My understanding is that the price of a stock at the stock exchange is determined by supply demand mechanics during trading hours, and the price of futures is determined by the price of the underlying stock. In effect its the price of the underlying stock that controls the price of the future(Black–Scholes model) The price of the stock-future is strongly coupled to the price of the underlying stock price.
Consider the commodity exchange where the futures price of a commodity is determined by supply demand during trading hours and is not directly determined by the real price(current price of commodity available to the public).
Contrast the scenario at the stock exchange with that of the commodity exchange. As an example, if the current real price of copper is Rs 340 per kg in the shops. The price of the copper futures is in no way directly determined by real price of the commodity the way the price of a stock-future is determined by the underlying stock. Hence the futures price of commodity is weakly coupled to the real price of that particular commodity. Hence it may be said that the price of commodity futures is much more volatile/speculative in nature than price of a stock future. Correct me if my understanding is wrong.