when did leonard nimoys character change?

This movie is very fresh in my mind as I saw it in a local theater last nite (they have a special event where they show old movies called CULT CLASSICS).

There have been several threads discussing this here over the years. He was a narcissistic A$$hole at the book party and I never liked him but my guess is he was human at the party and really believed it was some weird form of hysteria and got snatched sometime between the party and when he showed up at the mud bath. You notice he has a dull blank stare in his eyes when he shows up. I think the movie is trying to show he has changed. I think its ambiguous on purpose.

As with the strip show barker later in the film, an argument can be made that acting excited isn't synonymous with real emotion.

It's quite possible he was already a pod in the bookstore, ironically advocating the invasion through his own persuasiveness as a respected self-help author. Having seen the film about a dozen or more times, that's the theory I go with.

If you choose not to go with that interpretation, then an alternative is that he left the party, fell asleep, and emerged a pod in time to meet everyone at the Bellicec's mud bath.

No offense, but you saw the same film we all did. How can anyone know the answer?

I thought it was pretty obvious Kibner was human during the book signing party and a pod by the time he gets to the Belicec's bath house. It's all in the dialogue. During the book signing when speaking with Matthew he seems genuinely perplexed about what's going on with the complaints about people changing and even tells Matthew that the symptoms "seem to go away in a day or two" because he doesn't know that the people who are making these complaints are changed into pods within a day or two and then their complaints/symptoms of course disappear and he thinks they're back to normal.

By the time he gets to the Belicec's it's obvious he's a pod. He shows no emotion or reaction whatsoever when the Belicecs are running out of the door and scream in his face out of surprise. He of course dumps Jack's unfinished pod outside the window so the garbagemen could dispose of the evidence. When Matthew gets there and starts phoning the cops Kibner makes the remark "Who are you waking up now Matthew?" because he knows the transformation is made when people are sleep.

I thought he was a podman from the beginning. They went for the important people in society first, and Kibney was instrumental for them.

I'm certain he's not a pod in the beginning. He's too overtly emotional to be one.

Update: I listened to the audio commentary by Philip Kaufman and he seems to imply that he wasn't a pod in the beginning, as I suspected.

I got the impression right from the start that David was one from the very beginning of the film. Just wanted to punch him in the nose haha.

I've always assumed he was already a pod person at the book signing.