Perceiving the World: Vision, Audition, and Beyond

AP Psychology How Vision Works - Vision - pulses of electromagnetic energy (light) are received through the cornes, then the pupil, then the lens which focuses the light on the retina - As the light energy hits the retina, certain receptors (rods and cones) are activated and send neurochemical signals to the brain through bipolar and ganglion calls to your thalamus via the optic nerve - After reaching the thalamus, the neurochemical signals are for distributed to the rest of your brain - The human retina contains roughly 6 million cones and 120 million roots that populate more densely around the periphery of the retina Parts of the Eye - Cornea - specialized, transparent portion of the sclera through which light passes - Iris - colored part of the eye - Pupil - small opening in the iris through which light enters the eye. - Lens - transparent part of the eye inside the pupil that focuses light onto the retina. - Retina - layer containing the two types of photoreceptors - rods and cones - that transduce light energy to electrical impulses Rods and Cones - Rods - Located primarily in the retina’s periphery - Capable of receiving light energy in low light - Not involved with color perception - Cones - Concentrated in the middle of the retina in the fovea - Involved with color perception in the bright light - Both rods and cones synapse with bipolar cells, which synapse with ganglion cells, which form the optic nerve. The blind spot is where the optic nerve connects to the eye and contains neither rods or cones - Feature receptors in the occipital lobe relay info on shape, edges, angles, etc. to other parts of the brain and allow to recognize familiar objects from various angles colors, etc This allows people to perceive perceptual constancy - the recognition of things from different angles and colors - Ex - you can often recognize a person, animal, or object even if it is turned, colored differently, or moving - In fact, one can perceive all of these variables at once; this phenomenon is called as parallel processing - the simultaneous perception of speed, distance, texture, color, etc Theories on color - Transduction - Our brain is merely receiving light energy and converting it to neurochemical energy - Trichromatic theory - that theory that our cones and brains see colors in combinations of mixing red/green/blue receptors - Opponent process theory - proposes that some receptors eliminate opposing colors that share the same pathway - Ex - one who looked at a green, black, and yellow flag will briefly see a red, white, and blue afterimage when gazing upon a white background Eye problems - Cataracts - clouding of the lens of the eyes; affects acuity and color vision - Retinopathy - damage to the small blood vessels; begins to leak and may cause blurred vision, blind spots, or floaters - Glaucoma - fluid pressure builds up - Macular degeneration - inability to see objects clearly, distorted vision and dark spots in the center of vision - Hyperopia - focusing the image behind the retina, difficult to see objects close up - Myopia - focusing the image in front of the retina; difficulty in seeing objects far away Audition - Hearing - the process by which sounds waves enter the outer ear through the auditory canal to the eardrum - The eardrum, made of the hammer, anvil, and stirrup, transmits vibrations to the co - In the cochlea, the membrane is vibrated by the stirrup, which justified the cochlea fluid - Auditory nerve - The bundle of neurons that carries signals from each ear to the brain. - - - Auditory cortex Messages get sent to the thalamus Temporal lobe Transduction - The process where our eyes sense light energy and change it into neural messages that our brain can handle - The convergence of energy into a different form Sound Theories - Amplitude - the height of an energy wave (sound wave) - Determine loudness - Decibeis - the measurement of sound waves - Place theory - the theory that certain hairs are only activity by certain frequencies - Frequency theory - the theory that neurons fire in union with the vibrations to match the frequency of the vibrations, which is interpreted by the brain at the same rate Sensory disorders - Vision - color blindness or total blindness can occur due to malfunctioning of the cons or rods - - Hearing - sensochemical hearing loss can occur due to damage to the cochlear receptor hairs - Conductive hearing loss - can occur due to damage to the mechanical system Synesthesia - a perceptual phenomenon that stimulation of one sensory or cognitive pathway lends to automatic experiences in a sensory Touch - The sensation that allows us to experience pressure, pain,and temperature - Humans are more sensitive to unexpected stimuli - Gate-control - (transductions) the theory that small fibers are constantly sending pain signals to the brain, while the large fibers constantly block said signals until stimaluted - The large fibers allow said pain signals to travel to CNS - Sometimes the brain may create nonexistent pain from by ministering CNS signals, or large fibers can fail to block constant signals of pain - Additional errors include phantom limbs that can feel in anticipation from a functioning body - Pain management - Pain is not experienced equally amongst people, as factors such as psychological distactors, chemical influences, or genetic mutations can make pain more or less intense for each individual - Social factors can also impact pain, as, for example, people are more likely to feel pain if others do - Pai can also be managed or controlled by with drugs, surgery, placebos, distractors , exercise, hypnosis, or massage - Touch can even change the way yoy think or feel through embodied cognition Taste - (salty, sweet, bitter, sour, unami) - expressed through a series of interactions between taste, texture, and smell - People have 200 taste buds on each bump on the tongue - a pore that has 50 to 100 chemical taste receptors cells that detect food molecules - Certain receptors are more sensitive to one of the 5 tastes - Psychological influences can also impact taste Olfaction - Olfactory membrane helps with smelling at the top of the nasal cavity - Odorant receptors - catches chemical odorants, which activates neurochemical signals; these are activated by the particular chemicals that fit the receptor cell - The neurochemical impulses are then sent to the olfactory bulb, and then directly to the brain - olfactory cortex - deciphers the combination of activated receptors to recognize the smell - Psychological factors - also impact ones perception of smell - Ex - wintergreen flavor is oftened enjoyed in the U.S. as it is associated with gum and candy, while it generally disliked in the U.K. as it is associated with medicine Kinesthesia - Our sense of position regarding our body and its parts, as well as vestibular sense, which monitors head position and movement - To manage our balance, semicircular canals and vestibular sacs contain fluid that moves when your head rotates or tilts - The movement stimulates hair-like receptors which send messages to the cerebellum to determine your balance and stability Perception - Gustav Fechner - developed the concept of absolute threshold - Ex light’s absolute threshold is 5 light photons. Without at least 5 photons of light, a person will likely not be able to detect the pressure of light - Difference threshold - to detect variation - the ability to detect the difference in signals - Ex - the ability to identify a friend’s voice among many in the hallway - Signal detection - the ability to detect the presence of a weak stimulus (signal) amid an extensive amount of other signals - There is no single threshold for for signal detection, rather, signal detection is dependent on experience, expectations, motivations, and alertness - Ex - parents being more likey to be able to hear a crying baby compare to a nonparent - Subliminal messaging - the impact of stimuli on our cognition and judgement that is too quick or weak to consciously interpret or process - Ex - the puppy/werewolf experiment - While we are not able to identify something, we are still able to see and get the information to our brain - Interpreting sensory information - Bottom-up processing (using your brain) - starts at sensory receptors and works up to higher levels of processing - it is basically seeing something but having no understanding of what it is - Ex - would be seeing a pile of lumber as someone who doesn’t understand woodworking-they could only look to the shape, color, texture, etc. of the wood and attempt to understand it with that data alone - top-down processing (using our senses) - constructs perceptions that draw from our own experiences and expectations - not just the object or stimulation itself - Ex - would be seeing lumber as someone who is familiar with woodworking-they see the type and size of the wood and think about how or what tehy can build with it - Attention - Selective attention - the conscious focus on one stimulus among many - - - Ex - cocktail party effect - listening and responding to a friend in the noise and clutter of a party - Losing attention - Inattentional blindness - not noticing stimuli when focused on others - Change blindness - failing to recognize changes in the environment, especially when selective attention focuses our conscius thought on a single stimulus - sensory adaptation - diminished sensitivity as a consequence of constant stimulation (not smelling one’s own house, clothes, odor) - Gestalt principle - A predisposition for seeing continuity and interpreting things as wholes (using different parts to fill in the hole - The formation of whole, meaningful, or continuous stimuli when given mixed or unintergrated pieces of information - Figure-ground - the organization of the visual field into objects that stand out from their surroundings - Grouping - the perceptual tendency to organize stimuli into coherent groups based on continuity, proximity, and closure Perceptual phenomenons - Emergence, multistability, reification, invarriance, closure, similarity, proximity, continuity Perception - can be impacted by what we think or see first, as well as the context - Perceptual set - a mental disposition to see one thing over another - Explains why once you see a pattern or shape in something, it’s nearly impossible to NOT to see that pattern or shape - Context effects - trigger varying perceptions based on the context or set of expectations one has about an object, sound, touch, etc. - Ex - someone were to be talking about pioneers, and said ‘the eel is on the wagon broke,’ your brain will retroactively interpret it as ‘wheel’ not eel - This is why we misread some incorrect or misspelled words as correct in a sentence’s context Gustav Fechner and Ernst Weber - absolute threshold experiments with light photons and sound waves David Hubel and Torsten Wiesel - feature receptors and visual cortex research (motion detection)