Chart Source: Market Harmonics

The charts below show the current and historical volatility indexes of the US stock market.

The Volatility index is also know as fear index, varies inversely with general stock market, say S&P 500.

Volatility index VIX is based on SP 100 index and VXN in based on NASDAQ 100 index. When the "fear factor" increases, the result can be seen as higher Put/call ratio.

Look for divergences between the Put/Call ratio and VIX/VXN data sets, which are more apt to occur during periods of complacency, and at convergences, and in particular in-synch movement, to confirm the persistence of trend, and as an aid in marking sentiment extremes. These extremes, of course, are always followed by a reversal of the trend.