How the Human Mind Works

How Human Mind Works

• The lecture slides come from the lecture notes of Dr. Yavuz Inal.
• This lecture covers attention, context, preception, Gestalt principles, Fitt's law, and human memory.

Attention

• It's a process where an individual concentrates on particular aspects of the environment.
• Human attention capacity is limited.

Constructivism

• Brains do not create pixel-by-pixel images.
• Minds construct models summarizing input from our senses, which we then perceive.
• When observing something, details are not fully retained, only those considered meaningful.

Familiar Objects

• People filter out irrelevant factors and remember only the important details.
• Examples of details not stored:
  • The number of links on a top menu.
  • Colors on Google’s logo.
  • Lines in the IBM logo.

Context

• Play a major role in what people see in an image.
• Mindset are all factors that we know and bring to a situation.
• Can profoundly affect a website's usability.
• If you have no idea what to expect, because there was no context, it's harder to recognize.
• Once we have context, it becomes easier to recognize.

Perception

• It is a process where information gets organized and interpreted to recognize meaningful objects and events

Gestalt Principles

• German psychologists sought explanations for human visual perception, resulting in Gestalt principles.
• The German word "Gestalt" means "shape" or "figure".
• There are five principles of Gestalt psychology: proximity, similarity, symmetry, continuity, and closure.
• We organize things into meaningful unites using these principles.

Principles of Gestalt psychology

• Organizes information into meaningful units.
• Proximity: Grouping based on distance or location.
• Similarity: Grouping based on type.
• Symmetry: Grouping based on meaning.
• Continuity: Grouping based on flow of lines or alignment.
• Closure: perceiving shapes that are not completely there.

Proximity

• Related objects are put together so they can be read together
• The relative distance between objects in affects perception of how objects are organized into subgroups.

Similarity

• The objects that look similar appear grouped, with other factors being equal.

Symmetry

• We use our experience and expectations to make groups of things.
• Example group of 2 triangles.
• A group of 3 paired square brackets

Continuity

• Continuity is the term for flow or alignment.
• We see curves AB and CD and not AC and DB, and not AD and BC

Closure

• We mentally "fill in the blanks".
• All shapes are identified as circles even if they are an incomplete circle.

Figure and Ground

• Images are separated into figure (foreground) and ground (background).
• Image can be ambiguous

Fitt's Law

• The farther away a target is, the longer it takes to acquire it with the mouse.
• The smaller a target is, the longer it takes to acquire it with the mouse.
• Larger, labeled controls can be clicked more quickly
• Scroll bars on Windows versus the Mac (pre OSX Lion).
• Windows has the up arrow at the top of the scroll bar and the down arrow at the bottom, likewise with left and right.
• The Mac however puts the arrow buttons side by side because, due to Fitts' Law, navigating between them is much quicker in that format.

Hick's Law

• The time it takes to make a decision increases as the number of alternatives increases.
• For time-critical tasks, minimize the options to reduce response times and minimize errors.

How Memory Works

• Information flows between sensory, short-term, and long-term memory. Sensory memory captures environmental stimuli via touch, hearing, and vision.
• Through processing, some information moves to short-term "working" memory, while unretained information is lost.
• Rehearsal can retain the information in short-term or transfer it to long-term memory.
• Short-term memory can either pass onto long-term memory or lost.
• Information not attended to is lost.
• Info fades from memory in 20 seconds.

Magical Number 7

• George A. Miller (1956) wrote that people can remember 5 to 9 (7+/- 2) things and process 7+/- 2 pieces of information at a time.

Peripheral Vision

• Critical, just not for detail. Acts as a detector for where to focus.
• Cones and Rods:
  • Cones: 6-7 million per eye, sensitive to different frequencies of light (low, medium, and high) and Highest density in fovea.
  • Rods: 120 million/eye, Sensitive to overall brightness and motion; used most in low light levels and Highest density outside of fovea.

Change Blindness

• Affect critical information such as error messages and navigation menus, leading to user confusion and task failure.
• The tendency of people to overlook alterations in images, especially when those changes appear immediately after a visual interruption such as a flickering screen.

Combatting Change Blindness

• Minimize visual interruptions by avoiding page reloads where possible.
• Use appropriate visual emphasis for significant new elements (such as contrast, size, and padding) to ensure they are noticeable.
• Strategically place important new visual elements close to the point where the users' eyes are already focused.

Banner Blindness

• Users have learned banner ads don't help them reach their goals, causing them to pay it no mind.