Examine these papers for their experimental designs

1. Grim T (2008). A possible role of social activity to explain differences in
   publication output among ecologists. Oikos
   
2. Huber R, MJ van Staaden, LS Kaufman, & K Liem. 1997. Microhabitat use, trophic patterns, and the evolution of brain structure in African cichlids. Brain, Behav. Evol 50: 167-182