Wally World


For this week’s assignment, I was instructed to pick a system of interactive technology in public used by multiple people. The goal was to take notes on how people use the object and come to a conclusion about the successes and failures of the interactivity of the system.

I chose the Wal-Mart self-checkout system. Here is what I found…


I visited the local Wal-Mart Supercenter and observed people as they used the system. Here is what a self-checkout system looks like:


I have used this system before. This system is placed next to a typical cashier’s station (one that has a cashier there to check our your groceries). This system allows for the customer to check their own groceries and place them in the bag himself. There are usually a group of 4 in a store, with a Wal-Mart worker available for assistance should the customer need any.

It begins with a conveyor belt apparatus allowing me to remove my groceries from my cart and place them there for easier access. I then press the “Start” button found on the touch screen. I proceed to scan each item’s bar code on the scanner, placing each item in to the bags on the left. Once finished, I press “Pay”, and options to pay come up. My receipt then prints out on the far left.


Each customer that I observed go through the self-checkout system behaved very similarly. Most of them did not even utilize the first major part of the system: the large conveyor belt. They instead chose to leave their groceries in their shopping cart as their starting point. This perhaps could have been because most of the customers had less than 20 items and they may not have thought it was worth their time to put each item on the conveyor belt first.

Another common observation I made was that nearly every customer took a long time to find the barcode on an item (much longer than a cashier employee). This made for a slower checkout then going through the traditional cashier checkout aisle.

Positives of the System:

  • The feedback of the system was phenomenal. Each time an item was scanned properly, a “beep” sound was heard in addition to five green lights around the sensor that flashed momentarily. Simple, yet very important according to Norman’s “Psychopathology of Everyday Things”.
  • Every step of the system is in the following correct chronological order: the conveyor belt, the touch screen  and scanner, the bags, the credit card slide machine, and the receipt dispenser. This conceptual design is in perfect agreement with Norman’s thoughts on “natural mapping” (the physical analogies and cultural standards that lead to immediate understanding.)
  • Each step is designed so that the function is very obvious to anyone who has been in a supermarket before. The self-checkout is designed very similarly to the cashier checkout. This allows for the customer to know what to do without any added instructions.

Negatives of the System:

  •  There are many features on this system. I believe they could be consolidated to be even more simple in design. The receipt and the credit card machine are too far away from one another. They should both be integrated with the touch-screen display, allowing for the customer to just focus on one central part of the system.
  • Sometimes items had to be scanned multiple times. The scanner simply did not register the barcode the first time on every item for whatever reason. I believe it could have been due to the quick nature that a few customers sped through the scanning process, resulting in each of them waving the item back and forth three or four times.
  • The system would speak instructions to customers in Spanish (and display Spanish text on the touch screen) if the last customer to use the self-checkout chose Spanish on the languages setting. I believe this is a design flaw as the first thing that most of the customers had to do was change the language back to English. This is an extra step that should not be there for the vast majority of customers.

The part of the self-checkout that took the least amount of time was the beginning. Simply press “Start” and scan away. The “Start” button is also very hard to miss:

The part that took the most amount of time was the payment process. Once the customer completed scanning items, he then had to press “Pay”. From there, he had to choose how he wanted to pay–credit, debit, or cash. If he chose credit or debit, he had to shift his focus to the card-reading machine where he swiped his card. If he chose cash, he deposited his money in to the “Cash-In” spot next to the touch-screen. The payment process is finally finished after the customer grabs his receipt at the very end of the self check-out system.


This assignment was a great way for me to understand the thought processes that go in to making a public interactive technology system. There is a lot to think about from the design perspective. I was able to connect many of the ideas we discussed in class from the Crawford and Norman readings. Overall, I really enjoyed this assignment and I look forward to what we do next in this class!

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