The perception of audio cues, or auditory is recognised as an automation process. This was recognised by a group of psychologist who studied about sound and sleep in the Northwestern University in Evanston. According to them, sound may enhance your memory while sleeping. Then, they conducted some experiments with 2 groups of people. The first group of participants were asked to memorise a computerised-image associated with sound. For example, a picture of a dog, along with some barking sound, infront of a computer. They were asked to nap later. The barking sound was played for them to listen when sleeping. The results of analyses have proven that the first group could remember better than the second group.


Caption: sleeping

Sound is something important, that will enhance a person's memory. The same theory applies to scent. A group of scientist at the University of Lübeck (Germany) found that people were usually better at remembering objects belonged on a computer screen with the scent of a particular object which they had smelled during the learning task and when sleeping. The two scenarios above were proven to be useful to boost a person's sleep learning capacity.

In fact, sleeping is something very important for human. Sleeping is usually a process for us to continue our healthy life. It is a natural restorative cycle that allows our body to rest properly by regenerating itself, so that it can continue to function appropriately. Therefore, taking a nap in the afternoon is healthy for you. A researcher at the Loughborough University (UK) who studied about sleep as a part of his research, suggests that a 10 minutes sleep will enhance performance. This applies to overtired drivers, and could save plenty of lives. On the other hand, computer game players who dreamed about that particular game during their sleep would play the game better in the next day, compared to other players. A brief explanation is that their mental effort increases as soon as they dream of something, and so, sleeping do improve our learning capacity. Although a short nap is useful, but do remember to NOT ignore long sleep. There are various research suggest that long sleep may improve memory performance.


Caption: stages of sleep

My traditional understanding of NOT sleeping enough often refers to the delay of growth rate. Since young, everyone have been telling me that sleeping late / insufficient sleep may cause our body to not grow well. In fact, there are many research proven that sleeping late may become obese. The research by a group of researcher in the Case Western Reserve University (Cleveland, in Ohio) found that 15 per cent of short-sleeping women have grown fat compared to other people (click HERE to read the PDF). In other words, there are possibilities that the sleep deprivation effect may increase your weight rapidly! Anyway, the lack of sleep is usually hazardous. Some people recognised the lack of sleep may cause grumpiness. A research from the University of Pennsylvania (Philadelphia) found that the person who had lack of sleep may usually feel groggy. They could not perform simple mathematical calculations!


Caption: the hippocampus

By the way, how will sleep improve our memory? In psychology, our working memory is usually associated to the hippocampus (click HERE to read more about the hippocampus). The memory improvement is referred to the transferring of information from the hippocampus to other brain regions (cortex) while sleeping. Here is a depiction of our brain: when we were sleeping, our short-term memory will transfer information to the hippocampus (long-term memory). The information will be processed in the long-term memory, and sent to the cortex after processing. This explains why sleeping will improve our memory. Other evidence include a reveal from the psychologist of the University of Kansas Medical Centre (Kansas). The psychologist believes that sleeping may enhance the motor region in our brain (a component that deals with muscles control; i.e. eye-movement, limbs etc.).

How many hours do we need to sleep everyday? Well, this is an important question. According to most health journals, childrens (age 10 and below) do need 11-12 hours everyday. At age 10, we need approximately 9 hours of sleep a day. For most adults, 7.5 a night appears to be the best amount of sleep. Elder adults (age 55 or more) usually need 5 hours of sleep a day.