If you think about options as a form of insurance, then we can infer something about the marginal investors beliefs about various scenarios by the price they're

If you think about options as a form of insurance, then we can infer something about the marginal investors beliefs about various scenarios by the price they're willing to pay to protect themselves from them. Right now, the risk-neutral expectation is that the S&P will appreciate by 5 to 30% over the next year, but the strong concern that the market will drop catastrophically drives up demand for insurance against a depression. So on average the options market looks pessimistic even though in some sense the median belief is that the market will go up. This is not the way perceptions have to go, for example the greatest mass of investors might have been around -5% to -30% but a smaller group, convinced the market would quickly rebound to beyond its former glory, might produce a net effect of slightly rosy. So in essence using options prices we can determine that in general investors are not thinking "yay, bargains" rather "yikes, mattress"