Asta666 wrote:The point I was trying to make is that those things one experiences or re-experiences are not the same as the behavior of experiencing/feeling/fantasizing,"
The thing you experience in your example is "a forest", and (of course) a forest is not a behavior. But this doesn't mean that you're experiencing some mental or physiological representation: what you're experiencing is, precisely, a forest. Both the forest and your biological structures are participating, in their way, in your perceptual activity of "seeing a forest": the forest participates with its disposition to reflect light, and your biological structures (e.g. eyes and brain) participate with their disposition of being affected by light. Your biological structures are adapted for that task: they were selected in phylogeny (a long time before hominization) precisely because they allow organisms to behave according to some aspects of the physical world, and therefore, they made a difference to our ancestor's survival and reproductive success.
Asta666 wrote:whether one thinks of them as mental or physiologically derived.
A forest is neither "mental" nor "physiologically derived": it's a large tract of land covered with trees. Your visual perception of a forest is neither "mental" nor "physiologically derived" either: it's a biological interaction between the forest's disposition to reflect light, and your biological structure's disposition to be affected by light.
Asta666 wrote:I wonder if it's a viable object for psychology or if it's neurology's field.
IMO, perceptual activity is a viable object for both. Psychology and neurology study different levels of interaction (organismic and suborganismic levels, respectively), and they're both subdisciplines of biology.
Asta666 wrote:Especially since one can read many reputed sources claiming that cognitive psychology is the study of the "mind" or computational processes that work with mental representations, which would be a viable stance if one accepts the premise of multiple-realizability of cognitive processes, but I don't think it's well supported.
As I told you, I don't believe in "mental representations" at all. Also, I don't think cognitive psychology is commited to the existence of mental representations (not all usages of the word "representation" imply a commitment with the existence of mental representations). Only some cognitive psychologists believe in mental representations, but their personal beliefs about this issue are usually innocuous for the advancement of their research programs, and of psychology in general.