Perhaps the strongest way to send a message is to not say anything at all.

Roughly 20 people gathered on the T. Anne Cleary Walkway on Thursday to express their concerns about African-American students on the University of Iowa campus.

The demonstrators included student members of three different campus groups: NAACP, Hubbard Group, and Sistah Speak.

Some concerns are the support for African-American student organizations as well as racism across social media.

Participants linked arms across the walkway to block oncoming students. Several held signs reading, “Black Voices are Not Heard” and “Black Voices Matter.”

However, none of the protesters’ voices were actually heard. As a symbolic gesture, the protesters covered their mouths with duct tape and stood in silence as students walked by on their way to class.

It was a gesture that Hubbard Group member Matthew Bruce believed would capture the attention of the campus.

“The point today is to try to symbolically show that our voices do exist and make people see that fact,” Bruce said. “And we deserve to be heard. This is our campus as well as it is any other students’ campus.”

Demonstrators deferred to Bruce after interview requests.

The Hubbard Group was created to support black males on campus and to address the individual and institutional concerns of African-American students and faculty.

Among those concerns is what demonstrators call a spread of racist posts and comments on social media around campus, including anonymous posts on the mobile app Yik Yak.

“There are constantly racist updates on Yik Yak,” Bruce said, holding up a sign with examples of recent posts from around campus.

The Hubbard Group also raises concerns about diversity among faculty and the retention rates of African-American students.

“These are just some of the things we believe the university isn’t talking about,” Bruce said.

High-profile discussions of national racial issues and cases have reached Iowa City over the past few months with social-media activism and several demonstrations on campus.

In December 2014, controversy erupted over a statue in the likeness of a KKK robe placed on the Pentacrest, and President Sally Mason put a Black Student Advisory Committee in place. The group hosted a forum earlier this month.

Following Thursday’s demonstration, which lasted approximately 30 minutes, the participants huddled together in silence.

“Try to understand, or at least listen to the experiences that we go through,” Bruce said. “I feel like that’s the first step to maybe creating some change.”

Although they didn’t say a word, the message was heard loud and clear by some of those passing by.

His response was a thumbs up and a “Yes.”