Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
DOI 10.1186/s13002-015-0022-6
JOURNAL OF ETHNOBIOLOGY
AND ETHNOMEDICINE
RESEARCH
Open Access
Herbal remedy knowledge acquisition and
transmission among the Yucatec Maya in Tabi,
Mexico: a cross-sectional study
Allison L Hopkins1*, John Richard Stepp2, Christopher McCarty3 and Judith S Gordon1
Abstract
Background: Ethnobotanical knowledge continues to be important for treating illness in many rural communities,
despite access to health care clinics and pharmaceuticals. However, access to health care clinics and other modern
services can have an impact on the distribution of medical ethnobotanical knowledge. Many factors have been
shown to be associated with distributions in this type of knowledge. The goal of the sub-analyses reported in this
paper was to better understand the relationship between herbal remedy knowledge, and two such factors, age and
social network position, among the Yucatec Maya in Tabi, Yucatan.
Methods: The sample consisted of 116 Yucatec Maya adults. Cultural consensus analysis was used to measure
variation in herbal remedy knowledge using competence scores, which is a measure of participant agreement
within a domain. Social network analysis was used to measure individual position within a network using in-degree
scores, based on the number of people who asked an individual about herbal remedies. Surveys were used to
capture relevant personal attributes, including age.
Results: Analysis revealed a significant positive correlation between age and the herbal medicine competence
score for individuals 45 and under, and no relationship for individuals over 45. There was an insignificant relationship
between in-degree and competence scores for individuals 50 and under and a significant positive correlation for
those over 50.
Conclusions: There are two possible mechanisms that could account for the differences between cohorts: 1)
knowledge accumulation over time; and/or 2) the stunting of knowledge acquisition through delayed acquisition,
competing treatment options, and changes in values. Primary ethnographic evidence suggests that both
mechanisms may be at play in Tabi. Future studies using longitudinal or cross-site comparisons are necessary to
determine the whether and how the second mechanism is influencing the different cohorts.
Keywords: Knowledge acquisition and transmission, Ethnobotany, Medicinal plants, Yucatan
* Correspondence: hopkin28@email.arizona.edu
1
Department of Family and Community Medicine, University of Arizona,
Tucson, AZ, USA
Full list of author information is available at the end of the article
© 2015 Hopkins et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
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Resumen en Español
Antecedentes: El conocimiento de la etnobotánica continua siendo importante para el tratamiento de enfermedades
en muchas comunidades rurales del mundo, a pesar de que en muchos casos exista acceso a centros de cuidados
clínicos y farmacias. Sin embargo, este acceso a los centros de salud y otros servicios modernos, puede tener un
impacto sobre la distribución del conocimiento de la etnobotánica médica. Muchos factores han demostrado estar
asociados con distribuciones en este tipo de conocimiento. El reto de los sub-análisis reportado en este documento
fue entender mejor la relación entre el conocimiento de remedio herbal y dos de estos factores, la edad, y la posición
dentro de la red social, entre el Maya yucateco de Tabi, Yucatán.
Métodos: La muestra consistió de 116 adultos maya yucatecos. Se utilizó un análisis de consenso cultural para
medir la variación en el conocimiento de remedios herbales utilizando marcadores de aptitud, a través de una
medición de concordancia entre participantes sobre un dominio. También se utilizó un análisis de redes sociales
para medir la posición del individuo dentro de la red usando marcadores de grado, a través del número de
personas que preguntaron a un solo individuo acerca de su conocimiento de remedios herbales. Por otro parte se
utilizarán cuestionarios para obtener atributos personales relevantes, incluyendo la edad.
Resultados: Los análisis revelaron una correlación positiva significante entre la edad y los marcadores de aptitud
de conocimiento en medicina herbal para individuos de 45 años y menores, y sin ninguna relación para individuos
mayores a 45 años. Se encontró una relación insignificante entre marcadores de grado y aptitud para individuos de 50
años y menores, y una correlación positiva significante para aquellos individuos mayores a 50 años.
Conclusiones: Existen dos mecanismos posibles que podrían explicar las diferencias entre cohortes: 1) la acumulación
de conocimiento en el tiempo; y/o 2) el retraso en el crecimiento de la adquisición del conocimiento a través de la
adquisición tardía, compiten las opciones de tratamiento y los cambios en los valores. La principal evidencia
etnográfica sugiere que ambos mecanismos podrían estar en juego en Tabi. Futuros estudios utilizando comparaciones
longitudinales o entre sitios se consideran necesarios para determinar si se está influyendo sobre las diferentes
cohortes, y como el segundo mecanismo lo está haciendo.
Background
Ethnobotanical knowledge, including the knowledge of
how to grow and process plants for housing, clothing, food,
medicine, storage, and fuel, is important for survival and
well-being in most subsistence farming communities [1-3].
For example, medical ethnobotanical knowledge can be
used by community members to heal common illnesses
when access to medical doctors or pharmaceuticals is
limited or the side effects produced by medications are
undesirable. Many rural communities in developing
countries are increasingly obtaining access to modern
services, including public schools and health care facilities, and experiencing greater integration into the market
economy. These changes have the potential to impact the
distribution of medical ethnobotanical knowledge among
members of these communities.
Studies of medical ethnobotanical knowledge distribution have generally focused on determining the personal
attributes associated with variation in knowledge. The
attributes most commonly identified are age [4-8], gender [7,9-15], livelihood strategies [7,12,16,17], formal
education [8,18-20], range and migration [8,21], religion
[8,9], relative economic prosperity [8,12,17,22,23], lifestyle [8,9,24-27], and individual talents and motivation
[7,24,28,29]. The explanations for why these personal attributes are associated with variation in ethnobotanical
knowledge are often related to aspects of modernization. For
example, several studies have found that adults who went
to school for a greater numbers of years as children tend to
have less ethnobotanical knowledge than those who went to
school for less time [8,18-20]. Explanations for this difference
include: adults with more schooling spent less time interacting directly with the natural environment during their childhood; and they may have less direct dependency on the
environment as adults through increased non-farming job
opportunities and shifting values than those who went to
school for less time. This pattern may not always be the case,
as it is also possible that schooling could increase ethnobotanical knowledge by creating the potential for people to
utilize written sources of information [30].
Social networks are the structure through which
ethnobotanical and other types of cultural knowledge is
transmitted. In the past decade, researchers have started
to use network concepts to understand patterns in natural resource use, knowledge, and management [31-36].
Nevertheless, only a few studies have mentioned the
potential influence of relational variables on herbal
knowledge transmission and distribution [21,37], and
only one has linked relational variables to individual medicinal plant knowledge variation [38].
We carried out a study in Tabi, Yucatan, Mexico, a
Yucatec Maya community where people have access to,
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
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and utilize to varying degrees, the public schools, modern
health care facilities, and the market economy. The study
was designed to respond to the question, “to what extent
does individual network position explain variation in
herbal knowledge across households in Tabi, independent
of attribute characteristics of the individual?” Our approach was unique, not only because we focused on
relational variables, but also because we used a more comprehensive approach than most researchers in this area by
controlling for the influence of attribute variables that are
known to be associated with herbal remedy knowledge.
The main outcome of this study was that the individual’s
position within the herbal knowledge exchange network
was positively associated with herbal remedy knowledge
when analyzed individually, but when the attribute
variables were added, age masked all other associations,
including network position [39,40].
Following the example of researchers working in other
domains of ethnobotanical knowledge, we carried out an
age cohort sub-analysis to further understand the relationship between age and herbal remedy knowledge
[25,41]. We also carried out an age cohort sub-analysis
with individual position within the herbal remedy knowledge exchange network. In this paper, we report on the
results of these two sub-analyses.
schools was permanently installed in the clinic. Prescription pharmaceuticals are available at the state-run clinic,
and over-the-counter pharmaceuticals at one of the six
privately-owned corner stores in the community.
Methods
The setting
The study took place from April 2007-April 2008 in
Tabi, a small Yucatec Maya rural village located in the
central part of the state of Yucatan, Mexico. The economy of the community is mostly based on subsistence
agriculture, although increasingly the youth are migrating to the regional cities to perform low-skilled jobs.
The communally held land (known as ejido) surrounding
the village is characterized by low deciduous forest [42],
which is utilized in the process of swidden agriculture
practiced by most farmers. There is a public kindergarten, elementary school (grades 1–6), and middle school
(grades 7–9) located in Tabi. The nearest high school
(grades 10–12), which is also state-run, is located 11
kilometers from Tabi in Sotuta, the municipal center.
Bilingualism is common in the community (89%) with
only 9.5% the population monolingual in Yucatec Maya,
and 1.5% in Spanish [43]. The massive Catholic Church
that dominates the main plaza dates back to the 1700s.
Smaller Protestant churches have been built in Tabi over
the last several decades as an increasing number of
people are moving away from the Catholic Church. Access to modern medicine has also increased during the
same time period. In the late 1980s, a small, state-run
health care clinic with a visiting physician was established in the community, and then in 2002, a yearly
rotating medical resident from one of the medical
Type of participants involved
The village is comprised of 698 people living in 122
households. The study design was based on households,
and one adult from almost every household in Tabi participated in the study (n = 116). The adult selected was
the most knowledgeable about medicinal plants in the
household as determined by members of the household. In
households where no one was considered knowledgeable,
the participant was randomly chosen. Slightly more than
half of the participants were female (54.3%), and ranged in
age from 16 to 87, with a mean age of 46.4 (SD = 17.2)
(Table 1). Although few participants received no formal
education (15.5%), only 6.8% went on to middle school,
and 30.2% were illiterate.
The most common religion in Tabi continues to be
Catholicism (45.7%); however, many people had joined
one of the Protestant churches in the community
(33.6%) or had no religious affiliation (20.7%). All of the
women were homemakers who also care for the small
livestock raised and horticultural crops grown within the
area surrounding their houses. The majority of the men
(69.8%) dedicated all their work time to tending the agricultural fields and large livestock on ejido land away
from the home. Some men (26.4%) primarily performed
temporary wage labor, and tended their fields the rest of
the time, and only a very few (3.8%) were employed as
full-time wage laborers. Thus, most of the participants
spent much of their day outside in nature.
The majority of participants (81%) had lived in Tabi
their entire lives. Of the people who lived elsewhere, most
lived in Merida or Cancun (13%), the two largest regional
cities; the remaining few (6%) lived in other small towns
on the Yucatan Peninsula. The average distance people
from Tabi had travelled as the crow flies is 254.5 kilometers. The farthest the majority of people travelled were to
Merida (40.5%) or Cancun (27.6%). Of those who had
travelled farther, the most common destination was
Mexico City (5%). Two participants travelled to the United
States and Canada as guest farm workers.
Almost three-quarters of the participants practiced a
mix of traditional and modern lifestyles as determined
by a series of items assessed through participant observation, and identified by participants as key indicators of
a more modern lifestyle, including: consumption of
leavened bread; occasional or frequent purchasing of
machine-made tortillas; preference for speaking Spanish
with children; preference for speaking Spanish with
other adults; preference for wearing Western clothes;
and ownership of a bed (see [44]). Based on a series of
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
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Table 1 Participant demographics (n = 116) (Continued)
Table 1 Participant demographics (n = 116)
Variable [Unit]
Value
Used most to treat common illness [Percent]
Age in years [Mean (SD)]
46.4 (17.2)
Medicinal Plants
69
Pharmaceuticals
30.2
0.9
Gender [Percent]
Male
45.7
God’s Will
Female
54.3
General course of action for common illness [Percent]
Literate in Spanish [Percent]
Treat the illness at home
66.4
Yes
69.8
Visit a family member or acquaintance to treat the illness
3.4
No
30.2
Visit a traditional healer to treat the illness
0.9
Visit a conventional medical doctor to treat the illness
28.4
Have faith in God’s will
0.9
Education [Percent]
No formal schooling
15.5
Completed grades 1-3
46.5
Completed grades 4-6
31.1
Completed grades 7-9
6.8
Full-Time Subsistence Farmers
31.9
Subsistence Farmers and Temporary Wage Laborers
12.1
Full-Time Wage laborers
1.7
economic indicators assessed through participant observation, and identified by participants (including ownership
of a hammock, television, stereo, refrigerator, and/or
stove), the majority of participants (87.1%) had moderate
economic prosperity. Almost all participants reported an
interest in medicinal plants (94%). Over three-quarters of
participants (88.8%) had used medicinal plants to treat
their children, and over two-thirds of participants (69%)
had used medicinal plants more often than pharmaceuticals (30.2%) to treat common illnesses. Additionally, most
respondents (66.4%) reported treating common illnesses
at home.
Only Tabi
81
Data collection and analysis
Other regional small towns
6
Regional cities (Merida or Cancun)
13
Farthest Distance Travelled in Kilometers as
the Crow Flies [Mean (SD)]
254.5 (570.9)
Religion [Percent]
Agnostic/Atheist
20.7
Catholic
45.7
Protestant
33.6
Livelihood [Percent]
Homemaker
54.3
Places of residence [Percent]
Relative lifestyle scale [Percent]
0 (Very traditional lifestyle)
1.7
1
3.4
2
26.7
3
22.4
4
24.1
5
19.8
6 (Very modern lifestyle)
1.7
Relative economic prosperity scale [Percent]
1 (Very low relative economic prosperity)
8.6
2
31.9
3
34.5
4
20.7
5 (Very high relative economic prosperity)
4.3
Interest in medicinal plants [Percent]
Very interested and interested
93.9
Neutral
0.9
Very uninterested and uninterested
5.2
This was a cross-sectional study, meaning the variables
were measured at one point in time among one group of
people [45]. This research project was approved by the
University of Florida Institutional Review Board on April
3, 2007 (IRB protocol number 2007-U-0259), and verbal
informed consent was received from all participants prior
to participating in the study per IRB approval. Multiple
data collection and analysis techniques were utilized in
this study to address our five objectives, including cultural
consensus analysis (CCA), social network analysis (SNA),
and surveys and statistical analyses [39].
Our first objective was to assess variation in herbal
remedy knowledge in Tabi. First, we administered an
herbal remedy knowledge questionnaire, and then we
ran CCA. Typically CCA is a two part process. The first
is a free-listing task asking respondents in the cultural
context to list items, in this case herbal remedies consisting of a plant and an illness the plant can help treat.
We did this task with 40 respondents in Tabi. The second part of CCA is a systematics survey asking respondents about a subset of remedies listed by the first
group. For our study the survey developed in the second
step consisted of 43 questions in the format “Can plant
x cure illness y?”. We created the questionnaire by substituting plant x and illness y in approximately half of
the questions in plant and illness combinations that had
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
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been free listed by at least 2 out of 40 people from the
first step. The other half of the questions were plant and
illness combinations that were not known remedies in
Tabi or in the Yucatec Maya ethnobotanical literature.
These items were added because CCA is sensitive to
greatly unequal proportions of yes and no responses
[46]. For each question, the response choices were “yes”,
“no”, or “uncertain”. In cases where the individual was
uncertain, the response was imputed by a simulated coin
toss since CCA operates under the assumption that respondents will guess when uncertain [46,47].
We analyzed the data by running a CCA in UCINET,
which measured individual variation in agreement of
botanical remedies among households within Tabi and
determined if there was one common culture of herbal
remedy knowledge in Tabi [47,48]. The data from Tabi
did not violate any of the model’s assumptions, thus
there is one common culture of herbal remedy knowledge, and the first factor values represent individual
competence scores for that knowledge [39]. A more
detailed description of this methodology and some of
the results have been previously published [39,40]. In
summary, the average competence scores was 0.64
(SD = 0.20) with a range from a low level of competence
at 0.08 to a high level of competence at 0.95. To put this
in perspective, a competence level of 1.0 would mean
that a participant’s responses to herbal remedy survey
matched the group consensus in responses. A score of
zero means they never agreed with the group. The relatively large standard deviation and the wide range in
competence scores indicate that across households in
Tabi, there is a great deal of variation in agreement
about botanical remedies.
Our second objective was to describe the herbal remedy
knowledge network in Tabi, and determine participants’
positions within that network. First, we asked each participant: “Have you asked person x about herbal remedies?”
substituting the names of each of the other 115 participants for person x. Then, we analyzed the relational data
using UCINET and NetDraw [48]. UCINET produced
several overall measures of network structure and individual position within the network (centrality measures), and
NetDraw provided a visualization of the whole network.
Pearson’s correlations were performed to assess the
relationship between competence scores and relational
measures. We have reported on this methodology and
some of the results in a previous publication [39]. In this
paper we present new data and a novel focus specifically
on in-degree, the only centrality measure that was correlated with competence scores (r = 0.28, p < 0.01, N = 116).
In-degree represents the number of individuals who asked
a participant about medicinal plant remedies.
Our third objective was to measure individual attributes of the participants. Attributes of network members
can be used to try to explain their network position.
These attributes were collected by administering a survey.
The questions in the survey were informed by previous
research on intra-cultural variation in traditional ecological knowledge, and ethnographic information obtained
during the first six months of fieldwork. The questions
focused on age [4-8], gender [7,9-15], livelihood strategies
[7,12,16,17], level of formal education [8,18-20], religious
affiliations [8,9], economic prosperity [8,12,17,22,23], lifestyle [8,9,24-27], range and migration [8,21], treatment
preferences and perceived interest in herbal medicine
[7,24,28,29] since these are factors that have been associated with knowledge variation. Descriptive statistics
were performed and the results are presented in Table 1.
Pearson’s correlations and ANOVAs were performed to
assess the relationship between competence scores, and
continuous and categorical attribute variables, respectively.
A general description of the results and a discussion of the
inferential findings have been previously reported [44].
Our fourth objective was to test the hypothesis that
greater individual herbal remedy knowledge is positively
associated with the position of individuals within the
botanical remedy knowledge network; that is, the more
people report talking to someone about remedies the
more that person tends to agree with the group. The
alternative, a lack of association, would suggest that
people report talking about remedies with those who are
not experts. We did this test by running regressions
using permutation tests with competence scores as the
outcome variable, and individual centrality measures and
the attribute variables as the explanatory variables [49].
Description of these analyses and results are previously
published [39], but in summary the model predicted
26.1% of the variation in competence scores (F = 3.34,
p = 0.04, N = 116) and age masked the association between competence scores and all other variables including in-degree (B = 0.01, p < .01, N = 116). We then ran a
Pearson’s correlation between age and in-degree and determined that they are positively and strongly associated
(r = 0.48, p < 0.01), suggesting that not only are older individuals more knowledgeable about herbal remedies,
but they are also a source of information about herbal
remedies for more people.
Our fifth objective, and the primary focus of this
paper, was to determine if the relationship between age
and knowledge identified in objective four was consistent across age groups. We found that overall competence increases with age, but this pattern may not be the
same for all age cohorts. If the pattern differs by age
group and is associated with an event or major change
in the community, then it provides evidence for changes
in acquisition patterns which may be resulting in knowledge loss [25,41]. We divided the participants into two
different age cohorts, and ran Pearson’s correlations
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
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between competence scores, in-degree and age variables.
The age cohorts were 16–45 and 46–87 for age and
competence, and 16–50 and 51–87 for age and indegree. We also conducted ethnographic interviews with
a subsample of 20 participants related to the findings to
foster interpretation. The interviews were focused on
community history, and patterns in acquisition and
transmission.
integration, and westernization, and may have influenced
the quantity and quality of information acquired by younger individuals regarding traditional medicine. If this is the
case, these changes may be related to the variation we
found between age cohorts in competence scores. Zent
[25] found a similar pattern of knowledge among the
Piaroa in Venezuela. He determined that the difference
between the two cohorts corresponded to their relocation
and ensuing lifestyle change. Voeks and Leony [8] saw a
striking difference in knowledge levels between the 61–70
age group and 71–80 age group in Lençois, Brazil. Voeks
and Leony [8] argue that the extreme difference in knowledge was a result in the shift from using traditional medicine as the only illness survival strategy to having multiple
options for treated illnesses.
Changes in lifestyle may be affecting the timing of
knowledge transmission as well. There is some evidence
in populations where traditional peasant lifestyles are
the norm that the positive correlation between age and
medicinal plant knowledge is not as strong or nonexistent [26,51]. In the case of the Hoti of Venezuela, a
group with relatively low levels of acculturation, medicinal
plant knowledge acquisition starts in early childhood and
increases until 18–28 years of age [52]. These studies provide evidence that in less-acculturated groups, the bulk of
basic ethnobotanical knowledge is learned in childhood,
and knowledge accumulation slows or stops in adulthood.
Tzotzil Maya children living in a rural community know
more plants earlier than their counterparts living in the
town center [53]. In Tabi, almost all of the medicinal plant
remedy knowledge is learned in adulthood, suggesting that
lifestyle changes may be affecting transmission practices.
There were only two individuals from the subsample who
learned the bulk of what they know about medicinal plants
as children: a 77-year-old woman and a 59-year-old man.
Changes in lifestyle may also be affecting the modes of
cultural transmission. There is some evidence that when
knowledge about medicinal plants is acquired during
childhood the transmission mode is generally vertical
(i.e., from parent to child) [50,51,54] and/or concerted
(i.e., from older members of the social group to younger
members of the group) [55]. In Tabi, most participants
(66%) were asked by relatives for information about medicinal plants. However, more than a fifth of the people
(21%) asked about medicinal plants were identified as
healers or particularly knowledgeable about medicinal
plants. A little over one-tenth (13%) of the people asked
for information were neighbors, friends, and acquaintances. Of those who were asked about medicinal plants,
58% were from an older generation than the person asking, 29% from the same generation, and, surprisingly,
11% from a younger generation. Thus, a change in timing of acquisition may lead to a shift from primarily
vertical and/or concerted transmission to multiple
Results and discussion
Age and competence
The cohort analysis revealed that there was a positive
correlation between age and competence scores for individuals 45 and younger (r = .46, p < 0.01, N = 59), but no
relationship for individuals 46 and older (r = 0.13, p = 0.32,
N = 57) (Figures 1 and 2). In ethnographic interviews,
participants generally explained that they learned what
they know about medicinal plants after they had children, with 40% reporting they started learning about
herbal remedies shortly after they got married, 40% after
they had their first child, and 10% once their children
started getting sick. Only 10% reported that they learned
about medicinal plants as children. Prince [50] also found
increased motivation among the Luo in Kenya once they
had children. These findings provide evidence that the
relationship between age and competence scores in the
younger cohort is at least partially explained by accumulation of knowledge.
Another factor that could be related to the difference
between age cohorts is a decreased interest in learning
about medicinal plants as a result of modernization and
related lifestyle changes. Since the end of the Mexican
Revolution (~1920), the Mexican government has been
expanding basic services to rural communities. Around
50 years ago, these services finally reached Tabi. The
first change was the establishment of the elementary
school around 1955. During the 1960s, visiting doctors
began to come to the village weekly. Many additional
changes occurred in Tabi during Victor Cervera Pacheco’s
governorship of the Yucatan (1984 to 1988), including installation of reliable electricity and potable water, paving
of the road between Sotuta (the municipal capital) and
Tabi, and establishment of the Servicios de Salud de
Yucatán (SSY) health center. In 1994, the road to
Yaxcaba (the municipal capital of the municipality just
to the east of Tabi) was paved, and two years later, a
twice daily bus route began transporting people to and
from Merida. Internships by medical residents in the
SSY health center became a requirement in 2002, and
the interns began offering free daily medical services for
community members insured under Seguro Social or
Seguro Popular.
These gradual modernization efforts in Tabi led to
an intensification of inter-cultural contact, economic
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
Page 7 of 10
1
0.9
Competence Score
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
15
20
25
30
35
40
45
Age
Figure 1 Relationship between competence scores and age. There is a positive association between competence score (agreement about
medicinal plant remedies) and age (r = 0.46, p < 0.01, N = 59) for individuals from 16 through 45 years of age.
valuable experience using medicinal plants while raising
their children. That knowledge backed by experience is
sought out by individuals with young children who have
limited experience with herbal treatments. Additionally,
it fits with a widespread belief that younger people
know little about medicinal plants. After finishing an
interview with a participant, they would frequently ask
us who we were going to visit next. If we were speaking
with an older individual and we were going to visit a
younger member of the community, they would often
say something regarding the lack of knowledge of the
person we intended to interview. Then they would suggest two or three older individuals that we should interview. Also, on several occasions younger individuals
suggested we interview older community members instead of themselves, citing their lack of knowledge compared to the older individuals. Lastly, older individuals
have more spare time to help treat illnesses when they
modes of transmission including vertical, horizontal
(i.e., between individuals of the same generation), oneto-many (i.e., healer to others), and concerted [56]. This
shift in prevalence of different modes of cultural transmission may also help explain the relationship between
age and competence in that each mode varies in the degree with which knowledge is shared between individuals in a group [54].
Age and position in network
A cohort analysis between age and in-degree showed no
relationship between the two variables in the participants
ages 16–50 (r = 0.19, p = 0.11, N = 72), and a positive relationship from 51 to 87 years of age (r = 0.42, p < 0.01,
N = 44) (Figures 3 and 4). This pattern corresponds with
ethnographic findings that there is a general respect for
Tabi elders and the herbal remedy knowledge they possess
within the community. Older individuals have gained
1
0.9
Competence Score
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
45
50
55
60
65
70
75
80
85
90
Age
Figure 2 Relationship between competence score and age. There is no association between competence score (agreement about medicinal
plant remedies) and age (r = 0.13, p = 0.32, N = 57) for individuals from 46 through 87 years of age.
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
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20
18
16
In-Degree
14
12
10
8
6
4
2
0
15
20
25
30
35
40
45
50
Age
Figure 3 Relationship between in-degree and age. There is no association between in-degree and age for individuals from 16 through 50 years
of age (r = 0.19, p = 0.11, N = 72).
occur. One mother explained to us that although she is
very interested in medicinal plants, she found it difficult
to learn about them with all the demands of raising
several young children. Instead she chose to take her
sick children to her mother-in-law for treatment. However, she recognized the need for her to learn the
remedies so that she can use them and pass them on to
her children after her mother-in-law dies. This example
highlights the challenges, and potential risks, of learning
about herbal remedies as an adult.
Conclusions
The first age cohort and knowledge sub-analysis revealed
a positive correlation between age and herbal remedy
knowledge among the younger cohort, and no association among the older cohort. There are two possible
mechanisms that could account for the differences
between cohorts. The first is that younger individuals
are accumulating the knowledge they need for their
basic herbal remedy toolkit, whereas older individuals
have already acquired this knowledge. The second is that
individuals in the younger cohort are learning less
medical ethnobotanical knowledge because of: increased
access to modern services (e.g. schools and health care
clinics); reduced traditional learning opportunities; changed values; and greater treatment options. Ethnographic
evidence suggests that both mechanisms may be at play
in Tabi. The opposite pattern was observed with age
cohort and network position sub-analysis with no association between age and in-degree among the younger
cohort, and a positive correlation among the older cohort. This pattern was also supported by the ethnographic evidence.
The modernization processes affecting knowledge
acquisition and transmission are not unique to Tabi, and
communities like Tabi are rapidly becoming the norm.
20
18
16
In-Degree
14
12
10
8
6
4
2
0
50
55
60
65
70
75
80
85
90
Age
Figure 4 Relationship between in-degree and age. There is a positive association between in-degree and age for individuals from 51 through
87 years of age (r = 0.42, p < 0.01, N = 44).
Hopkins et al. Journal of Ethnobiology and Ethnomedicine (2015) 11:33
This suggests that the findings in this study may be representative of other communities where people are predominantly subsistence farmers, bilingual in their native
and national languages, have access to modern medicine, and have increasing contact with the national culture. Comparisons between already existing studies
suggest that ethnobotanical knowledge is acquired earlier in life and there is less variation between individuals
in communities with less disruption of daily life by
external processes than in communities with more
changes [19,25,51,52,57,58].
Changes in ethnobotanical knowledge can be more
fully understood by designing and carrying out studies that
use systematic approaches to data collection and analysis.
There are several approaches that are particularly well
suited to facilitate our understanding of cultural knowledge change, including: 1) comparing knowledge variation
in communities with varying degrees of modernization or
participation in market economy but have otherwise
similar characteristics [25,52,53], 2) comparing knowledge between migrants and those continuing to live in
their home country [59] and 3) by carrying out longitudinal studies to assess changes in knowledge over time
in the same location u. In cases where these types of
studies are not feasible, an alternative strategy is to
standardize a methodology, such as the one used in this
study, which researchers can use to systematically measure knowledge variation across studies and sites. More
research using these approaches is needed to develop
and test theories regarding ethnobotanical knowledge
acquisition, transmission, variation, dynamism, and loss.
Abbreviations
IRB: Institutional Review Board; CCA: Cultural consensus analysis; SNA: Social
network analysis; SSY: Servicios de Salud de Yucatan (Health Services of Yucatan).
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
ALH designed and coordinated the study, performed the field work with the
help of two field assistants, carried out the analyses and prepared and drafted
the manuscript. JRS and CM made substantial contributions to theoretical
background, conception and design of the study, fieldwork, data analysis and
interpretation of results. JSG contributed substantially to interpretation of results.
All authors read and approved the final manuscript.
Acknowledgments
The authors would like to thank National Science Foundation for awarding
the Doctoral Dissertation Improvement grant (BCS-0719053) used to carry
out this research. The authors are grateful for the local logistical and technical
support received from Juan Jimenez-Osornio, Armando Inurreta Diaz,
Guadalupe Chan Poot, Layda Chan Ku, Germán Carnevali Fernández-Concha,
and José Luis Tapia Muñoz. A special thanks to the people of Tabi who
participated in the study.
Author details
1
Department of Family and Community Medicine, University of Arizona,
Tucson, AZ, USA. 2Department of Anthropology, University of Florida,
Gainesville, FL, USA. 3Department of Anthropology and Bureau of Economic
and Business Research, University of Florida, Gainesville, FL, USA.
Page 9 of 10
Received: 28 September 2014 Accepted: 14 April 2015
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