Cant pass Author ID using variable

Hi,
I’m trying to get more posts from the current author for single.php to output thumbnails from their other posts. If I pass the number directly it works, but if I put the ID in a vairablea and put the variable into the args it stops working. Any

<?php
  $curUserID = the_author_meta('ID');
  echo $curUserID;
 $argsmore = array('post_type' => 'base_project', 'author' => $curUserID);
  $more_query = new WP_Query( $argsmore );

  // The Loop
  if ( $more_query->have_posts() ) :
  while ( $more_query->have_posts() ) : $more_query->the_post();
    the_title();
  endwhile;
  endif;

  // Reset Post Data
  wp_reset_postdata();

  ?>