This chapter discusses the categories of cognitive heuristic and cognitive bias. These categories have come to define a burgeoning research program in cognitive science (the “heuristics and biases” program) and are widely considered to be universal features of human thought. On closer inspection, both categories are found to be too heterogeneous to identify real cognitive kinds, though some of their sub-categories may. In particular, the chapter examines the construct myside heuristic (closely related to the phenomenon often known as “confirmation bias”). This is found to be a better candidate for being a cognitive kind, since it seems to pertain to a specific feature of human cognitive architecture. Moreover, the myside heuristic, which (roughly speaking) attaches more weight to one’s own opinions than to contrary opinions, can be rational in certain contexts. Thus, distinguishing the heuristic from a corresponding bias can only be done against the background of a cognitive task or problem. This constitutes another instance of contextual or environmental individuation of a cognitive construct, making it unlikely that it will correspond to a neural kind.

In the literature on judgment and decision making, a distinction is drawn between the effortless, fast, and automatic thinking of System 1 and the effortful, slow thinking of System 2, which requires deliberate attention and control. Owing to its cognitive ease, the uncritical thinking of System 1 operates by default. When the stakes are sufficiently high, we can engage in more critical thinking. We conceptualize critical thinking as scientific reasoning, an array of human inventions specifically designed to overcome the limitations and biases inherent to the efficient but error-prone System 1 thinking. We organize this discussion of critical thinking around five guidelines for scientific reasoning: consider alternative explanations to establish competing predictions, collect data as systematically and comprehensively as possible, establish a specific and reliable protocol, consider the role of chance, and weigh all available evidence. As a concrete illustration, running throughout this chapter is an examination of the power of sports momentum. We define the construct, attribute its appeal to aspects of System 1 thinking, and show how a more critical appraisal that follows the guidelines for scientific reasoning suggests that sports momentum may be little more than a cognitive illusion.