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Thinking and Deciding 2: The study of thinking

08/31/2013

Descriptive, normative, and prescriptive

Descriptive models are theories about how people normally think. Two different models describe how we ought to think. Prescriptive models describe how we ought to think, and can be composed of certain rules (take prior probability into account, sequences of equally likely events are equally likely to occur), and normative models are the standards that we use to decide what prescriptive model to use.

I’m not sure I’m clear on how prescriptive and normative models differ. Page 34 offers a good explanation. The normative models are higher order descriptions of what the best action may be. It uses probability theory and utility theory to evaluate the best option.

In normal decision making, it is not possible to make such elaborate calculations, and doing so may lead us sacrifice the very things we are striving for because we wasted too much time calculating how to get them. That’s where the prescriptive models come into play. They are general rules or heuristics that allow us to come closer to thinking as the normative models say we should, but without having to go through timely calculations.

Methods of empirical research

Both observation and computer models are used to study thinking empirically. Observation involves many different types, like process tracing (people describe their thought processes), interviews, experimental economics, and physiological measurements. Each method has shortcomings, but combining multiple lines of inquiry and seeing if they line up is a good way to make stronger inferences.

Descriptive models and heuristics

These take the forms of mathematical models, or of heuristic models. Heuristics are rules of action that are “not regarded as final and strict but as provisional and plausible only, whose purpose is to discover the solution to the present problem” (53).

The aim of prescriptive models is to either find better heuristics, or find ways to get around the systematic biases that certain heuristics introduce.

Classification of biases

There are three types of biases in this extremely useful table. There are biases of attention, motivated biases, and psychophysical distortions (don’t really get the last one yet).

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