Noise in Judgement

'Noise: A Flaw in Human Judgement' by Daniel Kahneman, Olivier Sibony, and Cass Sunstein is one of my top recommended readings. While I'm still very much a junior behavioural scientist, as I read I found myself connecting the insights to my experiences within my own domains of expertise.

The authors make use of Pythagorean theorem and triangles to explain the relationship between different components of error within human judgement. But what I liked most were the visualisations.

I've recreated the key diagram as an interactive infographic. Clicking on a component will render a description below the diagram:

Mean Squared Error (MSE) Mean Squared Error (MSE) Mean Squared Error (MSE) Bias² Bias² System Noise² System Noise² Level Noise² Level Noise² Pattern Noise² Pattern Noise² Occasion Noise² OccasionNoise² Stable Pattern Noise² StablePattern Noise²

Occasion Noise²

Occasion noise is the set of transient factors in pattern noise. These factors change readily, often from one case to the next. Different conclusions may be reached for the same case given different environments or at different times.

Mood and hunger are well known causes. Hunger levels affect behaviour a lot, and not just in how one makes judgements. Room temperature, lighting, smell, and even the clothes you're wearing are 'potential' sources of occasion noise. Notice the emphasis on the word 'potential' because the relevance of different influences are not consistent either. What's more, these factors can constructively and deconstructively interfere with one another.

The impact of different factors, including their combinations, can vary with the individual. Those sensitive to audible noise tend to become irritable in loud crowded areas (I do). Thus their judgements are more influenced by situational acoustics than others. Not convinced, ever noticed yourself turning down the music when trying to read, think, or park a car!

While occasion noise can represent a big part of Pattern Noise, the authors of Noise note that it's influence is surprisingly small compared to Stable Pattern Noise.

Sources

[book] Noise: A Flaw in Human Judgement. 2021. D Kahneman, O Sibony, C R Sunstein [Pub] Harper Collins [ISBN] 978-0-00-830903-9.

[book] Knowledge and decisions. 1996. T Sowell [Pub] Basic Books [ISBN] 978-0465037384.