Objectives: This study investigated the role which the mode of transmission plays in the preservation of traditional medical knowledge.

Method: A post-positivist methodology was adopted. A purposive sampling technique was used to select three communities from each of the six states in South-Western Nigeria. The snowball technique was used in selecting 228 traditional medical practitioners, whilst convenience sampling was adopted in selecting 529 apprentices and 120 children who were not learning the profession. A questionnaire with a five-point Likert scale, key-informant interviews and focus-group discussions were used to collect data. The quantitative data was analysed using descriptive statistics whilst qualitative data was analysed thematically.

Results: The dominant mode of knowledge transmission was found to be oblique (66.5%) whilst vertical transmission (29.3%) and horizontal transmission (4.2%) occurred much less.

Conclusion: Traditional medical knowledge is at risk of being lost in the study area because most of the apprentices were children from other parents, whereas most traditional medical practitioners preferred to transmit knowledge only to their children.

Hewlett and Cavalli-Sforza (1986) examined transmission of bush skills and cultural knowledge amongst the Aka Pygmies of the tropical forest region of Central Africa. The study revealed that vertical transmission (parent to child) was by far the most important mechanism for IK transmission, accounting for 80% of the cases studied. A related study by Ohmagari and Berkes (1997) reported that parents were primarily responsible for their children’s education although other members of extended families were readily available to take over these responsibilities whenever needed. Lozada, Ladio and Weigandt (2006) also analysed medicinal and edible plant utilisation in Cuyin Manzano, a small rural population located near the Andean forests of Argentina. Interviews were carried out in 16 families in order to examine the present use of wild plants. The study reported that the transmission of wild-plant knowledge was mostly vertical through family dissemination. Similar patterns of plant use were found in young and old people alike, and learning was as a result of family tradition. In a recent study, Demps et al. (2012) reported that, amongst the Jenu Kuruba, a tribal community in South India, children tend to acquire the local knowledge required for collecting wild honey from their parents.

However, studies on cultural transmission have reported that horizontal and oblique transmission are more important during adulthood than during childhood as individuals gain exposure to a greater variety of social models as they grow older (Aunger 2000; Demps et al. 2012; Hewlett & Cavalli-Sforza 1986). Hence, they have opportunities to update what they had learned from parents or to seek specialised knowledge (Henrich & Broesch 2011; Henrich & Henrich 2010).

For example, some studies have shown the dominance of the horizontal mode of transmission of IK (Aunger 2000; Eyssartier, Ladio & Lozada 2008), especially considering the fact that the amount of time children spend with parents decreases with age (Aunger 2000). Usually, children spend large portions of time with siblings and age peers which give them the opportunity to share knowledge. Reporting this pattern, Rogoff (1981) suggested that direct interaction of Kenyan children with adults declines significantly as they grow older as they engage more with other children in the same age and sex cohort. Moreover, later in life, young adults turn to age peers rather than to parents for information, most probably due to similarity in their social positions (Reyes-García et al. 2009). New information provided by age peers might allow a person to update the information previously acquired from parents (Aunger 2000).

Aunger (2000) reported that, in a community of horticulturalists and foragers in the Democratic Republic of Congo, the degree of non-parental transmission was insignificant in the belief system, at least during the early years of life when most knowledge about which food to avoid was acquired. The study however noted that, as individuals grew older and were influenced by people from outside of their close family, they continued to learn about their culture, obliterating to some degree the traces of knowledge acquired earlier from parents. This observation was also reported by Eyssartier et al. (2008) amongst the Pilcaniyeu and Cuyin Manzano communities in North-Western Patagonia, Argentina, where the transmission of traditional plant knowledge begins at an early age, as a family custom. However, horticultural learning continued into adulthood during which time locals interchange knowledge and practices, probably relearning and changing their previously acquired information. This knowledge may or may not agree with what they have learnt as a family tradition.

The influence of the horizontal mode of transmission is especially evident in the absence of a parental generation. This observation was made by Setalaphruk and Price (2007), noting the contribution of other social contacts and interaction channels. In a study carried out in a rural community in Northeast Thailand, it was observed that some children primarily acquired their knowledge of wild food resources through peers as their parents were away and as they have not engaged in gathering with their grandparents. Such children had an opportunity to learn the practical knowledge about wild food resources with friends during their play and interactions in the fields.

Oblique transmission takes place from individuals of one generation to unrelated individuals of the next generation (Hewlett & Cavalli-Sforza 1986). This can take the form of one-to-one, one-to-many (when one person, for example a teacher, transmits knowledge to many people of a younger generation) or many-to-one (when an individual learns from older adults other than the parents) (Cavalli-Sforza & Feldman 1981). Very few studies have reported on the oblique form of transmission. Hewlett and Cavalli-Sforza (1986) reported transmission by others, probably the whole social group (many-to-one), as important for sharing and dancing. This form of transmission was reported by Reyes-García et al. (2009) as important during adulthood in the transmission of ethno-botanical knowledge and skills amongst the Tsimane adults in the Bolivian Amazon. Henrich and Henrich (2010) found that about one third of Fijian women interviewed learned specific food taboos from older, knowledgeable women who were not their kin.

In Nigeria, there is no evidence of literature that extensively investigate modes of transmission amongst traditional medical practitioners (TMPs). Traditional medical practice was chosen as the form of IK to study because, in Nigeria, most rural communities lack access to orthodox medical facilities. There has been an expansion of orthodox health care facilities and an increase in the number of orthodox health care providers, but these are not accessible to the majority of people living in rural communities as over 90% of Nigerians in rural areas depend wholly or partly on traditional medicine (Oladele & Adewunmi 2008), a situation that will most probably not change in the near future. This situation has led to a call for the utilisation of TMPs in primary-healthcare delivery (Alves & Rosa 2007; Elujoba, Odeleye & Ogunyemi 2005; Olatokun 2010; World Health Organisation [WHO] 2001). Hence, the persistence of the knowledge of traditional medicine, especially in the rural communities where it is the only means of primary health care for the rural poor, has been a concern to information professionals, especially in developing countries.

This study was carried out to examine the modes of TMK transmission amongst TMPs in selected communities in South-Western Nigeria with the aim of answering the following questions:

1. What are the modes of traditional medical knowledge transmission evident amongst TMPs in South-Western Nigeria?
2. What are the reasons for the observed trend?
3. What does the observed trend portend for the preservation of TMK?

The remainder of this paper is organised as follows: The details of the study’s research methodology are presented in the next section, followed by the findings and discussion. The article ends with conclusions from the study and suggestions for further study.

The people of South-Western Nigeria are mainly of the Yoruba ethnic group and distributed over six states, namely Oyo, Ogun, Ondo, Osun, Ekiti and Lagos. South-West is the second-most populous region in Nigeria with a population of over 27 million according to the 2006 census figures (Olagunju 2012). The natural vegetation is composed of coastal and swampy forest, high forest, rainforest and derived savannah towards the north. The people living in the rural areas make up about 70% of the total population, and their main occupations include farming, fishing, blacksmithing, pottery making and indigenous medical practices (Olagunju 2012).

The study population included TMPs, apprentices and children of TMPs who were neither learning nor practicing the occupation. The choice of the TMPs from amongst other major occupational groups was based on their relevance in primary-healthcare delivery in developing countries, including Nigeria, as reported in the literature. The technique of purposive sampling was used to select three communities from each of the six states in South-Western Nigeria. Each state was divided into three, based on senatorial districts. One local government was purposively selected from each senatorial district, and a community was selected from the local government. The choice of local government and rural communities was based on the recommendation of the head of traditional medical practitioners in each state, and this recommendation was based on the concentration of TMPs in the selected areas. The snowball technique was applied in selecting TMPs. Using the technique, each TMP introduced the researcher to other TMPs. Neis et al. (1999) reported using a snowball sampling technique to select local experts in a study conducted amongst fishermen living along the northeast coast of Newfoundland, Canada. Jesajas and Packham (2003) and Ngunyulu and Mulaudzi (2009) also adopted the technique in their studies. Convenience sampling was however used in selecting the apprentices and children of the TMPs who were not learning nor practicing the profession. In all, a total of 228 TMPs, 529 apprentices and 120 children of TMPs, who were not learning nor practicing the profession, participated in the study.

Eighteen in-depth interviews were held with key informants who were leaders of the associations of TMPs in each locality. This interview preceded the FGDs. The interview provided additional information on knowledge transmission amongst the TMPs, especially information that could not be revealed during FGDs. This information proved useful as additional guide in data collection when carrying out the FGDs. Interviews were also held with the TMP’s children, aged 21–47, who were not in the occupation. Interviews were conducted with them in order to understand why they are not engaged in the occupation. Two FGDs were held in each state with seven to nine participants in each group. The groups were heterogeneously based on the demographic characteristics of respondents. The FGD provided information on the group’s opinions, beliefs and attitude towards knowledge transmission. A five-point Likert questionnaire was used to collect quantitative data from the TMPs and apprentices after the FGDs were conducted with the TMPs. A total of 757 copies of questionnaire (Ekiti – TMPs 37, apprentices 101; Lagos – TMPs 39, apprentices 90; Ogun – TMPs 40, apprentices 85; Ondo – TMPs 39, apprentices 83; Osun – TMPs 35, apprentices 91; Oyo – TMPs 38, apprentices 79) were administered, and a 100% return rate was achieved because they were researcher-administered. Data collection took place over a period of six months.

Both the FGD guide and the interview schedule included questions on the TMPs’ view of transmission of their knowledge to their children and others. The questionnaire was divided into two sections. Section-A contained questions on demographic attributes of the TMPs and other pieces of information that were required for the study, including age, sex, marital status, educational level, religion, number of children and number of children in their occupation. Section-B, which was completed by the apprentices, contained questions on demographic attributes and other information such as the amount of knowledge acquired. For data collected with the questionnaire, frequency distribution was used for analysis. Data collected through the FGD and in-depth interview was analysed thematically. The data was transcribed into text, and the transcribed text was searched to identify recurrent themes conveying similar meanings. Such recurrent themes were illustrated with some quotations from the original text in order better to communicate their meanings.

The frequency distribution of the TMPs’ religion showed that 101 (44.3%) were Muslims, 92 (40.4%) belonged to traditional religion and 35 (15.4%) were Christians. Generally, Muslims were dominant amongst the respondents. However, this was only the case for the Ekiti, Osun and Oyo States whilst respondents who belonged to traditional religion were dominant in Lagos, Ogun and Ondo. The highest level of education amongst members of TMPs was secondary education (43.4%). In the same group, 38.2% had only primary education whilst 18.4% had no formal education. A breakdown of this category showed that, whilst most of the respondents in Ogun, Ondo and Osun attained secondary education, a large proportion of respondents in Ekiti, Lagos and Oyo concluded their education at the primary level. It was interesting to observe that all the respondents in Ondo had either primary or secondary education; none were without formal education.

Only 29.4% of the TMPs transmitted all their knowledge of traditional medicine. Whilst 68.9% transmitted just more than half of their knowledge, less than two per cent transmitted only half of their knowledge. The study observed that, generally, TMPs have a positive attitude towards the transmission of their knowledge.

Overall, 58.6% of apprentices were Muslims, and 25.5% belonged to a traditional religion whilst 15.9% were Christians. A similar trend was noted in all six states as between 50% and 65% of apprentices in each state were Muslims. The highest level of education attained by apprentices was the secondary level (85.1%) with only 1.3% having received no formal education. A similar pattern was observed in all the states. Ondo had the highest proportion of apprentices (96.4%) with secondary education whereas Ekiti had the lowest (76.2%). In Lagos and Ogun, the apprentices were educated at least at the primary level.

More than 90% of the apprentices had spent one to five years learning the occupation. The expected length of training was one to five years for 73.7% of the apprentices, with six to 10 years the expected length of training for about 25% of the apprentices. Only 7.2% had spent six to 10 years acquiring the knowledge of traditional medicine. Of the 1074 children of the TMPs, only 291 (27.1%) were either learning or practicing the occupation. In addition, only 29.3% of apprentices who participated in the study acquired their knowledge through the vertical mode whereas 67% obtained knowledge through the oblique mode of acquisition. About 60% of the apprentices acquired more than half of their knowledge of traditional medicine from their TMPs. Only 9.1% acquired all the knowledge they possess from the TMPs whereas 23.4% acquired half of their knowledge from TMPs.

FIGURE 1: A stacked bar graph showing modes of acquisition by TMPs and modes of transmission to apprentices.

‘You see, whether traditional medical practitioners or Imams or Christians, a person who fails to transmit his knowledge to his child, that ‘my child come and learn this thing’, when he dies, he dies in vain’. (Camp Community)

‘We inherited it, we must also leave it for some people … If I want to cut a leaf, I will take my child there, ‘I am going to cut so-and-so leaf, let us go’. When I cut the leaf, he will see it and next time when I say ‘go and cut so-and-so leaf’ he will recognize it since I had cut it in his presence earlier’. (Olode Community)

Responses by some of the participants however showed that vertical transmission was not automatic but depended on the attitude of the child:

When we were young, our fathers will study the attitude of their children. A child who is cool-headed and not a trouble maker, our fathers will ponder: ‘If I transmit my knowledge to this child, I hope he will not bring my name or the family name to disrepute, I hope he will follow it and use it as specified.’ If they realized that the child is a trouble maker who will bring the family name into disrepute, they will rather die with their knowledge’. (Igbonla Community)

Many of the participants also expressed their views on transmitting their knowledge of traditional medicine to others who were not their children: ‘Anybody is my child. Whoever wants to acquire this knowledge is my child’ (Eporo Community); ‘Whoever wants to learn this work from me, I’ll teach willingly because I don’t want this work to perish’ (Butubutu Community); ‘It is compulsory we give it to another person’s child as long as it is not a very powerful medicinal knowledge’ (Kajola Community).

Further:

‘Not just your child alone. There are others who are not your children but when you are comfortable with their attitude you might transmit your knowledge and that child will praise you forever just as I always praise the baba who taught me’. (Igbonla Community)

‘About what we know, me must teach our children … another person’s child too who comes to us we teach, because what we also know is not only what our fathers taught us. Other fathers also taught us, that is why we must also teach children of other parents’. (Olode Community)

Participants expressed their minds on the limitations of the oblique mode of knowledge transmission specifically in relation to incomplete transmission of knowledge and lack of trust in apprentices: ‘My master did not teach me everything. My master did not transmit all his wisdom to me because you don’t have everything. You can’t take everything from your master’ (Labaile Community).

Further:

‘Another person’s child is difficult to teach. You might teach him and thereafter he will use the power against you. One must be careful with teaching a child who was not born into traditional medicine’. (Fakale Community)

‘If a person says he wants to learn it, we can teach him, but only our children inherit all our knowledge, it is our children, they inherit our knowledge. So that when it becomes obvious that we are dying, we will call our child who knows how to read and write and instruct the child to write everything. We will not hide anything from him. He will write everything completely’. (Olode Community)

‘You see this knowledge you are talking about, transmitting it to another person’s child is difficult, it is difficult, this is the reason, o [long emphasis]; you see the work of traditional medicine is powerful you see, when I wanted to learn this work from baba, the baba was not my father, he was not my father’s brother, he was not my mother’s brother … when I got to him, he first watched me for about 4 years, he used that period to study me, whether he will reveal the knowledge to me or not. But when he realised that I had an open mind to what I came for, he then revealed the knowledge to me … so I will study the person first just as baba studied me … because somebody might be sent to spy out your power … It is more important to transmit the knowledge to one’s child … one’s child is different from an outsider’. (Labaile Community)

Whilst vertical transmission was without cost, horizontal and oblique modes were not free. Many of the TMPs reported that they received money before transmitting their knowledge:

‘When an outsider comes and says, ‘Please I heard about something you have, please give me’, we will say, ‘Well then, go and bring so and so amount’. Once he brings it, we will teach him well and he will know it’. (Olode Community)

The TMPs were asked why they receive money from children of other parents and generally their responses are reflected in those of two TMPs as the following:

‘We cannot give it free because when we wanted to receive it from our fathers in those days, you might have to work in his farm for five days. Then, you will keep going to his house every day, and they will tell you that baba has gone to the farm. You will go to him at his farm, and you will work for him so much until he is satisfied and he sees that ‘yes, this child is in fact a good child, I will give him this knowledge’, and he will give him’. (Ago-Ayo Community)

‘We suffered before we learnt this work o [long emphasis]. You make a living with your secular education. We suffered. We carried loads, we cleared bushes, we cut trees, we washed clothes before they gave us knowledge of traditional medicine’. (Camp Community)

‘It is not that they can’t teach others but who will want his child to learn traditional medicine. Even you sitting down, you cannot allow your child to do so, you will rather send him to school. If your child lives with me, can I tell him to go to the bush and cut some leaves for me? It is not possible’. (Oke-Ojumo Community)

‘No youth can acquire traditional medical knowledge because most of them are interested in quick wealth’. (Labaile Community)

‘They prefer to be 419s (fraudsters), they are not interested in practising traditional medicine. Once they have some knowledge of traditional medicine, they become 419s, defrauding people everywhere, and this can lead to their death’. (Eporo Community)

They are rather interested in daily work that will bring quick money such as breaking gravel and loading sand, that is most common among them. (Fakale Community)

A lack of interest by children of TMPs as reported by their parents was corroborated by the children who were not in the profession. Few of them were comfortable with their parents’ occupation, as indicated by the following quotes: ‘It is God’s gift for those who have the knowledge. It is a good job’; ‘They should just continue with their work of healing as long as they are happy with it’; ‘As long as he is happy, what is my problem about how he gets his source of livelihood?’

However, some children expressed negative feelings about their parents’ profession – traditional medicine – when they were asked about their views on their parents’ occupation. Some of them were not supportive of their parents’ occupation because they believed that traditional medicine as a job is dirty: ‘It is a very stressful and dirty work’; ‘It is dirty, orthodox medicine is more prestigious’.

Some believed that traditional medicine is shrouded in secrecy: ‘My parent’s work is good but I don’t have interest because it has some secret power’; ‘It is an ungodly work which I do not have interest in. It is about being in the secret cult’.

Strong religious sentiments were the basis for the negative views of some of the children. Some specific responses along this line were: ‘God does not support such work. You will worship idols’; ‘Islam does not support idols. I have chosen Islam’; ‘I pray she changes and know Jesus as I do now. The work will not take her anywhere’; ‘I would not be happy to see my father perish in hell but what can I do?’; ‘It is an ungodly work. I do not support bowing down or relying on idols for power’.

The reason for the observed lack of interest of children of TMPs can be viewed from two perspectives. The first is related to their educational aspirations. Most of them aspired to acquire degrees in tertiary institutions and did not perceive TMK as valuable for their future needs. Tsuji (1996) and Grenier (1998) identified educational systems as one of the means by which IK is being lost. Subsequent studies have shown that educational systems caused bias in the attitude of the younger generation towards IK (Akullo et al. 2007; Dube & Musi 2002).

Another source of bias is associated with the religious beliefs of children of TMPs. Many of them believed that traditional medicine should exclusively be practiced by the adherents of traditional religion whilst the adherents of Christianity and Islam should not be involved in traditional medicine. In view of this, they condemned and resisted their parents’ efforts to impart the knowledge to them. Such religious bias has been traced to the days of African colonial rule when traditional medicine was perceived to be a threat to the spread of colonial power and Western religious belief systems. African traditional medicine was labelled as ‘witchcraft’, and this has continued to influence modern perceptions of African traditional medicine (King et al. 2009).

Findings from this study concerning a lack of interest by youths in acquiring TMK agree with reports from other studies (Ragupathy et al. 2008; Srithi et al. 2009; Voeks 2007; Voeks & Nyawa 2001). A lack of interest in traditional values amongst the younger generation has been worsened by exposure to modern education (Giday et al. 2003). Srithi et al (2009) studied the transfer of TMK amongst the Mien in Northern Thailand and reported that some elderly Miens who were custodians of this knowledge complained that ‘it is difficult to find younger people with an interest in learning skills concerning local healthcare’. Amongst the Chepang communities of the Mahabharat hills of the central part of Nepal, Rijal (2008) listed Western education as one of the factors responsible for the limited knowledge of plant that the younger generation has. In a similar study by Voeks (2007) amongst communities in the Eastern Bahia State, North-East Brazil, there was little interest on the part of the young ones in the communities to sustain the medicinal knowledge of their communities. For example, young boys between the ages of 13 and 17 clearly stated that ‘they knew very little about the medicinal properties of the plants and that they were distinctly uninterested in learning them’ (Voeks 2007:13).

In South-Western Nigeria, Oladele, Alade and Omobuwajo (2011) reported that the younger generations are not active in the practice of traditional medicine. In their study on the conservation and cultivation of medicinal plants by TMPs in the Aiyedaade Local Government area of Osun State, the authors noted that more than half of the practitioners had no apprentices at the time of the study. This was attributed to the decision of the younger ones to prefer formal education and other activities, leaving them no time to acquire TMK. A similar observation was made in a more recent study by Salako and Sholeye (2012) where all the traditional healers who participated in their study were middle aged and elderly.

Concerning the mode of transmission, findings show that most of the apprentices were not children of the TMPs. However, most apprentices that have a vertical relationship with the TMPs are in the group of apprentices who have acquired at least more than half of the knowledge of traditional medicine whereas, for apprentices in the oblique mode, they are mostly in the group of apprentices that have acquired at most half of their TMPs knowledge. An explanation for this is that children of TMPs spend more time with their parents compared to those who have a horizontal or oblique form of relationship with the TMP. Apprentices in the latter categories return to their homes each day and do not have the opportunity to learn at informal settings. However, the situation of the group with horizontal relationships is reminiscent of the teaching approach encouraged in ancient Israel where parents could take advantage of walking with their children on the road, eating with them at home, lying with them in bed and being in other informal settings to teach them. Hence, apprentices with vertical relationships have opportunities to learn more than those with other forms of relationships. Added to this is the observation by Akintilo (2000:250) that traditional medical practice in South-Western Nigeria is shrouded in secrecy because most of the TMPs make covenants with their ancestors not to disclose ‘the secrets of the practice to strangers’.

Another explanation for the finding in the previous paragraph can be deduced from some of the responses from focus-group discussions and in-depth interviews held with TMPs. Whilst all TMPs are comfortable transmitting their knowledge to apprentices irrespective of their relationship, children of TMPs who are learning about traditional medicine tend to be at an advantage compared to apprentices who have horizontal or oblique relationships with the TMPs. According to the participants, they are more comfortable transmitting all their knowledge to their children. Other apprentices will also benefit from receiving this knowledge from the TMPs but the acquisition of everything they know about traditional medicine is believed to be the exclusive right of their children.

The findings of this study contradict the opinion that the transmission of TMK is mainly through family inheritance (Christian 2009). From the discussions held with TMPs, they are very comfortable transmitting their knowledge irrespective of their relationship with the learner, but most would not transmit all their knowledge to those who are not their children. Most of the TMPs do not see anything wrong with this. It was inferred that TMPs who acquired their knowledge through others who are not their parents are aware that they themselves did not acquire all the required knowledge of traditional medicine. The implication of this is that, in this situation where we have more apprentices in oblique relationship with the practitioners, TMK risks being incompletely transmitted, and eventually, vital aspects of the knowledge might be lost. No matter how good the attitude of an apprentice is and no matter how long he or she stays with the TMP, as long as he or she is not related to the custodian, that particular knowledge might not be transmitted.

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