Johns Hopkins University Principles of Human Computer Interaction

April 7, 2013

POET AssignmentBy Frances Advincula

Potato Peeler1. Afforadances => VisibilityI knew that this was a potato peeler because I have seen and used one before. But I suspected that if one hasn't seen one previously, it looks pretty alien. To test this, I asked my younger sister what it was, and she said it was part of a blender!

Figure 1: A beater, part of a mixer.

Figure 2: Ergonomic handles of a potato peeler.

I also think that which end to hold is quite confusing, at least from the picture.Some potato peelers have bright, ergonomic handles, which make them quite obvious.

2. ConstraintsOne end is a handle, and the other is the peeler part, but it is not quite clear from the picture. It might be more obvious in person when one can tell which end has the sharp edges.

3. Mappings

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If one sees that one end's edges are sharp, it makes sense that that is the peeling part...but I think that only works if one knows this is a peeler. What if you don't know what it is for? What if, in your culture, only knives are used in the kitchen?

4. Causality =>FeedbackIf one slides it through the skin of a potato, it will peel it -- so one will know it's a peeler! One a worse scenario, if one cuts himself on the sharp side, you know that that is the sharper side and should take precaution when handling it!

5. Transfer I only knew what this was for because I have seen it used in the kitchen previously, but personally, I don't think the design affords its purpose. It's like a wine opener -if you don't drink wine from a bottle, you might not know what it is.

6. Consistency/Cultural StandardsWhat if the potential user came from a country without potatoes? I’m sure most cultures use knives to peel, I wonder how they peel their fruits and vegetables other than a knife! I just watched the movie, The Croods, so I wonder what cavemen used to peel their food, especially before men started using tools!

Figure 3: A Thai woman peeling fruits.

7. Mental Models/Conceptual ModelsI think this is one of those things that is pretty obvious once you've seen it, but should be shown for the first time.

8. Comfort=>Undo

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There is no "undo" action in this context. As far as comfort though, once one knows the sharp side, it should be safe. That being said, potato peelers are a lot safer than knives!

Amazon.com1. Afforadances => VisibilityThere is a big searchbox front and center in the page. Because we are used to Google, we know we are supposed to type into it if you want to look for things. There are also links all over the page, and when I hover on them, a hand shows up so I know I can click. It is interesting to note that for this homework, I had done a Google search for "potato peelers" and when I went to Amazon, they had a showcase of potato peelers at the bottom of the page for me!

Figure 4: Amazon.com homepage.

2. ConstraintsThere are a limited things you can do. Search for products through search by typing things on a textbox, click on links. It is interesting to note that one can type in special characters on the search box, like "!@**" I wonder if there are products that use those types of characters?

3. MappingsWe know we are supposed to type into the searchbox and press the Go button, and we know we can click on links to view products. They map into our brain because we've seen how Google works, and the product information hierarchy mimics that of a traditional print catalog.

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4. Causality =>FeedbackI like the tooltips that I get when I hover on buttons, and the more expressive ones when I hover on the links in the left side -- it gives me a preview of what is in there and tells me what kind of things I will probably find.

Aside from that, since you pretty much can type anything in the searchbox, I don't see much feedback as far as errors are concerned. 5. Transfer effectsWe know how to search for products because that is the information model of almost every single e-commerce site, regardless of language.This is what the China site looks like, exactly the same as far as layout!

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Figure 6: Amazon China homepage

6. Consistency/Cultural StandardsVery consistent across cultures. I would say the products featured are customized to geography. Notice the China site above, versus the UK site below. Notice how the products change (Harry Potter is a British creation) and how the currency, and of course, the language is localized.

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Figure 7: Amazon UK homepage

7. Mental Models/Conceptual ModelsWe know how to use these because they mimic traditional catalogues -- products are by category and each product has more information in it. I'm not sure if the stars (for reviews) would make sense to a person who isn't aware of how a review system works. They might assume it is granted by a professional organization (like stars for a hotel) and not regular people.

8. Comfort=>UndoThe only undo I see is when typing on the search box through the backspace and delete keys of the keyboard, but that is standard to every text field and not the Amazon home page.

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