Specifically looking at Pathfinder’s Join Pasts, which reads:
With touches to the targets’ foreheads, you bring them into mental communion. The targets can share thoughts and experiences, but not words. When one target attempts to Recall Knowledge, the other can Aid the first target’s skill check, using any Lore skill (even if that Lore wouldn’t normally apply) without having made any preparations to Aid.
Could someone under the effect of this cantrip lie when sharing a thought or an experience? In my game, we’ve used this spell to look at a target’s past experiences and see things through their eyes – but the idea that they could just lie (for instance, by sharing that they grew up impoverished or were stolen from) came up recently.