Why is my Psychology tab empty?

Because it is built from report cards, and this page is where those are written. No debriefs, nothing to read.

Analytics → Psychology has six sub-pages and every one of them reads the nine mental scores, the emotion tags and the wellness field off your daily report cards. It computes nothing from your trades alone.

So the sequence is: trade, come here, open the day, fill the report card, mark it complete. Do that for a few weeks and Psychology starts having something to say — it needs a run of days to correlate against, not one.

The Debriefs done figure under the month grid is the honest progress bar for this. If it reads 2/18, Psychology is working from two days.