This blog is purely for a layman.
We are humans. And we are social animals. The term social means we like to live in a society that consists of humans or animals.
In a society, every thing depends on each other. For an example in a farming society a rice farmer depends upon the sunflower farmer for oil, a sunflower farmer depends upon dairy farmer for compost. Like this manner every living being in a society depends on each other. This is the fundamental principle of a society.
But, to form a society the people needs to communicate with each other. Without communication, the society will be called as gathering.
This communication is called interaction.
When two persons interact with each other, they share their feelings.
Let's consider two person Jyoti and Pratyush.
When they meet for first time the only medium of interaction is verbal. Just like hello, hi, what's your name etc.
When they met several times and become friends, new medium of interaction took place i.e. sign language like hand waving, handshake, thumbs up, thumbs down etc.
With the flow of time when they become best buddies, uncountable number of mediums included into their interaction process. And for this reason Pratyush can make Jyoti understand difficult things with lesser effort.
The same thing happens here in HCI research. The scientists study the human psychology, prepare algorithms, coding, sensors, hardware. So that, combinely they can help both human and computer to interact with each other with minimum effort.
The core aim of the HCI research is to reduce the effort of Human and increase the accuracy of the computer while interaction occurs.