One of my advisers once drew a vertical line on a white sheet of paper and told me, in research, one needs to think vertically. He then continued, explaining, that graduate students should dig deeper and deeper into the problem until a solution is found. Vertical thinking is an analytical and sequential process and it is widely adopted by researchers in the academia because it finds a solution to the problem faster than the horizontal thinking strategy. In addition, it builds more experienced researchers in the field of investigation.
Horizontal thinking, unlike vertical thinking, is to investigate wider not deeper. Howard Gardner calls vertical thinkers the experts and horizontal thinkers the visionaries. Others, use Edward De Bono’s coined term lateral thinking to define horizontal thinking. In general, lateral thinking means being creative and thinking outside the box.
Each thinking strategy has its advantages and disadvantages. Therefore it is good to know how we think and how different we think. People who think vertically are usually concerned in how to solve the problem. They also usually know everything about something. On the other hand, people who think horizontally are usually concerned in why a particular problem occurs. They know something about everything, related to their field.
Most outstanding research results are the ones that produced from interdisciplinary fields. Investigating one field to find an answer will solve a problem but making links between two fields or more to find an answer will lead to a breakthrough solution. This is why horizontal thinking is linked to breakthrough research.
The figure below depicts the differences between these two thinking methods. Unlike vertical thinking, horizontal thinking requests more time, data, and background study. While both concepts produce a solution to the problem, their outputs might not be the same. Vertical thinking discovers a solution faster than horizontal thinking, but its solution’s quality might not be as good as the horizontal thinking.