Observation in thenatural sciences refers to the active acquisition of information from aprimary source.[1] It involves the act ofnoticing or perceiving phenomena[2] and gathering data based on direct engagement with the subject of study.
In living organisms, observation typically occurs through thesenses. Inscience, it often extends beyond unaided perception, involving the use ofscientific instruments to detect, measure, and recorddata. This enables the observation of phenomena not accessible to human senses alone.
Observations in science are typically categorized as eitherqualitative orquantitative:
Qualitative observations describe characteristics that are not expressed numerically, such ascolor,texture, orbehavior.
Quantitative observations involve numerical measurements, obtained through counting or using instruments to assign values to observedphenomena.
The termobservation may refer both to the process of observing and to the information recorded as a result of that process.
Submit the findings forpeer review by researchers experienced in the same area of study
Each step depends on reliable and reproducible observations, which form the basis for scientific reasoning and validation of results.
Observations play a role in both the second and fifth steps of thescientific method. However, the principle ofreproducibility requires that observations made by different individuals be comparable and consistent.Humansense impressions aresubjective and yieldqualitative data, which are difficult to standardize, record, or compare across observers. To address this limitation, the use ofmeasurement was developed as a means of producing objective, quantitative observations.
Measurement involves comparing the observed phenomenon to astandard unit, which may be defined by an artifact, a process, or a shared convention. This standard must be reproducible and accessible to all observers. The result of the measurement process is a numerical value that represents the number of standard units corresponding to the observation.
By reducing observations to numerical values, measurement enables consistent documentation and facilitates comparison. Two observations that yield the same measured value are considered equivalent within theresolution or precision of the process.
Humansenses are limited in range and accuracy and are subject to errors in perception, such as those caused byoptical illusions. These limitations affect the reliability and precision of unaided observations in scientific inquiry.
One challenge encountered across scientific disciplines is that the act of observation can influence the process being observed, potentially altering the outcome. This phenomenon is known as theobserver effect. For instance, measuring the air pressure in an automobile tire typically requires letting out a small amount of air, which in turn changes the pressure being measured.
In many areas of science, the effects of observation can be minimized to negligible levels through the use of advanced and more precise instruments. These tools help ensure that the measurement process interferes as little as possible with the system under study.
When considered as a physical process, all forms of observation—whether performed by humans or instruments—involve some form of amplification. As such, observation is a thermodynamicallyirreversible process that results in an increase inentropy.
In certain scientific fields, the results of observation vary depending on factors that are not typically significant in everyday experience. These variations are often illustrated through apparent "paradoxes", where an event appears different when observed from two distinct perspectives, seemingly contradicting "common sense".
Relativity: Inrelativistic physics, which addresses phenomena at velocities close to thespeed of light, different observers may record different values for properties such as length, time, and mass, depending on their relative velocity with respect to the object being observed. For example, in thetwin paradox, one twin undertakes a high-speed journey and returns younger than the twin who remained on Earth. This outcome is consistent with the principles of relativity: time passes more slowly in reference frames moving at high velocities relative to an observer. In relativistic physics, all observations must be described in relation to theframe of reference of the observer.[citation needed]
Quantum mechanics: Inquantum mechanics, which examines systems at atomic and subatomic scales, it is fundamentally impossible to observe a system without influencing it. In this context, the observer becomes part of the system being measured. Quantum systems are described by awave function, which often exists in aquantum superposition of multiple possible states. When an observation or measurement is made, the system is always found in a definite state—not in a mixture. The act of measurement appears to cause thewave function collapse, transitioning the system from a superposition to a single, determinate state. This process is referred to asobservation ormeasurement, regardless of whether it is part of a deliberate experimental setup.
Human senses do not function like an impartial recording device such as a videocamcorder.[6] Perception occurs through a complex, largely unconscious process ofabstraction, in which certain elements of sensory input are selected and retained, while others are discarded.
This selection process depends on an internal model of the world—referred to in psychology as aschema—that is shaped by past experiences. Sensory information is interpreted and stored based on this schema. During recall, gaps in memory may be unconsciously filled with information consistent with the schema, a process known asreconstructive memory.
The degree of attention given to different aspects of a perceptual experience is influenced by an individual's internal value system, which prioritizes information based on perceived importance. As a result, two individuals observing the same event may remember it differently, potentially disagreeing on factual details. This subjectivity is a known limitation ofeyewitness testimony, which research has shown to be frequently unreliable.[7]
In scientific practice, rigorous methods are employed to minimize such observational biases. These include careful documentation of experimental data, distinguishing clearly between raw observations and inferred conclusions, and implementing procedures such asblind anddouble blind experiment designs to control for subjective influence.
Several of the more important ways observations can be affected by human psychology are given below.
Human observations are biased toward confirming the observer's conscious and unconscious expectations and view of the world; we "see what we expect to see".[8] In psychology, this is calledconfirmation bias.[8] Since the object of scientific research is thediscovery of new phenomena, this bias can and has caused new discoveries to be overlooked; one example is the discovery ofx-rays. It can also result in erroneous scientific support for widely held cultural myths, on the other hand, as in thescientific racism that supported ideas of racial superiority in the early 20th century.[9]
Modern scientific instruments frequently perform extensive processing of "observations" before the results are presented to human observers. With the increasing use of computerized instruments, it can be difficult to determine the boundary between the act of observation and the interpretation or conclusion drawn from that data.
This issue is particularly relevant in the context ofdigital image processing, where images used as experimental data inscientific publications are sometimes enhanced to emphasize specific features. While such enhancement can aid in highlighting relevant aspects of the data, it may also inadvertently reinforce the researcher's hypothesis, introducing a form of bias that is challenging to quantify.
In response, some journals have established explicit guidelines regarding permissible types of image processing in published research. To safeguard against processing bias, many computerized systems are designed to store copies of the unprocessed or "raw" data captured by sensors. Likewise, scientific best practices require that original, unaltered images used as research data be preserved and made available upon request.[citation needed]
