Perception

The lessons for the term are over, and in NM2216 Introduction to Interactive Media Design, I learnt about design concepts more pertinent to an interactive interface itself. What I learnt before the mid-semester break was mostly about design dimensions, and this time around the topics were more interesting yet challenging to understand.

Affordances and Constraints
The second half of the term started with affordances and constraints, which basically have opposite meanings. The former refers to controls or properties which determine how a system can be used, while the latter simply means the limitations of the system. A system or device may afford multiple things, which can be categorised into functional (what it does), cognitive (an indication to the user of its function), physical (its physical usability) and sensory (its properties which appeal to our senses). Constraints also exists in different contexts, mainly physical and logical, and sometimes cultural as well. These limits may aid the user in understanding and using the system.

Feedback
Feedback can be thought of as a response or output from the device or system, and is crucial for informing the user the outcome of his or her actions. There are five main states of a system with regard to feedback. The obvious ones are the ready, processing and reporting states. These fundamental feedback follow through the user’s action from start to end.  Two other important states are necessary when the system is busy or when the user attempts too many actions, and having feedback to indicate whether subsequent user actions will be carried out is important. Another critical aspect of feedback deals with errors, where generic statements bearing no meaning or sense to users often leave them helpless and frustrated. Having clear and concise messages, on top of actually guiding the user to rectify the error, is key to the user experience.

Mappings and Metaphors
Mappings of a device or its controls is the relationship between what the user does and what is expected to happen. A certain level of psychology is relevant here, and metaphors often aid users in understanding how a system can be used. Many mappings may be considered “natural”, whether born by tradition or years of experience and living, but in my own opinion, I believe many of such mappings are learnt over time, and definitely vary from societies and cultures. Saying such mappings are natural is subjective and biased.

Representation
Representation is a cognitive presentation of a certain concept in a medium that is abstracted away from irrelevant details. Through perceptual and naturalness principles, designers can use visual properties like colour, size, orientation and proximity to convey the relevant meanings. Experiential representation are often grasped by users more quickly, and using additive (e.g. size) and substitutive (e.g. colors) representation facilitate their understanding. Another type of representation, reflective, focuses on abstract concepts while ignoring real world instances.

Conceptual Models
The last concept covered was conceptual models, and essentially the important difference between the implementation model of the system, the represented model by the designer and the mental model of the user. Often, a user’s understanding (mental model) is different from how a system actually works (implementation model), and having a user-friendly interface (represented model) is crucial in allowing the user to utilise the functions of the system without actually have a grasp of the mechanisms behind it. The represented model should always try to be as close to the mental model to facilitate the ease of use, but it is not always easy to understand a user’s mental model as they tend to be incomplete, simple and unscientific. 

I realise I don’t really provide any examples in my posts on the design dimensions and concepts I’ve learnt, but this is basically just a brief overview of what’s been covered in this semester. The readings provided by the lecturers have been immensely useful, I must say, and if you would like them I’d be happy to share them with you.