Cognitive Bias in Software Development

Intro to research paper in ACM, considerable, technical, worth understanding

Cognitive Biases in Software Development

By Souti Chattopadhyay, Nicholas Nelson, Audrey Au, Natalia Morales, Christopher Sanchez, Rahul Pandita, Anita Sarma

Communications of the ACM, April 2022, Vol. 65 No. 4, Pages 115-122    10.1145/3517217

Cognitive biases are hardwired behaviors that influence developer actions and can set them on an incorrect course of action, necessitating backtracking. Although researchers have found that cognitive biases occur in development tasks in controlled lab studies, we still do not know how these biases affect developers' everyday behavior. Without such an understanding, development tools and practices remain inadequate. To close this gap, we conducted a two-part field study to examine the extent to which cognitive biases occur, the consequences of these biases on developer behavior, and the practices and tools that developers use to deal with these biases. We found about 70% of observed actions were associated with at least one cognitive bias. Even though developers recognized that biases frequently occur, they are forced to deal with such issues with ad hoc processes and suboptimal tool support. As one participant (IP12) lamented: There is no salvation!

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1. Introduction

Cognitive biases are systematic deviations from optimal reasoning17 that influence how we find, evaluate, and remember information. These "shortcuts" to potential solutions can take several forms, and regularly occur in our everyday behavior. For example, confirmation bias (tendency to pay more attention to information that agrees with our preconceptions) is demonstrated in some individuals' characterization of the COVID-19 virus as "just another u," prompting them to engage in social behavior contrary to experts' and health organizations' advice. As with this example, the occurrence of cognitive biases can cause significant impacts on society.

Software developers are not immune from such behavior, and may exhibit biases for several reasons. For example, some biases are a result of attempts to bypass our limited cognitive capacity (for example, availability bias may prompt developers to choose solutions based on examples they readily remember), whereas others are a result of prior experience with a solution (for example, belief perseverance bias may force developers to focus more on the code they believe has the bug), or individual problem-solving styles (for example, hyperbolic discounting bias may encourage developers to choose a solution with smaller and quicker rewards).

Although these cognitive biases often result in desired solutions, they may also cause significant negative consequences. Controlled lab studies have identified the harmful effects of specific cognitive biases on several aspects of software development such as defect density,1 requirements specification,6 originality of design,18 and feature design.4 Mohanani et al.9 conducted a survey of 65 such studies. However, despite these efforts, we still do not understand how cognitive biases manifest in the real world, and how they influence developer actions, behavior, and decision-making in situ. Only by understanding real-world behavior, we can begin to understand how to curtail such nonoptimal behavior.

Here we present results from a two-part field study examining to what extent cognitive biases occur in a developer's daily work activities. We consider how frequently, and when, certain biases occur. We also list some current practices and tools that developers currently use to mitigate biases.  .... '