Clarity of the Sample Space and the Sampling Process
The clarity of the sample space and repeatability of trials influence how people reason about probabilities. In social domains, sample spaces are often obscure, leading people to rely on the representativeness heuristic rather than probabilistic reasoning.
THE IDEA
Clarity of the Sample Space and the Sampling Process
Randomizing devices are usually designed so that the sample space for a single trial is obvious and so that the repeatability of trials is salient. The die has six faces and can be tossed again and again; the pointer can stop on any of eight sectors and can be spun over and over. Clarity of sample space makes it easier to see what knowledge is relevant. For randomizing devices, the most relevant knowledge is often just the observation of symmetry of the different die faces, spinner sectors, and so forth. The salience of repeatability makes it easier to conceptualize one’s observations as a sample.
In the social domain, sample spaces are often obscure, and repeatability is hard to imagine. For example, the sample space consisting of different degrees of helpfulness that might be displayed by a particular person in a particular situation is quite obscure, and the notion of repetition is strained. What is it that could be repeated? Placing the same person in different situations? Or other people in the same situation? The probability that Person P will exhibit Behavior B in Situation S is abstract and not part of the inductive repertoire of most people most of the time. Even though people recognize the possibility of errors in their judgments of social situations, they do not try to construct probability models; rather, they rely on the representativeness heuristic.
When to use it
Assessing the probability of a friend's reaction in a social setting
Evaluating the odds of winning a game with a spinner or dice
Interpreting survey results where the sample space is defined versus anecdotal evidence
Deciding whether to use statistical reasoning or heuristics in social decision-making
FROM THEORY TO EVERYDAY LIFE
In practice
Judging a Person's Helpfulness
Consider the probability that a specific person will act helpfully in a given situation. The sample space of possible degrees of helpfulness is obscure, and repeatability is hard to imagine, leading people to rely on the representativeness heuristic instead of formal probability.
Rolling a Die
When rolling a fair six-sided die, the sample space of outcomes (1-6) is clear, and the repeatability of trials is obvious, making it easy to calculate probabilities.
A MOMENT TO REFLECT
Put it to work.
Think of a social situation where you need to judge the probability of a behavior. How does the obscurity of the sample space affect your reasoning?
How might the repeatability of trials influence your confidence in probability judgments?
In what ways does the representativeness heuristic replace probabilistic reasoning when sample spaces are unclear?
CONTINUE THE CONVERSATION
Source texts
- Heuristics and Biases The Psychology of Intuitive Judgment (Thomas Gilovich, Dale Griffin, Daniel Kahneman)