Which of these months has 30 days?
AnswerApril
April, June, September and November each have 30 days.
Challenge · Facts & stats
30 Days facts & stats
7 fact-checked facts about 30-day habits, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
In habit research, what is a 'cue'?
AnswerA trigger that prompts a habit
A cue, such as a time, place or feeling, sets off an automatic behaviour.
Going deeper
In a 2009 University College London study, about how long did new habits typically take to become automatic?
AnswerAbout 66 days
Researchers led by Phillippa Lally found a median of about 66 days, with wide variation.
What are the three parts of the classic 'habit loop'?
AnswerCue, routine, reward
A cue triggers a routine, and a reward reinforces the loop so it repeats.
About how long is the Moon's full cycle of phases?
AnswerAbout 29.5 days
The synodic month, from one new moon to the next, lasts about 29.5 days.
Expert level
In the 2009 UCL habit study, what was the range of days participants took to reach automaticity?
Answer18 to 254 days
Times varied hugely by person and habit, from 18 days to an estimated 254 days.
Which brain chemical is closely linked with reward and motivation in habit learning?
AnswerDopamine
Dopamine signals help the brain learn which actions lead to rewards.
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