If a seller really wants to sell the price will reflect reasonable market influences. The price may be slightly higher than the competition due to condition factors (or upgrades) but it will still be attractive enough to invite prospects. It will generate activity.
But what if no activity occurs? It doesn't take long for sellers to realize their house is listed above market. A few weeks of no showings and sellers will be likely on the phone to their agent wanting to lower the price.
The price reduction may be significant (the light came on) or it may be as little as a hundred dollars (still holding out hope). Minimal price changes are largely symbolic.
As a seller becomes more desperate the frequency of the changes may increase.
So why do sellers make these symbolic price changes? Because price changes in the MLS system get noticed. Price changes make the "hot sheet" which highlights activity with listings on that day (new listings, price changes, properties back on the market, under contract and sold).
Still most buyer's agents recognize these tell tale signs of a desperate seller.... chronic price reductions of about a hundred dollars at a time.