pituitary gland for hormone regulation.

• Forebrain: Largest, includes telencephalon (site of most consciousness) and diencephalon.

• Midbrain: Mesencephalon.

• Hindbrain: Controls basic biological processes; includes metencephalon and myelencephalon.

• Telencephalon: The cerebral cortex is its prominent feature.

• Limbic System: Part of the telencephalon that contains the amygdala, hippocampus, and cingulate cortex.

• Basal Ganglia: Deeper brain area (caudate + putamen = striatum) that manages motor output, habits, and muscle memory.

Mapping the Cortex

The cortex is mapped through fissures (sulci) and ridges (gyri), with key structures like the corpus callosum separating hemispheres. It includes lobes (frontal, parietal, temporal, occipital) and six functional layers, with the primary motor cortex responsible for motor control and contralaterally organized—each hemisphere controlling the opposite side of the body.

Describe the mechanisms that support the brain’s healthy functioning (blood, meninges, cerebrospinal fluid).

The brain relies on structures like blood flow from four key arteries (internal carotid and vertebral), protected by the blood-brain barrier, meninges(Meninges(layers) to protect brain: - skin of scalp, bone of skull, dura mater (tough protectant layer), arachnoid mater (spidery membrane), fluid, pia mater(hugs the brain), blood vessels.), and cerebrospinal fluid (CSF), which delivers nutrients, removes waste, and cushions against injury.

Neuroplasticity

The brain's ability to reorganize and adapt after damage, allowing non-damaged areas to take on functions of lost areas, often supported by therapies like constraint-induced therapy to improve functionality.