Research carried out by the Association for Research into the Science of Enjoyment (ARISE) has shown that happy thoughts and pleasant smells can boost the immune system. A study by Professor Warburton at Reading University in England showed that within 20 minutes of happy thoughts being experienced, the amount of antibody immunoglobulin (sIgA) found in the saliva doubled, remaining raised for at least three hours. By contrast, memory of traumatic or painful experiences caused the sIgA levels to drop. Another study carried out by Angela Clow at the University of Westminster showed a similar response to unpleasant and pleasant smells. Strangely the smell of water appears to have had an effect similar to unpleasant smells such as rotting meat. The good news though is that this effect could be counteracted by the smell of chocolate. Professor David Warburton, found of ARISE and head of psychopharmacology at Reading University, said "Previous scientific experiments have observed a correlation between changing moods and the immunity system, but these new studies provide a direct causal link. Identifying this direct link proves that happiness could make you healthier. Instead of worrying about the often ill-founded health scares created by so- called health experts most people would do better to listen to their bodies. These studies illustrate how our bodies naturally seek to protect themselves from disease by doing the things we enjoy."