The hidden cognitive biases that make software fail

Science · Published 20 October 2026 Swipe more like this →

In short: Most modern programming languages are designed to fail safely, automatically throwing errors when a system call fails. However, older languages require developers to manually check every operation. This creates a psychological trap where even experts can fall victim to optimism bias, skipping vital checks and leading to erratic system behavior.

Programming languages are governed by syntax and semantics, much like natural languages, but their primary purpose is controlling machine behavior. While thousands of languages exist, only a few achieve widespread adoption. Interestingly, many of the most common languages—including Perl and Standard ML—lack formal international standardization, despite their ubiquity in professional environments.

A critical distinction exists in how languages handle input/output (I/O) failures. Modern languages like Python, Rust, and Java often feature 'failsafe I/O,' where the system automatically throws an exception or prints an error if a call fails. In contrast, older languages such as C, COBOL, and Perl require programmers to explicitly check for these errors. If a developer neglects these checks, the program may continue to execute in an erroneous state.

The risk of human error in these manual systems is compounded by cognitive biases. Research suggests that optimism bias can affect both novices and experts alike, leading them to assume a system call will succeed. This highlights a fundamental shift in software engineering: moving from manual error handling to language-enforced safety. While benchmarks exist to compare language performance, experts warn that these are often micro-benchmarks that can be easily misinterpreted without context.

The evolution of these comparisons is well-documented, with notable comparative analyses dating back to the 1970s. From the 1974 notes on Algol 68 and PL/I to the 1993 retrospective on the growth of languages like C and Pascal, the field has moved toward balancing expressive power with robust, automated safety mechanisms.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Can we build software that is mathematically guaranteed to never fail?
• Why high-level programming languages are the ultimate abstraction for human-readable code
• Writing a program is the cheap part; keeping it alive costs far more
• The invisible safety net that prevents modern software from collapsing
• A language few people used became the ancestor of Java, C and Pascal
• Why humans need units and proportions to understand the universe
• The geography of a name: How a county became a monument
• Why your food doesn't actually contain energy
• The humble coal ship that accidentally launched the age of the aircraft carrier
• How a seventeenth-century mission to the poor evolved into a global four-million-person movement.
• From temporary quarters to a 55,000 square foot science hub
• Why skaters spin faster when they pull their arms inward

More in Physics · More in Science · Latest · A–Z · All topics