What type of brain wave is primarily observed in idling or calm states?

Alpha waves are the brain waves that are primarily observed in idling or calm states, particularly when an individual is awake but relaxed, such as during moments of quiet reflection or while daydreaming. These waves typically oscillate at a frequency between 8 to 12 Hz and are associated with a state of relaxed alertness.

In contrast, gamma waves are linked to higher mental activity, such as problem-solving and cognitive processing, and do not represent a calm state. Delta waves, which are the slowest brain waves, are predominantly seen during deep sleep, not during calm wakeful states. The term "Mittens" does not refer to any recognized brain wave pattern in neurophysiology, making it irrelevant in the context of brain wave categorization. Thus, alpha waves are the signature brain waves that indicate a state of relaxed wakefulness.