Once upon a time, although it seems barely credible to us now, we were all children. We gurgled, we cried, we laughed, we explored, we fell down, and we had very little idea about the journey on which we had just embarked.

Barring mishap, over the first few years of our lives we developed memory, language, self-concept, cognitive, social and emotional abilities. We took our first steps towards our future selves.

Child psychology - or, more broadly, developmental psychology - is not just the study of children, it is the study of you and me and how we came to be this way. Just as discovering your history can teach you about the future, so child psychology shows us what we once were and even what we will become.

Here are 10 classic studies that have illuminated crucial areas of childhood development. Each one is a piece in the jigsaw puzzle that is ourselves, and each one reminds us, through examining just one piece, how aspects of experience we now take for granted were once so complex.

1. Infant Memory Works From Very Early
2. When the Self Emerges: Is That Me in the Mirror?
3. How Children Learn the Earth Isn't Flat
4. The 'Strange Situation': Window on a Child's Past and Future
5. Infants Imitate Others When Only Weeks Old
6. When Children Begin to Simulate Other Minds
7. Infants are Intuitive Physicists: Object Permanence
8. How Infants Start the Journey to Their First Word
9. 6 Types of Play: How We Learn to Work Together
10. Jean Piaget's Four-Stage Theory: How Children Acquire Knowledge

[Image credit: Patrick Q]