According to Kraus’s research, as well as years of previous research, when music is played, the brain’s neurons produce an electrical mirror of the sound heard.

Also fascinating is the brain’s dependence on experience. For example, if the brain hears a few notes of a song it recognizes, even if the song stops playing, the brain will often continue mirroring the next few notes of the song.

For a recording of the brain’s electrical responses to music, watch the slideshow.

“What this proves to us is that music experience enhances sound processing, and this is applied to language skills,” said Kraus.

Learning music also boosts communication skills (hearing in noise, auditory working memory, auditory attention, and rhythm) and biological functions (the way the brain processes and identifies consonants, speech in noise, and patterns of rhythm), said Kraus. “And all of these processes are necessary for literacy.”

But Kraus and her team wanted to narrow the research, focusing on the questions: “What affect does music have in school-based, group settings?” and “Can music help close the knowledge gap in low-income students?”

Kraus studied second grade Los Angeles students enrolled in the Harmony Project (HP), a community-funded program that gives low-income students ages eight  to 18 and older instruments, five or more hours per week of music classes and rehearsals, the ability to build full-time bands and orchestras, and access to peer mentors and trained supervisors.

This multi-year commitment to HP usually occurs through high school and beyond. So far, more 1,600 students in three states are involved in HP, and the program has received two presidential awards from the White House.

“Music not only helps with learning skills, but helps students process and express deep feelings,” said Margaret Martin, founder of the Harmony Project. “It also elevates mood and brings people together.”

Over the past six years, 96 percent of HP high school seniors have graduated in four years and have gone to college.

Intrigued by this success, Kraus studied 80 students from the L.A. HP, as well as 150 freshman high school students in the Chicago Public Schools (CPS) music program. All students come from low-income areas.

“We already know that there’s a strong relationship between maternal education income and reduced linguistic stimulation,” said Kraus. “If a mother has little education and the student lives in a low-income home or neighborhood, by age five many kids have a significant word gap. They also experience more neural noise and response to sound is diminished and less consistent.”

Kraus wondered if low-income children who had participated in at least two years of music education would catch up to middle-income students’ linguistic and processing skills.

(Next page: The results of Kraus’s study)