In the double-slit experiment, the behavior of photons (or any other particles) is influenced by the act of measurement or observation, regardless of whether it is done by a human observer or by scientific apparatus. The key point is that the act of observation disturbs the system being observed, and this disturbance affects the behavior of the particles.
When a double-slit experiment is conducted, a beam of photons is directed toward a barrier with two slits. Behind the barrier, a screen or detector is placed to observe the pattern formed by the photons that pass through the slits. When no measurement or observation is made between the slits and the screen, the photons exhibit an interference pattern, indicating their wave-like behavior.
However, as soon as the photons are observed or measured to determine which slit they pass through (such as by placing detectors at the slits), the interference pattern disappears. Instead, the photons behave more like particles, creating two distinct bands on the screen corresponding to the two slits.
The crucial point here is that any interaction that allows us to gain information about the path of the photons disrupts their wave-like behavior and collapses the wave function into a particle-like state. It is not limited to the specific method of observation or the type of observer (human or scientific apparatus). The act of measurement fundamentally alters the behavior of the particles.
This phenomenon is not exclusive to photons but applies to other particles as well. It demonstrates the wave-particle duality of particles in quantum mechanics, where particles can exhibit both wave-like and particle-like behavior, depending on the context of observation or measurement.