What do readers learn from the first person narration about the narrator subjective or personal experience

This device allows the audience to see the narrator's mind's eye view of the fictional universe,[7] but it is limited to the narrator's experiences and awareness of the true state of affairs. In some stories, first-person narrators may relay dialogue with other characters or refer to information they heard from the other characters, in order to try to deliver a larger point of view.[5] Other stories may switch the narrator to different characters to introduce a broader perspective. An unreliable narrator is one that has completely lost credibility due to ignorance, poor insight, personal biases, mistakes, dishonesty, etc., which challenges the reader's initial assumptions.[8]

Explanation:

A mental image or mental picture is an experience that, on most occasions, significantly resembles the experience of visually perceiving some object, event, or scene, but occurs when the relevant object, event, or scene is not actually present to the senses.[1][2][3][4] There are sometimes episodes, particularly on falling asleep (hypnagogic imagery) and waking up (hypnopompic), when the mental imagery, being of a rapid, phantasmagoric and involuntary character, defies perception, presenting a kaleidoscopic field, in which no distinct object can be discerned.[5] Mental imagery can sometimes produce the same effects as would be produced by the behavior or experience imagined.[6]

The nature of these experiences, what makes them possible, and their function (if any) have long been subjects of research and controversy in philosophy, psychology, cognitive science, and, more recently, neuroscience. As contemporary researchers use the expression, mental images or imagery can comprise information from any source of sensory input; one may experience auditory images,[7] olfactory images,[8] and so forth. However, the majority of philosophical and scientific investigations of the topic focus upon visual mental imagery. It has sometimes been assumed that, like humans, some types of animals are capable of experiencing mental images.[9] Due to the fundamentally introspective nature of the phenomenon, there is little to no evidence either for or against this view.

Philosophers such as George Berkeley and David Hume, and early experimental psychologists such as Wilhelm Wundt and William James, understood ideas in general to be mental images. Today it is very widely believed that much imagery functions as mental representations (or mental models), playing an important role in memory and thinking.[10][11][12][13] William Brant (2013, p. 12) traces the scientific use of the phrase "mental images" back to John Tyndall's 1870 speech called the "Scientific Use of the Imagination". Some have gone so far as to suggest that images are best understood to be, by definition, a form of inner, mental or neural representation;[14][15] in the case of hypnagogic and hypnapompic imagery, it is not representational at all. Others reject the view that the image experience may be identical with (or directly caused by) any such representation in the mind or the brain,[16][17][18][19][20][21] but do not take account of the non-representational forms of imagery.

the purpose of the heading in the passage is to identify who is telling the story.

this excerpt is part of the book sugar changed the world (2010) written by marc aronson and marina budhos. as the book has been written by two people, the heading "marc" indicates that this specific excerpt is being narrated by aronson. in the fragment, marc describes his grandfather's story after hearing it from his cousin. however, there are other excerpts where budhos is the one that tells the story of her family.

aronson and budhos, who are husband and wife in real life, decided to write sugar changed the world when they found out how sugar, which had an important role in slavery and economy, changed their ancestors' lives.