I took a picture of the couple while I was traversing middle of India on the Express train.
They were walking firmly on their field of life..
1. The climatic variation hypothesis
proposes that human intelligence was mainly beneficial in decoupling humans from dependence on any particular ecology defined by a constant climate or other invariant features. According to the hypothesis, general intelligence allowed humans to adapt to rapidly changing climates of the Pleistocene and greatly increased their range of settlement.
2. The foraging hypothesis
highlights the advantages to be gained from better methods for extracting resources from the environment (e.g., managed foraging), and in enlarging the range of human settlement and supporting larger populations. The foraging hypothesis is supported by data indicating that humans evolved as super predators and manufacturers of highly complex tools by around 50,000 years ago, resulting in a wave of mass extinctions of large animals. These changes coincide not only with a larger brain but a smaller gastrointestinal tract and higher metabolism dependent on high quality food made possible by these improved foraging techniques.
3. The social competition hypothesis
proposes that after humans achieved ecological dominance, intelligence evolved because of it was beneficial for between-group and within-group competition among humans. This hypothesis emphasizes that cognitively, socially, and behaviorally sophisticated individuals are able to outmaneuver and manipulate other individuals to gain control of resources in the local ecology and to gain control of the behavior of other people. This hypothesis is supported by correlations between brain size and group size, especially where there are complex social relationships within groups.
Representation of General Intelligence of Human..