Thanks, that sounds right. I want to say that that was my impression as well, but if I try to be honest with myself I really don't know if that's true.

It still seems like a big leap, and from what I understand Luke may be misrepresenting self-perception theory. Luke claims that "our knowledge of ourselves is exactly like our knowledge of others" while your link says that in the introspection illusion "people wrongly think they have direct insight into the origins of their mental states, while treating others' introspections as unreliable" (my emphasis). These sound like different claims and Luke's is more extraordinary. And for that matter it doesn't seem necessary or helpful for the ensuing discussion of the overjustification effect.

It occurs to me, though, that I'm just arguing because I'm confused about the material, so I'm going to go read some more.