had a chat with my supervisor today and he was talking about post doc study but said it in suc a way that indicated people never change field from their PhD topic? is this the case? im a little confused as that would restrict my job potential to like 2 or 3 places.

Noo - there's plenty of scope to change. It's the skills you're obtaining which are more important than the study area.

What field are you in for your PhD, and what are you thinking of moving into? Obviously, going from neuroscience to tourism would be a huge change, and might be difficult. Neuroscience to another medical discipline, or microbiology for instance may be perfectly within your scope.

i00t2000 is right. i was worried about that myself but i spoke to one of the academics at my uni and he explained that it is the experience gained that counts and can be transferred to another field which relates to yours. You can, of course, change to a totally different field but i think that's headache for me.

Hi there... I realise this thread is a bit old so sorry in advance, but just came across it now!!! I am just looking for some advice in a similar area...

I am currently doing a PhD in computing and my original undergrad degree was in computing also. What I ended up doing for my PhD is a bit too technical for my liking so I've started thinking I'd rather get into the 'human side' of it all!

My idea is to finish the PhD and then do an undergrad degree (part-time!) in Psychology - so then I have a degree in both subject areas... my question is would I be qualified to do research that merges computing and psychology, even though my PhD is just in computing???

hm rosy, perhaps rather than a BSc in psychology, you could do a diploma, or a Master of Advanced Studies, maybe in parallel to working? much of what one learns as an undergraduate is not strictly topic-related, but rather stuff like study skills, organised thinking, essay writing, etc. and you wouldn't have to re-do all this.
you will have demonstrated through your PhD that you can think, work independently, do research. what you need next is the psychological knowledge. yes, if you get some sort of formal education in psychology, i do believe you should be able to do research in both areas/interdisciplinary. but i'm no expert, maybe this is just how i think it ought to be, and far from reality.