An interesting aside from a 1983 study that describes how some elderly psychiatric patients experienced photos and TV images as real people with whom they could interact:
A new sub-type of perceptual disorder was identified in 7 patients who treated T.V. images and newspaper photographs (e.g. a nude calendar girl) as if they were real and existed in the three-dimensional space. These patients talked to the images, saw them moving freely and on occasions offered them food and drink. This disorder which the authors would like to term the “picture sign” can best be described as a “sensory delusion”; no significant association between this sign and sex, age, underlying pathology, impending death or cognitive score was identified.
I’ve often heard the clich√© that patients with dementia believe that people on television are in the room with them, but this is the nearest I’ve come to discovering any published research on the topic. If you know of any, do let me know.
However, if you’re a Spanish speaker, there was an interesting incident captured on a phone-in TV game show, where an elderly and presumably somewhat confused contestant calls the show, hears her own voice coming from the television and thinks it is someone else joining in the conversation.
Brilliantly, the exasperated game show host sticks with it and everything gets delightfully surreal.
Mind Hacks 
Well, not public research, but my friend, who work at a home for elderly people with dementia, have a patient that cuddle with every picture of a child she sees. That is, she strokes the pictures with her finger and says the Swedish equivalent of “gootchie gootchie goo”.