Hypothesis I thought of the other day daydreaming:
A test of lows or highs is similar to how when you break up with a lover you always go back for a second try to probe to see if you made the right decision. Both parties are usually willing (bulls/bears and man/woman or etc/etc. If test falls short, low/high rejection a new trend is formed or new high/low is formed and trend is resumed. If two partners give it a second try either their relationship moves to new deeper levels of intimacy or they split up and look for new partners.
Of course break out failures and failed failures happen, but at least the scenarios can be confined to a limited set of outcomes.