Emotional portrait photography

I found some examples of amazing emotional portrait photography online. I want to find the best ways to capture emotion and which emotions are most recognisable when caught on camera as well which emotions are photographed most often.

http://psdcollector.blogspot.co.uk/2010/08/portrait-photography-expression-of.html

Portrait Photography : The Expression of the Emotions

Portrait photography or portraiture is the capture by means of photography of the likeness of a person or a small group of people (a group portrait), in which the face and expression is predominant. The objective is to display the likeness, personality, and even the mood of the subject. Like other types of portraiture, the focus of the photograph is the person's face, although the entire body and the background may be included. A portrait is generally not a snapshot, but a composed image of a person in a still position. A portrait often shows a person looking directly at the camera.

The photo above stands out to me from the rest on the site, there are about 20 other photos but this one has caught a genuine feeling. This image shows a moment in time where this little girl felt a certain way. The photo is called 'Stop killing people' by Surinda Singh. At first glance I thought the girl was on a playground sliding down a zip wire type of thing, I thought she was expressing fear from doing so and it's only because of a clearer inspection and help from the title that I'm assuming she's protesting. It looks like she's holding a sign up and shouting but the thing that interests me is how passionate she looks about the potential 'Stop killing people' protest when she's only a small child, because of this adult like quality she seems to hold, this photo is quite uncanny. 

Another site that caught my attention when researching emotions within portrait photography is the only shown below. 

http://www.dzineblog360.com/2010/12/50-inspiring-examples-of-emotional-portrait-photography/

50 Inspiring Examples of Emotional Portrait Photography

Photography is all about capturing and preserving the moments of real life forever. Photography involves expressions, inspirations and emotions all captured in one fine click of the camera. For good photography, camera, set and make-over is secondary. It is based on the aesthetics present in the person doing it. That is the reason it is said when it comes to photography, “Beauty lies in the eyes of the camera-holder”. This post gives you 50 inspirational examples of emotional portrait photography. Enjoy!

This photo looks to me like the man is showing great determination. The look to the right suggests he's moving that way, he's moving forward. The man in the image could be fighting something for example a disease. His face looks determined and like he's not ready to give up.