Visual Cues: Sensory Perception

Sensory Perception - Visual Cues: Depth is important for establishing how far something is. A couple different things help us with this: 2 eyes/binocular vision cues: Retinal disparity which is a small difference between the images projected on the two retinas when looking at an object or scene. This slight difference or disparity in retinal images serves as a binocular cue for the perception of depth Convergence shows that when things are far away, our eyes aren’t strained, but up close they are, so it’s another way of telling our brain how far something is Monocular vision cues: Relative size allows us to use size to see how far something is (the bigger it is, the closer it must be) Interposition allows us to see if something is covering something else, it must therefore be closer to us Relative height is a concept used in visual and artistic perspective where distant objects are seen or portrayed as being smaller and higher in relation to items that are closer Shading & contour allows us to depict depth with regards to light/shadows Motion parallax shows that things closest to you are moving super quick while things farther away are moving slower (assuming you’re driving in a car lol) Sensory Adaptation: Hearing → inner ear muscle contracts when it senses really loud noises in order to dampen the incoming intensity of sound (so your eardrum doesn’t explode) and takes a while to kick in Touch → for example, when you place your hand into a cold tub of water, eventually the receptors get saturated and therefore no longer fire (get used to it) Smell → same as touch but with smell (desensitized) Proprioception → (knowing where you are in space) can adjust even if input is super weird Sight → can get down or up regulation (i.e. bright vs. dark light) Weber’s Law & Thresholds: Just noticeable difference is the threshold where you begin noticing a difference in a stimulus I is the intensity of the stimulus, ΔI is the just noticeable difference, and Weber noticed that the ratio of ΔI/I was constant for that person in that moment (K = ΔI/I) → is also known as the Weber Fraction and shows a linear relationship Absolute Threshold of Sensation: Absolute threshold of sensation is the absolute minimum of a stimulus that is detectable 50% of the time (i.e. what is the lowest stimulus a person can reliably detect) Subliminal stimuli is stimuli that is below the 50% detection threshold Somatosensation: Thermoception is the ability to sense temperature and changes to it Mechanoreception is the ability to detect different pressures (i.e. how hard did the hamburger hit your face?) Nociception is the ability to detect pain Proprioception is the ability to know where your body is in space - The Vestibular Sense, Balance, and Dizziness: Vestibular System is responsible for our sense of balance and spatial orientation, which a lot of it comes from our inner ear Semicircular canals allow us to sense rotation and movement in 3D space (all orthogonal to one another) Otolithic organs which include the utricle and the saccule and allow us to detect linear acceleration and head positioning (crystals are located in here) Dizziness can be caused by when you stop vigorously moving, the endolymph inside of your inner ear keeps moving for a period of time, signaling to your head that you never truly stopped moving Signal Detection Theory: Signal detection theory has to do with how we make decisions under conditions of uncertainty (i.e. at what point is a signal strong enough to where we can notice it?) Bottom-up vs. Top-down Processing: Bottom-up processing is an explanation for perceptions that start with an incoming stimulus and working upwards until a representation of the object is formed in our minds (data driven) Top-down processing uses background knowledge/information in order to influence our perception of an object 1. 2. 3. 4. 5. Gestalt Principles: Gestalt principles of grouping: Similarity states that items that are similar to one another, are grouped together by your brain Pragnanz states that reality is often reduced to the simplest form possible Proximity states that objects that are close to one another are grouped together Continuity states that lines are seen as following the smoothest path Closure states that objects grouped together are seen as a whole Ignore the law of common region