Psychology

1. Psychology Sensation and Perception Chapter Three - Pearson R. M. Tolles

2. Module 7: Distinguish between sensation and perception, and explain how they contribute to an understanding of our environment Sensation and Perception: The Basics • Sensation - the stimulation of sensory receptors and the transmission of sensory information to the central nervous system. • Perception - the process through which we interpret sensory stimulation

3. Continued… • Thresholds Absolute - weakest amount of a stimulus that can be sensed Animals have different levels Difference - minimum amount between two stimuli • Signal Detection Theory - method of distinguishing sensory stimuli that takes into account not only strengths buy also setting, physical state, mood and attitude • Sensory Adaptation - process by which we become more sensitive to weak stimuli and less sensitive to unchanging stimuli

4. Visual Information Processing • Hubel and Wiesel demonstrated that neurons in the occipital lobe’s visual cortex receive information from individual ganglion cells in the retina – these cells are Feature Detectors • Feature Detectors– pass information to other cortical areas where teams of cells (super-cell clusters) respond to more complex patterns.

5. Visual information processing

6. Color Vision • Young-Helmholtz trichromatic (three color) theory • Red – Green - Blue • Monochromatic vision • Dichromatic vision • Note: People who are colorblind see the color they are deficient in as a shade of muted gray or brown

7. Color Vision • Opponent-process theory= the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green. • Wave • Three sets of colors • Red-green • Blue-yellow • Black-white • Afterimage (textbook)

8. The structure of the ear The technical name of the collection of bones in the middle ear is ossicles. Each bone also has a more technical name: Hammer – malleus Anvil – incus Stirrups - stapes The ear is divided into the outer, middle and inner ear. The sound waves travel down the auditory canal to the eardrum. Eardrum = tight membrane that vibrates when struck by sound waves. Bones of the middle ear = the hammer, anvil, stirrup which vibrate with the eardrum.

9. The Ear - Perceiving Pitch • Place theory – Hermann von Helholtz • High pitched sounds • Frequency theory • Low pitched sounds • Volley principle • Note the difference between the two: • P.T.: different frequencies of sound wares are said to vibrate different places on the cochlea. These places are wired to different parts of the auditory cortex in the brain so the sound can be processed correctly. • F.T.: the entire cochlea is believed to vibrate at a particular frequency, thus sending the signal of the quality of sound to the brain.

10. The EarLocating Sounds • Stereophonic hearing • Localization of sounds • Intensity • Speed of the sound

11. OTHER SENSES – Touch • Types of touch • Pressure • Warmth • Cold • Pain • Sensation of hot

12. Touch • There are two types of skin: • Hairy skin; contains hair cells, which detect movement and pressure • Glabrous skin; contains no hair cells, so the receptors in this type of skin are more sensitive. • Rubber hand illusion

13. Touch • Kinesthesis= the system for sensing the position and movement of individual body parts. • Vestibular sense = the sense of body movement and position, including the sense of balance. • Semicircular canals

14. Module 8: Summarize the laws of sensory perception. Rules of Perceptual Organization • Closure

15. In visual perception, figure-ground is a type of perceptual organization in vision that involves assignment of edges to regions for purposes of shape determination, determination of depth across an edge, and the allocation of visual attention

16. Perception of Movement • Movement Perception • The illustrations that, undoubtedly you have been looking at demonstrate that motion perception is very complex. Recall that we perceive motion if we hold our heads and eyes still as a moving object passes in front of us. If we decide to hold our heads still and let our eyes follow the object we still see it move. Finally, we could even decide to hold our eyes steady and move only our head to follow an object. The interesting thing is all three modes of viewing a moving object result in about the same perception.

17. Perceptual Constancies • Perceptual constancy denotes the tendency of animals and humans to see familiar objects as having standard shape, size, color, or location regardless of changes in the angle of perspective, distance, or lighting. The impression tends to conform to the object as it is or is assumed to be, rather than to the actual stimulus. Perceptual constancy is responsible for the ability to identify objects under various conditions, which seem to be "taken into account" during a process of mental reconstitution of the known image.

18. An optical illusion (also called a visual illusion) is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a percept that does not tally with a physical measurement of the stimulus source. There are three main types: literal optical illusions that create images that are different from the objects that make them, physiological ones that are the effects on the eyes and brain of excessive stimulation of a specific type (brightness, tilt, color, movement), and cognitive illusions where the eye and brain make unconscious inferences.