A new study from UC Berkeley shows Americans often make political decisions using just one factor—like age or gender—instead of weighing all available information. Source: greatergood.berkeley.edu.
How People Make Political Choices
Most people don’t deeply analyze complex issues. Instead, they use mental shortcuts to decide between candidates or policies.
The study, titled ‘Classifying Strategy Use in Multi-Attribute Subjective Choice: Application to Conjoint Experiments in Political Science’, was published in the Proceedings of the National Academy of Sciences. It involved nearly 3,800 participants.
Each person faced three scenarios: choosing which migrant to admit, which U.S. Senate candidate to support, and which climate policy to prefer.
For each choice, participants compared two options based on six factors: age, gender, education, English proficiency, origin, and motivation—whether seeking asylum or economic opportunity.
For example, in the migrant task, profiles were shown side by side. Participants chose one migrant to admit. The computer generated 30 such sets to track patterns in how people made decisions.
What the Study Found
- 54% of participants chose based on just one factor—like age or gender—without considering the others.
- 14% counted how many factors they preferred for each option and picked the one with more favorable traits.
Most people didn’t analyze all six factors. Instead, they relied on heuristics—mental shortcuts that focus on one key trait.
Patterns in Decision-Making Across Domains
People didn’t use the same strategy in every situation.
Some consistently favored younger candidates. Others prioritized economic impact when choosing climate policies.
When asked to rate each profile first, participants were more likely to consider all factors. This suggests reflection increases cognitive effort.
Participants generally preferred younger candidates, climate policies with low household costs, and immigrants seeking asylum over those seeking jobs.
Why People Use Mental Shortcuts
People aren’t infinite computational machines. As cognitive scientist Nidhi Banavar said, ‘We have these amazing brains, but they’re not infinite computational machines that would be necessary to do the kind of rational we imagine in our paper.’
Real-world decisions are limited by time, emotion, and cognitive load. Ideal rationality requires evaluating all factors. Most people can’t do that.
People shift strategies depending on the issue. A person might care about age when choosing a candidate, but weigh all factors when considering immigration.
Limitations of the Study and Their Implications
The study has key limitations that affect how we interpret its results.
- Comparisons were limited to two attributes at a time—like male vs. female or 50s vs. 70s. This simplifies diversity and may misrepresent how people evaluate different groups.
- Political party was not included in Senate candidate comparisons. This could have triggered strong emotional reactions or bias, skewing results.
- Participants weren’t always asked to rate each profile first. This may have reduced their attention to all factors.
Despite these limits, the study reveals public opinion is not uniform. It changes based on context, emotion, and personal values.
Implications for Real-World Politics and Communication
Political leaders and media must understand how people actually think.
When policies include many dimensions—economic, environmental, social—voters may still focus only on one, like cost or jobs.
As UC Berkeley political scientist Kirk Bansak noted, ‘Our understanding of public opinion is often based on surveys that ask people to choose between complex options defined by many factors. This study shows that individuals often base their opinions on a single factor, and that can create a clearer picture of what people want in public policy, and why they want it.’
Political campaigns may miss the mark. If a policy balances job creation and environmental goals, voters might only see the job part. That could lead to short-term gains, not long-term solutions.
Communicators should identify what matters most to different groups. For example, younger voters might care about jobs. Older voters might value environmental protection.
Public opinion isn’t static. It shifts with the issue, the message, and personal values. Messaging must be flexible and grounded in real decision patterns.
As Banavar asked, ‘How much are people going to read or listen to that?’ When issues are layered, people often skip the deeper parts. Clear, focused messaging improves understanding and trust.
This research doesn’t say people are irrational. It shows human reasoning works within cognitive limits shaped by experience and emotion. Recognizing those limits helps leaders build better, more empathetic messages.
The study, titled ‘Classifying Strategy Use in Multi-Attribute Subjective Choice: Application to Conjoint Experiments in Political Science’, was published in Proceedings of the National Academy of Sciences.
For more on cognitive biases and public opinion, see rational ignorance.
Sources & further reading
Featured image: original publisher image. Via original publisher. Image source
