COGNITIVE BIAS

Question 1

Peak-End Rule

Answer 1

People judge an experience largely based on how they felt at its peak and at its end, rather than the total sum or average of every moment of the experience.

Takeaways

1. Pay close attention to the most intense points and the final moments (the “end”) of the user journey.
2. Identify the moments when your product is most helpful, valuable, or entertaining and design to delight the end user.
3. Remember that people recall negative experiences more vividly than positive ones.

Origins
A 1993 study titled “When More Pain Is Preferred to Less: Adding a Better End” by Kahneman, Fredrickson, Charles Schreiber, and Donald Redelmeier provided groundbreaking evidence for the peak–end rule. Participants were subjected to two different versions of a single unpleasant experience. The first trial had subjects submerge a hand in 14°C water for 60 seconds. The second trial had subjects submerge the other hand in 14°C water for 60 seconds, but then keep their hand submerged for an additional 30 seconds, during which the temperature was raised to 15 °C. Subjects were then offered the option of which trial to repeat. Against the law of temporal monotonicity, subjects were more willing to repeat the second trial, despite a prolonged exposure to uncomfortable temperatures. Kahneman et al. concluded that “subjects chose the long trial simply because they liked the memory of it better than the alternative (or disliked it less)”.

Question 2

Serial Position Effect

Answer 2

Users have a propensity to best remember the first and last items in a series.

Takeaways
1. Placing the least important items in the middle of lists can be helpful because these items tend to be stored less frequently in long-term and working memory.
2. Positioning key actions on the far left and right within elements such as navigation can increase memorization.

Origins
The serial position effect, a term coined by Herman Ebbinghaus, describes how the position of an item in a sequence affects recall accuracy. The two concepts involved, the primacy effect and the recency effect, explains how items presented at the beginning of a sequence and the end of a sequence are recalled with greater accuracy than items in the middle of a list. Manipulation of the serial position effect to create better user experiences is reflected in many popular designs by successful companies like Apple, Electronic Arts, and Nike.

Question 3

Von Restorff Effect

Answer 3

The Von Restorff effect, also known as The Isolation Effect, predicts that when multiple similar objects are present, the one that differs from the rest is most likely to be remembered.

Takeaways

1. Make important information or key actions visually distinctive.
2. Use restraint when placing emphasis on visual elements to avoid them competing with one another and to ensure salient items don’t get mistakenly identified as ads.
3. Don’t exclude those with a color vision deficiency or low vision by relying exclusively on color to communicate contrast.
4. Carefully consider users with motion sensitivity when using motion to communicate contrast.

Origins
The theory was coined by German psychiatrist and pediatrician Hedwig von Restorff (1906–1962), who, in her 1933 study, found that when participants were presented with a list of categorically similar items with one distinctive, isolated item on the list, memory for the item was improved.

Question 4

Zeigarnik Effect

Answer 4

People remember uncompleted or interrupted tasks better than completed tasks.