When is using haptic feedback for button presses a good idea?

Question

I've noticed that on Android phones only some button presses result in haptic feedback. For example, pressing any of the 3 main buttons (Back, Home, Multitask) will cause the phone to vibrate. So does any key on the keyboard, and the "All Apps" button on the Home Screen app. But a lot of other buttons don't use vibration at all. When is using vibration on button tap as feedback a good idea?

(I kind of have an idea of the answer but would like to see what other people think)

Answer 1

I think that the study "The Value of Haptics: A summary of published findings on the value of haptic feedback in human-computer interaction" provides interesting information about this subjects.

On page 6 you can find a list of contexts where haptic stimulation is ideal for communication:

1. Private information: haptic feedback is silent, non-visual, and individually communicated (not broadcast).
2. Warning or alerts: haptic feedback can be distinctive and unanticipated, helping users to re-focus their attention.
3. Confirmations: haptic feedback can provide intuitive verification of an action.

The keyboard vibration in a smartphone belongs to the third group: we use vibration to provide the user with intuitive verification of his/her successful typing.

In this other study, "Tactile Feedback in Mobile: Consumer Attitudes about High-Definition Haptic Effects in Touch Screen Phones", we can find some recommendations for developers which I think are relevant to this discussion.

They include:

1. Handset manufacturers should provide users with the ability to customize the haptic settings on their device to provide both sensation control as well as UI personalization.
2. The design of haptic effects must take into account the demographic characteristics of the target market for the intended applications and provide users with the capability to customize haptics settings for their applications.

Answer 2

I would use the haptic feedback when I would like to notify the user that he made an important action (can be negative or positive). Like deleting something important or adding something important to a list or so.

Answer 3

I think also as previous comment. I use vibration for critical cases. E.g. if user cancels the payment or registration process. Think about frequency too. More than needed is always a ux killer.

Answer 4

A haptic feedback is used to strengthen the feedback for a normal user, post visual implication of the action taking place, so it should always be used to make the user a repeat feedback other than visual and audio that should make him more conscious amongst the audio/visual biases.

Answer 5

Many users prefer physical keyboards that have a degree of click to them because this acts as a confirmation that their action was positive. Research has shown this affects actual performance

Each subject is given a poem and asked to type after a practice with device. Lab session showed that with tactile feedback users entered significantly more text, made fewer errors and corrected more of the errors they did make. from thesis by Seckli Celik

Thus a keyboard should always have haptic feedback HOWEVER this is not necessarily the same clumsy 'buzzing' in the phones of today. I expect to see highly tuned feedback that convinces user their action is confirmed, with essentially zero distraction

• http://research.microsoft.com/en-us/projects/tactilefeedbackoonscreens/
• http://www.computerworld.com/article/2511869/emerging-technology/will-touch-screens-kill-the-keyboard-.html

So the appropriate haptic signals depends on the control you have on the degree of feedback.

Answer 6

As a research excercise it'd be good to take a look at what the founders of the on-screen keyboard (OSK), Apple, are working on now.

iOS 8 predicts what you’ll likely say next. No matter whom you’re saying it to. Now you can write entire sentences with a few taps. Because as you type, you’ll see choices of words or phrases you’d probably type next, based on your past conversations and writing style. iOS 8 takes into account the casual style you might use in Messages and the more formal language you probably use in Mail. It also adjusts based on the person you’re communicating with, because your choice of words is likely more laid back with your spouse than with your boss. Your conversation data is kept only on your device, so it’s always private.

Which means:

Keyboard will adapt to different apps: mail/messenger and also to different people: your friends, your family, your pals at work...

Predictive text, available around the world. The iOS 8 predictive text engine is optimized for languages around the world. Which means you’ll see suggested words and phrases that are right for your language. And as you use the keyboard over time, it will learn the way you communicate, get to know your favorite phrases, and suggest a logical next word. Supported languages include English optimized for the U.S., UK, Canada and Australia; French; German; Italian; Portuguese optimized for Brazil; Spanish; and Thai. And, Simplified Chinese, Traditional Chinese and Japanese Kanji input also continue to feature predictive input.

Which means:

Keyboard will help you don't have to type anymore (at certain extent) and keyboard will keep record of your messages and will use them later.

New third-party keyboard experiences. Swipe rather than type, or go old school with the classic keyboard layout. For the first time, iOS 8 opens up the keyboard to developers. And once new keyboards are available, you’ll be able to choose your favorite input method or layout systemwide.

Which means:

Sweeping will allow users to type more efficiently and there will be more flexibility for developers.

Furthermore, if we take a look at the iOS Human Interaction Guidelines regarding notifications:

You can supply a custom sound, or you can use a built-in alert sound. If you create a custom sound, be sure it’s short, distinctive, and professionally produced. (To learn about the technical requirements for this sound, see “Preparing Custom Alert Sounds” in Local and Push Notification Programming Guide.) Note that you can’t programmatically cause the device to vibrate when a notification is delivered, because the user has control over whether alerts are accompanied by vibration.

Also from the iOS Multimedia Programming Guide:

The similar AudioServicesPlayAlertSound function plays a shortsound as an alert. If a user has configured their device to vibrate in Ring Settings, calling this function invokes vibration in addition to playing the sound file.

Conclusion:

• Apple is giving more and more importance to the on-screen keyboard and is giving developers more flexibility to play with it, which is a good starting point, although is far from getting rid of the keyboard which is one of the worst user expeciences phone wise.
• Sweepping + vibrations won't be good friends. I can't imagine a scenario where the user will be sweeping letters and the vibration mode on.
• As per the UX Guidelines and also best coding practices for iOS, vibrations are always an extra feature that the user "may or may not" choose.
• What will happen to the on-screen keyboards of devices that don't have vibration like tablets or phablets? It makes no sense to me to install same app in the phone and tablet and show two different behaviours: vibrating keyboard for phone and non vibrating keyboard for tablet.

My advice:

• Make vibration always optional.
• Don't pre-default vibration in any of the app settings.
• Use it as an "accesibility" extra feature.