The player is particularly good at focusing thier mind.
The player must make a Concentration check whenever they might potentially be distracted (by taking damage, by harsh weather, and so on) while engaged in some action that requires your full attention. Such actions include casting a spell, concentrating on an active spell (such as detect magic), directing a spell (such as spiritual weapon), using a spell-like ability (such as a paladin’s remove disease ability), or using a skill that would provoke an attack of opportunity (such as Disable Device, Heal, Open Lock, and Use Rope, among others).
In general, if an action wouldn’t normally provoke an attack of opportunity, you need not make a Concentration check to avoid being distracted.
If the Concentration check succeeds, you may continue with action as normal. If the check fails, the action automatically fails is wasted. If you were in the process of casting a spell, the spell lost. If you were concentrating on active spell, the spell ends as if you had ceased concentrating on you were directing a spell, the direction fails but the spell remains active. If you were using a spell-like ability, that use of the ability lost. A skill use also fails, and in some cases a failed skill check have other ramifications as well.