Attentional bias is a psychological phenomenon where individuals pay more attention to certain stimuli over others based on their emotional relevance or personal significance. This concept is crucial in understanding user behaviour and optimising app user experience (UX). Attentional bias can significantly impact how users interact with an app, what elements they notice first, and how effectively they can achieve their goals.

Chunking is a cognitive psychology principle that involves breaking down large amounts of information into smaller, more manageable units, or "chunks." This technique helps users process, understand, and remember information more easily. In web design, applying chunking to your information architecture can significantly enhance the user experience by making content more digestible and navigable.

Hick’s Law is a principle in psychology that states the time it takes for an individual to make a decision increases with the number and complexity of choices. In web design, this means that the more options you present to users, the longer it will take them to make a decision, which can affect their overall experience on your website.

Cognitive load refers to the amount of mental effort required to process information. In the context of web design, it’s the burden placed on a user’s working memory when interacting with a website. Understanding cognitive load is crucial for creating user-friendly websites, as excessive cognitive load can lead to confusion, frustration, and ultimately, abandonment of the website (and a potential sale).