Why a skill tree makes you finish branches you do not need

The skill tree shows every node, including a whole branch of abilities irrelevant to how you play. You find yourself grinding to unlock them anyway — not because you need them, but because the branch sits there half-empty on the screen, and the empty nodes nag until they are filled, useful or not.

What everyone sees

An unfilled skill node is assumed to be pursued for the ability it grants — you unlock it because you want what it does. Often the node is chased purely because it is visible and empty. A displayed gap in a structure you are building creates a pull to close it that is independent of the gap’s value, so players complete branches they will never use, driven by the incompleteness of the picture rather than by any benefit.

What is actually happening

Loewenstein’s information-gap theory of curiosity holds that becoming aware of a gap between what one knows or has and a visible reference point produces a felt deprivation that people are driven to resolve — the gap itself, once salient, generates the urge to close it. Litman’s work on curiosity distinguishes the wanting of missing information from the liking of it, showing that people will act to fill a gap even when the filling brings little enjoyment. A fully displayed skill tree makes every unfilled node a visible gap against the complete picture, so the empty branches generate a curiosity-driven pull to complete them, quite apart from whether the abilities are wanted.

Why it stays hidden

The mechanism hides because filling a node feels like a considered choice about build strategy rather than a response to a visible gap. The player rationalises each unlock as potentially useful, not seeing that the pull came from the incompleteness of the display. Because a skill tree that hid unavailable branches would remove the gaps and the pull with them, and is never shown as an alternative, the role of visibility in driving completion goes unrecognised.