Following Lev Vygotsky’s ideas, a teacher decided to give hints and cues to the students who were stuck on a given problem and let the students try to solve that problem again. By doing so, teacher is practicing the concept of __________.

The correct answer is Scaffolding.

Explanation:
In Lev Vygotsky’s Socio-Cultural Theory of Cognitive Development, scaffolding refers to the temporary support provided by a teacher, peer, or knowledgeable adult to help a student master a task that they cannot perform independently.

Key components of Vygotsky's concept include:
1. Zone of Proximal Development (ZPD): The distance between what a learner can do independently and what they can achieve with guidance. Scaffolding takes place within the learner's ZPD.
2. Hints and Cues: By providing hints, promptings, or breaking down a complex problem into manageable steps, the teacher supports the student's problem-solving process without giving away the complete answer directly.
3. Gradual Fading: As the student gains competence and confidence, the support (scaffold) is gradually removed until the student can solve similar problems independently.

Analysis of Incorrect Options:
• Assimilation: A concept from Jean Piaget's cognitive development theory, referring to taking in new information and fitting it into existing cognitive schemas.
• Collective monologue: A form of speech observed in young children (also studied by Piaget) where children talk in front of each other or alongside each other without actual interaction or response.
• Functional Fixedness: A cognitive bias that limits a person to using an object only in the way it is traditionally used, obstructing creative problem-solving.

Therefore, giving hints and cues to guide students when they are stuck on a problem is a direct application of Vygotsky's concept of scaffolding.