for example when the price is falling and traders have switched strategy from buying to shorting, they obviously want the price to drop more so they can make more profit. many will start talking about doomsday so that maybe the price goes lower and they make a little bit more profit.
the opposite is true about rises.
how effective this bullshit is, i have no clue but this is what's happening!
I have zero doubts that this is happening, but I'm pretty sure a good chunk is also genuine fear for losing their investments and/or excitement over doubling their money. I'd say it's very effective, because it gets weak hands to buy in and then dump in a hurry. The people who get swayed are always the losers.