Rest in peace, Ellie.
The late-'50s-to-early-'60s girl group "movement" is one of my favorite phases of pop music. They had superb songwriters, great producers and above all, they wrote amazing melody lines and harmonies. Many of these attributes had a strong influence on the biggest names in the British Invasion (a movement which, if you believe the accepted wisdom about pop history, weakened the public's appetite for "Brill pop").
You can hear strong influences of the girl groups on the Beatles, particularly in their earlier albums. Their lyrics, vocal performances, song structures, arrangements and production all owe a great deal to the music that came out of that one building in New York city.
Soundscapes examines this influence in great detail in an article titled "Boys will be girl group". Here's an excellent excerpt from the analysis. (The emphasis is mine):
"Beyond the vocals, however, other facets of Girl Group arrangement abound in the Beatle oeuvre. Those echoed handclaps, tambourines, little obbligatos playing the melody in the middle, the use of realistic sound effects, all have their beginnings among the Girl Groups. Doubled instruments — for example, piano and harmonica playing the exact same thing to produce a "new" sound — was a Phil Spector technique developed for girl groups, later expanded and mastered by both the Fabs and the Beach Boys."Check out the the Beatles' BBC Sessions album for some fantastic covers of music from this era. (Also read this review of the Beatles' cover of "Baby it's you" on PopMatters.) This version of "To know her is to love her", covered so wonderfully on the BBC sessions is not from the album but from an older Silver Beatles' session (?).