Planning

The experiment was held in laboratory, since location plays a part in metaphor (in a semantic view), we consider that placing the prototype in a street corner or in a restaurant may affect people feel it more machine-like or more human-like. Meanwhile, to set cam-coders and computers are much easier in the laboratory.

Two cameras were set to capture both subject’s facial expression and behavior through whole, operational process, in order to provide observation data.

a. Comparative Observation

The contrast observations were only held in the primary stage. Before the primary experiment starts, we recorded each subject’s behavior of buying things in a fast food restaurant and buying beverage from a vending machine in a campus corner, for realizing if there were any individual differentiations varied from each subjects, at the same time, we also need to compare their different behaviors with other two different situations (figure 4.2).

Figure 4. 2 Observation from other two activities. a. Buying beverage from vending machine, b. Buying beverage from a clerk in fast food restaurant.

b. Wizard of Oz

Wizard of Oz is an approach to obtain a dynamic interaction and with a person impersonates the product, especially the part of “computing program”. In the experiment, a person will hide behind the model and control the mechanical part of the paper mock-up. By realizing the designed functions and interaction sequences, this person will watch subject’s behavior through a monitor connecting with one of the cam-coder, and responses after subject does specific things. So the whole interaction task can be complete. The conductor of experiment stood behind the main cam-coder and monitored the whole process; he would not involve and disturb subjects’

operation.

Figure 4. 3 Experiment set up. The operation course was held in laboratory. Two cam-coders were set, one recorded whole behavior and process of task, another recorded subjects’ facial expression and connected with monitor behind prototype for operator.

c. Introduction

Every subject was told that it is a new designed vending machine, implanted sensors and having special

mechanical device. Though it is a paper mock-up, subjects may imagine it is real with a die cast and possessing computing abilities. There is one thing need to be mentioned that according to the different operational sequences against contemporary vending machines, the process are particularly reminded to them: “order first then pay”, and all they have to do is to finish the five steps mentioned above.

A scenario was given to them: “One day you walk on the street and feel thirsty, suddenly you see a vending machine standing on the street, and then you walk toward it…” Then subjects may begin to buy a beverage. Each time every subject was given adequate money for buying one beverage and a fixed task proceeded in several main procedures: approaching, paying, taking beverage and leaving. Function for choosing beverage was not under discussion while we go through this procedure by same operational cues as normal vending machine does – a slit for dropping money in.

d. Operation Task

In order to focus on the evaluation points for our interactive design, we constrained the operation task in the following steps: (1) Approach, (2) Order, (3) Pay for order, (4) Get beverage, (5) Leave. (See details in figure 4.5 to figure 4.10) These five steps base on five subject’s actions. Subject only need to choose and buy a beverage from our prototype. The whole purchase procedure is depicted as following figure.

Figure 4. 4 Operation procedure for purchase a beverage

Although a real situation of purchasing beverage from a vending machine is much more complicated, and people do have frustrations, sometimes their money paying for nothing, sometimes they regret after depositing coins into vending machine and want to get their money back. These situations are interesting but unable to be discussed while the experimental prototype lacking of complete functions and these situation may blur the main focus.

Approaching vending machine

Ordering a beverage

Paying for an order

Getting beverage

Leaving

Figure 4. 5 Sequences of subject’s operating prototype and prototype’s reactions.

Figure 4. 6 Approaching Step: Approach, stick wave, stick stop, subject choose beverages. When somebody approaches, the stick will wave. While being stared, it stops and waits for customers’ choice.

Choose beverage

Push button

Pay for the order Stand at machine

Wait while preparing

Take the order

Leave Approach

Customer’s Action

Beverage lifted up Slit plate lifted up

Slit plate move back

Beverage move down from the shelf

New beverage move on shelf

Stick wave Stick wave

Stick stop waving

Prototype’s Action

Figure 4. 7 Ordering Step: Order beverages. Outlet’s door opens. Slit plate lifted up. After customer chooses one beverage, the outlet’s door will open and slit plate will then be lifted up to charge for order.

Figure 4. 8 Paying Step: Pay for order. Slit plate move back. After receiving money, the slit plate then move back.

Figure 4. 9 Getting Beverage Step a: Beverage moves down first and shows up in the outlet later.

Figure 4. 10 Getting Beverage Step b: Beverage lifted up for customers. Door closes.

After slit plate lifted the beverage out, subjects take away their order, then the door will close.

Figure 4. 11 Leaving Step: New beverage moves up to the shelf. Stick wave. After customer take their beverage, new beverage move up to the shelf and then the stick wave to customers.

e. Developing Questions in Interview

The following questions were asked during the interview after subjects interact with the prototype.

Part 1

ƒ During operation, what are the most impressive features?

ƒ What is that mean to you?

ƒ How do you feel about its motion (behavior)?

ƒ Compare with buying things from vending machine and normal purchase experience; please tell the difference you find in our prototype.

ƒ After interacting with the prototype, what are your expectations on it and for further advance product?

Part 2

ƒ Use keywords (Table 4.1) to compare with contemporary vending machine and our prototype.

Inspired from perceptive sorting method (Forlizzi, J., 2003), 12 keywords have been given to help subjects inducing their experience (see Table 4.1), including two categories, narrative words and affective words. Narrative words relate to people’s mechanistic models of how they understand products and systems and their ability to control them; affective words relate to people’s emotional response, as our goal is to

understand people’s attitude and feeling toward the new-designed features. In each descriptive category we have 3 pairs of adjective words. Further, subjects may be allowed to add other words by their opinions. We change two original words “simple” and “complex” into “simple performance” and “high performance”, in order to know whether the prototype have a functional improvement over contemporary vending machine, though they have the same purpose as “selling beverage”, and we know the adding motion attributes actually do not improve in any usability function.

Table 4. 1 12 keywords to help recalling experience “ * ” is the word we change for our experimental purpose.

Narrative Words Affective Words

S

Breakable Bewilder

*High performance Boring

Easy to use Delight

Requires Efforts Disappoint

*Simple performance Entertain

Durable Understandable