So, Don Norman's seven stages of action give us insight into some of the ways that, systems can fail to support users goals, and users actions, and trying to accomplish those goals. So, one thing we can notice is that these steps over here, form a pathway that lead to execution of an action on the world or on the system. Starting with forming the intention to perform a certain action, selecting the action, and then executing that action on the system or the world. And over here on the other side, we have the pathway of evaluation of looking at the state of the world after acting on it and evaluating whether the action was successful and whether the action has led the person closer to their goal. So, looking at these two sides of the model, execution and evaluation, it helps us to see some of the places where breakdowns can occur, and Don Norman refers to these as gulfs. And he talks about the gulf of execution as being the challenge that a user faces when trying to map their goals onto the possibilities that are in the world, and selecting appropriate actions that will help them accomplish their goals. So, an example of the gulf of execution might be illustrated here with these glass doors that, imagine that those signs were not there. A person trying to get inside the building would look at these doors and have difficulty knowing what action they needed to take to get those doors open and get inside the building. And you can see that it was challenging and that many users faced this gulf because the people whose door this is had to put signs up, explaining in quite some detail how to operate this door. So, it says, ''Push this glass door to enter,. After pressing the buzzer, do not push the black button.'' And you can see that many people weren't even sure which door to push, because they had to put another sign that said, ''Push the glass door on the right.'' This is an example of a door that presented the gulf of execution to people that wanted to get in, In order to bridge the gulf of execution, the somebody had to put some signs on the door explaining how to use a door. A door probably should not have to have instructions and how to use it. So, here is an example of a more elegant way to bridge the gulf of execution, which is to use features of the door itself to indicate what actions are possible. So, by including a push bar like this one, it makes it very clear where you should push, what action you need to take, which is pushing rather than pulling in order to operate this door. The other side, Norman calls the gulf of evaluation, and that is the gulf that uses face when trying to interpret the state of the world to determine whether their actions were successful and whether they moved them closer to meeting their goals. So, an example of this might be these two buttons, that are used for activating the crosswalk signals, that don't give any indication of when they've already been pushed, whether the system received their input and whether there is in fact going to be some change in the walk signal at some point in the future. So, you'll often see people standing at intersections like this, pushing the button over and over again in the hopes that at least one time, the system will accept their input and change the signal. Slightly better version of this would be just to add a little light that changes color or turns on when somebody pushes the button so that the user knows that their input has been received and the system is going to take action on their behalf. So, when designing systems, we want to bridge these gulfs, the gulf of Execution and the gulf of Evaluation. And how do we go about doing that? Well, if we understand users goals, what it is that they're trying to accomplish with the system, and how they think about accomplishing them, we can make sure that the actions that they need to take and expect to be there will be visible and available. So, we need to make sure that the likely actions, the things that people are likely to do are visible when they're needed and that they make sense. That people are expecting them to be there, they understand what will happen when they execute those actions, and it's framed in language or using images that they will associate with their goals. We also need to make sure that the results of their actions are visible and that they make sense. That they can tell that the feedback that they're getting indicates to them that their actions were successful and that the actions are leading them towards the goals or away from their goals, so that they can take a different course of action. So, when we're designing systems, we need to keep the gulf of execution and the gulf of evaluation in mind, so that we can make sure we're designing systems that bridge those gulfs and help users accomplish their goals.
