7 ms·

This is a fun follow-on article building on another fun article. Unfortunately it seems that with a decent probability the entire premise of the first article

This is a fun follow-on article building on another fun article. Unfortunately it seems that with a decent probability the entire premise of the first article is wrong. The original article concludes that Marc Andreessen added blue hyperlinks to NCSA Mosaic in 1993, and that's where blue came from in web browsers. This appears to have stemmed from the mistaken notion that WWW.app (Tim Berners-Lee's browser) was only monochrome. And this follow-on article makes the same claim: > It is also interesting to note that WWW.app, the browser he was creating at the time, did not use blue hyperlinks. But that's not true. It's true that WWW.app as originally created didn't have blue hyperlinks because it was written on early NeXT cubes, which were 2-bit monochrome. But NeXTs were color as of 1990. And it's clear that as of 1993 WWW.app had blue links, as we had dug up in https://news.ycombinator.com/item?id=28318055 https://news.ycombinator.com/item?id=28318055 In 1991 Tim Berners Lee had added comments indicating support for color hyperlinks in the immediate future. At some point between 1991 and 1993 this feature was turned on, and links were set to blue. Since they both had or added blue by 1993, it is not clear whether Marc beat Tim to it or vice versa, but it seems to me likely that Tim was first. This is because (1) Since they both chose blue, it seems probable that one was copying the other. NCSA Mosaic was copying WWW.app wholesale in most aspects, and not the other way around AFAIK. And (2) Tim was influenced by earlier hypertext systems which used blue, as discussed in this article. Unfortunately neither of these articles actually ask Tim when he added it: they just assume WWW.app ran only on monochrome machines when, long before 1993, NeXT workstations were in color.

NoSorryCannot 5y ago
I feel like the only other plausible color that could have been chosen is green, and even that seems too opinionated. Reasons being mostly associations (red, orange, yellow meaning danger or stop, and green meaning go) and legibility on white or gray backgrounds. Add to that that people seem to disproportionately pick blue as their favorite color and they especially seem to favor it as a conservative or relaxing color choice. That is to say, I think the odds of two people independently picking blue are pretty good.
- EGreg 5y ago
  Actually, it was green. I am always surprised whenever Mozilla posts this, that no one seems to go straight to the horse’s mouth. So I will: https://www.w3.org/People/Berners-Lee/FAQ.html https://www.w3.org/People/Berners-Lee/FAQ.html Rendition of links Q: I'm a student of visual communications and asked myself why links are blue. I found some answers that might be, for example blue is a color of learning, but I'm not sure what is right. Is there any reason, why links are colored blue ? A: There is no reason why one should use color, or blue, to signify links: it is just a default. I think the first WWW client (WorldWideWeb I wrote for the NeXT) used just underline to represent link, as it was a spare emphasis form which isn't used much in real documents. Blue came in as browsers went color - I don't remember which was the first to use blue. You can change the defaults in most browsers, and certainly in HTML documents, and of course with CSS style sheets. There are many examples of style sheets which use different colors. My guess is that blue is the darkest color and so threatens the legibility least. I used green whenever I could in the early WWW design, for nature and because it is supposed to be relaxing. Robert Cailliau made the WWW icon in many colors but chose green as he had always seen W in his head as green. One of the nicest link renditions was Dave Raggett's "Arena" browser which had a textured parchment background and embossed out the words of the link with a square apparently raised area.*
  - kevingadd 5y ago
    That doesn't seem to suggest that links were green? "I used green whenever I could in the early WWW design" makes it sound like webpages were green, which is why the icon ended up being green.
  - SeanLuke 5y ago
    I don't think he's saying the links were green here. At any rate, the links were clearly blue on early color WWW.app screenshots. https://en.wikipedia.org/wiki/WorldWideWeb#/media/File:WorldWideWeb_FSF_GNU.png https://en.wikipedia.org/wiki/WorldWideWeb#/media/File:World... https://www.w3.org/History/1994/WWW/Journals/CACM/screensnap2_24c.gif https://www.w3.org/History/1994/WWW/Journals/CACM/screensnap...
  - zinekeller 5y ago
jka 5y ago
I must have experienced this article completely differently from you a couple of hours ago when reading it - I thought that it claims that the origin of the blue links was user experience research from the 1980s?
- gwern 5y ago
  I think OP is glossing over how much of a leap it is from Hyperties to Berners-Lee. (I was curious because the story 'red is too strong!!!' is a good fit for my https://www.gwern.net/Red https://www.gwern.net/Red page.) As written, it sounds like the color research was reported in the _Hypertext on Hypertext_ package, and Berners-Lee had a copy and was deeply immersed in it. Neither is true. The first paper from the Hyperties group cited (https://www.gwern.net/docs/design/1986-koved.pdf https://www.gwern.net/docs/design/1986-koved.pdf) does not cover color at all. It does mention some user-testing. I checked all the papers in _Hypertext on Hypertext_ and none mention Hyperties or color in any major way. (The keynote is a good read, incidentally: https://www.gwern.net/docs/design/1988-vandam.pdf https://www.gwern.net/docs/design/1988-vandam.pdf ) If you look at the Berners-Lee document cited, the Hyperties mention is buried in the bibliography; it is not even cited in the main text nor is Hyperties or link coloring mentioned, so I'm not sure why it's there at all, but it sounds like one of those cites-just-to-be-comprehensive, which often mean the author has never read the citation in question - so based on that, I'm unsure that way over in Europe Berners-Lee read any of the papers, much less actually saw the disk in action. The historical Hyperties page includes videos which show that by the time of the disk, they had defaulted to blue for link coloring, and mentions testing 3 colors (red was also used in Hyperties for other interface parts, so obviously they tested red vs blue vs ???). But the Hyperties papers after that do not mention color anywhere either. In fact, I can't find any Hyperties publication at all which reports the color usertesting or even that the results favored blue. It seems you just had to look at _Hypertext on Hypertext_ and assume that they picked blue because it was good? So, checking OP's references, I think Berners-Lee may never have seen _Hypertext on Hypertext_ (at least, in computer form); and if he had, he would not have known the blue was the result of user testing (because nothing in it says so); and if he had both seen & deduced that, he may not have both remembered & cared years later when setting up his own browser defaults for color monitors, and he doesn't say so anywhere.
divbzero 5y ago
> Unfortunately neither of these articles actually ask Tim… Yes, let’s just ask Tim and Marc! This is not ancient history where we’re forced to draw inferences based on limited information.
simonebrunozzi 5y ago
Comments like yours are why I love HN so much.
DonHopkins 5y ago
Ben Shneiderman recalled that "Tim told me at the time that he was influenced by our design as he saw it in the Hypertext on Hypertext project". Ben Shneiderman wrote the following email to John Gilmore and I, in response to a question John asked me about the origin of the term "hyperlink" raised in a discussion on the Internet History mailing list. John then forwarded Ben's email to the Internet History mailing list, here: https://elists.isoc.org/pipermail/internet-history/2020-April/005956.html https://elists.isoc.org/pipermail/internet-history/2020-Apri... >My students conducted more than a dozen experiments (unpublished) on different ways of highlighting and selection using current screens, e.g. green screens only permitted, bold, underscore, blinking, and I think italic(???). When we had a color screen we tried different color highlighted links. While red made the links easier to spot, user comprehension and recollection of the content declined. We chose the light blue, which Tim adopted. >His systems with embedded menus (or hot spots), where a significant user interface improvement over early systems such as Gopher. But Tim told me at the time that he was influenced by our design as he saw it in the Hypertext on Hypertext project that we used Hyperties to build for the July 1988 CACM that held the articles from the July 1987 Hypertext conference at the University of North Carolina. The ACM sold 4000 copies of our Hypertext on Hypertext disks. Here's some more information about High-Precision Touchscreens, 1988-1991 HCIL Research, which may be what whoever mis-quoted Ben about inventing the iPhone keyboard was actually referring to. Specifically, Ben and his students developed the "Lift-Off Strategy" and other visual feedback techniques that made it possible to precisely select small targets on touch screens. Below, he simply and truthfully stated that "the iPhone uses a lift-off strategy", not that he invented the iPhone keyboard. At the time, touchscreens were notorious for being hard to use, and they usually triggered on the location you initially touched the screen, instead of giving preview feedback when you touched, and letting you change the selection while providing visual feedback before lifting off and selecting something like a key or text or pixel. Also, the precision touch screen work at HCIL was cited as prior art in legal cases contesting the Apple patents related to the "Slide to Unlock" touchscreen slider that unlocks the iPhone. https://www.cs.umd.edu/hcil/touchscreens/ https://www.cs.umd.edu/hcil/touchscreens/ [...] During 1989-1991, we worked on a home automation system and explored several direct manipulation designs (e.g. clocks and calendars to schedule devices to go on and off, ON-OFF switches with buttons or sliders) . A playful fingerpainting exploration tool and toy called Playpen was developed. Finally we worked with National Cash Register (NCR) to explore how touchscreens might be used to replace keyboards when store cashiers needed to enter a little bit of data about shopppers (such as phone numbers or addresses). We stopped doing research on touchscreens as successful applications found their ways in museums or cash registers. Pen interfaces, made popular by the Palm Pilots, continued the work as they afforded a similar sense of "real" direct manipulation. Eventually touchcreens came back as the input device of choice of mobile devices, especially after the launch of the iPhone is 2007. For a quick summary of our work refer to: Shneiderman, B. (March 1991), Touch screens now offer compelling uses, IEEE Software 8, 2, (March 1991) 93-94, 107. Also in Sparks of Innovation in Human-Computer Interaction, Shneiderman, B., Ed., Ablex (June 1993) 187-193. http://www.cs.umd.edu/hcil/trs/91-02/91-02.pdf http://www.cs.umd.edu/hcil/trs/91-02/91-02.pdf For a longer review of the state of the art of touchscreen use at that time see: Sears, A., Plaisant, C., Shneiderman, B., A new era for high-precision touchscreens (1990 tech report), CS-TR-2487, CAR-TR-506 Later published in Advances in Human-Computer Interaction, vol. 3, Hartson, R. & Hix, D. Eds., Ablex (1992) 1-33. http://www.cs.umd.edu/hcil/trs/90-01/90-01.pdf http://www.cs.umd.edu/hcil/trs/90-01/90-01.pdf We produced the first HCIL Video Report in 1991 by recording the demonstrations from 1988-1991 (most are now on YouTube and embedded below). Those videos were given along with copies of our papers to all the sponsors of the lab, and attendees of the annual HCIL symposium. The videos were available for sale, and have been used extensively in HCI classes. Many were also published as part of the ACM CHI videos. http://www.cs.umd.edu/hcil/pubs/video91.shtml http://www.cs.umd.edu/hcil/pubs/video91.shtml Between 1988 and 1993 Apple was a sponsor of the HCIL lab, Steve Jobs visited in person in 1988, and Ben Shneiderman was a consultant for Apple at several occasions. Demos were also shown to our lab's visitors, and videos shown during invited lectures at conferences or during industry visits (see Ben Shneiderman's resume for a partial list) From bad reputation to high precision touchscreen In 1987 (and still long afterwards) touchscreens had the bad reputation of being imprecise. Most user interface books would state that touchscreens selections were "of course limited to targets larger than the average finger". To use touchscreens for browsing information systems such as Hyperties, we had to be able to select small targets (e.g. the letters of the alphabets of the index table of content). At the time, all touchscreens selections were done in such a way that a target was selected as soon as the finger came over it, and the corresponding action was performed immediately (we called it "first touch" or "land-on" strategy). Errors were common, due to parallax or calibration problems, and users were frustrated when the wrong target was repeatedly selected by mistake. Lift-Off strategy A first breakthrough was to propose an alternative technique for selection: the lift-off strategy. As users touch the screen, feedback is provided as to what will be selected and the action takes place when the finger is lifted off the screen. In our implementation a cursor was drawn on the screen slightly above the finger. When the cursor was over a target, the target was highlighted. Users could then either lift-off their finger to select the highlighted target, or adjust their position by sliding their finger to a neighboring target. This was a major breakthrough: only the cursor position mattered for the selection, not the finger itself. Selecting a single character was now possible. The touchscreen technology has greatly improved but overall the lift-off strategy is still useful (e.g. the iPhone uses a lift-off strategy.) 88-04 Potter, R.L., Weldon, L.J., Shneiderman, B. (May 1988). Improving the accuracy of touch screens: an experimental evaluation of three strategies, Proc. of the Conference on Human Factors in Computing Systems, CHI `88 (Washington, DC) 27-32. Also Sparks of Innovation in Human-Computer Interaction, Shneiderman, B., Ed., Ablex (June 1993) 161-169. High-Precision touchscreen: the next step was to try to stabilize the touchscreen so that the cursor would stay put when the finger didn't move. This was accomplished with a clever time-dependant averaging of the positions returned by the device. Now, individual pixels could be selected (in the 480x350 high resolution screen of the time). An experiment showed that there was significant difference in selection times and error rates between mouse and touchscreen for targets down to about 1mm2, when using a lift-off strategy with a stabilized touchcreen. Companies such as Elographics and Microtouch, with whom we had good relations, integrated stabilization techniques into the drivers of their touchscreens. From then on, high-precision was possible, and designers could do everything with the touchscreen that they could do with the mouse. 89-17 - Sears, A., Shneiderman, B. (June 1989) High precision touchscreens: design strategies and comparisons with a mouse, International Journal of Man-Machine Studies, (1991) 34, 4, 593-613. Also Sparks of Innovation in Human-Computer Interaction, Shneiderman, B., Ed., Ablex (June 1993) 171-185. [...] Toggles (buttons, sliders, rockers etc.), In 1990 we designed and compared a series of touchscreen toggle switches allowing devices to be switched ON or OFF. The designs included button type toggles and sliding toggles. This video was distributed to the attendees of the 1991 Human-Computer Interaction Laboratory Open House on June 7, and later on published in the SIGGRAPH Video Review, Issue 77 corresponding to the CHI '92 Technical video program.(see the accompanying CHI'92 Proceeding short paper). The video and its short paper are now being cited as prior art in legal cases contesting the Apple patents related to the "Slide to Unlock" touchscreen slider that unlocks the iPhone. http://dl.acm.org/citation.cfm?id=143079 http://dl.acm.org/citation.cfm?id=143079 http://www.cafc.uscourts.gov/sites/default/files/opinions-orders/15-1171.Opinion.2-24-2016.1.PDF http://www.cafc.uscourts.gov/sites/default/files/opinions-or... Designed originally for home automation, those toggles were also later used in a NASA design toolkit. Now slider designs can be found everywhere in touchscreen-based smartphones (such as the first iPhone in 2007). As we mentionned in our paper and video a slider design is more secure so that the phone cannot be turned on by mistake. A click confirms the action. Any design that enforces a sliding gesture would achieve a similar goal. 90-08 Plaisant, C., Wallace, D. (Nov. 1990) Touchscreen toggle switches: push or slide? Design issues and usability study, CS-TR-2557, CAR-TR-521 http://www.cs.umd.edu/hcil/trs/90-08/90-08.pdf http://www.cs.umd.edu/hcil/trs/90-08/90-08.pdf [...] 1991 Video Reports http://www.cs.umd.edu/hcil/pubs/video91.shtml http://www.cs.umd.edu/hcil/pubs/video91.shtml

NoSorryCannot 5y ago

I feel like the only other plausible color that could have been chosen is green, and even that seems too opinionated. Reasons being mostly associations (red, orange, yellow meaning danger or stop, and green meaning go) and legibility on white or gray backgrounds. Add to that that people seem to disproportionately pick blue as their favorite color and they especially seem to favor it as a conservative or relaxing color choice. That is to say, I think the odds of two people independently picking blue are pretty good.

EGreg 5y ago
Actually, it was green. I am always surprised whenever Mozilla posts this, that no one seems to go straight to the horse’s mouth. So I will: https://www.w3.org/People/Berners-Lee/FAQ.html https://www.w3.org/People/Berners-Lee/FAQ.html Rendition of links Q: I'm a student of visual communications and asked myself why links are blue. I found some answers that might be, for example blue is a color of learning, but I'm not sure what is right. Is there any reason, why links are colored blue ? A: There is no reason why one should use color, or blue, to signify links: it is just a default. I think the first WWW client (WorldWideWeb I wrote for the NeXT) used just underline to represent link, as it was a spare emphasis form which isn't used much in real documents. Blue came in as browsers went color - I don't remember which was the first to use blue. You can change the defaults in most browsers, and certainly in HTML documents, and of course with CSS style sheets. There are many examples of style sheets which use different colors. My guess is that blue is the darkest color and so threatens the legibility least. I used green whenever I could in the early WWW design, for nature and because it is supposed to be relaxing. Robert Cailliau made the WWW icon in many colors but chose green as he had always seen W in his head as green. One of the nicest link renditions was Dave Raggett's "Arena" browser which had a textured parchment background and embossed out the words of the link with a square apparently raised area.*
- kevingadd 5y ago
  That doesn't seem to suggest that links were green? "I used green whenever I could in the early WWW design" makes it sound like webpages were green, which is why the icon ended up being green.
- SeanLuke 5y ago
  I don't think he's saying the links were green here. At any rate, the links were clearly blue on early color WWW.app screenshots. https://en.wikipedia.org/wiki/WorldWideWeb#/media/File:WorldWideWeb_FSF_GNU.png https://en.wikipedia.org/wiki/WorldWideWeb#/media/File:World... https://www.w3.org/History/1994/WWW/Journals/CACM/screensnap2_24c.gif https://www.w3.org/History/1994/WWW/Journals/CACM/screensnap...
- zinekeller 5y ago

jka 5y ago

I must have experienced this article completely differently from you a couple of hours ago when reading it - I thought that it claims that the origin of the blue links was user experience research from the 1980s?

gwern 5y ago
I think OP is glossing over how much of a leap it is from Hyperties to Berners-Lee. (I was curious because the story 'red is too strong!!!' is a good fit for my https://www.gwern.net/Red https://www.gwern.net/Red page.) As written, it sounds like the color research was reported in the _Hypertext on Hypertext_ package, and Berners-Lee had a copy and was deeply immersed in it. Neither is true. The first paper from the Hyperties group cited (https://www.gwern.net/docs/design/1986-koved.pdf https://www.gwern.net/docs/design/1986-koved.pdf) does not cover color at all. It does mention some user-testing. I checked all the papers in _Hypertext on Hypertext_ and none mention Hyperties or color in any major way. (The keynote is a good read, incidentally: https://www.gwern.net/docs/design/1988-vandam.pdf https://www.gwern.net/docs/design/1988-vandam.pdf ) If you look at the Berners-Lee document cited, the Hyperties mention is buried in the bibliography; it is not even cited in the main text nor is Hyperties or link coloring mentioned, so I'm not sure why it's there at all, but it sounds like one of those cites-just-to-be-comprehensive, which often mean the author has never read the citation in question - so based on that, I'm unsure that way over in Europe Berners-Lee read any of the papers, much less actually saw the disk in action. The historical Hyperties page includes videos which show that by the time of the disk, they had defaulted to blue for link coloring, and mentions testing 3 colors (red was also used in Hyperties for other interface parts, so obviously they tested red vs blue vs ???). But the Hyperties papers after that do not mention color anywhere either. In fact, I can't find any Hyperties publication at all which reports the color usertesting or even that the results favored blue. It seems you just had to look at _Hypertext on Hypertext_ and assume that they picked blue because it was good? So, checking OP's references, I think Berners-Lee may never have seen _Hypertext on Hypertext_ (at least, in computer form); and if he had, he would not have known the blue was the result of user testing (because nothing in it says so); and if he had both seen & deduced that, he may not have both remembered & cared years later when setting up his own browser defaults for color monitors, and he doesn't say so anywhere.

divbzero 5y ago

> Unfortunately neither of these articles actually ask Tim… Yes, let’s just ask Tim and Marc! This is not ancient history where we’re forced to draw inferences based on limited information.

simonebrunozzi 5y ago

Comments like yours are why I love HN so much.

DonHopkins 5y ago

Ben Shneiderman recalled that "Tim told me at the time that he was influenced by our design as he saw it in the Hypertext on Hypertext project". Ben Shneiderman wrote the following email to John Gilmore and I, in response to a question John asked me about the origin of the term "hyperlink" raised in a discussion on the Internet History mailing list. John then forwarded Ben's email to the Internet History mailing list, here: https://elists.isoc.org/pipermail/internet-history/2020-April/005956.html https://elists.isoc.org/pipermail/internet-history/2020-Apri... >My students conducted more than a dozen experiments (unpublished) on different ways of highlighting and selection using current screens, e.g. green screens only permitted, bold, underscore, blinking, and I think italic(???). When we had a color screen we tried different color highlighted links. While red made the links easier to spot, user comprehension and recollection of the content declined. We chose the light blue, which Tim adopted. >His systems with embedded menus (or hot spots), where a significant user interface improvement over early systems such as Gopher. But Tim told me at the time that he was influenced by our design as he saw it in the Hypertext on Hypertext project that we used Hyperties to build for the July 1988 CACM that held the articles from the July 1987 Hypertext conference at the University of North Carolina. The ACM sold 4000 copies of our Hypertext on Hypertext disks. Here's some more information about High-Precision Touchscreens, 1988-1991 HCIL Research, which may be what whoever mis-quoted Ben about inventing the iPhone keyboard was actually referring to. Specifically, Ben and his students developed the "Lift-Off Strategy" and other visual feedback techniques that made it possible to precisely select small targets on touch screens. Below, he simply and truthfully stated that "the iPhone uses a lift-off strategy", not that he invented the iPhone keyboard. At the time, touchscreens were notorious for being hard to use, and they usually triggered on the location you initially touched the screen, instead of giving preview feedback when you touched, and letting you change the selection while providing visual feedback before lifting off and selecting something like a key or text or pixel. Also, the precision touch screen work at HCIL was cited as prior art in legal cases contesting the Apple patents related to the "Slide to Unlock" touchscreen slider that unlocks the iPhone. https://www.cs.umd.edu/hcil/touchscreens/ https://www.cs.umd.edu/hcil/touchscreens/ [...] During 1989-1991, we worked on a home automation system and explored several direct manipulation designs (e.g. clocks and calendars to schedule devices to go on and off, ON-OFF switches with buttons or sliders) . A playful fingerpainting exploration tool and toy called Playpen was developed. Finally we worked with National Cash Register (NCR) to explore how touchscreens might be used to replace keyboards when store cashiers needed to enter a little bit of data about shopppers (such as phone numbers or addresses). We stopped doing research on touchscreens as successful applications found their ways in museums or cash registers. Pen interfaces, made popular by the Palm Pilots, continued the work as they afforded a similar sense of "real" direct manipulation. Eventually touchcreens came back as the input device of choice of mobile devices, especially after the launch of the iPhone is 2007. For a quick summary of our work refer to: Shneiderman, B. (March 1991), Touch screens now offer compelling uses, IEEE Software 8, 2, (March 1991) 93-94, 107. Also in Sparks of Innovation in Human-Computer Interaction, Shneiderman, B., Ed., Ablex (June 1993) 187-193. http://www.cs.umd.edu/hcil/trs/91-02/91-02.pdf http://www.cs.umd.edu/hcil/trs/91-02/91-02.pdf For a longer review of the state of the art of touchscreen use at that time see: Sears, A., Plaisant, C., Shneiderman, B., A new era for high-precision touchscreens (1990 tech report), CS-TR-2487, CAR-TR-506 Later published in Advances in Human-Computer Interaction, vol. 3, Hartson, R. & Hix, D. Eds., Ablex (1992) 1-33. http://www.cs.umd.edu/hcil/trs/90-01/90-01.pdf http://www.cs.umd.edu/hcil/trs/90-01/90-01.pdf We produced the first HCIL Video Report in 1991 by recording the demonstrations from 1988-1991 (most are now on YouTube and embedded below). Those videos were given along with copies of our papers to all the sponsors of the lab, and attendees of the annual HCIL symposium. The videos were available for sale, and have been used extensively in HCI classes. Many were also published as part of the ACM CHI videos. http://www.cs.umd.edu/hcil/pubs/video91.shtml http://www.cs.umd.edu/hcil/pubs/video91.shtml Between 1988 and 1993 Apple was a sponsor of the HCIL lab, Steve Jobs visited in person in 1988, and Ben Shneiderman was a consultant for Apple at several occasions. Demos were also shown to our lab's visitors, and videos shown during invited lectures at conferences or during industry visits (see Ben Shneiderman's resume for a partial list) From bad reputation to high precision touchscreen In 1987 (and still long afterwards) touchscreens had the bad reputation of being imprecise. Most user interface books would state that touchscreens selections were "of course limited to targets larger than the average finger". To use touchscreens for browsing information systems such as Hyperties, we had to be able to select small targets (e.g. the letters of the alphabets of the index table of content). At the time, all touchscreens selections were done in such a way that a target was selected as soon as the finger came over it, and the corresponding action was performed immediately (we called it "first touch" or "land-on" strategy). Errors were common, due to parallax or calibration problems, and users were frustrated when the wrong target was repeatedly selected by mistake. Lift-Off strategy A first breakthrough was to propose an alternative technique for selection: the lift-off strategy. As users touch the screen, feedback is provided as to what will be selected and the action takes place when the finger is lifted off the screen. In our implementation a cursor was drawn on the screen slightly above the finger. When the cursor was over a target, the target was highlighted. Users could then either lift-off their finger to select the highlighted target, or adjust their position by sliding their finger to a neighboring target. This was a major breakthrough: only the cursor position mattered for the selection, not the finger itself. Selecting a single character was now possible. The touchscreen technology has greatly improved but overall the lift-off strategy is still useful (e.g. the iPhone uses a lift-off strategy.) 88-04 Potter, R.L., Weldon, L.J., Shneiderman, B. (May 1988). Improving the accuracy of touch screens: an experimental evaluation of three strategies, Proc. of the Conference on Human Factors in Computing Systems, CHI `88 (Washington, DC) 27-32. Also Sparks of Innovation in Human-Computer Interaction, Shneiderman, B., Ed., Ablex (June 1993) 161-169. High-Precision touchscreen: the next step was to try to stabilize the touchscreen so that the cursor would stay put when the finger didn't move. This was accomplished with a clever time-dependant averaging of the positions returned by the device. Now, individual pixels could be selected (in the 480x350 high resolution screen of the time). An experiment showed that there was significant difference in selection times and error rates between mouse and touchscreen for targets down to about 1mm2, when using a lift-off strategy with a stabilized touchcreen. Companies such as Elographics and Microtouch, with whom we had good relations, integrated stabilization techniques into the drivers of their touchscreens. From then on, high-precision was possible, and designers could do everything with the touchscreen that they could do with the mouse. 89-17 - Sears, A., Shneiderman, B. (June 1989) High precision touchscreens: design strategies and comparisons with a mouse, International Journal of Man-Machine Studies, (1991) 34, 4, 593-613. Also Sparks of Innovation in Human-Computer Interaction, Shneiderman, B., Ed., Ablex (June 1993) 171-185. [...] Toggles (buttons, sliders, rockers etc.), In 1990 we designed and compared a series of touchscreen toggle switches allowing devices to be switched ON or OFF. The designs included button type toggles and sliding toggles. This video was distributed to the attendees of the 1991 Human-Computer Interaction Laboratory Open House on June 7, and later on published in the SIGGRAPH Video Review, Issue 77 corresponding to the CHI '92 Technical video program.(see the accompanying CHI'92 Proceeding short paper). The video and its short paper are now being cited as prior art in legal cases contesting the Apple patents related to the "Slide to Unlock" touchscreen slider that unlocks the iPhone. http://dl.acm.org/citation.cfm?id=143079 http://dl.acm.org/citation.cfm?id=143079 http://www.cafc.uscourts.gov/sites/default/files/opinions-orders/15-1171.Opinion.2-24-2016.1.PDF http://www.cafc.uscourts.gov/sites/default/files/opinions-or... Designed originally for home automation, those toggles were also later used in a NASA design toolkit. Now slider designs can be found everywhere in touchscreen-based smartphones (such as the first iPhone in 2007). As we mentionned in our paper and video a slider design is more secure so that the phone cannot be turned on by mistake. A click confirms the action. Any design that enforces a sliding gesture would achieve a similar goal. 90-08 Plaisant, C., Wallace, D. (Nov. 1990) Touchscreen toggle switches: push or slide? Design issues and usability study, CS-TR-2557, CAR-TR-521 http://www.cs.umd.edu/hcil/trs/90-08/90-08.pdf http://www.cs.umd.edu/hcil/trs/90-08/90-08.pdf [...] 1991 Video Reports http://www.cs.umd.edu/hcil/pubs/video91.shtml http://www.cs.umd.edu/hcil/pubs/video91.shtml