Independent learning, also known as self-directed learning or autonomous learning, is a form of learning in which the learner welcomes and takes responsibility for his own learning. The learner determines his learning needs and objectives, and acquires knowledge through his own efforts. The key traits of an independent learner are maturity and the motivation to learn. He must be able to reflect continuously on his learning and critically assess both the learning experience and the material so that he can initiate correction and modify his learning strategies if necessary.

One of the fundamental skills all first year medical students must develop is the ability to identify different structures in the human body correctly. The study of human anatomy serves as an entry point to clinical medicine and introduces students to specialised vocabulary used internationally in the practice of medicine.

Flashcards have long been used as a study aid in vocabulary learning. With this tool, the learner writes a new word or phrase on the front of each card and its meaning on the back. The cards are then shuffled, and the learner can use the cards in a question and answer format to acquire new vocabulary. In this way, the cards provide instant feedback on the learner's performance in a safe environment without peer pressure. One example of such cards is "Netter's Anatomy Flash Cards", where different parts of the human body are illustrated on the front of the cards in full colour (using the same anatomy illustrations found in Netter's Atlas of Human Anatomy) with names of the structures printed on the back.

However, the learner may encounter problems if he were to go through a stack of flashcards sequentially. Research has shown that we forget most of what we learn within a short time. Furthermore, some course materials are inevitably more difficult to learn than others. Thus study time could be more effectively spent by focussing on the difficult materials (i.e. selective learning) rather than relearning an entire series of flashcards sequentially, which could lead to boredom and frustration.

To address this, a German psychologist, Sebastian Leitner (1919-1989), developed a Cardfile System¹ for selective learning. The learner starts with a box with several compartments and goes through his entire stack of flashcards. Cards that have been correctly answered are transferred to a higher compartment, while incorrectly answered cards are left in the first compartment. Thus the first compartment contains cards that the learner finds difficult and he is able to prioritise his time and put in more effort on these. The whole process is repeated several times until all the cards are promoted to the final compartment.

One advantage of using the Leitner Cardfile System for learning anatomy is that the learner does not merely review the flashcards passively or memorise anatomical terms mindlessly. Since the learner has to recall the material rather than rely on recognition, the learner is encouraged to draw on his personal experience and utilise learning techniques such as association and reflection to master and internalise the new knowledge.

The Leitner Cardfile System is not limited to learning new anatomical terms. In recent years, the NUS undergraduate medical curriculum has undergone numerous changes, including a greater emphasis on horizontal integration across different subjects and disciplines, and vertical integration across all five years of study. Medical students studying anatomy in lectures, small group tutorials, practical classes and problem-based learning groups can construct flashcards that integrate information from other medical sciences. For example, first year students learning about the course and distribution of the median nerve in the upper limb in anatomy can construct a set of flashcards that incorporates information on nervous impulse propagation (physiology) and neurotransmitters (biochemistry). As students proceed to higher levels, information on neurotropic drugs (pharmacology), carpal tunnel syndrome (medicine and surgery) and repetitive stress injury (occupational medicine and epidemiology) can be added to the cards. In a manner similar to mind maps, flashcards work best when the learner customises their design. Thus students should be encouraged to prepare their own flash cards as the preparatory process will sharpen their thinking skills and help them assess the study material critically. As illustrated by the above example, customised f lashcards that are prepared conscientiously are useful in helping students learn human anatomy and other disciplines in the medical curriculum independently.