How Much Brain Can You Pack Into a Spider Head?

Thirty years ago, state-of-the-art "minicomputers" (as they were then called) were refrigerator-size contraptions loaded with large, flat circuit boards, heavy cables, and noisy fans. Disk drives the size of washing machines spun stacks of large metal plates for a grand total of 300 megabytes of storage. If a minicomputer bore unquestionable evidence of advanced intelligent design just a few years ago, how much more so a modern smartphone (now a smartwatch) with more processing power, and on...