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There are several laws in Interaction Design. These psychological principles help guide designers to make intuitive user interfaces. We'll look at three popular laws: Hick's, Fitts's, and Tesler's.
New Terms:
- Hick’s Law: The more choices a person is presented with, the longer the person will take to reach a decision.
- Tesler’s Law (aka Law of conservation of complexity): Every application has an inherent amount of complexity that cannot be removed or hidden.
- Fitts’s law: The amount of time required for a person to move a cursor to a target area is a function of the distance to the target divided by the size of the target. Thus, the longer the distance and the smaller the target’s size, the longer it takes. source: interaction-design.org
Further Reading:
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The field of interaction design consists
of several psychological principles.
0:00
In this video,
we'll take a look at three laws,
0:05
Hick's Law, Fitts's Law and Tesler's Law.
0:09
Hick's Law states that the more
choices a person is presented with,
0:14
the longer the person will
take to reach a decision.
0:18
It was defined by psychologist
William Edmund Hick.
0:22
Applied to design,
0:25
this means user interfaces should
be created with simplicity in mind.
0:27
Make content interactive and
provide categories, sorting, filtering and
0:32
sections to allow the user to narrow
down what they'd like to see.
0:38
This reduces cognitive load and
makes it easier to use the products.
0:43
Next up is Tesler's Law.
0:48
It was articulated by Larry Tesler,
0:51
a computer scientist who works in
the field of human computer interaction.
0:53
It states that for
0:58
any system there's a certain amount
of complexity that cannot be reduced.
0:59
While Hick's law states user interfaces
should be simplified, Tesler's law
1:04
knows that there's a certain point where a
product cannot be simplified any further.
1:09
Let's imagine an ecommerce shop.
1:15
You can simply visit the website and
add products to your card, that's easy.
1:18
There's no need to enter any billing or
shipping information yet.
1:23
But when you're ready to check out,
1:28
the store will need payment and they'll
need to know where to ship the order.
1:30
Okay, so that's where
the inherent complexities lie.
1:35
But even so, several decisions can be
shifted to a back-end process, and
1:38
it's up to you as a UX designer
to identify these opportunities.
1:43
Perhaps as the user enters their address
the system offers recommendations
1:48
to auto-complete the street name,
city, state and zip code.
1:52
Even better, this serves a dual purpose
of ensuring the address is validated.
1:58
There can also be an option
to create an account,
2:03
which would save the previously
entered information for next time.
2:06
The last law we'll look at is Fitts' Law.
2:10
Coined by psychologist Paul Fitts,
it states the amount of time required for
2:14
a person to move a pointer
to a target area
2:19
is a function of the distance to the
target divided by the size of a target.
2:22
Now, that's a lot of
logic to make sense of.
2:28
To put it in simpler terms,
a target area that's small and far away
2:31
will take the user more time to interact
with than one that's larger and closer.
2:37
It sounds like common sense, but
2:42
it's laws like these that
help inform design decisions.
2:44
This is just a sampling of the laws
you will encounter in the field of
2:48
interaction design.
2:51
If you're hungry for more,
check out the teacher's notes.
2:53
May these principles guide and
inspire you in your next project.
2:57
In the next video,
we'll look at sensation and perception.
3:01
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