Background The free list, also written “freelist”, or “free recall”, is an ethnographic method that characterizes the local knowledge of a population about a given cultural domain. However, there is still much to elucidate about the variables that can influence the number of items that participants cite using this technique. This study applied a casual-comparative experimental design to analyze whether 3 months’ time, age, and external stimuli influence the similarity of plant free lists applied at different times. Methods Data was collected from 103 farmers from the rural community Alto dos Canutos, in the municipality of Picos, Piauí state, Brazil. Two free lists were conducted at two different times, with an interval of three months between them. Subsequently, the similarity between the first and second free lists of each participant was calculated using the Jaccard Similarity Index. The generalized linear model (GLM) with binomial errors and stepwise approach was used to analyze the effects of age and external stimuli on information collection when comparing free lists applied at different times. Results Participants’ age influenced the information that the free lists collected, demonstrating that the older the participants, the lower the similarity among the free lists. Among the external stimuli analyzed, only the presence of third parties influenced the content of the free lists at the time of the interview. However, contrary to expectations, third-party presence positively influenced the similarity of the lists. Conclusion The results show that the studied variables age and third-party presence can influence the capture of knowledge. These findings warrant future research into the influences’ causes and their potential mitigation, e.g., by isolation or by breaking the medicinal plant domain into focused sub-domains and conducting simpler, successive free-lists, which can mitigate memory issues.

Background: The free list, also written “freelist”, or “free recall”, is an ethnographic method that characterizes the local knowledge of a population about a given cultural domain. However, there is still much to elucidate about the variables that can influence the number of items that participants cite using this technique. This study applied a casual-comparative experiemental design to analyze whether three months’ time, age and external stimuli influence the similarity of plant free lists applied at different times.Methods: Data was collected from 103 farmers from the rural community Alto dos Canutos, in the municipality of Picos, Piauí state, Brazil.Two free lists were conducted at two different times, with an interval of three months between them. Subsequently, the similarity between the first and second free lists of each participant was calculated using the Jaccard Similarity Index. The Generalized Linear Model (GLM) with binomial errors and stepwise approach was used to analyze the effects of age and external stimuli on information collection when comparing free lists applied at different times.Results: Participants’ age influenced the information that the free lists collected, demonstrating that the older the participants, the lower the similarity among the free lists. Among the external stimuli analyzed, only the presence of third parties influenced the content of the free lists at the time of the interview. However, contrary to expectations, third-party presence positively influenced the similarity of the lists. Conclusion: The results show that the studied variables age and third-party presence can influence the capture of knowledge. These findings warrant future research into the influences' causes and their potential mitigation, e.g., by isolation or by breaking the medicinal plant domain into focused sub-domains and conducting simpler, successive free-lists, which can mitigate memory issues.

Background: The free list is an ethnographic method that characterizes the local knowledge of a population about a given cultural domain. However, there is still much to be elucidated about the variables that can influence the number of plants cited by the participants with the use of this technique. This study analyzed whether age and external stimuli influence the similarity of free lists applied at different times.Methods: Data was collected from 103 farmers from the rural community Alto dos Canutos, in the municipality of Picos, PI. For that purpose, two free lists were applied at two different times, with an interval of three months between them. Subsequently, the similarity between the first and second free lists of each participant was calculated using the Jaccard Similarity Index. The Generalized Linear Model (GLM) with binomial errors and stepwise approach was also used to analyze how age and external stimuli affect the collection of information when comparing the free lists applied at different times.Results: The age of the participants influenced the information collected in the free lists, demonstrating that the older the participants, the lower the similarity among the free lists. Among the external stimuli analyzed, only the presence of third parties influenced the content of the free lists at the time of the interview. However, contrary to expectations, it positively influenced the similarity of the lists. Conclusion: The results show that the studied variables can influence the capture of knowledge if the objective of the research is to influence the individual knowledge of the participants.