Gen Psyc 04 - Sensation and Perception A BLACKBOARD VISION ONLY.ppt

* * * 鸡尾酒会的长桌上摆满各式各样的食品，与会者可根据自己的口味选择喜欢的食品。同样人耳对不同的音源也有选择功能，如在剧场休息厅里彼此交谈的人群中会发现一种有趣的现象：在嘈杂的声音中可把自己的听力完全集中在某个人的谈话上，而把其他人的声音都推到背景声中。这种效应就称“鸡尾酒会效应”（cocktail party effect）。 * * Stare at the dot in the middle of the flag for at least 30 seconds. Then look at the dot in the blank space to the right. Because your receptors have adapted to the green and yellow in the first image, the afterimage appears in the complementary colors of red and blue. * * The Hermann grid is another demonstration of lateral inhibition at work. Look at the figure as a whole and you will immediately see darkened spots at the intersections of the white lines. However, it you look directly at the intersections, or cover all but one row of squares, you see that the dark spots are illusory. What is happening? Receptors coding information from the white lines are inhibited by their neighbors on two sides. Those receptors that code information from the intersections, however, are inhibited from four sides, so they respond less vigorously. This makes it look as though the intersections are darker than the lines. * * * * Slide 2 of 5 Part 2: What are the sensory processes for our primary senses? In vision, the eye detects light waves IN HEARING, THE EAR IS A SOUND-WAVE DETECTOR In touch, stimuli are coded for pain, temperature, and pressure In smell, the nasal cavity 鼻腔gathers particles of odor. In taste, stimuli are coded for sweet, sour, salty and bitter * Figure 5.11 on page 138 The human ear. Sound waves enter the auditory canal, causing the eardrum to vibrate. These vibrations are carried along as waves in the liquid of the inner ear. * Figure 5.12 Path of transduction in the inner ear. When sound waves hit the fluid of the inner ear, the fluid causes the basilar membrane to move up and down, activating electrical potentials in the hair cells (the receptor cells for hearing). * * * Temporal coding is used to encode relatively low frequencies, such as the sound of a tuba. The firing rates of cochlear