The Free Energy Principle - Deepstash





A Neuroscientist’s Theory of Everything

The Free Energy Principle

It states that the world is uncertain and full of surprises. Our brain, through perception, beliefs and action are trying to remain stable by minimizing the spikes, triggers and surprises.

We live inside our brains, and each of us has a unique perception of the outside world. Anything we say or document is just our way to explain the world we have lived. It has nothing to do with reality.




The ghost ball trick
The ghost ball trick

A magician sat at a table in front of a group of schoolchildren. He threw a ball up in the air a few times, but before his last throw, he secretly let the ball fall into his lap. Then he continued ...

The role that social cues play during magic tricks

In the vanishing ball illusion, a study found that when the magician pretends to throw the ball in the air, and his gaze follows the imaginary trajectory of the ball, almost two-thirds of the participants will be convinced that they had seen the ball move up. If his gaze did not follow the imaginary ball, the illusion was far less effective.

This illustrates that the illusion is mostly driven by expectations. Our eyes find it difficult to track fast-moving objects. Looking at the ball is only possible when we can predict where it will be in the future.

Perception does not take place in the eyes

Although most participants experience an illusory effect during magic tricks, the eyes are not tricked. The conscious perception has been fooled by the illusion, but your eyes have not.

Lots of neural calculations are required before we can experience the world. Neural signals start in the retina, then it passes through different neural centers to the visual cortex and higher cortical areas, and eventually build a mental representation of the outside world. It takes about a tenth of a second for the light registered by the retina to become a visual perception. The neural delay means we perceive things at least a tenth of a second after they happened.

The olfactory sense at work
The olfactory sense at work

Our sense of smell works in wondrous ways since the chemical composition of our surrounding change instantly and constantly. Our noses pick up volatile airborne compounds that interact with...

Facts about our olfactory sense
  • It is different from other sensory cortices in a way that it has a multidimensional stimulus.
  • Some things can smell different not just between different people but also for the same person.
  • Can measure an array of an uncertain variety of chemicals that can trace changes that detects pleasure, pain, or danger.
  • It does not require a map mirroring because its chemical stimulus is constantly changing. It relies on the brain to recognize the pattern or memory associated with the smell.
Contributors to the study of the olfactory sense
  • Santiago Ramón y Cajal: A founding father of neuroscience, he drew attention to the sense of smell as an exemplary model to learn how the brain makes sense of the world. He also believed that understanding smell would grant us better insight into other sensory systems
  • Linda Buck & Richard Axel: They discovered the olfactory receptors which happened to be the most structurally diverse and sizable member of the largest multi-gene family of protein receptors. They received the 2004 Nobel Prize in Physiology or Medicine.
The first views on motivation
The first views on motivation
  • At first, psychologist William James thought that only the initial act was conscious, thereafter behaviour was a spontaneous cascade of habits. He suggested we struggle with motivation when ...
Mathematics of motivation

When Ivan Pavlov and his dogs led to the discovery of learned behaviour through repeated exposure, and Edward Thorndike discovered the Law of Effect that stated that rewarded behaviours tended to increase, many psychologists were impelled to separate psychology from armchair introspection and formulated their theories as mathematical formulas.

  • The Drive x Habit Theory. Clark Hull's formula was sEr = D x sHr, which states that excitatory tendency (E) is the result of the drive (D) combined with the habit (H). The drive is nonspecific, such as hunger or thirst. The habit, however, depends on the stimulus (s) and response (r). But the theory turned out to be wrong and even opposite in many cases. 
  • Expectation x Value Theory. Drawing on ideas in economics and game theory, Edward Tolman and Kurt Lewis formulated an alternative account by evaluating motivation based on expectations. Tolman expressed the ideas as the mathematical formula: Subjective Expected Utility = Probability1 * Utility1 + P2U2 + P3U3 + … where subjective expected utility of an action equalled the motivation to act. But, if you expect a reward, why act and not simply passively wait for the expected reward? 
Motivation as change

Donald Hebb realised that existing theories were too focused on reacting to the immediate environment. Thoughts, ideas and goals could be just as strong for triggering action as sights and sounds.

Together with John Atkinson, they noted that the study of motivation had undergone a "paradigm shift", where motivation couldn't be seen as how actions get started, but how the organism decides to change its behaviour from one thing to another.