Scared of punishment:

The employees avoid sharing their ideas in the fear of mistake. Usually they avoid giving their ideas as the feel they might be punished for creating problem while processing their ideas. A person will grow up in their career or in their life only when they commit mistakes. You as a leader must create opportunity to them even if you know that they may commit mistakes. You must allow them to work on their ideas and make them confident enough to come up with good ideas in the future days. You must always remember that only when the employees commit mistakes they have the opportunities to learn from those mistakes to get better for the next time.

They tend to avoid future problems:

Even if the employee does any major mistake if he or she is new to work, avoid shouting at them because they may be thinking that if they commit any mistake they should be paying a big price in the future and they might come to the conclusion to keep their mouth shut every time and just do what they are asked to do. So, if you want your employees to come up with their own thoughts, it is advisable for you to create a friendly atmosphere between you and your employee. Avoid the habit of immediately rejecting the ideas without even giving a second thought on it.