KA P_S - The Lazy OCD Version (2) (1) PDF

**Processing the Environment** **Sensory Perception** Visual Cues - Depth, Form, Motion, Constancy - **Binocular Cues** - - **Retinal disparity** (eyes are 2.5 inches apart) - **Convergence** -- things far away, eyes are relaxed. Things close to us, eyes contract. -...

**Processing the Environment** **Sensory Perception** Visual Cues - Depth, Form, Motion, Constancy - **Binocular Cues** - - **Retinal disparity** (eyes are 2.5 inches apart) - **Convergence** -- things far away, eyes are relaxed. Things close to us, eyes contract. - Monocular Cues - **relative size**, **interposition** (overlap), **relative height** (things higher are farther away), **shading and contour**, **motion parallax** (things farther away move slower) - Constancy -- our perception of object doesn't change even if it looks different on retina. - Ex. size constancy, shape constancy, color constancy. Sensory Adaptation - Hearing - **inner ear muscle**: higher noise = contract. - Touch - temperature receptors desensitized - Smell -- desensitized to molecules - Proprioception -- mice raised upside down would accommodate over time, and flip it over. - Sight -- down (ex. Light adaptation, pupils constrict, rods and cones become desensitized to light) and upregulation (dark adaptation, pupils dilate) **Weber's Law** - 2 vs. 2.05 lb weight feel the same. - 2 vs. 2.2 lb weight difference would be noticeable. - The threshold at which you're able to notice a change in any sensation is the **just noticeable difference (JND)** - So now take 5 lb weight, in this case if you replace by 5.2 weight, might not be noticeable. But if you take a 5.5 lb it is noticeable. - I = intensity of stimulus (2 or 5 lb), delta I = JND (0.2 or 0.5). - Weber's Law is delta I to intensity is constant, ex..2/2 =.5/5 =.1. - **Delta I/I = k** (**Weber's Law**) - If we take Weber's Law and rearrange it, we can see that it predicts a **linear relationship** bet - ween incremental threshold and background intensity. - Delta I = Ik. - If you plot I against delta I it's constant Absolute threshold of sensation - The minimum intensity of stimulus needed to detect a particular stimulus **50%** of the time - At low levels of stimulus, some subjects can detect and some can't. Also differences in an individual. - Not the same as the **difference threshold (JND)** -- that's the smallest difference that can be detected 50% of the time. - Absolute threshold can be influenced by a \# of factors, ex. Psychological states. - Expectations - Experience (how familiar you are with it) - Motivation - Alertness - **Subliminal** stimuli -- stimuli below the absolute threshold. The Vestibular System - Balance and spatial orientation - Focus on **inner ear** - in particular the **semicircular canals** (posterior, lateral, and anterior) - Canal is filled with **endolymph**, and causes it to shift -- allows us to detect what direction our head is moving in, and the strength of rotation. - **Otolithic organs** (utricle and saccule) help us to detect linear acceleration and head positioning. In these are Ca crystals attached to hair cells in viscous gel. If we go from lying down to standing up, they move, and pull on hair cells which triggers AP. - Also contribute to dizziness and vertigo - Endolymph doesn't stop spinning the same time as we do, so it continues moving and indicates to brain we're still moving even when we've stopped -- results in feeling of dizziness. **Signal Detection Theory** - Looks at how we make decision under conditions of [uncertainty] -- discerning between [important stimuli] and unimportant "noise" - At what point can we detect a signal - Origins in radar -- is signal a small fish vs. large whale. - Its role in psychology -- which words on second list were present on first list. - Real world example -- traffic lights. Signal is present or absent (red). Strength of a signal is variable **d'**, and **c** is strategy - d': hit \> miss (strong signal), miss \