Have you ever stubbornly held onto your initial judgment despite mounting evidence to the contrary? That’s conservatism bias at work—our tendency to insufficiently update our beliefs when presented with new information.
We pride ourselves on being rational thinkers, weighing evidence objectively before forming conclusions. Yet cognitive science reveals a systematic flaw in how we process new information: conservatism bias. This tendency to insufficiently revise our beliefs when presented with new evidence affects everything from personal finances to organizational strategy.
What is Conservatism Bias?
Conservatism bias occurs when people update their existing beliefs too slowly in the face of new, relevant information. First documented by psychologist Ward Edwards in the 1960s, this bias shows how we tend to “anchor” to our initial judgments, making only modest adjustments even when confronted with substantial contradictory evidence.
Unlike confirmation bias (where we seek information supporting our existing views), conservatism bias focuses on how we process new information once we encounter it—typically giving it less weight than statistical reasoning would suggest is appropriate.
How Conservatism Bias Manifests
Investment Decisions
Consider an investor who believes a particular stock is undervalued. When the company releases disappointing quarterly earnings, they might acknowledge this negative news but still underestimate its significance. Research from the Indian Securities and Exchange Board shows retail investors typically adjust their price expectations by only 40% of what would be statistically justified following earnings surprises, whether positive or negative.
Medical Diagnoses
A 2020 study in the Indian Journal of Medical Research found that physicians who made initial diagnoses were 30% less likely to completely revise their assessment when contradictory test results arrived compared to doctors seeing the case fresh. This “diagnostic momentum” demonstrates how early judgments resist appropriate updating.
Business Strategy
Organizations frequently underreact to market changes that challenge their existing business models. Kodak famously recognized the threat of digital photography (their engineers actually invented the first digital camera in 1975) but significantly underweighted this evidence when planning their future, clinging to their film-based business model until it was too late.
Why We’re Conservative With New Information
Several factors contribute to conservatism bias:
Cognitive Effort
Thoroughly revising beliefs requires significant mental energy. It’s simply easier to make minor adjustments to existing views than to completely reconsider our position.
Confidence Illusion
We tend to overestimate the accuracy of our initial judgments. This overconfidence makes us less receptive to evidence suggesting we might be wrong.
Status Quo Preference
Humans have a natural tendency to prefer existing states over change. This status quo bias reinforces conservatism in updating beliefs.
Social Reinforcement
Changing our minds dramatically can feel uncomfortable, especially when we’ve publicly committed to a position. This social pressure reinforces incremental rather than transformative belief updates.
Overcoming Conservatism Bias
Quantify When Possible
Using numerical probabilities rather than vague beliefs makes it easier to update appropriately. For instance, assigning specific likelihood percentages to potential outcomes forces more rigorous updating when new evidence arrives.
Seek Outside Perspectives
People without attachment to initial judgments can more objectively assess new information. Creating “red teams” tasked with challenging existing views helps organizations overcome institutional conservatism bias.
Pre-commit to Evidence Thresholds
Decide in advance what evidence would change your mind, before seeing the results. This prevents moving the goalposts when confronted with belief-challenging information.
Practice Bayesian Thinking
Named after 18th-century mathematician Thomas Bayes, Bayesian reasoning provides a formal framework for updating probabilities based on new evidence. Even informal Bayesian thinking—explicitly considering both prior beliefs and the strength of new evidence—can improve belief updating.
Real-World Impact
Conservatism bias isn’t just an academic curiosity, it has substantial real-world consequences. Companies that fail to adequately update their strategic thinking face extinction. Investors who insufficiently revise their market views sacrifice returns. Medical professionals who inadequately integrate new test results may miss critical diagnoses.
By recognizing our tendency toward conservatism bias, we can deliberately counteract it, ensuring that our beliefs more accurately reflect all available evidence rather than giving undue weight to our initial judgments.
The next time you encounter information challenging what you believe, ask yourself: Am I giving this evidence the weight it truly deserves, or am I being conservative in updating my beliefs?
