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PSYC 1020 Sensing and Perceiving I

This article delves into the various sense modalities and explores the psychophysics behind our ability to sense and perceive the world around us. It discusses external states and events such as skin sensations, visual and auditory sensations, as well as the concept of extrasensory perception. It also explores internal states and events, including proprioception and interoception. The article further discusses classical psychophysics, absolute thresholds, and signal detection theory.

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PSYC 1020 Sensing and Perceiving I

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  1. Y PSYC 1020Sensing and Perceiving I Dr. Jack Broerse Sense Modalities Psychophysics Light, Eye & Brain Internet : http: // www.psy.uq.edu.au

  2. Sensing States & Events: External versus Internal Movement Conscious elaboration & thought Skin sensation Visual elaboration Auditory sensation Perceptual judgement Visual sensation (visual cortex) Body sensation (cerebellum)

  3. Burned Putrid Fruity Flowery Resinous Spicy Bitter Sour Salty Sweet External States & Events Skin Senses Vision Touch, Temperature, Pressure, Pain Hue, Brightness, Saturation (Density) Audition Volume, Frequency, Tonal Quality (Density) Taste & Smell

  4. Extrasensory Perception: Phenomena in Science or Pseudoscience? ! ? ?

  5. Extrasensory Perception: Charles Darwin’s Scepticism Thought Transference (1870s) For: Alfred Russel Wallace Against: Charles Darwin Thomas H. Huxley (see Scientific American, October, 1996).

  6. Internal States & Events Proprioception & Kinaesthesis Sensations of body/limb/muscle position & movement Interoception Vague sensations of internal organs & deep pain

  7. Psychophysics & Measurement Stimulus to Conscious Experience Psychophysical Relationship

  8. Vision A candle flame at 60 km on clear dark night Hearing A watch ticking at 6 m in quiet conditions Touch Wing of a bee falling on your cheek from 1cm Smell One eye drop of perfume in 3-room appartment Taste One teaspoon sugar in 10 litres water Classical Psychophysics Absolute Thresholds Detection Threshold (Limen) SensoryModality

  9. Difference Thresholds Just Noticeable Differences (JND) L1 L1 + D L where = D L D L WEBER’s LAW = Constant L L2 Discriminations: Same vs Different L2 + D L

  10. Sensitivity vs Decision Criterion Thresholds & Decisions Signal Detection Theory (SDT) Stimulus Reality Same/Present Diff/Absent FALSE ALARM Same/Present HIT Response/Decision CORRECT REJECTION MISS Diff/Absent Key Words Hits – False Alarms

  11. Motivation Mental Set Subliminal Perception? A case study for SDT Key Words Perceptual Defence

  12. Motivation Mental Set Subliminal Perception? A case study for SDT Key Words Perceptual Defence

  13. The Stimulus for Vision Electromagnetic Radiation Visible Light Spectrum 400 – 700 nanometres (10 -9m) Wavelength (l) l = 10 15m Amplitude Frequency= 1/l l = 10 7m–10 13m

  14. The Eye Anatomy & Physiology Retina (photosensitive rods & cones) Pupil Fovea (central vision) Lens Blind Spot Cornea Optic Nerve Iris Approx. 9 cm at normal viewing distance +

  15. Retinal Rods and Cones Sensitivity & Dark Adaptation Rods 6.0 7.0 300 x 5.0 6.0 Cones 4.0 5.0 Cones Log. Relative Sensitivity Log. Threshold 3.0 4.0 2.0 3.0 Rods 1.0 2.0 1.0 400 500 600 700 Wavelength (nm) 10 20 30 40 50 Minutes in Dark

  16. Retina to Brain Central Visual Pathway Thalamus Corpus Callosum Brodmann Areas 17, 18, 19 Cerebellum Visual Cortex

  17. B N R K F V M W X L Basic Visual Functions:Everyday Tests of Visual Acuity E E Snellen Chart C Landolt ‘C’

  18. Optical Disorders:Focussing the image Enmetropic (normal acuity) Myopic (nearsightedness) Hyperopic (farsightedness) Astigmatic (Blurring in some axis) Presbyopic (Accomodation problems)

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