Psychology Session 9 Sensation and Perception Date: November 4 th, 2016 Course instructor: Cherry Chan Mothercraft College
Agenda 1. Sensation and perception 2. Vision 3. Perceptual organization 4. Sound 5. Smell 6. Taste 7. Touch
What is sensation and perception? Sensation: detecting external stimuli and sending those stimuli to the brain Perception: internal representations of external stimuli (Wood, Wood, Boyd, Wood, & Desmarais, 2017)
Sensation and Relaxation Sensory rooms were first developed for patients with cognitive impairments, learning disabilities, dementia, and young children with complex disabilities. Staff and patients have reported an increase state of relaxation, lower levels of distress, and psychological and physiological improvements. (Smith & Jones, 2014) Multisensory environment relaxes students and provides opportunities for students to focus on particular activities (Stephenson & Carter, 2011)
Signal detection theory Detecting a stimulus against a background noise (Wood et al., 2017). A signal is detected based on subjective experience. It is a sensory process, depending on the intensity of the stimulus, and a decision process, influenced by the individual s bias (Wade, Tavris, Saucier, & Elias, 2014).
Figure 1. Responses in Signal Detection. Adapted from Psychology (p.194) by C. Wade, C. Tavris, D. Saucier, and L. Elias, 2014.
Sensing without perceiving Selective attention: focus on certain aspects of the environment and block out others Inattentional blindness: unable to consciously perceive something you are looking at because you are not paying attention to it (Wade et al., 2014)
Vision Cornea: bending the light towards pupil Pupil: opening where light enters eye Iris: muscles contract and dilate pupil Lens: focus objects onto retina Retina: membrane that contains lightsensitive receptor cells (rods and cones) (Wood et al., 2017)
Figure 2. Major Structures of the Eye. Adapted from Psychology (p.198) by C. Wade, C. Tavris, D. Saucier, and L. Elias, 2014.
Nearsightedness vs farsightedness Figure 3. Normal, nearsightedness, and farsightedness. From Normal, nearsightedness, and farsightedness by Lusby (2013) Retrieved from http://www.nlm.nih.gov/medlineplus/ency/imagepages/19511.htm
Rods and cones Figure 4. Differences between Rods and Cones. Adapted from Psychology (p.199) by C. Wade, C. Tavris, D. Saucier, and L. Elias, 2014.
Cones Figure 5. Three types of cones. From Seeing colour by Arizona State University (2010) Retrieved from http://askabiologist.asu.edu/rodsand-cones
What s wrong with this child? Figure 6. Scheibe illusion. From Upside-down optical illusions again by Vurdlak (2008) Retrieved from http://www.moillusions.com/2008/03/upside-downoptical-illusion-again.html
Perceptual organization Figure 7. Gestalt grouping principles. From Perception by Diane (2010) Retrieved from http://www.rhsmpsychology.com/ha ndouts/gestalt_grouping.htm
Perceptual constancy An object has stable properties regardless of distance, viewing angle, and lighting. Size Brightness Colour Shape (Wood et al., 2017)
Size Figure 9. In the left panel, the man in the background appears to be about the same height as the woman in the foreground From Do artists see their retinas? by Perdreau & Cavanagh (2011) Retrieved from http://c431376.r76.cf2.rackcdn.com/12334/fnhum-05-00171- HTML/image_m/fnhum-05-00171-g001.jpg
Brightness Figure 10. Brightness constancy. From Accuracy and inaccuracy in perception by Fong (2011) Retrieved from http://students.flatworldknowledge.com/bookhub/10145?e=stangor-ch04_s05
Colour Figure 11. Colour constancy. From Colour constancy in perception by Gurney (2010) Retrieved from http://gurneyjourney.blogspot.fr/2010/01/colorconstancy.html
Depth cues Binocular depth cues Convergence: focusing on nearby objects by turning eyes inward Binocular disparity: differences between two retinal images (Wood et al., 2017)
Monocular depth cues Interposition: One object blocking the view of another Linear perspective: parallel lines come closer together when they recede into distance Relative size: larger objects are closer Texture gradient: fuzzy objects are further away Atmospheric perspective: blurry and bluish-tint objects are further away Shadow or shading: light creates shadows Motion parallax: when you are moving, objects move in the opposite direction and at different speeds (Wood et al., 2017)
Impossible figures Figure 12. Elephant feet. From Cognitive illusions by World Mysteries (2011) Retrieved from http://www.world-mysteries.com/illusions/sci_illusions3.htm
Context and perception Figure 13. The Cat. From Context effect by Wikipedia (2013) Retrieved from http://upload.wikimedia.org/wikipedia/commons/3/3a/thecat.png
Sound Frequency: the pitch of the sound Amplitude: intensity of sound A cue for sound distance Timbre: sound quality Our two ears helps to discern sound direction i.e. sound coming from the right will reach the right ear a fraction of a second before the left ear (Wade et al., 2014; Wood et al., 2017)
Figure 14.Major Structures of the Ear. Adapted from Psychology (p.213) by C. Wade, C. Tavris, D. Saucier, and L. Elias, 2014.
Kinesthetic and vestibular Kinesthetic sense: body position Vestibular sense: movement (Wood et al., 2017) Figure 15. Balance disorder illustration. From Semicircular canal by Wikipedia (2013) Retrieved from http://upload.wikimedia.org/wikipedi a/commons/3/33/balance_disorder _Illustration_A.png
Smell Figure 16. Receptors for Smell. Adapted from Psychology (p.218) by C. Wade, C. Tavris, D. Saucier, and L. Elias, 2014.
Figure 17. Taste Test. Adapted from Psychology (p.217) by C. Wade, C. Tavris, D. Saucier, and L. Elias, 2014. A Taste Test
Touch and pain Tactile information is transmitted to the brain when an object touches and depresses the skin. Nerve endings in the skin send signals to the somatosensory cortex in the parietal lobe. Two point threshold: the distance between two points of stimulation before a person is able to feel two separate points of contact. Endorphins relieve pain and promote positive mood (Wood et al., 2017)
References Smith, S., & Jones, J. (2014). Use of a sensory room on an intensive care unit. Journal of Psychosocial Nursing and Mental Health Services, 52(5), 22-30. Stephenson, J., & Carter, M. (2011). The use of multisensory environments in schools for students with severe disabilities: Perception from teachers. Journal of Developmental and Physical Disabilities, 24(1), 95-109. Wade, C., Tavris, C., Saucier, D., Elias, L. (2014). Psychology (4 th Canadian ed., DSM-5 Update ed., 4 th ed.). Toronto, ON: Pearson Education Canada. Wood, S.E., Wood, E.G., Boyd, D., Wood, E., & Desmarais, S. (2017). The world of psychology (7 th Canadian ed). Toronto, ON: Pearson Canada