are there any researchers who have conducted a study on this state of hunderstanding?
Yes, George Mandler is one of them.
Consciousness
In 1975 George Mandler published an influential psychological study which distinguished between slow, serial, and limited conscious processes and fast, parallel and extensive unconscious ones. 
the type of consciousness we experience when we are conscious of external sensations UNANSWERABLE what is the definition of consciousness? The Cambridge Dictionary defines consciousness as ""the state of understanding and realizing something." what are the different types of it? Ned Block proposed a distinction between two types of consciousness that he called "phenomenal" (P-consciousness) and "access" (A-consciousness). besides humans, are there any animals which have developed this state of understanding? Most people have a strong intuition that some animals, such as cats and dogs.
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Consciousness [SEP] Scientific study
For many decades, consciousness as a research topic was avoided by the majority of mainstream scientists, because of a general feeling that a phenomenon defined in subjective terms could not properly be studied using objective experimental methods. In 1975 George Mandler published an influential psychological study which distinguished between slow, serial, and limited conscious processes and fast, parallel and extensive unconscious ones. Starting in the 1980s, an expanding community of neuroscientists and psychologists have associated themselves with a field called "Consciousness Studies", giving rise to a stream of experimental work published in books, journals such as "Consciousness and Cognition", "Frontiers in Consciousness Research", "Psyche", and the "Journal of Consciousness Studies", along with regular conferences organized by groups such as the Association for the Scientific Study of Consciousness and the Society for Consciousness Studies.