Tversky & Kahneman (1973) AVAILABILITY HEURISTIC

Year?

1973

Sample

152 students

Aim

To test the availability heuristic.

Research Method

Lab experiment

Procedure

Participants given several letters of the alphabet and asked if these letters appear more frequently in the 1st or the 3rd position of a word

Findings

105/152 participants overestimated the number of words that began with the given letter ("K" for example). There was a bias favouring the 1st position.

How does this study support cognitive biases?

Participants answered based on the availability heuristic: they could more easily think of a word beginning with a given letter so they are led to believe this position must be more likely. This caused 105/152 participants to incorrectly guess, supporting the idea that cognitive biases are systematic errors in thinking that negatively affect decision making.

Strengths

⬆️internal validity- lab experiment is highly controlled

⬆️replicable- easy to reproduce experiment

⬆️construct validity of survey- questions given in different orders

Weakness

⬇️low population validity: student sample unrepresentative (in 1973 would be white males)

⬇️mundane realism: artificial task

LINK

Tversky and Kahneman demonstrate the availability heuristic.

For example, 105/152 participants incorrectly judged the first position as the most likely.

This is important because it suggests participants answered based on what they could more easily recall (mental shortcut) which led them to the wrong conclusion. Therefore cognitive biases negatively effect thinking and decsion making.