Worshiping is expression of gratification towards someone who has helped us achieve something in our life. Prayer is an expectation for some achievement. There are different ways of worship and prayer towards the almighty who we presume is the one who fulfils our requirements. Same human has made different rules for worship and if we see statues are worshipped across all religions in some or the other form. We can ask something from someone who is able to understand our requirements and is also someone with whom we can attach ourselves freely without inhibitions. Therefore in all religions we identify the God in some of the human form, the God with whom we converse should be similar to us and speaking our language since then only He can understand our requirement but before Him. We personified every such medium where we acquired God to be interacted. In hinduism this concept was taken further ahead by personifying even the animals, plants, rivers, mountains and any other thing which in some way fulfils or has the capacity to fulfil our requirements.
A need to personify also arose from the fact that one attaches oneself only to a like figure for example when we are out of our country we get easily attached to a compatriot. Usually anyone gets attached to someone of his like. Every animal feels comfortable in the company of his own species. So most of the religions personified their Gods in human forms to keep their folks attached to the Gods. Hinduism understood this need of personified attachment quite early, hence quite early Hindu thinkers personified all those things to whom they felt gratitude. Sun, Moon, Rivers, Cows, Trees, Earth, Air, anything for which Hindus felt gratification were personified to create an attachment towards them for the general masses, so that the general mass helped in protection of these things just like their own folks.
A sense of attachment creates a sense of responsibility towards protection and conservation of those things we are attached to.The trees of Peepal and Barhgad are worshipped to protect them as trees which provide most oxygen and bind the soil. Barghad (Banyan) tree expands to large expanse and give protection from soil erosion near rivers where most of the early civilisation lived. These personification of Godly images were required to be converted to statues where everyone visualises the same form and is bound in their visualisation of the same God. After personification for greater attachment a need for cohesiveness among different individuals for seeing the same personified image led to creation of statues and calendar images. This was a step towards unification of human mind to a single thought, it was a mental unification of large masses. With statues everyone sees the same God in the same form and is there unified in his thought.
Across the world such unification of thought helps in creation of cults, societies and religions. The religious beliefs and their passing on from generation to generation helps cement the foundation of a larger thought process unified for a single cause. The visualisation of a unified cause is thus achieved through statues.
So when next time you bow your head and pray in front of a statue, do believe that several others are doing the same thing and praying for the same boon and you all have a common cause to stand before the statue with a common thought.