Fast and Slow Thinking Index

About

Receptiviti’s Fast and Slow Thinking Index is adapted from the dual systems model of cognition to measure two fundamental thinking modes: Slow thinking (effortful, careful, incremental) and Fast thinking (intuitive, reflexive, holistic). Fast and Slow thinking is also known as System One and System Two thinking. Both modes of thinking have implications for the nature, quality, and speed of decision-making and reasoning. These measures are crucial for understanding how people think in various scenarios, including market research, audience segmentation, personnel selection, and leadership assessment. Neither way of thinking is inherently superior or inferior. Without flexible use of both modes of thought, it would be nearly impossible to effectively process our environments or make decisions.

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Note: The Thinking Fast and Slow Index is currently in the beta phase within the Receptiviti API.

Interpreting Scores

Low scores are indicative of Fast thinking, which involves intuitive, efficient thought processes, often based on mental shortcuts or heuristics.

Decisions made using Fast thinking often rely on emotions, habits, and implicit associations rather than deliberate thought. Despite the risk of bias or irrationality, these rapid judgments are crucial in the daily mental triage process. For instance, reflexive decisions ensure personal safety, such as instinctively stopping before crossing traffic or avoiding a potentially dangerous situation. Intuitive reasoning also saves time and mental effort when performing routine tasks like making coffee or riding a bike, which benefit from Fast and frugal thinking. In contrast, overthinking such routine tasks can actually make them awkward and less efficient.

High scores suggest a Slow thinking style, which is more reflective and more painstaking than Fast or intuitive thinking. It requires more attention, working memory, and conscious effort. As a result, Slow thinking is harder to do when a person is more distracted or fatigued. Slow thinking tends to be more abstract, often involving reflections and deductions based on general principles rather than immediate reactions. People use this more effortful, deliberative mode of thinking when they are carefully considering alternatives, working through challenging problems using rule-based logic, or when evaluating new ideas.

Interplay Between Fast and Slow Thinking

Fast and Slow thinking complement each other, and the ability to strategically employ either mode of thought is essential for efficiently navigating most aspects of daily life. Individuals naturally use both Fast and Slow thinking depending on the situation, but oftentimes people spend more time in one system or the other. When analyzing someone's language over time or in different situations, if their average leans towards Fast thinking, they are more likely to make quick, emotional, and instinctive decisions. If a person’s average is further in the direction of Slow thinking, they likely spend more time making carefully-reasoned decisions.

Psychology research shows it’s best to balance both modes of thinking, letting the harder work of deliberation inform later cognitive shortcuts, i.e., thinking carefully now in order to facilitate smart, fast decisions when needed.

Using Receptiviti to Measure Fast and Slow Thinking

Receptiviti’s Fast and Slow Thinking Index measures are based on both psychological theory and data on how people use language in real life. Using data from our proprietary corpora, we analyzed how language measures theoretically related to Fast and Slow thinking correlate to each other across dozens of contexts. Results showed that Fast and Slow thinking form opposite ends of a spectrum that is common across all kinds of communication. Fast thinking is measured by words reflecting concrete, narrative, lower-effort thinking and basic, instinctive emotions. The Slow end of the spectrum is measured using words reflecting abstract, formal, rule-based, effortful thinking and complex emotions.

Specifications

Scores in the Fast and Slow Thinking Index framework are normed, and thus always in the range of 0 to 100. Our measures are baselined against our proprietary datasets, which consist of language samples that exceed 350 words. A language sample that generates a score of 80 implies that 80% of all samples in our curated baseline dataset have scores that are less than the score of the language sample being analyzed.

If you are analyzing multiple people in the same context, it can be useful to compare normed scores within the same sample. For example, most language in formal, carefully constructed documents like legal decisions or scientific reports will score high on this measure, indicating slower, more careful and effortful thinking than average. In that context, a text that scores at or slightly above the median of the norming data may represent thinking that is strikingly Fast for that context.

State versus trait measures

While the Fast and Slow Thinking Index was initially intended to gauge an individual's habitual inclination towards Fast thinking, Slow thinking, or a combination of both, it can also provide insights into how someone is processing information in a specific moment, such as during a discussion about a particular problem or while making a decision. The optimal mode of thinking will vary depending on the complexity of the task at hand. Deciding whether to rely on Fast thinking, Slow thinking, or a balanced approach depends on your understanding of the task's demands and potential benefits of each thinking mode. Fast thinking may be preferred for crises where quick, decisive actions are needed, whereas slower thinking may be preferred for major decisions that require careful planning and unbiased, objective judgments.