The brain changes state throughout the day. We don’t have to consciously think about it. It just happens easily and automatically.
The most obvious changes in state are when you go to sleep but have you ever wondered at the blank emotionless faces of commuters and how some people just seem to ‘switch off’ during that time. Do you ever just zone out in front of the television after a hard days work?
In reality we change state even more subtly all through the day and we actually use lots of tools to alter our state. We often use neuro-active drugs such as caffeine, taurine or alcohol or listen to certain music to alter our states.
Some of these tools we take for granted but take a moment to imagine a pampering day spa . Now imagine that spa playing loud urban rap music to its guests – It is unlikely they’d keep the same ambience! Music has a powerful effect on state yet it is something we often overlook.
Brain frequencies have been grouped together by psychologists since 1920s* into broad categories. They are indicative of certain states of consciousness
| Brain Wave Name |
Frequency Hz |
Indicating state of consciousness in healthy adults** |
| Gamma | 34 – 100 Hz | Certain cognitive functions |
| Beta | 13 – 33 Hz | Normal waking activity, active, busy or anxious thinking, active concentration |
| Alpha | 8 – 12 Hz | Relaxed awake |
| Theta | 4 – 7 Hz | Snoozing or drowsy through to light sleep |
| Delta | up to 3 Hz | Deep sleep |
*German physiologist and psychiatrist, Hans Berger named the first group he detected as ‘Alpha waves’
**This table indicates normal state where there is a dominant frequency
It is possible to measure these frequencies using an EEG (Electroencephalography) machine which uses small electrodes placed on the scalp. It is often used by cognitive neuroscientists as an easy and non-invasive way of measuring brain activity.
