Think the info from that training session will stick with you? Think again. More than a century ago, a German psychologist named Hermann Ebbinghaus proposed a theory called the 'forgetting curve'. It even had a formula. Simply, it states that once you have learned something the first time, if no attempt is made to recall it you will forget half of it after a day or so, half of the remaining info after another day, and so on. All is not lost though – the best ways to retain it are to memorise it using, for example, mnemonic techniques and best of all, is to use spaced practice, i.e. practise what you have learned repeatedly over time.