---
date: '2024-02-07'
description: how a researcher's expectations can alter an observed result
id: observer-expectancy effect
modified: 2026-08-08 09:16:06 GMT-04:00
tags:
  - seed
title: observer-expectancy effect
created: '2024-02-07'
published: '2024-02-07'
pageLayout: default
slug: thoughts/observer-expectancy-effect
permalink: https://aarnphm.xyz/thoughts/observer-expectancy-effect.md
generator:
  quartz: v4.6.0
  hostedProvider: Cloudflare
  baseUrl: aarnphm.xyz
full: https://aarnphm.xyz/llms-full.txt
---
The researcher’s expectations can influence how they treat the people or animals in front of them. This can also change what she/he records from the experiment.

In [Rosenthal and Fode’s 1963 paper](https://doi.org/10.1002/bs.3830080302), twelve students were each given five ordinary rats. Half were told the rats were “maze-bright”. Others were told theirs were “maze-dull”. The labels were random. Each student ran a maze for five days. The bright group ended with more correct responses. The paper suggested differences in handling as one possible cause.

Blinding is the simplest control, where the person handling a subject or recording a result does not know which outcome the hypothesis predicts.