This is an interesting curatorial decision, as it affords many opportunities for learning if one is willing to take the time over each painting - but you have to spend the time!. A number of empirical studies have shown that, in general, visitors to museums spend strikingly little time looking at individual paintings. Here's an extract from the abstract of a 2001 study:
In order to counter such tendencies, researchers (Steve Seidel and others) at Harvard's Project Zero strategies for investigating art that aim to help people learn more from the experience. Following these principles, I spent considerable time in each room observing each painting very closely. I asked myself "What do I see in this painting?" (making no interpretive or quality judgments), "What questions do I have about this painting?" (for example, "why does the upper left hand corner of the painting seem unfinished?"), and "What hypotheses do I have about the answers to my questions?" Of course, I refrained from reading the commentaries that accompanied each painting.
This was an enlightening experience. By the end of my visit, I could I found myself able to predict, occassionally, which artist was responsible for a given painting. I had identified for myself stylistic differences and similarities. I had correctly identified that some works were unfinished, and where the unfinished sections occurred in the canvas. All this from looking and thinking.
Perhaps, when you are next at an art exhibition, take longer than those 27 seconds! It can be extremely rewarding...