Applied Cognitive Psychology - Leiden University (2019)

Lecture 3: Human Computer Interaction

Succesful interaction with computers results in achieving our goals

We spend more time with our computer than our partner ---> worth investing in a good human computer interaction

We, as humans have limitations, such as not being able to pay attention for too long, having biases etc. We have to take our cognitive abilities into account when we design computers. 

In the ACP model, to achieve a goal we either have to change cognition or environemnt. In the case of HCI we aim to change the environment, as it is much more difficult to change human cognition (e.g.: you can't tell someome to just be more flexible, rather change the design so it is easier for the user).

User experience (UX)

Levels of UX:

1. Utility - is it useful?

2. Usability - can the product be used easily?

3. Desirability - does the product look and feel good?

4. Brand experience - is the overall feeling about product good?

Goal: "It works well and makes me say wow!"

Displays

The system conveys information to the user through the display. Can be something you see or hear that indicates a certain information (e.g.: phone beeps when you get a new text).

Graphical User Interterface (GUI): you can draw things with pixels --> easy to shape the digital environment

Design principles

Perceptual:

1. Legibility - e.g.: info conveyed through text should be legible - right color, font, positioning...

2. Absolute judgment - e.g.: only using one property to convey info (e.g. dark green means good, light green means bad ---> can lead to confusion)

3. Top down expectation - e.g.:  A I3 C or 12 I3 14

4. Redundancy gain - e.g. traffic lights. We have to use both the position and the color, because it can lead to confusion if e.g. we don't use position (color blind people) or color (difficult to see position from afar)

5. Discriminability: e.g.: icons look too similar to eachother

Mental model (understanding what you see):

6. Pictorial realism: e.g.: the higher the volume the higher the indicator is

7. Moving part: e.g.: if you have a moving stick, reverese shouldn't be marked forward 

Attention:

8. Information access: e.g.: you need to put a code into Usis that you can only access through the e-studyguide - bad design

9.Proximity compatibility: e.g.: similar backgrounds indicating similar applications

10. Multiple resources: e.g.: having GPS tell you where to go and also showing it

Memory:

11. Knowledge in the world: having the options ready and havign to only choose (not having to know by heart)

12. Prediction: e.g.: weather apps let you know what to expect

13. Consistency: it's wise to be consistent with other apps so users learn how to use your app faster

Conflicts:

Example: Using a remote control with a button for everything  -->knowledge in the world but legibility bad

Alerts, labels, icons:

Alerts:

-Warnings

-Cautions

-Advisories

Labels, icons:

-Visibility

-Discriminability

-Meaningfulness

-Location

Usability goals:

Effectiveness - Accuracy and completeness with which users achieve specified tasks

Efficiency - Resources expended in relation to the accuracy and completeness with which users achieve goals

Safety - Avoid danger of carrying out unwanted actions accidently; means of recovery when they happen

Utility - Is it the right functionality? 

Learnability - Easy to learn, easy to master

Memorability - Retention over time

How do we develop an app or website?

Waterfall model:

1. Initiation: Good idea for new app, should I build this?

-Define it: what is different about the app compared to competitors?

2. Analysis: analyze target,take into account who can pay for it/invest in it

-Check for requirenmnets: interviews etc

3. Design: definining all systems, subsystems, displays etc

- System design phase

4. Implementation

Problem with the model: at the end the software doesn't fit the needs of it's environmnet etc...

Improvement: repeated evalutation

7 stages of action (Norman):

1. Forming the goal - I want to eat

2. Forming the intention - I will get something from the vending machine

3. Specifying the action - Outline steps needed for getting food from the machine

4. Executing the action - Selecting item and paying  

5. Perceiving the state of the world - Has anything changed? Item fell from its place.

6. Interpreting the state of the world - The food is ready to be taken from the machine

7. Evaluating the outcome - I will get the item I payed for and eat

HCI Guidelines (Nielsen's list)

Match real world

Consistency and standards

 Visibility of system status

 User control and freedom

 Error prevention, recovery

Memory

 Flexibility, efficiency

 Simplicity and aesthetics