Psychology Foundations
Understanding *why* patterns work lets you apply them to new situations. These are the research foundations beneath UX practice.
About This Skill
This skill contains research-backed principles only. Each concept includes:
- The original researcher(s)
- Year of key publication(s)
- What the research actually showed
- Limitations or caveats where relevant
1. Dopamine and Anticipation
Researchers: Wolfram Schultz (1990s), Robert Sapolsky Field: Neuroscience
What Research Shows
Dopamine neurons fire in response to prediction of reward, not reward itself. When a reward is expected and received, dopamine levels don't spike at reward time—they spike at the cue predicting the reward.
Schultz's experiments with monkeys showed:
- Unexpected reward → dopamine spike at reward
- Expected reward (after learning) → dopamine spike at predictor, not reward
- Expected reward that doesn't come → dopamine dip (disappointment)
UX Implication
Progress indicators work because they signal approaching reward. The anticipation phase is neurologically active.
Source: Schultz, W. (1998). Predictive reward signal of dopamine neurons. *Journal of Neurophysiology*.
2. Peak-End Rule
Researchers: Daniel Kahneman, Barbara Fredrickson Field: Behavioral economics, Psychology Recognition: Nobel Prize in Economics (2002)
What Research Shows
In studies of colonoscopies and other experiences, participants rated overall experience based on:
- The peak moment (most intense)
- The end moment
Duration had little effect ("duration neglect"). A longer painful experience ending gently was rated better than a shorter one ending abruptly.
UX Implication
- Create one memorable positive peak
- End interactions well
- A graceful error recovery can redeem a frustrating experience
Source: Kahneman, D. et al. (1993). When more pain is preferred to less. *Psychological Science*.
3. Loss Aversion
Researchers: Daniel Kahneman, Amos Tversky Field: Behavioral economics Recognition: Foundational to Prospect Theory (Nobel Prize 2002)
What Research Shows
Losses loom larger than gains. In experiments, losing $10 felt roughly 2x as bad as gaining $10 felt good. This asymmetry affects decision-making: people take irrational risks to avoid losses.
UX Implication
- Data loss is disproportionately frustrating
- Auto-save, undo, and preservation matter more than features
- Frame choices in terms of what users might lose
Source: Kahneman, D. & Tversky, A. (1979). Prospect Theory: An Analysis of Decision under Risk. *Econometrica*.
4. Flow State
Researcher: Mihaly Csikszentmihalyi Field: Positive psychology Timeline: Research from 1970s, book *Flow* published 1990
What Research Shows
Csikszentmihalyi interviewed hundreds of experts (artists, athletes, surgeons, chess players) about their optimal experiences. Common characteristics:
| Condition | Description |
|---|---|
| Clear goals | Know what success looks like |
| Immediate feedback | See results of actions |
| Challenge-skill balance | Task matches ability |
| Sense of control | Autonomy over actions |
When conditions are met, people report:
- Deep concentration
- Loss of self-consciousness
- Distorted time perception
- Intrinsic reward from the activity itself
Limitations
- Original research was qualitative (interviews, experience sampling)
- "Challenge-skill balance" is hard to operationalize
- Neurophysiological validation is still emerging
Source: Csikszentmihalyi, M. (1990). *Flow: The Psychology of Optimal Experience*.
5. Cognitive Load Theory
Researcher: John Sweller Field: Educational psychology Timeline: Theory developed 1988
What Research Shows
Working memory has limited capacity. Sweller identified three types of cognitive load:
| Type | Description | Reducible? |
|---|---|---|
| Intrinsic | Complexity inherent to the task | No (task-dependent) |
| Extraneous | Load from poor presentation | Yes (design target) |
| Germane | Load that aids learning | Desirable |
Instructional design should minimize extraneous load to free capacity for intrinsic and germane processing.
UX Implication
- Reduce visual clutter
- Group related information
- Use familiar patterns
- Don't make users remember across screens
Source: Sweller, J. (1988). Cognitive load during problem solving. *Cognitive Science*.
6. Miller's Law (Working Memory Limits)
Researcher: George Miller Field: Cognitive psychology Year: 1956
What Research Shows
Miller's famous paper "The Magical Number Seven, Plus or Minus Two" found people can hold approximately 7±2 "chunks" in working memory.
Limitations
Important: Modern research suggests the number may be closer to 4±1 chunks for novel information (Cowan, 2001). Miller's "7" applies to well-practiced, chunked material.
UX Implication
- Limit simultaneous options
- Group items into meaningful chunks
- Don't rely on users remembering many items
Sources:
- Miller, G.A. (1956). The magical number seven. *Psychological Review*.
- Cowan, N. (2001). The magical number 4 in short-term memory. *Behavioral and Brain Sciences*.
7. Serial Position Effect
Researcher: Hermann Ebbinghaus Field: Memory research Year: 1885
What Research Shows
When recalling lists, people remember:
- First items (primacy effect) — transferred to long-term memory
- Last items (recency effect) — still in working memory
- Middle items are poorly recalled
UX Implication
- Put important items first or last
- Don't bury critical information in the middle
- First impressions and final interactions matter most
Source: Ebbinghaus, H. (1885). *Über das Gedächtnis* (On Memory).
8. Zeigarnik Effect
Researcher: Bluma Zeigarnik Field: Gestalt psychology Year: 1927
What Research Shows
Interrupted tasks are remembered better than completed ones. The mind keeps incomplete tasks "open" in memory.
Limitations
Caution: Replication studies have been mixed. The effect appears real but smaller and more context-dependent than originally claimed.
UX Implication
- Progress indicators leverage incompleteness
- Unfinished onboarding motivates return
- But: incomplete tasks also create cognitive burden
Source: Zeigarnik, B. (1927). Über das Behalten von erledigten und unerledigten Handlungen. *Psychologische Forschung*.
9. Choice Overload (Paradox of Choice)
Researchers: Sheena Iyengar, Mark Lepper Field: Decision-making psychology Year: 2000
What Research Shows
The famous "jam study": shoppers shown 24 jam varieties were less likely to purchase than those shown 6 varieties. More choice led to decision paralysis.
Limitations
Important: Meta-analyses (Scheibehenne et al., 2010) found the effect is smaller and more context-dependent than popularized. Choice overload occurs under specific conditions:
- Unfamiliar domain
- Difficult to compare options
- No clear preference
- High decision stakes
UX Implication
- Reduce options when users lack expertise
- Provide smart defaults
- But: experts may want more choices
Sources:
- Iyengar, S. & Lepper, M. (2000). When choice is demotivating. *Journal of Personality and Social Psychology*.
- Scheibehenne, B. et al. (2010). Can there ever be too many options? *Journal of Consumer Research*.
Laws of UX (Quick Reference)
These are practitioner heuristics with varying levels of research backing:
| Law | Principle | Evidence Level |
|---|---|---|
| Hick's Law | Decision time increases with options | [Research] |
| Fitts's Law | Larger, closer targets are easier to hit | [Research] |
| Miller's Law | ~7±2 items in working memory | [Research] (with caveats) |
| Jakob's Law | Users expect familiar patterns | [Expert] NNg |
| Aesthetic-Usability | Pretty things seem more usable | [Research] |
| Postel's Law | Be liberal in input, strict in output | [Expert] |
Source: Laws of UX
Key Sources
- Schultz, W. (1998). Predictive reward signal of dopamine neurons.
- Kahneman, D. & Tversky, A. (1979). Prospect Theory.
- Kahneman, D. (1993). When more pain is preferred to less.
- Csikszentmihalyi, M. (1990). *Flow: The Psychology of Optimal Experience*.
- Sweller, J. (1988). Cognitive load during problem solving.
- Miller, G.A. (1956). The magical number seven.
- Cowan, N. (2001). The magical number 4 in short-term memory.
- Ebbinghaus, H. (1885). *Über das Gedächtnis*.
- Iyengar, S. & Lepper, M. (2000). When choice is demotivating.
- Scheibehenne, B. et al. (2010). Can there ever be too many options?