- Thank you Michelle for the introduction.
Hello everyone, I'm Chi Vi from
the SCHI Lab, University of Sussex.
So today, I would like to present
Okay, that's better, thank you.
Today I would like to present our work in collaboration
with Kasper Hornbaek at University of Copenhagen
and Sriram Subramanian at University of Sussex
about our work of neuroanatomical correlates
of perceived usability.
So let me start by showing you some examples
of what I consider good and poor
usability in our daily lives.
So the first picture here was taken on a Barcelona metro.
I consider this good design, in the way that
you can see how many stops are ahead of you,
which stops have you passed, and which one is next
so that you can plan your travel.
But the one on the right, here, for recycling,
as you can see closer, with conflicting instructions
at the front, and also at the top of the bin.
So when you open the door, you go okay
I want to recycle a can, or bottle,
you go in, and you say oh that's impossible on the left.
You have to go in on the right.
So another example that was taken recently
on our exploration around Quebec City.
So this was a map that was taken on the Plains of Abraham.
So we were at the top of this place and interestingly,
four of us, including two Ph.D holders and two Ph.D students
could not figure out where were we and how do we get around
by looking at this map for five minutes.
What we were looking for was probably something like
this map with a clear indication of, oh, you are here.
(laughter)
So those are the examples to show that usability is
an important aspect in our daily lives.
But first, let's look into what is usability.
So according to Merriam-Webster dictionary
Usability is the ease of use and learnability
of a human-made object such as a tool or device.
But Jakob Nielsen defined usability in his book as,
usability is a quality attribute that assesses
how easy user interfaces are to use.
But also, the International Standards Organization, ISO
defines usability with concern of the ease, effectiveness,
and satisfaction with which a user
achieves their goals when interacting with it.
So these are slightly different definitions of usability
which do not give a clear construct of usability.
But also another key remaining question is that although
the relationship between aesthetics, which is beauty
and usability is well researched,
but still remains the question of if what is beautiful
is also perceived as usable or not.
Or whether our immediate impressions of aesthetics influence
the subsequent performance and assessment of usability.
So, to answer those questions we first look
at how to measure usability, first.
So currently there can be, the metric to measure usability
can be categorized through two metrics.
Either subjective or objective.
So, subjective measure of usability can be seen
in the form of questionnaires such as AttrakDiff 2,
or in the User Experience Questionnaires.
But objective measure of usability can include
physiological signals, measurements such as the functional
near-infrared spectroscopy, fNIRS,
in usability testing, such as like Hill and Bohil,
or in adaptive interface such as in Hirshfield.
Or another example is in Lukanov, et al. to understand
the effect of web form layout on mental workload.
But in our study we used a different technique which is
Functional Magnetic Resonance Imagine or fMRI.
So let me first explain the technique, briefly first.
So fMRI measures brain activity
by detecting the change in blood flow.
So the most common approach in using fMRI
is using the BOLD contrast which stands for
the Blood Oxygenation Level Dependent.
So BOLD measures the ratio of oxy-
and deoxy-hemoglobin in the blood
so it does not directly measure the neuron activities.
However it does measure the metabolic demands of the neurons
so it can lead you to construct
the structure of the brain or function of the brain.
So my constructing images from fMRI during
the performance of different tasks.
It can reflect parts of the brain that are active,
and which ones are not active,
and can reveal the brain structures
that are activated together.
So this technique provides much higher
spatial resolution and more accurate
activation localization compared to
other techniques such as EEG and fNIRS.
So fMRI has been used widely in literature
such as to study aesthetics,
so you can see an example, like
investigating the brain activation area
when viewing different types of faces,
or attractiveness of faces with eye contact
and also aesthetics of paintings.
However while it is well researched on aesthetics,
there is no previous study that investigates the construct
of usability or perceived usability using fMRI.
So this technique in the field HCI,
it is not a new technique to understand
what is going on in the user's brain
during a certain interaction or performance.
So, some examples can be seen in previous work in the field
in Pine et al. where they analyze the brain area
activated during the performance of a navigation task.
Or another study, Baumgartner et al.,
studies experience of presence during
a video of a virtual experience.
Or Clemente et al. used fMRI to investigate
the sense of presence during a VR free navigation task.
Also Anderson et al. used fMRI to study
user habituation to security warnings.
So in our study we used the fMRI technique
with the aim to answer the research question
of what is the neuroanatomical correlates of usability,
and whether the overlaps of usability and aesthetics exist,
and by how much.
So that's why in our first experiment
we collected 400 static webpages
ranging from low to high beauty
and also low to high usability.
So we used these 400 webpages to give to people
on CrowdFlower website to rate
and 492 people rated these websites.
Each rated about five to 15 webpages.
Based on the results we selected 25 webpages of each level
of beauty, such as low, medium and high,
and we did the same for usability.
For each category we have three levels.
These stimuli were then used for participants
to view and rate in the fMRI machine.
As you can see, here is the procedure of a trial.
In our trial, participants first see
eight to ten seconds of cross hair.
This is followed by viewing the webpage stimuli
for five seconds, then followed by three seconds.
And then at the end, participants will be asked
to rate the stimuli of how beautiful it is
or how usable it is.
This is repeated for all trials in one group,
which is 75 stimuli first before
they move to another group.
So if they do beauty first, they do usability next.
And the order is counterbalanced between participants.
We then looked at the results of the activated brain areas
specifically to aesthetics and usability.
In terms of aesthetics, we found
brain areas activated in our study here
is in line with those found in non webpage stimuli.
So for instance, we observed strong activation
in part of the brain, suggesting that people rate
the perceived aesthetics of webpages similarly
to the picture and architecture stimuli.
So this may be because most webpages
include commodity design elements
such as columns, frames, or headings.
These commodity design elements
add architectural features to the static webpage,
thus capturing the user's attention.
We also found that the activation in parts of the brain
are similar to previous studies demonstrating baby schema,
suggesting that particpants may perceive
the features of the webpage as cute,
or motivating a sense of connecting in the subjects.
We also found activation which suggests
the perceived aesthetic of the webpage
is also judged based on the visual aesthetic perception.
So although a webpage is a complex stimuli,
people still judge it the same way
or a similar way as a simple one, a simple stimuli.
Interestingly, in terms of perceived usability,
we found the brain areas specific to usability
were found in several premotor areas
which are associated with planning complex movements.
This result suggests that the process of planning to
use a webpage and self-reflection on how to use a webpage
were stimulated when people are assessing the usability.
We also found that usability was related
to the activation of the brain paths
that are often related to linguistic processing and reading.
In some studies these areas have also been implicated
in higher-order expectancy in usability.
This suggests that even if the webpage
is only viewed for five seconds,
users look at the quality of the headings in the webpage
and perceive usability and judge them.
We also found that increase in usabilty
activated the somatosensory cortex
which normally associates with our sense of touch.
This has been seen in the process of observing touch action,
which is a kind of mirror effect.
You see other people perform the touch action
and you have the same effect in your brain.
This result suggest that because nowadays
people normally view webpages on a touch-based device,
which might lead to participants assessing usability
of a webpage by asking themselves,
what happens if I go there?
Usually by touching it, when they view the webpage.
Finally, we found brain activation in the part
which is related to emotion and specifically to usability.
This suggest the effective influence of a webpage
is a key factor in perceived usability.
In the first experiment we used a static webpage as stimuli.
However, the literature have shown that
the measures of aesthetics and usability are often
strongly correlated at the time of initial exposure,
when you're first seeing it.
But it is less correlated, or maybe not at all,
after interaction with the interface.
That's why in the first study we present initial data
on the association between activation of the brain networks
and usability and aesthetic ratings.
This relationship may differ in interactive systems.
That's why in Experiment Two, we added
dynamic elements to the stimuli in very simple forms.
Such as, you can see here, you can scroll down the webpage,
and click on one link to navigate to another one.
We added these dynamics to the stimuli and we performed
the same experimental protocol in the second study.
The results we found in this experiment show that
in terms of perceived aesthetics,
the brain areas activated are in line
with previous studies shown in cartoons
or story comprehension involving animation stimuli.
But interestingly, for perceived usability,
We found activation in the brain areas
in the primary motor cortex,
which controls all our voluntary movements.
This result suggest that perceived usability
is somewhat more related to action
as compared to perceived aesthetics.
So, let me make a quick summary
of the key points to take away from our work.
Perceived usability has a brain basis
that differs from that of perceived aesthetics.
Here we identify four key points, four key connections
between the brain and perceived usability.
The first point is that our findings suggest that emotion
does indeed play a key part in perceived usability,
and the findings from our first experiment
suggest that the anticipation of physical interaction
is an important part of perceived usability.
Also, our second experiment suggests that
the interaction depicted in video triggers
higher anticipation of interaction with the webpage.
So the third key point is that the area activated
specifically for perception of usability
is related to task intention,
like the example I mentioned,
what happens when I'm going to touch that.
And also the fourth point is that usability has elements
of high-order thinking, such as linguistic processing,
categorization, and rational thought.
So even without the opportunity to interact,
because people were lying down in the fMRI machine,
they could not interact with the webpage directly,
people still attempt to categorize and recognize
navigation options for the webpage being shown.
We also found overlaps of the brain activation area
between usability and aesthetics.
So we think there are two possible explanations for this.
This result may suggest that users
assess some confidence of perceived usability
by substituting an assessment of perceived aesthetics.
But also, on the other hand, perceived aesthetics
may form part of perceived usability
leading to the overlap between these areas.
With this I want to conclude my talk today.
My co-author Kasper is looking for postdocs,
so please contact him if you are interested.
Thank you.
(applause)
- [Man In Audience] So, I have a quick question.
- Yes.
- So, I find this study fascinating,
especially the idea that when you look at the page,
you have signs of the intention of action with that page.
- Yes.
- Now, how do you think, I know in an fMRI setup
it's very hard to let users do very much.
- Yes.
- But, how do you think it would be different if you let
the users actually interact with the page as opposed to
watch an interaction or imagine an interaction?
- Yes, so that's just one direction of our next,
of our future work, where we imagine that our work's, like,
we monitor their brain while letting them interact
with the webpage for example,
and see what is going on in there.
But obviously that's one direction of the future work here.
Where we see the change in real-time
of the brain activation in that particular area.
So in our work here, we just identify,
here is the area to look at during the usability assessment.
But now we know it is so when we manipulate the level
of usability for example and let them interact with it,
we can see how it changes in real time.
That's obviously a good suggestion, yes.
- [Man In Audience] And are you meaning
to test some hypothesis I mean
on the whole debate about affordances vs. signifiers,
the fact that the capability is there
but is not perceived, or is perceived?
Or other theories of human action with tool-mediated action?
Are you, I didn't see reference to theory
that are related to human behavior there.
- So, are you asking like
- Well, so to me the question is really
do you have theories of human interaction
that ground the work or are you just observing
the difference between different types of pages?
- So in here we try to end the debate actually,
like what is the relationship between usability and beauty,
and we answer it, right.
But we did not manipulate the usability
or look at different people's behavior,
but that is probably for the future.
- Okay, thank you.