function add_below_the_post () {

    $category = get_the_category();
    $category = $category[0]->category_nicename;

    if (!is_wp_error($category))
    {
        if ($category == 'student-stories')
        {
            if (is_page(42, 36, 54)) {  // Enter any list of page/post ID's here
                echo '';
            } else {
                echo('<a class="postFootLink" href="' .site_url() .'/people/student-stories/">Return to ' .$category .'</a>');
            }

        } else if ($category == 'news' & $postID == '16') //this is where I am going wrong
        {
            echo('<a class="postFootLink" href="' .site_url() .'/news/">Return to ' .$category .'</a>');

        } else if ($category == 'research')
        {
            echo('<a class="postFootLink" href="' .site_url() .'/research/research-snippet/">Return to ' .$category .' snippets</a>');
        }

    }
}

add_action('thematic_belowpost', 'add_below_the_post');