Psychopaths learn to be organized killers by killing and improving what might have almost failed before. He apparently was caught after he first killed, thus the end to the learning curve. Thank goodness.
A BIG part of the mindset is the fantasizing and planning of " the perfect crime". The psychopath thinks he is smartest person on earth. That he is superhuman.
A Psychopath has no conception that a 13 year old girl NEEDS anything or anyone, except him. Just him. Her world was narrowed to a portion of a house for 3 months, parts of that spent in a 2 1/2 clearance space BY FORCE.
He knew that HE would be uncomfortable under his own bed, but psychopaths do not have the ability to understand her discomfort. He understands it is TORTURE, but not the extremely painful feelings of being tortured. Her torture was part of his fantasy game.
The reason he did not buy any shampoo, and likely no basic personal care items for Jayme is that to the psychopath, they SEE other people but they do not RECOGNIZE that others have the SAME NEEDS, HURTS,WANTS, PHYSICAL HUNGER, and so on THAT THEY HAVE.
PEOPLE ARE OBJECTS.. MOST PSYCHOPATHS WILL PLAY WITH A VICTIM LIKE SOMEONE PULLING WINGS OFF A BUTTERFLY. ( Stalking, weird messaging, peeping and maybe photographs through a window. After the victim is in his possession, it is common to find survivors or bodies with overt signs of torture, burning hair or body part, cutting hair off a female, making a female thinner by not feeding her well for various reasons, leaving in urine and fecal material.
I am speaking in general and not about Jayme specifically, of course except for why he did not buy her shampoo. I'm so very happily surprised she wasn't almost starved to death with open wounds from malnutrition and having to lie on the floor underneath a child's twin sized bed for hours and hours at a time.
Also, FTR, I do not, in any way, believe he played Monopoly with her, or acknowledged the holidays with her except that maybe he told her it was Thanksgiving, then Christmas, and no one cared about her.
Depersonalization is achieved by a variety of means, but misuse of two major holidays with a girl who has just seen the dude murder her parents would be diabolical and so incredibly SADISTIC.
I think he's very very high on the SADISM scale. I also see high amounts of depersonalization, which is a major trait of ASPD violent men.