Forgetting occurs due to the collective influence of psychological, biological, social, information-related, and environmental factors. Psychological factors like encoding failure, lack of attention, interference, and disuse are major causes of forgetting. Biological factors include damage from injury, disease, drugs, or aging that obstruct neural networks involved in memory. Social factors like level of social interaction and collective forgetting also influence forgetting. The nature of the information, such as meaninglessness or lack of interest, contributes to forgetting. Environmental contexts different from the learning context, such as changes in place or physical location, can also lead to forgetting.