Question

Most people are right-handed, and even the right eye is dominant for most people. Molecular biologists have suggested that late-stage human embryos tend to turn their heads to the right. In a study reported in Nature (2003), German bio-psychologist OnurGüntürkün conjectured that this tendency to turn to the right manifests itself in other ways as well, so he studied kissing couples to see which side they tended to lean their heads while kissing. He and his researchers observed kissing couples in public places such as airports, train stations, beaches, and parks. They were careful not to include couples who were holding objects such as luggage that might have affected which direction they turned. For each kissing couple observed, the researchers noted whether the couple learned their heads to the right or to the left. They observed 124 couples, ages 13–70 years. Suppose that we want to use the data from this study to investigate whether kissing couples tend to lean their heads right more often than would happen by random chance.​

Answer 1

Homo habilis fossil evidence suggests brain lateralization similar to modern humans. Left hemisphere is superior for memory, attention, and positive emotions; right hemisphere is superior for pitch perception, arousal, and negative emotions.

Step-by-step explanation:

Homo habilis, an early human ancestor, is believed to have exhibited brain lateralization, similar to modern humans, as evidenced by striations on the teeth of a 1.8-million-year-old fossil.

This supports the idea that lateralization, along with increasing brain size and tool use, are key developments in the human lineage.

Studies on brain lateralization in modern humans have shown that the left hemisphere is superior for forming associations in memory, selective attention, and positive emotions, while the right hemisphere is superior in pitch perception, arousal, and negative emotions.

However, research on which hemisphere is dominant for specific behaviors has produced inconsistent results, suggesting that it is better to think of the interaction between the two hemispheres rather than attributing behaviors to one hemisphere or the other.