Misremembering could be an indication of optimal memory function.

Recently, when asked about a local bakery, I mentioned enjoying its chocolate chip cookies, only for my spouse to point out that I had actually eaten oatmeal raisin. Why did I misremember this? Does it hint at early cognitive decline, or is it simply a normal part of how memory works when faced with countless daily details?

As a cognitive scientist with over 30 years of experience in studying perception and thought, I have explored why such memory errors occur. Are they signs of faulty thinking, or could they reflect a brain functioning optimally under natural limits? Current research suggests the latter: mistakes may actually indicate a rational, efficient cognitive system.

Rethinking Rationality in Human Thought

For decades, psychologists have debated whether humans think rationally. In the 1960s, Daniel Kahneman and Amos Tversky discovered that people often rely on heuristicsmental shortcuts that simplify decision-making. For example, when asked whether English has more words starting with k or with k as the third letter, most people say the former. This availability heuristic arises because words beginning with k come to mind more easily. While heuristics usually work well, they sometimes lead to errors, demonstrating that human cognition is not always perfect.

Optimal Perception and Cognitive Efficiency

Research in the 1980s began to suggest that human perception might often operate optimally. Studies showed that people integrate information from multiple sensessuch as sight and hearingin statistically optimal ways, even when sensory inputs are noisy. For example, people tend to underestimate the speed of moving objects when visual information is unclear. Rather than being a flaw, this bias aligns with an optimal combination of sensory input and prior knowledge about the world, suggesting that the brain makes the best possible judgment given the available information.

Similar principles apply to memory and reasoning. Errors frequently occur when recalling, deciding, or planning under uncertainty. Yet studies indicate that these mistakes resemble the outcomes predicted by statistically optimal strategies, showing that human cognition may be performing as well as it can within its limitations.

The Role of Constraints in Memory

Our brains face inherent constraints: limited attention, finite memory, and the need for timely decisions. These limitations mean we cannot always process all information perfectly. However, within these constraints, our minds can achieve the best possible outcomes. For example, when solving a complex problem, attending to the most informative factors allows for an optimal solution given cognitive limits.

This perspective, often called resource-rationality, views memory as a communication channel with restricted capacity. Details that cannot be stored are naturally lost, while critical information is preserved. Consequently, when recalling an event, the brain may fill in missing details using the most common or expected properties. In my cookie example, I remembered the essenceenjoying cookiesbut substituted chocolate chips for oatmeal raisins because chocolate chip is more typical. This error demonstrates a memory system operating efficiently, not failing.

Conclusion

Memory errors are not necessarily a sign of decline. Instead, they reflect a brain that prioritizes important information and operates effectively under natural limits. Forgetting minor details may actually be a hallmark of an adaptive and optimal cognitive system, allowing us to navigate a world filled with overwhelming information efficiently.

Author: Caleb Jennings