Do you have actual scientific and researched proof for that or you just pulled it from air? The bitcoin money processor (bitpay) said that every spike in price results in a spike of sales; that goes against what you are saying. If the price of a currency increases significantly, the purchasing power of the holder of that currency increases too. Which means he can spend more.
But I don't have any data to back my claim either, and bitpay doesn't release their volume numbers.