hiya! the way EP/PPL works is as such:
there are 5 different modules you can choose for 1st year - Introduction to Psychology, Introduction to Philosophy, Introduction to Linguistics, Neurophysiology and Probability Theory & Statistics.
you choose your combination of these when choosing the course on your UCAS application. everyone doing Psychology also does stats. these are the combinations you can do:
Experimental Psychology: Intro to Psych, Neurophysiology, Stats
Psychology and Philosophy: Intro to Psych, Intro to Phil, Stats
Psychology and Linguistics: Intro to Psych, Intro to Ling, Stats
Philosophy and Linguistics: Intro to Phil, Intro to Ling
so for any combination including Psychology, you will still have the same teaching for the Intro to Psych module, which is a mainly scientific course. however only EP does Neurophysiology, which is a very Biology-based module.
hope this helps! let me know if you have any more questions about it (i take psychology + linguistics)