Undergraduates should not be spoon-fed, and indeed some students resent teachers who simply load them with facts no matter how well the information is synthesised and organised. Many students, in fact, prefer to explore and discover things by themselves. From our own experience, the satisfaction of acquiring knowledge in a selfdirected manner driven by curiosity is one of the most important factors that brought us to pursue a career in scientific research.

At NUS, independent study modules (ISM) require students to do a fair bit of self-directed learning (SDL). Designing a full, (four modular credit) ISM de novo and getting it accepted by the curriculum review committee is a great challenge. It may be very difficult for a single person to cover a novel topic not already in the curriculum in sufficient breadth and depth that would be worthy of an ISM. However, incorporating an SDL component in an existing module that comprises largely didactic lectures is common practice. This article provides a brief description of our experience in adding an SDL component to a module on life sciences.

An SDL exercise was included in a 3000-level module, LSM3213 "Molecular and Cellular Neurobiology" consisting mainly of lectures, mass tutorials and dry laboratory exercises in Semester 2, Academic Year 2006/2007. Students were instructed to do their own readings on a theme-molecular and cellular basis of learning and memory. The theme was not specifically discussed during lectures or tutorials, but aspects of it were mentioned in passing during various lectures. Students who have done compulsory core courses on molecular and cell biology in their second year would already have sufficient foundation knowledge to digest the review articles fairly well.

The SDL component aimed to challenge students to go beyond that by requiring everyone to write a mini-review or commentary on the theme. Based on a few papers from the primary literature, students could choose their own essay topic as long as it was related to the theme. Students were told that they will be awarded grades for organisation, originality, in-depth discussions and the synthesis of ideas. Getting students to do the essay by themselves was a deliberate deviation from the general group-based projects to which students were accustomed.

For some students, it was their first time working alone and they had to learn to tackle the readings by themselves. Some questions and comments from students included: "Why can't I base my essays on reviews since these are easier to understand?" Or "Exactly how many papers should I refer to?" And "I really don't know what to do, Please help!" While some needed a little more encouragement and hand-holding, the majority required no more than a little guidance on their thought processes via email to build up their confidence. Another interesting phenomenon was that some students felt strongly about certain neurological disorders (e.g. Autism and Alzheimer's disease), and wanted very much to write on these despite the risk of detracting from the theme. Students wrote on a sufficiently wide range of topics to suggest that many, if not all, followed the instructions and did their own work.

Students' achievement in the SDL component was generally satisfying. From the results, it was clear that a good number of students took the challenge seriously and put in a lot of effort to tackle the primary literature. Some essays have standards close to those written by professional scientists. Only a minority did not spend much time on the assignment. Although we did not conduct a proper debrief of the exercise for logistical reasons, students learnt much from it found the experience interesting. However, such a component can be a real chore to students who just want to cramp as many modules as possible into a semester in order to graduate early.

On another level, the SDL was structured to serve a more important purpose. Students taking this third year, Semester 2 module were either graduating or advancing to the honours year, where they will conduct a research project carrying 16 modular credits. Graduates taking up a research position or honours students tackling their research project would need to read, extract and synthesise facts and methodologies from the primary scientific literature. Thus a prior exposure to such an activity would help students cope with the demands of their research work or projects and impress their future supervisors.

Any SDL component should enhance students' learning experience by building on their prior understanding of the topic and developing their ability to assimilate new information independently. Essentially, for an SDL component to be effective, it should be structured to stimulate students' interest by getting them to think about gaps in their knowledge of the topic. This requires students to assess the information taught in class and question whether their knowledge of the topic is sufficient to understand what has been taught. Getting students to develop interesting questions is key to encouraging students to delve deeper into an area of their interest and to read beyond the topics covered in class. More importantly an SDL component should create in students, an awareness that the information on any given field is not cast in stone and that what is taught in class or written in textbooks are not complete or absolutely correct.

The SDL component also made students learn how to gather information. This is fast becoming a critical skill with the exponential increase in information in a given research area. Students should be able to sieve through a vast amount of literature and limit themselves to papers pertinent to the key issue at hand.

Finally, students should learn to be able to critically evaluate and to synthesise a coherent and interesting review which addresses a specific topic and provide their own perspectives on existing data and ideas. An SDL exercise, properly designed to stretch the independence of students, will certainly add value to any module and enhance students' learning experience.