Imagination is the representation of sensations or physical objects in the mind without any immediate input of the senses. Often described as forming pictures in the mind, it is commonly equated with mental imagery, though imaginary experiences do not have to be purely visual, and can include other sensory experiences, thoughts, and emotions. Imaginings can be re-creations of past experiences, such as vivid memories with or without changes, or completely invented and possibly fantastical scenes. Imagination helps apply knowledge to solve problems and is fundamental to integrating experience and the learning process.