Studies on animals done in the 1930s indicate that stomach juices were the controlling cue for eating. However, this was later contested by researchers noting that animals without stomachs have normal eating habits. Subsequent work done in the 1096s indicated that an “eating center” in the brain controls hunger. More recent work suggest the presence of specific hungers for materials lacking in a given diet; for example, wolves put on low-calcium diets will seek out and eat bones.
In the passage above, the author
- Favors one theory over two others by citing specific evidence to show its superiority
- Cites no important differences information from different studies without favoring any particular theory