change next links and previous link names to actual post tiltle name

hello

i want to change next previous links and previous post links to actual post title name

i am using twenty eleven theme
and here is the code in my single.php
<span class=”nav-previous”><?php previous_post_link( ‘previous post’, __( ‘<span class=”meta-nav”>←</span> Previous’, ‘twentyeleven’ ) ); ?></span>
<span class=”nav-next”><?php next_post_link( ‘%link’, __( ‘Next <span class=”meta-nav”>→</span>’, ‘twentyeleven’ ) ); ?></span>