Observer effect, observer bias, observation effect, or observation bias may refer to a number of concepts, some of them closely related:
General experimental biases
Hawthorne effect, a form of reactivity in which subjects modify an aspect of their behavior, in response to their knowing that they are being studied Observer-expectancy effect, a form of reactivity in which a researcher's cognitive bias causes them to unconsciously influence the participants of an experiment Observer bias, a detection bias in research studies resulting for example from an observer's cognitive biases
Physics
Observer effect (physics), the impact of observing a physical system
Probe effect, the effect on a physical system of adding measurement devices, such as the probes of electronic test equipment
Computing
Heisenbug of computer programming, in which a software bug seems to disappear or alter its behavior when one attempts to study it Observer effect (information technology), the impact of observing a process while it is running
Other uses
"Observer Effect" (Star Trek: Enterprise), an episode of Star Trek: Enterprise, named after the effect in physics
See also
Actor–observer asymmetry, a bias one makes when forming attributions about the behavior of others or themselves Demonstration effect, a effect on the behavior of an individual caused by observation of the actions of others and their consequences Personal equation, the idea that different observers have different reaction times, which can introduce bias when it comes to measurements and observations Placebo and nocebo effects, positive and negative effects autosuggested by a patient under an inert substance or treatment Schrödinger's cat, a thought experiment that illustrates a paradox of quantum superposition, devised by Austrian physicist Erwin Schrödinger Uncertainty principle, any of a variety of mathematical inequalities in quantum mechanics, introduced by German physicist Werner Heisenberg