The behavior of particles, such as electrons in the double-slit experiment, is not determined by any conscious decision-making or pre-knowledge on the part of the particles themselves. The idea of particles "knowing" or making decisions is a common misconception when it comes to understanding quantum mechanics.
In reality, the behavior of particles in the double-slit experiment is described by the wave-particle duality, which means that particles can exhibit both wave-like and particle-like characteristics depending on the experimental setup and the way they are observed or measured.
When a single electron is sent through the double slits, it can pass through either one of the slits or both simultaneously due to its wave-like nature. The electron's wave function describes the probability distribution of where the electron is likely to be found. When the electron's wave function encounters the two slits, it splits into two separate waves that pass through each slit. These waves then overlap and interfere with each other, leading to an interference pattern on the screen behind the slits.
However, if a measurement is made to determine which slit the electron passes through, such as by placing a detector at the slits, the act of measurement disturbs the electron's wave function. This disturbance causes the electron to "collapse" into a localized particle-like state, and the interference pattern disappears. The electron now behaves as if it went through either one of the slits, resulting in a particle-like pattern on the screen.
In summary, the behavior of particles in the double-slit experiment is not influenced by any pre-existing knowledge or decision-making on the part of the particles themselves. Instead, their behavior is determined by the properties of quantum mechanics, wave-particle duality, and the interaction between particles and the measurement apparatus.