Cognition & Brain
The human brain weighs approximately 3 pounds (1,300 – 1,400 g). Although it only makes up about 2% of the total body weight of an average adult human, brain tissue consumes a large amount of energy in proportion to its volume.3 Most of the brain’s energy consumption goes into sustaining the electric charge of neurons.4 Most vertebrate species devote between 2% and 8% of basal metabolism to the brain. In primates, however, the percentage is much higher—in humans it rises to 20–25%.5 The mind is a composite of approximately one hundred billion neurons connected together into a neural network. Neural networks are made of neurons and connections between them called axons, with have synapses where the different neurons meet. Neurons generate electrical signals that travel along their axons. When a pulse of electricity reaches a junction called a synapse, it causes a neurotransmitter chemical to be released, which binds to receptors on other cells and thereby alters their electrical activity.6 The property that makes neurons unique is their ability to send signals to specific target cells over long distances. 7 They send these signals by means of an axon, which is a thin protoplasmic fiber that extends from the cell body and projects, usually with numerous branches, to other areas, sometimes nearby, sometimes in distant parts of the brain or body. Each of the one hundred billion neurons has on average 7,000 synaptic connections to other neurons.8 In its functioning, a neuron is a form of switch i.e. a cell that is either on or off. Any given neuron has a number of inputs from other neurons if those inputs are above a given threshold then it is activated and fires. If a neuron is activated it then sends our signals to other neurons that it is connected to; its output then becomes the input to other neurons. Where the output of one neuron meets the input to another there is a synapse. The synapses change in their chemical composition as one learns in order to create stronger connections. In such a way the cognitive system can adapt and changes over time to form new patterns of neural networks.
The brain is physically built as a neural network and cognition happens in patterns.9 Every pattern corresponds to an idea or memory. If two neurons are turned on when a pattern is stimulated then the synaptic connection between them becomes stronger. If they are not on at the same time then the connection becomes weaker. Over time if the same pattern keeps getting excited then the connections get stronger between the neurons that are activated. After a time a pattern can form that remains there even when not excited. By repeating something over and over a pathway is activated to form a pattern. This pattern is a memory or concept that one can then use for cognition.10 The brain is hardwired to discern patterns. Humans have a well-documented tendency for pattern recognition. It is both a great cognitive strength but also can be a weakness because we may see patterns that do not actually exist. Humans are generally very good at pattern recognition—so good in fact that we may often see patterns that are not actually there.11 Brain processing is based largely on processes of pattern recognition which matches the underlying biological structure of the brain as a massive parallel processors with many connecting neural networks. One of the advantages of this is our innate strength at making connections between different ideas, visual patterns, words, events, objects etc.12 Pattern recognition is filtered through a particular module of the brain that undertakes what is called reality testing. We see many apparent patterns in the world around us, and then we run those patterns through a reality-testing algorithm to decide whether it agrees with our internal model of reality.13 Once one has formed a pattern exciting one part of the network may then stimulate the full pattern. For example, a slight aroma of fresh bread in the kitchen can trigger a whole network of connections associated with some memory in a cafe a few years earlier. We identify and learn about new things in relation to preexisting patterns within our conscious. This means one can only learn something new, or understand something if one can associate it with something already known. If we want to communicate with someone we have to accommodate the fact that what we say has to be associated with something they already know for it to be effectively interpreted.14 We can learn something new very quickly if we can associate it with other things and fit it into a larger pattern. We can readily identify a new type of dog as an instance of our pre-existing pattern of a generic dog. Likewise, we think and learn by association. For example when explaining something new we typically give an example as this helps to create associations.