Boyce scored a ludicrous fluke as Wigan pegged Swansea back to 2-1 on Saturday, but despite a late surge in possession and chances they left south Wales with nothing.
He said: "We had to go 2-0 down before we started playing and already there's been too many times this season we have done that.
"We are only playing when we are forced to like at the end of last season and we have to change that.
"When we were 2-0 down we started playing and we got a goal back and we were a much better team. At this level it's ourselves we have to blame - give a team a two-goal lead and it's always going to be hard to pull it back."