1. Nowak KL, Biocca F. The Effect of the Agency and Anthropomorphism on Usersʼ Sense of Telepresence, Copresence, and Social Presence in Virtual Environments. Presence: Teleoperators and Virtual Environments. 2003;12(5):481-494. Available at: http://www.mitpressjournals.org/doi/abs/10.1162/105474603322761289 [Accessed May 25, 2011].
Presence can be split into several dimensions including:
Telepresence - Feeling like you are 'there' in the media.
Copresence - Feeling that other people are there too.
Social presence - The extent to which you are able to 'access another's mind'.
Tested agents vs avatars, and no image, hi-anthropomorphic image, low-anthropomorphic image. I don't like the 'high-anthropomorphic' heads - they look odd. The low ones are kind of friendlier looking, even though they are only eyes and mouth. Sounds like (in the discussion) the participants agreed with me, calling them 'not very attractive' and 'funny looking'.
They found any image is better for immersion in the environment than no image.
There are some consequences of the choice of image, although this paper found that users felt more copresence, social presence and telepresence when someone used a less anthropomorphic image. That apparently contrasts with other studies (Koda 1996; Wexelblat 1997).
They note that teh reaction to the high-anthropomorphic images wasn't bad, just not as good as the low-anthropomorphic image. The similarity to the results with no image suggests that the users may be putting in some default anthropomorphic mental image when no picture is supplied.
I think I'll give a brief overview of avatar research, but not focus on it. There's too much!