University of Lugano
Via Buffi 13
University of Lugano
Via Buffi 13
10 Heuristics for an Optimal User
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CHI’12, May 5–10, 2012, Austin, Texas, USA.
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In this paper we present 10 heuristics for ensuring a
good user experience, derived from a critical inspection
of flow theory and applying it to the context of humancomputer
interaction. The heuristics are intended as
guidelines for practitioners when designing and
evaluating interactive products. We show how each
heuristic derives from flow theory, provide design
recommendations based on the heuristic, and give an
example that illustrates it.
Heuristics, User Experience, Flow Theory
ACM Classification Keywords
H.5.m. Information interfaces and presentation (e.g.,
Interactive products have become ubiquitous
companions of all facets of everyday life. In humancomputer
interaction research, these changes are
reflected in a shift away from investigating how to
make task-related interaction more effective and
efficient towards finding out how interaction can
happen in a more joyous and satisfying way. After a lot
of discussion on competing frameworks and
terminology, the term user experience has emerged for
this direction of research.
We argue that there is only little consensus on what
user experience is or should be, and an abundance of
possible definitions that while stimulating make it
difficult to come up with a working one. As a
consequence, practitioners are left without guidelines
on what constitutes a good user experience and how
they can design for it.
In an effort to build an understanding of enjoyment in
games, Sweetser and Wyeth  develop the
GameFlow model. They do so by mapping elements
from game literature to flow theory. The result is a list
of 8 criteria that can be used to evaluate how enjoyable
a particular game is.
In this paper, we follow a similar approach by deriving
general user experience heuristics from flow theory. In
doing so, we pursue two goals. From a theory
perspective, we aim at informing, expanding, and
contributing to the ongoing discussion on what good
user experience is or should be. For practitioners, we
provide a list of heuristics that can be used in the
design and evaluation of interactive devices and
The notion of heuristics is not undisputed in humancomputer
interaction research. Under the user-centered
design paradigm that demands involvement of users as
early and often as possible in the development process,
the idea of relying on experts inspecting a system
based on a number of heuristics has come under heavy
Our motivation for proposing user experience heuristics
here comes from our background. Both authors have
worked in small design companies and often witnessed
how the requirement of involving users was neglected,
justified with a number of reasons such as time or
money constraints. In consequence we believe there is
still a lot of merit to the discount usability claim that
while it may not be the best usability methodology to
use, it is better than using none. Our list of heuristics is
intended as a resource-friendly way to ensure good
user experience of a product when time and money are
Flow is a well-established and validated psychological
theory developed by Mihaly Csikszentmihalyi, that
describes what an optimal experience is.
Csikszentmihalyi  defines flow as a mental state of
deep enjoyment and intense engagement in a certain
activity, where most of a person’s attentional resources
are devoted to accomplish that activity. An optimal
experience is what a person experiences when being in
a state of flow and it is characterized by universal
conditions: 1) clear goals; 2) feedback; 3) focused
concentration; 4) loss of self-consciousness;
5) merging of action and awareness; 6) challenging
activity that requires adequate skills; 7) sense of
control; 8) a distorted sense of time; 9) autotelic
These 9 major components (in , 8 components are
given, but we split “clear goals and feedback” for
convenience) are the most often mentioned
accompanying factors of an optimal experience
regardless of the activity performed and of one’s
sociocultural characteristics. As stated by the author
there is no need to meet all these conditions to
Flow theory has been already used in HCI studies (for a
review see  , ) as a framework for modeling
mental states like enjoyment, engagement, and
There are still two main limitations when using flow
theory for HCI research. First, there is still a lack of
consistency in the conceptual and methodological
definitions of flow used by different researchers 
even though researchers generally agree on the original
conceptual definition of flow as presented by
Csikszentmihalyi in .
The second limitation is that flow theory, in its original
form, looked into the optimal experience by considering
solely the person, the activity performed by her and the
interaction between the two. But when this interaction
is mediated by an artefact (or system, we use these
two terms interchangeably) then it would be better to
re-conceptualize flow in order to consider this third
component as well as its interaction with the person
and the task (or the user and the activity).
Some authors already stressed the importance to
distinguish task from artefact , and consequently,
task flow from artefact flow . But to our best
knowledge there are no works specifically focused on
providing a detailed list of recommendations on how a
system should be designed in order to facilitate an
optimal user experience. In this paper we try to fill this
gap as much as drawing a clearer link between flow
theory and HCI while enabling researchers to overcome
the above-mentioned limitations. The heuristics we
present are the result of an extensive literature review
and of a deductive approach in which we map the flow
components into guidelines for providing an optimal
User Experience Heuristics
In the following we present each heuristic, describe
how it derives from flow theory, provide design
recommendations based on the heuristic and give an
example that illustrates it. The first 9 are directly
mapped from the aforementioned flow components
(following the same order). The tenth heuristic
(conservative innovation), derives from
Csikszentmihalyi’s finding that what all flow activities
have in common is providing a sense of discovery, a
creative feeling of transporting the person into a new
1. Clear goals
The purpose of the system should be clear. The system
has to fulfill, or even better exceed, user’s
Flow theory states that in order to be engaged in an
activity, one should define clear goals to be obtained
from the activity itself, and should strive to achieve
When the experience is mediated by a system, users
have some expectations on how the system will support
them in performing a certain activity. These
expectations depend on the affordances of the system.
Affordances make it obvious how an object is meant to
be used  even though the actual perception of
affordances will be determined in part by the observer’s
culture, social setting, experience and intentions .
Obviously designers do not have control over such
variables, but they can determine which affordances
are present in the system and how users will perceive
them. As such we recommend:
! the system should be designed with the right
affordances to explicitly tell users its purpose(s):
! the system must be functional, meaning that it
must fulfill the purposes highlighted by the affordances
and meet users’ expectations;
! additional features (other than the core ones) are
welcome, even better if they foresee possible
alternative uses of the system: a product that is
actually exceeding users’ expectations is often a
predictor of a good user experience .
As an example consider so-called bridge cameras.
These are often comparable in size, weight and
appearance to digital single-lens reflex (DSLR)
cameras, but they lack the advanced functionalities and
image quality of the latter. However their DSLR like
camera-body (affordance) could create expectations
that are not met by the system.
This discrepancy between users’ expectations and
system purpose could explain (amongst other factors)
the low commercial success of this specific category of
digital cameras. This could also explain the increasing
popularity of mirror-less interchangeable-lens camera
(MILC) where the expectations suggested by their
affordance (they look like compact cameras) are
exceeded by the system.
2. Appropriate feedback
The user-system interaction should be sustained
through steady, prompt and unobtrusive feedback.
Feedback is important as it increases users’ confidence
in interacting with a system by creating order in
consciousness, and strengthening the structure of the
self. Feedback can increase engagement provided it is
logically related to a goal in which one has invested
mental energy .
But feedback alone is not enough; it should be provided
steadily (to sustain user interaction), promptly (to
increase awareness) and unobtrusively (to not interfere
with the experience).
From this we derive as design recommendations that:
! the system should provide steady and prompt
! the feedback should be as less obtrusive as
! the “obtrusiveness” of the feedback should be
proportional to the level of priority (to establish a sort
The Web 2.0 paradigm provides a good example on
how feedback can influence user experience. The most
important technological innovation of Web 2.0 is
it possible to provide users with real-time feedback.
Moreover the obtrusiveness of the feedback was
reduced since with AJAX the page content can be
updated without refreshing the page, thus avoiding
interrupting user interaction with the webpage.
3. Focused concentration
The system should be simple and intuitive in its use; it
should facilitate user concentration on the task at hand
by providing meaningful feedback and avoiding nonrelevant
A characteristic of optimal experience is that for people
to reach this state, they must be able to focus their
attention at length on the task at hand. Concentrating
on the task further enhances one’s focus, often
enabling them to tune out other input .
According to perceptual load theory  task-irrelevant
stimuli are perceived in situations of low perceptual
load when the relevant task leaves spare capacity for
their processing, but not in situations of high perceptual
load where all available capacity is consumed. This
phenomenon is also known as inattentional blindness.
Mancero et al.  found that that the more relevant
and meaningful the stimuli are the more responsive the
From this we can obtain the recommendations that:
! the system must be usable;
! the system should provide feedback that is relevant
and meaningful for the task at hand;
! the system should avoid distractions, namely
stimuli that are not relevant for the task at hand;
Google AdWords provides a good example for all this.
When users perform searches on Google they are
provided with the result of the search together with
some advertisements based on their current search
terms. The main reason why these advertisements are
more effective, and users have a better experience,
than disruptive colorful blinking banners is mainly
because the stimulus provided to users is not
distracting them from their primary task (searching)
and it is relevant and meaningful to the task at hand.
4. Ergonomical transparency
The system should almost disappear, be transparent,
while used to allow users to focus on the activity and to
engage in the experience.
When an activity is thoroughly engrossing, there is not
enough attention left over to allow a person to consider
any temporarily irrelevant stimuli, including selfconsciousness
More mental energy devoted to the activity means
more engagement as well as less space in mind to keep
consciousness of the self and, equally important, of the
The loss of self-consciousness mainly depends on one’s
mental attitude, but the system can be designed to be
as “transparent” as possible. A technology that is well
fitted to our skills, our purposes and the activity we are
performing is almost invisible in use .
The aim is to move users’ flow into the realm of the
task and to engage them there (task flow) and to focus
their minds on the experience, rather than on the
system (artifact flow) . To be “transparent” the
system should then meet these characteristics:
! the system should be ergonomic, it should fit users’
skills and activity purposes;
! the system behavior should be consistent and
! the system should be designed with aesthetical
integrity, in other words the design should be visually
appealing and common principles of good design should
be followed; it should also provide a graceful flow,
namely the interaction between users and the system
should be smooth and graceful.
Loss of self-consciousness and invisibility of the system
are especially important to achieve while playing
videogames, indeed they are often referred as
indicators of immersion .
We can see how these principles work in practice in one
of the most-popular videogame of the last few years:
All the criteria we listed above are met by the system
consisting of the game engine (the gameplay, the
sound, the physic engine, etc. for a deeper review see
) and of the device on which it runs (the
touchscreen makes the interaction with the system
more intuitive and transparent). No matter which
mobile device we are using, if the battery is running
low or if our train stop is the next one: we must
destroy those loathsome pigs!
5. Technology appropriation
Users should be allowed to customize and manipulate
the system according to their peculiarities and
preferences, to feel familiar with the system, as if the
system was tailored specifically for them.
When people are completely absorbed by the activity,
they become so involved in what they are doing that
the activity becomes spontaneous, almost automatic;
they stop being aware of themselves as separate from
the actions they are performing .
As a result, the person will then feel part of a whole,
completely merged into a system of interaction
consisting of the person itself, the artifact and the task
We wrote above that a transparent system would
facilitate user engagement, but this feature alone is not
enough. The possibility to appropriate and adapt the
technology can improve the system’s situatedness
(adaptability to the context of use) and dynamicity
(adaptability to changes over time) and users’ sense of
ownership . Hence we recommend that:
! the system should be, to a certain extent,
customizable and manipulable by users in both its
appearance and its functionality;
! the customization process should be easily
accessible, and with a predictable outcome
! provide users with multiple choices for interacting
with the system (doing the same activity in many
An example of this can be found in office software
suites. Users can customize toolbars and menus, the
customization is easily accessible and reversible and
they have different options for accomplishing the same
activity (e.g. to paste the content of the clipboard one
can use the command-v keyboard shortcut, the
edit->paste menu bar item or the clipboard
6. Challenges/skills balance
The system should adapt to the user in that it should
be designed to dynamically provide adequate
challenges for both novice, average and experienced
An important factor in determining flow or frustration is
not the absolute challenges of the activity, nor the
absolute level of users’ skills, but rather the relative
balance between the two . Enjoyment comes at a
very specific point: whenever the opportunities for
action perceived by the individual are equal to his or
her capabilities .
It is worth noticing that this balance is dynamic. While
we interact with a system we implicitly masters new
skills, skills that need to be balanced by new adequate
Challenges should not be interpreted as “barriers to
use” but as a bundle of opportunities for action,
opportunities for a more efficient and fulfilling
interaction. So, to allow a dynamic balance between
challenges and skills:
! the system should have a steep learning curve to
help novice users;
! the system should encourage users to explore it
and to discover all the features and opportunities for
! the system should provide advanced features or
extra functions (e.g. accelerators, macros, advanced
settings, etc.) and make them accessible for
This dynamic balance can be found in Mac OS X
operating system. The system is intuitive and simple
enough for novice users (Have you ever tried to install
a new application both on Windows or OSX?); it is
possible for intermediate users to customize and
optimize it (e.g. create macros with Automator and
customize keyboard shortcuts, trackpad gestures or
screen hot corners); while it gives full control to
experienced users (with the UNIX shell you can hack
7. Potential control
The system should make users feel “free” of constraints
and, at the same time, in control of the experience.
The flow experience is typically described as involving a
sense of control or, more precisely, as lacking the
sense of worry about losing control that is typical in
many situations of normal life . Needless to say that
feeling in control of the system is a precondition for
feeling in control of the experience.
The adjective “potential” is used intentionally, meaning
that actually users do not have to always be in
complete control of the system: what people enjoy is
not the sense of being in control, but the sense of
exercising control in difficult situations .
Or, to use Shneiderman’s words the system should
“support internal locus of control” , meaning that
users have to believe that activity outcomes result
primarily from his own behavior and actions. In order
to do so:
! the system should help users to improve their skills
and to reduce the margin of error in performing the
! the system should not make users feel trapped.
Avoid (as far as possible) constraining users’ actions,
provide them an exit strategy and make the actions
! users should be always allowed to enable or disable
automatic processes or system aids.
If we look at modern racing simulation videogames
they all provide driving aids (e.g. traction control) in
order to support players in the first phases of the
gaming experience. But each of these features can be
easily disabled by users whenever they want, in some
videogames even while they are playing: the possibility
of enabling/disabling this kind of aids is crucial for
supporting internal locus of control.
Finally, players can always restart the race (exit
strategy) and in some games even rewind
(reversibility) if they have committed some mistakes.
8. Follow the rhythm
The pace of the system should adapt to the user and to
the rhythm of the experience.
One of the most common descriptions of optimal
experience is that time no longer seems to pass the
way it ordinarily does. The objective duration of time is
rendered irrelevant by the rhythms dictated by the
Thus to enable an optimal user experience it is not
crucial to have a fast and hyper-responsive system, it is
rather crucial that the system pace is appropriate to the
experience and to the user.
This does not mean that “fast is bad”: time still has an
important role when it comes to user experience, but in
this case the focus should be on the user’s perception
of time rather than on “mere” efficiency. For this
! the system’s pace should be suitable for the
activity for which it was designed;
! the experience should not be interrupted by the
system but users should be allowed to suspend the
interaction and to restart it from the point of
achievement he reached;
! users should be allowed to speed up or slow down
the rhythm of the interaction.
We know that this heuristic could sound odd for
videogames where speed increase is crucial for keeping
the user engaged, like Tetris for instance. Let us take it
It is true that users are not allowed to slow down the
game but the purpose of “soft/hard drop” and “pause”
controls is to give users a certain degree of control over
the game speed. This will allow them to adapt the
game speed to their skills thus improving gaming
By looking at file sharing systems, we can understand
the importance of adapting system pace to the user.
Downloading on a dial-up connection a large file is
frustrating. But it is also true that the opposite situation
could be misleading: downloading at high speed a very
small file could result in the users not being aware of
the task being completed. In order to avoid this, the
system should “deceive” users. By showing, for
instance, a progress bar for more than the actual time
of download (as it happens on http://ge.tt).
9. Know thy user’s motivations
The system should help users to fulfill the motivations
behind its use and to satisfy basic psychological needs.
Enjoyable events occur when a person has not only met
some prior expectation or satisfied a need or a desire
but also gone beyond what he or she has been
programmed to do and achieved something
unexpected, perhaps something even unimagined
The system should help users to fulfill their
motivations, then it will be more likely for them to
perceive the experience as enjoyable.
Moreover, when applicable, the system could help users
to have “basic psychological needs”  (need for
competence, autonomy and relatedness) satisfied as
well, thus resulting in an improvement of enjoyment
. Then to allow an optimal user experience:
! the system should be designed by looking at final
users and the activity they seek to accomplish, this
means that you should know them first;
! but knowing all the possible users and activities is
impossible so, the system should be flexible in order to
adapt to various users for various activities and in
! when applicable, the system should help users to
satisfy the three basic psychological needs (in a broad
sense): need for competence, autonomy and
Facebook is a perfect example of a system that fulfills
motivations behind its use and satisfies basic
10. Conservative innovation
The system should be innovative (and conservative at
the same time).
Though innovation is not among the nine key principles
of Flow, in his studies Csikszentmihalyi found that what
all flow activities have in common is providing a sense
of discovery, a creative feeling of transporting the
person into a new reality .
The system can enhance this “sense of discovery” by
actually implementing novelty and variety, by allowing
users to perform the activity in a more fulfilling way or
experiencing “something new”.
But at the same time the system should not be
completely different from existing systems, which serve
the same purpose. We approve of things that comply
with standards, things we are familiar with, and we
disapprove of things that conflict with standards .
Still according to Desmet et al.: “Standards are our
beliefs, norms or conventions of how we think things
should behave.” . It follows that:
! the system should provide a certain degree of
novelty and variety to users;
! the system’s should be the result of a tradeoff
between innovation and tradition, where tradition is
meant as consistency with familiar systems and
compliance to standards;
! the system should ensure interoperability to
seamlessly integrate into the existing context.
Nowadays smartphones provide a good example. Multitouch
has been undoubtedly a breakthrough
innovation, but modern smartphone are “just” a
mixture of existing technologies people were already
familiar with (i.e. touchscreens were already used in
We presented a list of 10 heuristics, which we derive
from flow theory. We described how each flow
component applies to a HCI context and gave design
recommendations based on each heuristic.
We believe these heuristics can help interaction
designers deliver good user experiences. In flow
theory, not all of the flow components have to be met
for someone to experience flow. Similarly, not all
heuristics have to be considered in the same way in
order to design good user experiences. It is up to
designers to prioritize heuristics for each context in
order to produce the most engaging user experience.
 Bederson, B.B. Interfaces for staying in the flow.
Ubiquity 2004, September (2004), 1.
 Bird, J. The phenomenal challenge of designing
transparent technologies. interactions 18, 6 (2011), 20.
 Blythe, M.A., Overbeeke, K., Monk, A.F., and
Wright, P.C. Funology: From Usability to Enjoyment.
Kluwer Academic Publishers, 2004.
 Cartwright-Finch, U. and Lavie, N. The role of
perceptual load in inattentional blindness. Cognition
102, 3 (2007), 321-40.
 Csikszentmihalyi, M. Flow: The Psychology of
Optimal Experience. Harper Perennial, 2008.
 Desmet, P.M.A., Porcelijn, R., and Van Dijk, M.A.
Emotional Design; Application of a Research-Based
Design Approach. Knowledge, Technology & Policy 20,
3 (2007), 141-155.
 Dix, A. Designing for Appropriation. Proceedings of
the 21st British HCI Group Annual Conference on
People and Computers (BCS-HCI ‘07), British
Computer Society (2007), 27-30.
 Finneran, C.M. and Zhang, P. A person–artefact–
task (PAT) model of flow antecedents in computermediated
environments. International Journal of
Human-Computer Studies 59, 4 (2003), 475-496.
 Finneran, C.M. and Zhang, P. Flow in computermediated
environments: promises and challenges.
Communications of the Association for Information
Systems. 15, (2005), 82-101.
 Gaver, W.W. Technology affordances. Proceedings
of the SIGCHI conference on Human factors in
computing systems Reaching through technology - CHI
‘91, ACM Press (1991), 79-84.
 Hoffman, D.L. and Novak, T.P. 2009. Flow Online:
Lessons Learned and Future Prospects. Journal of
Interactive Marketing. 23, 1 (Feb. 2009), 23-34.
 Holtzblatt, K. What makes things cool? Intentional
Design for Innovation. interactions 18, 6 (2011), 40.
 Mancero, G., Wong, W., and Amaldi, P. Looking but
not seeing: implications for HCI. Proceedings of the
14th European conference on Cognitive ergonomics
invent! explore! - ECCE ‘07, ACM Press (2007), 167.
 Mauro, C.L. Why Angry Birds is so successful and
popular: a cognitive teardown of the user experience.
Pulse>UX, 2011. https://bitly.com/dSPfdn.
 Norman, D.A. The design of everyday things. Basic
Books, New York, NY, USA, 2002.
 Pace, S. A grounded theory of the flow experiences
of Web users. International Journal of Human-
Computer Studies 60, 3 (2004), 327-363.
 Pearce, J. and Howard, S. Designing for Flow in a
Complex Activity. APCHI 2004!: Asia Pacific conference
on computer human interaction, Springer (2004), 349-
 Ryan, R.M. and Deci, E.L. Self-determination theory
and the facilitation of intrinsic motivation, social
development, and well-being. American Psychologist
55, 1 (2000), 68-78.
 Shneiderman, B. and Plaisant, C. Designing the
User Interface: Strategies for Effective Human-
Computer Interaction. Addison Wesley, 2004.
 Sweetser, P. and Wyeth, P. GameFlow: a model for
evaluating player enjoyment in games. Computers in
Entertainment 3, 3 (2005).
 Voiskounsky, A.E. 2008. Flow Experience in
Cyberspace: Current Studies and Perspectives.
Psychological Aspects of Cyberspace: Theory, Research,
Applications. A. Barak, ed. Cambridge University Press.