>>35099050Not sure what level of explanation you are seeking but I'll try.
On a plot level, it is meant as an anti-empathy test. If you recall from the original Blade Runner there was the Voit-Kompff test, which was an empathy test designed to elicit an emotional response, with the idea of catching a replicant who is not exhibiting the correct human emotions. The cells interlinked test is designed to test the opposite, to ensure that replicant Blade Runners aren't acquiring emotional responses to the job of killing replicants.
On a functional level, the test works by interleaving portions of a pre-memorized "baseline" with questions designed to provoke an emotional response. Whenever K hears a word or words from his baseline he has to repeat them. If he is calm and unemotional, he'll respond quickly (as he did after killing Sapper), if he is starting to develop emotional responses he'll respond more slowly, and with greater stress in his voice (as he did after returning from the memory doctor).
On a literary level, K's baseline is from the book Pale Fire, by Nabokov. Specifically it is from a poem within the novel, the novel itself being constructed of the foreword, the poem itself, and the afterword (a very extended and interpretive analysis of the poem), with the foreward and afterward supposedly written by a different author who is presenting and analyzing the poem of a Mr. John Shade, for the reader. The section of the book they selected is the poet himself describing a near death experience within the poem, and is about 700 lines into the poem, which continues for another several hundred more lines after this section.
I can't tell you how
I knew - but I did know that I had crossed
The border. Everything I loved was lost
But no aorta could report regret.
A sun of rubber was convulsed and set;
And blood-black nothingness began to spin
A system of cells interlinked within
Cells interlinked within cells interlinked
Within one stem. And dreadfully distinct
Against the dark, a tall white fountain played.
Within the movie, K has this book in his apartment, and Joi even picks it up and shows it to him, proposing that they read some of it together, but he points out that she doesn't like it. Not being an expert on the book myself (I haven't finished reading it yet), I will refrain from further speculation on the relationship of the book to K's character.
Hope that helps!
