psql: FATAL: Peer authentication failed for user “dev”

when i create a new user, but it cannot login the database.
I do that like this:

postgres@Aspire:/home/XXX$ createuser dev
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) y
Shall the new role be allowed to create more new roles? (y/n) y

then create a database:

postgres@Aspire:/home/XXX$ createdb -O dev test_development

after that, I try psql -U dev -W test_development to login, but get the error:

psql: FATAL:  Peer authentication failed for user "dev"

I tried to solve the problem but failed.