Paste the code below into your functions.php file. Once you saved the file, authors will only see their own posts in the admin post list.
<?php function mypo_parse_query_useronly( $wp_query ) { if ( strpos( $_SERVER[ 'REQUEST_URI' ], '/wp-admin/edit.php' ) !== false ) { if ( !current_user_can( 'level_10' ) ) { global $current_user; $wp_query->set( 'author', $current_user->id ); } } } add_filter('parse_query', 'mypo_parse_query_useronly' ); ?>
Thanks to WP Snippets for the code!