Mainly Known for his theory of evolution, Charles Darwin was a naturalist, geologist, and biologist. His theory of evolution by natural selection became the biggest building block for the modern studies of evolution.

Charles Darwin's observations

• Touch: Within the first 7 days of his son William's life, he noticed that the baby had many reflex reactions like yawning and stretching. He ran a piece of paper along the baby's foot and watched as the baby jerk away. He believed these involuntary reflexes occurred because of will. He would touch objects to his nose before moving to his mouth. 

• Hearing: During the first two weeks the baby was startled by loud noises and would stay in a nervous state for hours after. The baby could not recognize where the sound was coming from not even when he was 124 days old.

• Vision: When William was 9 days old until 45 days old, his eyes were fixated on a lit candle. He couldn't follow moving object very well, even at 7 months old. 

• Anger: On the baby's 8th day of life, he showed a behavior associated with anger and pain. At 4 months old he would become violently passionate noticed by blood rushing to his face. At two years and three months, William began throwing books and Darwin thought this was a trait only developed in boys.

• Fear: Being scared by loud sounds and then crying. At four and a half months, William was scared of unfamiliar sounds and places. The irrational fears that children have like of the dark and monsters made Darwin believe that these fears were passed down by ancestors for self-preservation. 

• Pleasure: Darwin believed that infants got pleasure from sucking. William enjoyed his father lightly pinching his nose and cheeks. He like the sound of the pianoforte. 

• Affection: William smiled at his caregiver after 2 months. Darwin didn't think his son recognized anyone until 4 months. The child did not outwardly show affection until after a year of life. He showed sympathy at 6 months and 11 days when someone was crying. At 15 and a half months he showed jealousy when his father would be affectionate to his sister. 

• Communication: Crying is an instinctive behavior that represents suffering. The cries were different if it was from hunger or pain. On day 46 he made nosies that meant nothing, just because he enjoyed it. At one year old he made a word for food "mum". He would say "ah" whenever someone he recognized came into his line of sight or he saw himself in a mirror. At 18-21 months, William was able to change his voice.