Taught by his father, who was an art teacher, Pablo Picasso had been a boy-genius, achieving technical mastership in the art painting, around the age of fifteen. Accomplished as he was, when exposed to the avant-garde art of his time, he must have realized that his technical virtuosity would be of little use him as a modern artist. His Blue Period consists in no small part of learning an entirely new style: expressionism. Many of the lessons he had learned from his father suddenly seemed useless and Picasso must have felt like having to start all over again. Picasso's Blue Period testifies of this struggle and one has to conclude that he was still young enough and had the courage to change himself from a prize-winning prodigy into an apprentice-expressionist. In Poor People on the Seashore, Picasso hasn't quite it got it right yet.
The composition of the painting doesn't add up. The woman figure on the left is supposed to be inert and looks perfectly natural, but the man on the right and the boy spoil the composition. The fact that the three figures together are almost perfectly centered on the canvas suggests a static scene. The way the man bows his head towards the woman without looking at her, suggests an intimacy between people that are standing still. However, the man's feet suggest that he's walking past her, so that the upper part of the painting gives a different impression than the lower part.
One has to suspect that composition wasn't much of an issue in Picasso's teenage days. People would marvel at the way he rendered the pattern and texture of a table cloth, or the translucence of a wedding dress, and surely it would have been petty to complain that the group portraits the boy painted, didn't look natural.