I think that by spending time with the child ,doing things that are fun to them, is one way for one to demonstrate their love to their child because the child might feel like you are listening to them. Another way would be to give them things they want. This may sound just like one is spoiling the child and bribing them for affection but this may actually mean, once again, that you are listening. And lastly, a way to demenstrate affection would be to just know the childs feelings and respectfully react because ones not all up in the childs face "hover".
The Swiss developmental psychologist Jean Piaget used the term assimilation to explain the process in which people understand an experience in terms of their current stage of cognitive development and way of thinking. Assimilation is included in the adaptation process and includes the learning of new information and incorporation of that new information into our existing knowledge.