Thinking is a group of information handling processes that operate on the information structures stored in the brain's memory and on information that flows through the brain. These higher level complex processes depend on the basic associations between nodes, on the ways that those associations are encoded, and on the firing status of nodes.

Problem solving

Retrieval of stored information is one of several types of thinking processes. Nodes that represent the target have to be activated based on their associations with the firing nodes that represent the givens. In reflexive retrieval, the synaptic weights between the givens and the target are such that the firing givens activate the target. In more elaborate tasks, additional processes are needed to activate the target. Initially, the firing givens activate too many or too few nodes. The brain then uses other processes in order to reach a satisfactory solution. It is not known what are the underlying biological correlates of those additional processes. A way of simulating them in the model is by the modulation of synaptic weights. If there are too many potential solutions, gradual down-modulation of the involved synaptic weights will reduce the number of activated nodes, until one solution remains. If there is no solution, or a partial solution, gradual up-modulation of the involved synapses should cause the activation of a target.

If no node is activated, it may mean that there is no solution in the memory records. It may also mean that there is an implicit solution, but it could not be reached just by up-modulation of the existing synaptic weights.

The synaptic changes in modulation are temporary, and after a solution is found or the retrieval process is abandoned, the weights return to their initial values.

The fact that the givens were able to activate a quiet node, in reflexive retrieval or through modulation, does not mean that this activated node is a satisfactory solution. The firing node may represent a solution to only a part of the retrieval request, or it may even violate some parts of it. The brain has mechanisms for appraising solutions. The appraisal mechanisms are another important part of the thinking process. The feeling that we found the right solution to a problem is very common, as is the feeling that we are not sure if what we found is right. Also common is the feeling that we could not find a solution. The underlying biological mechanisms of those appraisal feelings are not known. The model can use various ad hoc procedures for appraising a potential solution.

If the brain finds out that, in spite of all the modulations, a satisfactory solution could not be found, it may decide to relax the retrieval request, so that a solution that satisfies the modified request could be found. The brain may also construct new concepts from existing ones, so that the new concepts satisfy the retrieval request. For example, in ancient times, the retrieval request “which animal that you know has a single horn?” would retrieve in African people a record of a real experience –'rhinoceros'. In Europe, the same request prompted the construction of the concept 'unicorn'.

Problem solving may require trial and error iterations. Throughout the iterations, the givens have to remain active, or refresh-able, until a satisfactory solution is obtained. During the process, three groups of nodes become active: the givens, the target, and nodes that represent results of intermediary iterations. In some cases, nodes of those groups may remain active together, even when the target has been retrieved. There needs to be tagging mechanisms to distinguish between those groups. The tagging will enable the separation of the final outcome from the rest of the active nodes.

Organizing information

In addition to solving problems, another common thinking process is organizing information. In order to be useful, information in the brain's information-flow has to be associated with pre-existing concepts. The information-flow itself may be the result of external stimulation or internal processes. The brain continuously parses the information-flow and establishes item-parts, class-exemplars and temporal associations between the parsed entities and memory records.

For example, understanding what is happening around us relies on organizing incoming information. The brain parses the incoming stream of stimuli into items, and associates them with existing concepts. That creates our perceptions of the world; the ongoing external events are expressed as concepts that are associated with combinations of concepts that already exist in the brain.

The brain organizes information both consciously and unconsciously. When we are faced with a familiar situation, we are not aware that the brain is working on associating it with internal representations. However, sometimes when faced with a novel situation we are aware that the brain is trying to answer the question “what is this?” The answer to this hovering question is obtained through the association of the external stimuli with recorded concepts.


One of the most important features of the human brain is its ability to create and to analyze representations of hypothetical situations. In additions to nodes that fire due to external stimuli, the brain can activate nodes that have nothing to do with actual external events. Those internally activated nodes are play-backs of real experiences, or of new combinations of unrelated experiences. For example, we can play-back in our mind an event that happened in the past. Then we can modify some parts of the play-back and simulate what would have happened if some of the elements were different. We can also imagine what will happen in a situation that we have never experienced, by activating a combination of unrelated past experiences.

After a hypothetical event is created, it is exposed to the detectors and activators of the brain. They process it like they would a real event. They can define new concepts out of the hypothetical ones, and associate them with existing concepts. It is like spectators in an arena, watching a show that depicts an imaginary situation. They perceive it and draw conclusions using the same tools that they use for real events.

Simulating and analyzing hypothetical events may be very complicated processes that depend on numerous hypothetical concepts. Once a simulation is over, no permanent record of all the intermediary concepts has to be created. To satisfy this requirement, the brain has to rely on its working memory. Mirror representations of concepts that exist in short and long term memory are created in the working memory. In addition to those mirror concepts, new associations between them and between totally new concepts are defined. Those working-memory concepts, together with the other concepts, are detected by the brain's detectors and activate the brain's activators. They also participate in other thinking processes such as problem solving and organizing information, making simulation an indispensable thinking process of the human brain.