If interaction design really is the business of behaviour change I believe this must apply two ways. While it’s true that design can influence users and engender cultural change, this is always a product of our more tangible work: changing the behaviour of technology. As a user-centred designer of technology my goal is simple: to make its behaviour humane. But how should I approach this?

Humanity implies emotion and, beneath that, personality. These areas lie beyond the frontiers of classical HCI and usability. Fortunately, as often happens, we view the distant summit and see others have already planted the flag. Toymakers, for instance, have explored the art of bestowing personality on products for years. The results are fairly crude, but I defy anyone to watch the torture of a Pleo and successfully suppress a twinge of guilt. Even in its moments of crisis, Pleo has a distinct personality; that is to say, it conveys emotional information

Channels for personality

Perhaps the most obvious conduit for emotional content is appearance.

From BMW's grill to Pixar's Wall-E

The designs above show acts of visual anthropomorphism, where gesture and expression alone convey personality. They create empathy through closure, a projection of the self as explored in Scott McCloud’s classic Understanding Comics. Pareidolia, the brain’s propensity to recognise faces everywhere, is a powerful trick. Even an oval, two dots and a line create an unmistakable expression; with detail we can add further emotional nuance.

Closure: excerpt from Understanding Comics by Scott McCloud

We can also convey personality through message. In the words of Russell Davies, the rise of devices with personality will lead to a surge in “bubbly writing and objects talking to you in the first person”. Here, an Innocent smoothie prudishly asks us to avert our gaze from its most vulnerable area.

Innocent drinks carton with text "Stop looking at my bottom."

But anthropomorphism needn’t be visual. Consider how R2D2 conveys personality through sound alone – his shrieks and bleeps mapping to human expressions of emotion (See Chris Noessel and Nathan Shedroff at dConstruct 2009 [mp3, 43 minutes]). Similarly, IM programs happily announce incoming messages with a rising fanfare and send replies with a descending farewell.

These can be effective ways to communicate personality, but I’ve recently been reflecting about the fuzzier area of expressing personality through behaviour.

According to psychologist Kurt Lewin behaviour is product of the person in question and his environment (check out Lewin’s equation). Our behaviour changes with context. This suggests that we can only form an opinion about someone’s personality through exposure to various scenarios; a single interaction isn’t enough. However once we’ve formed this mental model, we believe it so thoroughly that we become blinded by it, believing that someone’s personality causes their every action – the fundamental attribution error.

Behavioural variance – acting differently according to our environment – is a celebrated part of being human. Anyone who lacks it is boring. Myself, I act quite differently as a Cardiff City fan than as a grandson, since the contexts are very different. At a party you’re expected to drink beer and flirt with girls, not quietly read a library book, if you expect to be invited back.

Dreary technology

This is why I look at modern technology with mixed feelings. As a tool, it’s unsurpassed. But when we engage with it on any human level, it doesn’t respond in kind. Technology has no behavioural variance and very little personality.

Yes, predictability is a key tenet of usability. High-risk systems must respond to input in forseeable ways: an air traffic control system, for instance, needs to be entirely unwavering. But as we’re learning to appreciate the power of play and emotion in our design activities, is there scope for non-critical technology to display behavioural personality?

Mobile devices, for instance, are increasingly a medium of sensory input as well as informational output. We’ll soon carry devices capable of reading our fingerprints, calculating our position and learning our closest social ties by analysing our SMS and email habits. Adding further richness, recent declarative technology encourages users to publish information that designers can use to build emotional responses:

Google map showing current location as Alton Towers theme park

Facebook status showing a user's engagement

So let’s imagine a Twitter client that asks if you really want to send that drunken tweet (maybe you should have read that library book after all). A mobile that loves going on rollercoasters. An MP3 player that longs to play (and listen to?) a new album for once.

Getting personality wrong

Looking, sounding or acting like a human is desirable only if the human is one we like. Some of our early forays have been spectacular failures. For an archetypal example of botched anthropomorphism, look no further than our most hated paperclip.

Designed to save labour and improve UI learnability, Clippy instead came across as smug and invasive. Not only did his brash tone rub many up the wrong way, but he was irritatingly clingy, appearing on simple tasks where users didn’t need or appreciate help.

The despotic HAL illustrates the other extreme of dislikable machine personality. Clarke and Kubrick created a terrifying villain for 2001 simply by highlighting the unflinching rationality of computation. HAL’s cold-bloodedness is the opposite of humanity. Our heroes are irrational, given to senseless acts in the name of compassion. We can all empathise: who hasn’t done something stupid when in the grip of emotion?

Appealing machine personality lies somewhere between the shores of impassivity and fake friendliness. Social psychology research tells us that we like people who share a similar personality to our own, and people who like us (reciprocal liking). Servile flattery isn’t the answer, of course, but through deep user understanding and reliance on our trusty companions trial, error and feedback perhaps designers will uncover a sweet spot.

We may speculate a few guidelines for conveying personality through behaviour (any additions would be welcomed):

• Personality should be easily overwritten. If you need to make an emergency call, your handset must revert to functionality above all else.
• Personality should be secondary to function. Clippy was disproportionate: his personality overruled his potential usefulness. Not only does this reduce usability, but we risk giving users false expectations of a system’s capabilities.
• Personality should be appropriate to the medium. It may be that desktop computers aren’t an ideal platform for behavioural personality; we still regard them largely as tools of business or home organisation. Mobile phones operate in our intimate space and it’s well known that people form emotional connections with their handsets. Could the mobile arena provide sensible starting points for exploration?

This is largely a thought experiment for now, and it’s clear that behavioural anthropomorphism would raise practical questions. How should users tell devices to stop their shenanigans and get on with the task at hand? Do I want my computer, and whatever systems it’s connected to, to know that I spent the night at my girlfriend’s flat? Would a machine object if I do something it doesn’t approve of?

Any attempt to give technology personality will be divisive. Succeed and we make the technological world a slightly more humane place. Fail, and we create an army of Clippies.

Related resources

• Why is that thing beeping? A sound design primer
• Russell Davies “Materialising and dematerialising a web of data” (mp3, 44 minutes)

Special thanks: Rebecca Cottrell
Photo credits: Duncan, estoril