Since its release in 2013, Frozen's Let It Go became a common household song. From children to adults, men or women. The song even became an LGBT anthem and sparked thousands of covers and parodies. However, what made people very hooked from this song? Science has an explanation for that.

Frozen's Let It Go received both popular and critical acclaim. It became the fifth selling song of 2014 with 10.9 million copies sold. The song also won both the Academy Award for Best Original Song in 2014 and the Grammy Award for Best Song Written for Visual Media in 2015. Some described it as a "musical epidemic" which has "cult-like" grip for children and adults alike.

However, aside from its widely popular singers, Idina Menzel for the movie version and Demi Lovato for the pop version, researchers explained the science behind the popularity of Frozen's Let It Go.  According to a study published in the journal of American Psychological Association, songs become potential earworms (songs that easily stuck in the mind) because of three main reasons -- fast tempo, generic shape of the melody and unusual interval patterns.

Frozen's Let It Go got all three components right. The repetitive melody of the three-note refrain of Let it go! in the chorus especially made the song easy to remember even for toddlers. "Even if I had only heard the song once... I'd remember that phrase," Dr Christopher Wiley, senior music lecturer from the University of Surrey told The Telegraph.

Experts also attribute the wide popularity of the song to the meaning of the song. "If you take it out of Frozen, Let it Go's messages of liberation and self-acceptance are just as strong," Dr Vasco Hexel, a composer professor from Royal College of Music said.

The song is also very unusual. Despite its hopeful message, Frozen's Let It Go generally has a negative tonality. Musicologist W Anthony Sheppard pointed out the negative vibe of the song. "There are five 'don'ts', four 'nevers' and three 'nos' in the lyrics," he said.