Written for Business Zone, you can view the original here.We are all creatures of compulsion. When we find something we like, we go back for more. Once we think we can get something we want, we perform the actions to get it. Slightly disturbingly, this pursuit of rewards isn't that different to our pets.There have been plenty of studies conducted by psychologists into our shopping habits, particularly based around this pursuit of rewards. Classic results encourage the careful placement of fresh flowers and baked bread in a store, and fresh coffee just brewing when a prospect views a house. We provide a pleasant experience (reward) for the buyer to associate with the product, making them more likely to return or buy. These principles can also be applied to the ecommerce marketplace, although the details are somewhat different.We all like treats. In ecommerce this might mean giving away a free gift with all orders for a short period. These gifts could vary from small low cost items to large valuable goods, depending on your own average order value.I have seen this work to great effect with several merchants who gave away prizes as wide ranging as free postage and packing to a holiday in the Maldives. Not only does this grab attention, it also creates excitement. A relevant treat can transform the casual browser into a buyer.However, as an etailer your best market is always your existing customers and selling to them is much easier than converting non-believers. Doing this is all about compulsion and association.Starting with compulsion, let's not be under any illusions; making an online store compulsive is difficult, so every possibility must be explored.For instance, when emailing customers, try to change the email subject line and body text based on who they are (if you know) or their buying habits, to make opening the communication more compulsive. A tennis coach may be attracted by a subject headlining cheap tennis balls, then go for a deal on fake tan once the email has been opened.Thinking about how products are marketed is another area. Maybe you could introduce limited product runs. So tell your existing customer base that the widget they bought in pink last month is now available in blue, but in limited numbers. The idea of shortage can create a gripping reason for customers to return.This leads us on to association. We all like our experience to be relevant to our own preferences. The retailer Amazon utilises this to great effect. As soon as you visit their site you are given recommendations based on previous shopping habits and browsing history. Creating that personalised one-to-one service helps turn a faceless shopping site into an extension of your life. The site knows about you, who you are and what you like. The potential for up selling is enormous.Like it or not, we respond to rewards. When running an online store, failing to recognise this fact is likely to lead to falling behind on the curve.