Why did David K. lose his job and what does it have to do with the history of psychology?
Friedrich Wilhelm Bessel noticed that the inaccuracies by David Kinnebrook could be attributed to individual differences in performance.
David Kinnebrook was employed by Nevil Maskelyne to make basic recordings in the movement of stars every night. Although the former was good and made precise recordings, it was noticed that there were some lapses in the work. In other words, Nevil Maskelyne realized that the recording of time by David Kinnebrook was off by half a second as compared to Nevil Maskelyne's own recording of the same time. As there was no reduction in David Kinnebrook's recording, Nevil Maskelyne had to fire David Kinnebrook for the inaccurate recordings.
Years later, Friedrich Wilhelm Bessel tried to analyze the recordings made by David Kinnebrook as there was an interest in studying the error of measurements. The former proposed that such systematic differences were seen in the recordings of any two people. They could be attributed to individual differences that cannot be controlled by the individual. This led to the proposal of the following two conclusions:
The role of a human observer became important, and this was studied by understanding the sense organs and the process of perception carefully. This line of inquiry became the central tenet of psychology.
Nevil Maskelyne fired David Kinnebrook for the inaccuracies in recording while observing stars moving. Despite being considered to be errors that David Kinnebrook did not improve, Friedrich Wilhelm Bessel saw the same pattern of differences between the recordings of other leading astronomers.
As these errors were made by leading scientists, Friedrich Wilhelm Bessel noted that these differences were not real errors. Rather, they were simply individual differences in one's ability to acquire sensory information, perceive it, and record it. For instance, two people may see a car on the road but one of them may be faster than the other to notice its color.
This meant that any task that humans did would see a difference in speed, accuracy, and so on. This led to the realization that these differences must be studied carefully in order to understand the different processes of perception and sensation. Psychology, as a field, became important because it was understood that humans did not function mechanistically. The need to study an organism's role went on to become the basic premise of psychology.