Why do people have a tendency to take extreme steps while taking decisions in group than alone ? why does this happen ?

Can someone read this article and tell me the 1) key ideas and 2) one key quote (copy and paste the link the article is not to long at all)from

Hurry locate the iberian peninsula question options: 1 2 3 4 which number shows the location of italy? question options: 1 6 5 3

Which statement best describes evidence of a mulitcultural mix in east africa? a. because of what he learned during his pilgrimage to mecca, mansa musa was able to build a center of islamic scholarship. b. the traders of ghana brought back with them slaves from the mediterranean who taught the ghana rulers about christianity. c. clans were made up of lineages that were descendants of multiple ancestors from different regions of africa. d. swahili became a language made up of words spoken by traders along the coast of the indian ocean.