Additional Design Journal #2 Principles

Control

The control principle is used effectively in the Itunes store. As shown in the screen shot below, users can choose between “Buy and download using 1-Click” or “Buy using a Shopping Cart”. They can control the level of confirmation required on their part to complete a successful transaction. This provides both beginner and advanced users with an Itunes shopping experience that meets their needs.

Entry Point

The “New Releases” section of the Itunes store acts as a clear entry point into the store portion of the application. As shown in the screen shot below, it uses progressive lures – a headline, images and colour – to attract people to the newly released albums.

Expectation Effect

The home screen of the Itunes store displays music and movie files available for purchase under the headings of “Top TV Episodes”, "Top Movie Rentals", “Top Songs”, and “What’s Hot?”. These headings are an example of the expectation effect. When users access the store, they expect the featured songs and movies to be of some quality because they are popular among other users.

Exposure Effect

In the screen shot of the Itunes store shown below, music by Beyonce is featured in 4 different sections of the application. This is an example of the exposure effect. The Itunes staff (and presumably, Beyonce’s record label) aim to increase the likability and potential purchase of her music by increasing the number of times users view her name and/or picture in the store.

Fitt’s Law

The scroll-bar along the right side of the Itunes Music Library uses Fitt’s Law to generate a realistic scrolling movement based on the size of the user’s music collection. For example, if the user’s collection is large, and he or she wishes to view their whole collection, the user must scroll for a longer period of time or at a quicker rate than would be required if the collection were smaller.

Forgiveness

When purchasing items in the Itunes store, the application forgives accidental clicks made by the user. For example, when a user clicks “Buy Song”, the application displays the dialog box shown below. This confirms the intent of the click and forgives any actions he or she may have made unintentionally.