Recently, I was trying to understand the 4 phases of the "Hook Model". Trigger, Action, Reward & Investment.

From the study, I found there is 2 main category of the trigger. Internal & External trigger. In most of the articles, I got some common examples that are "check" engine light, "play" button, "buy now" button act as a trigger. In other words, they are called CTA's(Call to Action). CTA's like "buy now" creates sudden impulse or urge to buy something. These types of purchases are known as impulse purchases.

Now, My question is How does a button act as a Trigger? I don't understand or feel any trigger while I stare at a button like "buy now". Or am I missing something here?

  • 1
    Not sure if I understand the question correctly but the trigger only works in the right context. Just looking at a button that says "buy now" doesn't do much. But when it allows you to buy the thing you are informed about in the surrounding context and that you really want, the button becomes the trigger that makes you actually buy it (the action).
    – jazZRo
    Aug 20, 2021 at 10:41
  • @jazZRo I didn't understand the last line you said. " the button becomes the trigger that makes you actually buy it (the action)." Are you trying to say in some context button act as a trigger? I found CTA's act as a trigger from some research papers. On page no. 120, point 2.1: researchgate.net/publication/…
    – F.C. Akhi
    Aug 26, 2021 at 4:21
  • Point 2.1 states exactly what I meant: "Trigger phase: an external and/or internal trigger informs the user what to do next and how to act accordingly." The word "next" gives away that there is already some context. A CTA can function as an external trigger (the reason to click it being the internal trigger).
    – jazZRo
    Aug 26, 2021 at 9:19

1 Answer 1


Call-to-actions feature prominently on 'transaction' based websites like e-commerce shops or government website where there are clear and simple goals for the user (at least in their mind).

Often they will be going to these websites directly, so the buttons are clear triggers for them to link the goal they have in mind with the prompt that they are looking for. For example, you see an advertisement for a product and you click on the link (which is also a CTA in itself) and you are taken to the website where the purchase will happen. What you probably want to see most prominently is where you can go and make the purchase, and hence the "BUY NOW" / "SHOP NOW" text that you see on a lot of the primary CTA buttons on e-commerce websites.

The alternative scenario is that you are browsing for information and the website wants to convert you from a potential customer into a paying customer through their sales funnel process. In this case, you might ignore the obvious primary CTA buttons and instead look for more information or anything that will draw your attention or curiosity to find out more. And once you have gone through that journey, you'll come back and look for the primary CTA if you have been converted into a customer.

In theory this all sounds simple, but in practice it is probably more of a marketing art than UX design, although both rely on the application of psychological principles to real life situations.

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