A new study suggests that caffeine enhances long-term memory in people if given in the right dose and at the right time.
Researchers have long thought that caffeine enhances memory but studies that tried to prove the link were inconclusive, as perceived benefits in memory could have been attributed to another effect of caffeine intake – increased attention.
Neuroscientist Michael Yassa of the University of California recruited 160 adults who normally consume minimal amounts of caffeine. The volunteers studied images of objects before randomly receiving a pill containing either 200 milligrams of caffeine – equivalent to two espressos – or a placebo.
Receiving the caffeine after – rather than before – studying the images helped the researchers to isolate the effect of caffeine on memory as the impact of alertness should not matter after the images had been studied.
The volunteers returned 24 hours later and took a memory test involving images they had seen before, unseen images and images that were similar but not identical. They had to classify these as ‘old,’ ‘new’ or ‘similar.’
The researchers found no differences in accuracy for identifying old and new images between the two groups, but the group who had received caffeine were significantly better than the placebo group at identifying which images were ‘similar’ rather than ‘old.’
Yassa said that caffeine enhances long-term memory by improving the process of memory consolidation. People don’t only have to drink coffee after studying, as Yassa feels they will get the benefit if they drink it before or after.
However, the team found that caffeine isn’t much use once consolidation has finished, so drinking coffee one hour before an exam won’t help you retrieve memories more effectively.
The dose was also important. They repeated the experiment with 100 miligram and 300 miligram doses and found that neither was significantly different from placebo. This could be because other effects kick in at higher doses that negate the memory consolidation benefits. Volunteers given 300 miligrams also reported side-effects, such as headaches and jitters.
Responding to the research, Dr Ashok Jansari, from the University of East London's school of psychology, said caffeine appeared to "sharpen" memory, rather than actually improving it.
How is this applicable in the workplace? Coffee breaks can be scheduled to deliver caffeine at the right time during training – there's also evidence that training participants must reflect on what they've learned in order to remember it fully, so combining both caffeine and 'down time' in a break may help with the overall success of the training programme.
