Tag Archives: Fitts’ Law

Dat glaive: Enthrallment

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Several times throughout the movie, Loki uses places the point of the glaive on a victim’s chest near their heart, and a blue fog passes from the stone to infect them: an electric blackness creeps upward along their skin from their chest until it reaches their eyes, which turn fully black for a moment before becoming the same ice blue of the glaive’s stone, and we see that the victim is now enthralled into Loki’s servitude.

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You have heart.

The glaive is very, very terribly designed for this purpose. Continue reading →

The Dropship

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The Axiom Return Vehicle’s (ARV’s) first job is to drop off Eve and activate her for her mission on Earth. The ARV acts as the transport from the Axiom, landing on the surface of Earth to drop off Eve pods, then returning after an allotted time to retrieve the pods and return them to the Axiom.

The ARV drops Eve at the landing site by Wall-E’s home, then pushes a series of buttons on her front chest. The buttons light up as they’re pushed, showing up blue just after the arm clicks them. At the end of the button sequence, Eve wakes up and immediately begins scanning the ground directly in front of her. She then continues scanning the environment, leaving the ARV to drop off more Eve Pods elsewhere.

If It Ain’t Broke…

There’s an oddity in ARV’s use of such a crude input device to activate Eve. On first appearance, it seems like it’s a system that is able to provide a backup interface for a human user, allowing Eve to be activated by a person on the ground in the event of an AI failure, or a human-led research mission. But this seems awkward in use because Eve’s front contains no indication of what the buttons each do, or what sequence is required.

A human user of the system would be required to memorize the proper sequence as a physical set of relationships. Without more visual cues, it would be incredibly easy for the person in that situation to push the wrong button to start with, then continue pushing wrong buttons without realizing it (unless they remembered what sound the first button was supposed to make, but then they have one /more/ piece of information to memorize. It just spirals out of control from there).

What was originally for people is now best used by robots.

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So if it’s not for humans, what’s going on? Looking at it, the minimal interface has strong hints of originally being designed for legacy support: large physical buttons, coded interface, and tilted upward for a person standing above it. BNL shows a strong desire to design out people, but leave interactions (see The Gatekeeper). This style of button interface looks like a legacy control kept by BNL because by the time people weren’t needed in the system anymore, the automated technology had already been adapted for the same situation.

Large hints to this come from the labels. Each label is an abstract symbol, with the keys grouped into two major areas (the radial selector on the top, and the line of large squares on the bottom). For highly trained technicians meant to interact only rarely with an Eve pod, these cryptic labels would either be memorized or referenced in a maintenance manual. For BNL, the problem would only appear after both the technicians and the manual are gone.

It’s an interface that sticks around because it’s more expensive to completely redo a piece of technology than simply iterate it.

Despite the information hurdles, the physical parts of this interface look usable. By angling the panel they make it easier to see the keypad from a standing position, and the keys are large enough to easily press without accidentally landing on the wrong one. The feedback is also excellent, with a physical depression, a tactile click, and a backlight that trails slightly to show the last key hit for confirmation.

If I were redesigning this I would bring in the ability for a basic- or intermediate-skill technician to use this keypad quickly. An immediate win would be labeling the keys on the panel with their functions, or at least their position in the correct activation sequence. Small hints would make a big difference for a technician’s memory.

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To improve it even more, I would bring in the holographic technology BNL has shown elsewhere. With an overlay hologram, the pod itself could display real-time assistance, of the right sequence of keypresses for whatever function the technician needed.

This small keypad continues to build on the movie’s themes of systems that evolve: Wall-E is still controllable and serviceable by a human, but Eve from the very start has probably never even seen a human being. BNL has automated science to make it easier on their customers.

Who did it better? Fingernail-o-matic edition

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The Fifth Element

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When in The Fifth Element the Mangalore Aknot calls Zorg to report that the “mission is accomplished,” we get a few seconds of screen time with Zorg’s secretary who receives the call. During this moment, she’s a bit bored, and idly shoves a finger into a small, lipstick-case sized device. When she removes it, the device has colored her fingernail a lovely shade of #81002c.

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The small device is finger-sized, the industrial design feels very much like cosmetics, and its simple design clearly affords inserting a finger. There’s also a little icon on the side that indicates its color. This one device speaks well of what the entire line of products might look like. All told, a simple and lovely interaction in a domain, i.e. cosmetics, that typically doesn’t get a lot of attention in sci-fi.

But what is even more remarkable is that this isn’t the only fingernail interface in the Make It So survey. There is one other, 7 years earlier, and it happens to be used by someone with the exact same job. This other interface comes from the 1990 movie Total Recall.

Total Recall (1990)

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As you can see, this receptionist has an interface for coloring her nails as well, but the interaction is entirely different. This device has something like a a tablet with a connected stylus. It displays 16 color options in a full screen grid. She selects a particular color with the tap of the stylus. Then when she taps the stylus to a nail, the nail wipe-transitions to the new color from the tip to the cuticle.

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This device is cumbersome. It’s not something that could fit into a purse. Does she just leave it on her desk? Doesn’t her supervisor have opinions about that? My sense is that this is something better suited to a salon than an office space.

As a selection and application mechanism, the stylus is a bad choice. It requires quite a bit of precision to tap the tip of the nail. Our old friend Paul Fitts certainly would use something different for his nails. Since the secretary has to have to have some kind of high-tech coating, perhaps similar to electrophoretic ink, why is the stylus necessary at all? Can’t she just tap her fingernails to the color square of her choice? That would disintermediate the interaction and save her the hassle of targeting her nails with that stylus, especially when she has to switch to her off-hand.

The color display poses some other interesting problems as well. It needs to show colors, but why just 16? We don’t see any means of selecting others. Are these just this season’s most popular? Why not offer her any color she likes? Or some means of capturing her current outfit and suggesting colors based on that? Even the layout is problematic. Because of the effect of simultaneous contrast, the perception of a color alters when seen directly adjacent to other colors. These squares should have some sort of neutral border around them to make perception of them more “true.” But why should we burden her with having to imagine what the color will look like? Show her an image of her hand and let her see in advance what the new color will look like on her fingers. Any sort of low-level augmented reality would help her feel less like she’s picking paint for her living room wall.

And the winner is…

Comparing the two, I’d say that The Fifth Element fingernail-o-matic wins out. It’s more personal, more ergonomic, fits into the user’s lifestyle more, feels more fashionable than techy (which that receptionist clearly cares about). Yes, it’s more restricted in choices, but I’d much rather figure out how to augment that little device with a color selector than try to make a stylus and tablet fingernail-o-matic actually work.

The Door

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The door to unit 281-53 has security and control features that make it Not Like Our Doors.

Sweetie’s Door

Korben’s white cat is named Sweetie. After a long night of carousing the 5000 block, she wants to be let back in, so she meows at the door as soon as she hears Korben’s alarm go off. He presses the lowest on the 5-button panel and a little cat-sized door opens up to let her in. After she passes through, it immediately closes behind her.

The kitty door could be improved by lessening the work it requires of Korben to zero, by automatically opening and closing for Sweetie. Even if Korben wanted her outside for certain hours of the night, we’ve seen that the apartment knows about schedules, so could accomodate another few bytes of scheduling information. To provide automatic access, though, would require some kind of identification. Low-level tokens like an RFID on her collar could work (such systems are sold today) but Korben lives in a crime-ridden area and any criminal could swipe the collar and use it to open the kitty door to “case the joint” or use some trickery to open the big door. An implanted RFID chip would be worse since it would put Sweetie’s life at risk as a “key.” More passive systems like kitty-biometrics would be much more expensive, and all the other evidence in the film tells us that this is not a wealthy man’s apartment. Ultimately, though there are other solutions for the problem, none fit the circumstances as well.

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Four out of five of the panel’s icons are clearer than those seen on the apartment’s other panels.

  • A moon (the mysterious one. Night mode?)
  • A high star (for shining a light from above the door, downward?)
  • An ajar door, for opening or closing it
  • A low star (for shining a light below on Sweetie
  • A a cat face (and cat butt?) for opening Sweetie’s door

In addition to being readable, they’re also well-mapped. The button for the human is in the middle. The cat door is lower on the panel. Let’s presume the lights are similarly well mapped.

The only difficulty this system might have is accidental activation of the wrong thing since the buttons are so similar and close together. It might not be so bad to accidentally turn on a light when you meant to open the door, but if you’d intended to turn on the light to check who’s outside and then accidentally opened the door, it could mean a home invasion. This is a Fitts’ Law problem for a doorknob. Better would be for the “knob” to be a hand’s width distant from any of the other buttons. This would also save him from having to look to target it precisely to do something as common as shutting the door.

Video peephole

Unlike adorable kittens, humans on the other side of the door may pose a threat. Korben can see who has come calling via a video monitor, located above the panel. The feed is always on. The video camera sits above the lintel and aims straight down, so Korben can see all the way to where Sweetie would be. Three buttons below the monitor are not seen in use. For most cases, the monitor would work well. Korben can glance at it from anywhere in the room and have a good idea who is there. And, since it’s a one-way system, he has time to get quick things done before answering without seeming too rude.

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That said, the camera is not foolproof. Early in the film Korben checks it and though it looks as if the hallway was empty, upon opening it finds a would-be robber who has donned a “hat” with a picture of the empty hallway from the perspective of the camera. Though he’s ultimately unsuccessful in robbing Korben his ruse to appear invisible to the door monitor worked perfectly. Multiple cameras might make it harder for this trick to be effective, but some other sensors, like a weight sensor under the floor outside or heat sensor would be harder to fool.

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As if that weren’t bad enough, the fact that the camera has a very limited field of view allows anyone to hide just off to the side. Cornelius uses this tactic when he uses Leeloo as a sort of video bait to get him to open the door.

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This latter problem could be solved with a fisheye lens on the camera (y’know, like real peepholes), which would show him more of the hallway and reduce the places where an assailant could easily hide.