Strengths: The research method can be described as a longitudinal case study and therefore, allows in depth data to be collected and allows development to be studied over time. e.g. every utterance made by Kanzi, was documented by the researchers over a 17 month period.It's also possible to argue that the study was high in ecological validity as Kanzi and the researchers could rom around from place to place around the 55 acre site.The data gathered was both Quan and Qual data. The Quan data allowed for analysis and compaisons between different chimps to be made. Qual data was also collected which allowed detailed explanations of the chimps behaviour to be offered.
Weaknesses: The ecological validity of the study can be questioned as the chimps weren't reared in their natural environment. The data was gathered under rigorous controls (e.g. formal tests) and are therefore are less likely to be open to bias and subjectivity.It's possible to criticise the ethical nature of this study. Is it necessary to study chimps in a human environment and to test their language skills in this way?The researchers did note that they were generalising from a very small sample of chimps and a study of more subjects would have to be carried out for the study to be more representative. Many researchers still doubt whether Kanzi and Mulika were using language in the complex way that humans do.