BRAIN EVOLUTION AND INFORMATION EXPLOSION

Dr Sanjoy Sanyal MBBS, MS, MSc, ADPHAProfessor of Neuroscience

Evolution of Mankind and Their Skull

Hominid Species

BCE ~ Skull Capacity

Australo-pithecus africanus

4 million years

400 cc

Homo habilis

1.7 million years

600 cc

Homo ergaster / erectus

0.7 million years

900 cc

Homo sapien neander-thalensis

30,000 years

1450 cc

Homo sapien sapiens

Present 1500 cc

Neurons and Neural Connectivity Humans have 1011 Neurons

in their Brain (Rudolph Hanka, Cambridge)

They have been doubling every 3 million years (Dotted graph line)

Brain capacity is not determined by number of Neurons alone; Number of Synapses are more important

If ALL Neurons were connected to ALL Neurons, there would be 5 x 1021 Synapses (Given by the Formula n (n-1) / 2 (where n is the number of Neurons))

Such rate of synaptic connectivity would have doubled every 1.5 million years (Green graph line)

But that is not the case. Humans have limited Neural connectivity, of only 1014 Synapses (Red graph line)

STM vs. General Intelligence Factor Postulate: General Intelligence Factor (G) is

limited by channel capacity of Short Term Memory (STM)

Mental Power / Capacity of Short Term Memory (STM) = Mental speed of information processing X Duration of information in STM (memory span)

This is given by the Formula: C(bits) = Ck(bits/sec) × D(sec), Where;

C = Mental power or capacity of STM (in bits)

Ck = Mental speed of information processing (in bits / second)

D = Duration of information in STM (in seconds)

Information Explosion Since 1400, Information has been

doubling every 3 decades or so (Proved by Rudolph Hanka of University of Cambridge)

By 1500 it had increased 8-fold (23)

By 1600 it had increased 64-fold (26)

By 1700 it had increased 512-fold (29)

By 1800 it had increased 4,096-fold (212)

By 1900 it had increased 32,768-fold (215)

In this millenium it is expected to register a 262,144-fold increase (218 ) over 1400

Information Overload There is no change in

actual skull (and brain) capacity over last several thousand years

Human Brain has only limited number of Neurons and Synaptic connections

Channel capacity of Human Memory is limited

Information is increasing exponentially

Humans are already well past the stage when their Brains can handle all the information available today. Automation, Digital Storage and Seamless Access are the only solutions to leverage the value of Information Explosion