Just enough help

What the research found

The word comes from a 1976 study of a tutor helping young children build a puzzle. David Wood, Jerome Bruner and Gail Ross described the tutor taking care of the parts of the task the child could not yet manage, so the child could focus on, and finish, the parts within reach. They called this support scaffolding.

Lev Vygotsky's zone of proximal development describes where that help is useful: the gap between what a learner can do alone and what they can do with guidance. He defined it as

the distance between the actual developmental level as determined by independent problem solving
(Vygotsky, 1978)

and the level reached with an adult's guidance or a more capable peer. Teaching aims at that edge.

Help should fade

Strong guidance helps beginners. Kirschner, Sweller and Clark (2006) reviewed the evidence and wrote that

minimally guided instruction is less effective and less efficient than instructional approaches that place a strong emphasis on guidance
(Kirschner et al., 2006)

But the same help can get in the way later. This is the expertise reversal effect: techniques that work best for beginners can lose their effect as learners gain skill (Kalyuga et al., 2003).

Barak Rosenshine's summary of research for teachers puts it simply:

Present new material in small steps with student practice after each step
(Rosenshine, 2012)

Hints are one way to scaffold, and how they are given matters. Learners often use help badly, asking for it too soon or not at all (Aleven et al., 2003), and hints generated from past students' work helped students keep going in a logic course (Stamper et al., 2011).