Views on a topic are only increased when a user accesses the topic for the first time (thus only calculating unique views); this stops abusive users and bots from just refreshing the page to increase views on topics.
This code is managed by the following block in /scripts/showflat.inc.php:
// If this is our first visit to this topic, update the counter
if ($_SESSION['current_topic'] != $topic_info['TOPIC_ID']) {
$query = "
INSERT INTO
{$config['TABLE_PREFIX']}TOPIC_VIEWS
(TOPIC_ID)
VALUES
(?)
";
$dbh->do_placeholder_query($query, array($topic_info['TOPIC_ID']), __LINE__, __FILE__);
$_SESSION['current_topic'] = $topic_info['TOPIC_ID'];
}I would highly advise against ever changing this behavior, on any well trafficked (I'm mentioning TRAFFIC here and not posts) would likely spam your server with excess activity.
This is how it has always worked, as you wouldn't want additional connections to the database increasing views for every page reload as it'd severely impact your server.