Facets of Interaction: Text

July 2, 2007 Mohamad Eid

Facets of Interaction:Text

Chapter 13


Can you read this?

I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid! Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? Yaeh, and I awlyas thought slpeling was ipmorantt.


Outline

Human Issues Concerning Text Using Text in Interaction Design Technical Issues Concerning Text


Human Issues Concerning Text

Human Issues Concerning Text The Reading Process The Reading Purpose Paper versus Screens



The Reading Process Saccades: Quick, jerky movements Fixations: Intermittent pauses on areas of interest

Visual and cognitive processing occurs during fixation but not during saccades. If text is difficult to comprehend, if it includes long or

unfamiliar words, fixations increase in duration



The Reading Process

Experienced readers recognize word shapes



The Reading Process

We read extended text passages more quickly in lowercase than uppercase

Lowercase presentation is more common Lowercase words have more distinctive shapes



The Reading Purpose Continuous process (novel) Scanning Reading from screens or paper



Paper versus Screens

Paper is more flexible than electronic media

We often rely on our spatial memory when we search for information

Place holders


Paper versus Screens

The ability to annotate aids comprehension



Using Text in Interaction Design

Commentary/Instrumental Legibility Readability Physical Factors



Commentary – Text that informs The most common form is help text

Contextual help provides immediate assistance to users without requiring them to leave the context in which they are working, such as pop-up menus.

Procedural help provides the steps necessary for carrying out a task.

Reference help serves as an online reference book.Conceptual help provides background information,

feature overviews, or processes.



Instrumental – Text that does work (Ramey, 1989)

Controls: the control’s function and its label are viewed as one entity

ButtonsCheckboxesRadio ButtonsIconsHyperlinks



Hypertext

Hypertext links must give unambiguous indications of the target destination

Krug - Don’t Make Me Think (2006) - suggests that what is important is not so much the number of links that a visitor must click but rather the quality of the links



Legibility

Legibility is an essential first step in the reading process

We must take these environmental conditions into consideration when we are making determinations about font size and foreground/background contrast.

Design for the least favorable conditions



Legibility We must also consider age and possible vision

impairments

Our capacity to perceive details decreases with age



Readability Comprehension is affected by:

Line length Line spacing Formatting Margin width Scrolling It is also affected by grammatical issues, such as

semantics and syntax



Readability

Use the terms people will see in the interface

Technical terminology should be avoided

Word-for-word translations can create confusion

Italian street signs



Readability – Ambiguous text

Avoid noun stacks; they are ambiguous

Linguistic “Escher effects” (Ramey,1989) Input Mode Search Results



Physical Factors Font size Line length Margin width Vertical line spacing Alignment Contrast Scrolling versus paging



Font size Factors that affect font size: (Horton, 1994)

Reading Distance—Greater distances require larger text.

Screen Resolution—Smaller text requires greater resolution to keep the characters clear and legible.

Text/Background Contrast—Negative contrast is optimal (black type on a white background).

Visual Acuity of User—Not all users have 20/20 vision.

Type of Reading—Text can be scanned, read word by word, or read character by character



Font size General benchmark formula for font size, given

normal vision and optimal conditions

Font Size = 2d(tan(θ/2)) X DPI



Line length

Line length affects reading performance but not comprehension

Lines of greater length are read more quickly

People prefer medium line lengths



Margin width Shorter lines—4 inches—with large margins

increased reading performance (Youngman and Sharff, 1998)

Maximal use of white space



Vertical line spacing The spacing between lines of text (single spacing,

double spacing, etc.) is called leading Double spacing has been shown to improve

reading speed (Kolers, Duchnicky, & Ferguson, 1981)

It might necessitate a smaller font size to increase the amount of visible information per screen



Alignment

For optimal reading of lengthy texts, right and center alignments should be avoided

Text should also be considered a graphical component of a page



Contrast

Contrast sensitivity decreases significantly with age



Color Contrast Because black and white have the highest contrast the

addition of any color will reduce the contrast

Luminance contrast is more significant than color contrast



Scrolling versus paging

Consistent link location.

Paging

Scrolling



Scrolling versus paging

Scrolling facilitates maintenance and printing

The choice of paging versus scrolling depends on task and layout


متشکرم

谢谢

ありがとう

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Facets of Interaction: Text