Overall, cognitive psychology can be described as the study of the mind as well as major mental processes such as problem-solving, memory, or perception (Goldstein, 2011, p. 5). It is possible to distinguish several milestones in the development of this discipline. First, this branch of psychology began to develop very rapidly due to important breakthroughs in neuroscience. In particular, one can mention the work of Paul Broca who discovered that certain areas of the brain are involved in specific mental processes such as the use of language (Goldstein, 2011, p. 33). This discovery was crucial for transforming cognitive psychology into an experimental science. This is why Paul Broca’s findings should not be overlooked. Additionally, one should focus on Noam Chomsky criticism of behaviorism as a method for explaining various mental processes. In particular, he showed that the concept of positive and negative reinforcement was not sufficient for explaining the acquisition of languages (Chomsky as cited in Goldstein, 2011, p. 296). The publication of his article Verbal Behavior prompted psychologists to search for new ways of explaining mental processes. To a great extent, this critique led to the development of different research methods that were not based on behaviorism. Furthermore, it is critical to speak about the development of information processing model. This approach can throw light on the way in which the mind acquires, encodes, stores or retrieves information (Schiflett, 2004, p. 223). Moreover, it is helpful for explaining the connections between various mental processes. This model is based on the assumption that the functioning of the brain can be compared to the work of a computer. Admittedly, this framework is very schematic, and it is not always possible to simplify complex mental processes. Yet, it has proved effective for many experimental studies of the mind. Apart from that, one can mention that work of George Miller who introduced the notion of a chunk and its relation to memory. This concept can be described as a set of “elements that are strongly associated with one another” (Goldstein, 2011, p. 126). For instance, words can be viewed as the examples of such chunks. George Miller contributed to the development of cognitive psychology by showing that memory span is limited by chunks, rather than bits. This discovery is critical for understanding the way in which information is processed. This is why this study can be singled out. The second issue, which should be examined, is the importance of behavioral observation in cognitive psychology. This method of research is necessary for empirical demonstration of various models or theories. Without these data, the assumptions made by researchers become almost unfalsifiable, and their validity may be questioned. Certainly, such theoretical frameworks can remain plausible, but they cannot be used for practical purposes. This is one of the aspects that should be considered. Secondly, on the basis of behavioral observation, one can develop a model of various mental processing. For example, George Miller’s notion of a chunk is based on the results derived in the course of an experiment that was aimed at studying the way in which people process and retain information. Admittedly, the behavior of a person can be shaped by various independent va