Tickersense: Top or Coincidence?

Tickersense posted this chart of the S&P 500 and the VIX (options implied volatility index) and raises the question that is the tile of their post:

Short Term Top or Technical Coincidence?

The VIX does have a tendency to act as a kind of thermometer for market nervousness. This probably has many causes but the obvious (and oversimplified) ones are: 1. Far more people and institutions are long stock than are short and get far more worried when the market falls than when it goes up. 2. The two most popular strategies of the public in options is to sell calls against stock they own or to buy puts to protect against downside price movement. So at the margin the supply of options increases as prices rise and the demand for options increases as the market falls.