I have spamtrap@ and hamtrap@ addresses set up on my mail server and forward examples of spam to the spamtrap address. I was hoping that after a few examples, SpamAssassin would 'learn' to identify the particular characteristics of spammy mail with common attributes, but this doesn't appear to be the case - it still gets delivered as normal mail.

For example, some emails from the same sender and/ or with the same subject line, despite being sent several times to spamtrap@, are just delivered normally.

Does it sound like SpamAssassin isn't working or correctly configured, or have I misunderstood a fundamental aspect of how it works?