PSYC 212 Chapter Notes - Chapter 8: Emmetropia, Far-Sightedness, Presbyopia
8 Dec 2013
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Document Summary
Nearly one half of the brain is involved in processing visual information. For centuries, it was believed that light was made up of particles emitted by certain objects, such as the sun or a candle flame, which travelled through the ether in straight lines. Around the mid-17th century, this particle theory was questioned, and a wave theory emerged. In the early 1800s, it became clear that the particle theory did not explain certain phenomena. All waves must necessarily occur as a deformation of a medium. But the ether (medium) must be rigid so as to permit light to travel through it at such high speeds. This ether was believed to be in space, as well. But it didn"t make sense how planets could move through this rigid medium so easily. The particle theory began to make sense again. In the 20th century, it was found that light beams produce an ejection of electros from an object.
