IBM has developed a microprocessor capable of figuratively “rewiring” its connections as it encounters new information, similar to how biological synapses work, thereby emulating the human brain. That is how the system could learn, rather than be programmed.
Synaptic connections between brain cells physically connect themselves depending on experiences. The process of learning is essentially the forming and strengthening of these connections. A computer can simulate such a system by paying more “attention” to important inputs, and paying less attention to others.
Also, the human brain can perform complex tasks rapidly and accurately using “as much energy as a 20 watt light bulb in a space equivalent to a 2 liter soda bottle”.