International Journal of Advanced and Multidisciplinary Social Science

2019;  5(1): 1-6



Relationship between Secure Attachment Type and Relational Aggression among Pre-Schoolers in Kenya

Onyango Daughty Akinyi1, Benson Charles Odongo2, Peter J. O. Aloka3

1PhD Candidate in Early Childhood Education, Jaramogi Oginga Odinga University of Science and Technology, Kenya

2Department of Special Needs and Early Childhood Education, Jaramogi Oginga Odinga University of Science and Technology, Kenya

3Department of Psychology and Educational Foundation, Jaramogi Oginga Odinga University of Science and Technology, Kenya

Correspondence to: Peter J. O. Aloka, Department of Psychology and Educational Foundation, Jaramogi Oginga Odinga University of Science and Technology, Kenya.


Copyright © 2019 The Author(s). Published by Scientific & Academic Publishing.

This work is licensed under the Creative Commons Attribution International License (CC BY).


The role played by attachment of child to parent towards enhancing positive relations among pre-schoolers cannot be over-looked since children who display aggressive behaviors often experience a disruption in the of attachment with their primary caregivers. The purpose of the study was to establish the relationship between secure attachment and relational aggression among pre-schoolers. The study was based on Attachment theory by Bowlby (1973) and Ainsworth (1969) supported by Aggression theory by Bandura (1969). The study adopted Concurrent Triangulation Research Design within the mixed methods approach. The target population comprised of 131 preschool teachers, 923 parents, 1,159 Learners and 1 education officer in Nyakach Sub-County. A sample size of 40 pre-school teachers, 277 parents, 348 pre-schoolers and 1 Sub-county Coordinator of ECDE was obtained using a combination of simple random sampling, cluster random sampling and purposive sampling techniques respectively. Parent-child attachment and Relational Aggression questionnaires were used to collect quantitative data from parents while interview schedules were used to obtain qualitative data from teachers. The questionnaires were translated into Luo language with the help of experts. In addition, observation checklist was also used to obtain data. The research supervisors at Jaramogi Oginga Odinga University of Science and Technology evaluated the instruments to ascertain their content, construct and face validities. The reliability was ensured using cronbach alpha technique and a reliability coefficient of α =0.77 was reported. Trustworthiness of qualitative data was also ensured. Quantitative data was analyzed using both descriptive and inferential statistics such as Pearson correlation and linear regression while qualitative data was analyzed by thematic analysis. The study findings showed a significant (n=236; r = -.679; p < 0.05) moderate negative correlation between secure attachment and relational aggression among pre-schoolers. The study recommends that the County Government should consider organizing programs aimed at sensitizing parents and care-givers on the importance of parent roles and attachment. It also recommends that Kenya Institute for Curriculum Development to include best attachment type in the curriculum content of pre-service teachers training.

Keywords: Relational Aggression, Secure Attachment, Parent-child Attachment Style, Pre-schoolers, Kenya

Cite this paper: Onyango Daughty Akinyi, Benson Charles Odongo, Peter J. O. Aloka, Relationship between Secure Attachment Type and Relational Aggression among Pre-Schoolers in Kenya, International Journal of Advanced and Multidisciplinary Social Science, Vol. 5 No. 1, 2019, pp. 1-6. doi: 10.5923/j.jamss.20190501.01.

1. Introduction

Parents play many different roles in the lives of their children (Mercer, 2006) including teacher, playmate, disciplinarian, caregiver and an attachment figure. Of all these, their role as an attachment figure is one of the most important in predicting the child’s social and emotional outcome. Without an appropriate attachment (Bowlby, 1973) children suffer serious psychological and social impairment. How the parents respond to their infants in the first two years particularly during the time of distress (Waters, 2005) established the types of attachment their children form; secure, avoidant, ambivalent and disorganized. The attachment system serves to achieve or maintain proximity to the attachment figure (Berlin, 2008). Relational aggressive behaviors in preschool-age children tend to be overt and direct (and therefore easily observed) as opposed to indirect, discrete or subtle as more often manifest in older children (Ostrov, 2004).
The process of attachment with a new baby is natural for most mothers. According to Treleavan (2012), left alone, new mothers will hold their baby next to their bodies, rock them gently, strive for eye contact, sing or talk to the baby and begin to nurse. Often within just hours of birth, mothers report feelings of overwhelming love and attachment for their new baby. Crying and making other noises, smiling, searching for the breast, and seeking eye contact give cues for a caring adult to respond. When a caregiver consistently responds to an infant’s needs Hazan, (2013), a trusting relationship and lifelong attachment develops that sets the stage for the growing child to enter healthy relationships with other people throughout life and to appropriately experience and express a full range of emotions. Babies who are held and comforted when they need it during the first six months of life tend to be more secure and confident as toddlers and older children (Kayastha, 2010).
Hence, according to Aronoff, (2012), an attachment is especially important from birth since that's when the brain is growing the fastest. In particular, the emotion-focused right brain is developing rapidly (it slows down in the second year). While babies don't remember specific moments during these early months (Howe, 2011), they rely on what they've experienced to retrieve emotions. For instance, they will turn toward a comforting person for help in managing the stress of their world, especially if they've had a loving exchange with that person before. Being responsive and emotionally available to a child reinforces this connection. In fact building healthy attachment is an ongoing process. As children grow and gain the confidence to reach out into the world, parents are their teachers. Even teenagers need a safe place to turn and responsiveness from people who care. The emotional connections, established in the first year and strengthened over childhood and adolescence, will help a baby become a happy, productive adult (Ostrov, 2010). Secure attachment is a verbal and non-verbal emotional relationship between an infant and a primary caregiver. Parents in secure relationships are emotionally available, perceptive, and responsive to infant’s needs and mental states while the internal working model of these infants is likely to be one that expects that their needs will be known and met, that they will be attuned to and emotionally regulated, and that they can freely explore their environment in safety (Ainsworth, 1969).
The study was informed by the John Bowlby’s attachment theory (1973) and Albert Bandura’s social learning theory of aggression (1969). Attachment theory attempts to explain that a child has an innate need to attach to one main attachment figure and that children are born with the tendency to display certain innate behaviors (called social releasers) which help ensure proximity and contact with the mother or attachment figure (e.g. crying, smiling, crawling, etc.) – these are species-specific behaviors. According to Bowlby, (1980) all infants naturally attach to their primary caregivers, even to adults who are less nurturing not because caregivers feed them but because caregivers trigger the unfolding of infants’ inborn disposition to seek closeness with a protective other but it's the nature of the attachment – whether it's secure or insecure – that makes the lifelong difference. Babies with a healthy, secure attachment understand that the parent or caregiver is a source of comfort and a solid base from which to explore and play (Berlin, 2008). These babies miss their caregivers when they leave and feel relieved when they return. With a strong emotional foundation of trust, they grow into confident, competent, caring adults. Only when children feel they can count on their parents to be available – and when they consistently find the world to be a safe and approachable place – that they develop the confidence to fully explore and play on their own.
In the Japanese culture children tend to be with their mother all the time whereas American children frequently have experienced separations from their mothers. Van IJzendoom & Kroonenberg, (2008) conducted a meta-analysis of various countries including Japan, Germany, China, the UK and the USA using the strange situation which showed that though there were cultural differences secure attachment could be found in every culture in which studies have been undertaken, even where communal sleeping arrangements are the norm. Selection of the secure pattern is found in the majority of children across cultures studied. This follows logically from the fact that attachment theory provides for infants to adapt to changes in the environment, selecting optimal behavioral strategies. Tomlison, Cooper and Murray, (2005) in South Africa revealed that, at 18 months, 61.9% of the infants were rated as securely attached. A toddler who is securely attached to his or her parent (or other familiar caregiver) explores freely while the parent is present, typically engages with strangers, is often visibly upset when the parent departs, and is generally happy to see the parent return. The extent of exploration and of distress is affected, however, by the child's temperamental make-up and situational factors as well as by attachment status. A child's attachment is largely influenced by their parent’s sensitivity to their needs. Parents who consistently or almost always respond to their child's needs create securely attached children. Such children are certain that their parents are responsive to their needs and communications hence become less aggressive (Schacter, 2009).
Several studies conducted in Africa found out that aggressive tendencies among pre-schoolers were brought about by the type of parental bonding between children and their parents. For example, Ojedokun, Ogungbamila & Kehinde (2015) study in Nigeria found that parental bonding had significant influence on the tendency to perpetrate aggressive behaviour. This finding suggested that students who perceived their parents as less caring and paid little or no attention to them reported higher tendencies to perpetrate aggression. In South Africa, Troy and Sroufe (2011) also found out that aggressive tendencies in children was predicted by attachment history in toddlerhood. LeVine and Llyod (2007) study in Nyansiongo Gusii in Kenya revealed that child rearing among the Gusii of Kenya is distinctive in that infants are routinely cared by both mother and caretakers where the infant- mother interaction is primarily limited to activities which provide for the infant’s physical needs while the caretakers interaction is primarily limited to play and social activities. Caregivers often lack the capacity to supervise children adequately as they are preoccupied with their own stressors such as income insecurity which may directly affect the caregivers’ capacity to be responsive and supportive to the child.
A study by Obure et al (2012), in nine countries indicated that Kenya had the highest rate of Relational Aggression among pre-schoolers. Atieno, (2014) on the other hand examined major factors influencing indiscipline in public day schools in Makadara district Kenya which indicated that most indiscipline cases in Public day Schools in Makadara district were fuelled by inadequate guidance and counseling by parents and lack of school - based families. In Nyakach, though it is expected that with adequate parent-child attachment, parental involvement and support and quality teaching in Nyakach Sub-County, pre-schoolers should be of good behaviors. However, the records on learners behavior is not pleasing at all. According to the records from the Sub-County Director of Education’s office (2017), in the year 2012 the sub-county recorded a high rate of relational aggression among the pre-schoolers and in 2013 it recorded worse same to 2014. The preschoolers behavior was on a downward trend for two consecutive years from 2013 to 2015, and falling below the National and Kisumu County average behavior all the years. In Nyakach sub-county, data available indicated there is a worrying trend of Relational Aggression among the pre-schoolers; accidents, withdrawal and crying.
Literature on relationship between secure attachment and relational aggression is available. Rozita, (2013) conducted a study in Hamadan, Iran results that secure mother-infant attachment was observed to have a significant negative correlation with all subscales of aggression. In addition, secure attachment was observed to have a significant negative correlation with all subscales of aggression. Cole and Anderson, (2016) indicated that Parents of non-aggressive students tended to show little or no of aggression themselves and the students felt that their interactions with their parents was good depending on the situation. Maximo, Sabrina and Loy, (2014) revealed that verbal bullying/victimization is more frequent than other types. Generally, being a bully, victim, or bully-victim is negatively related with secure parental attachment. The reviewed study was done in Philippines but not in Kenya where the present study was done to fill the gaps in the literature. One study that focused on attachment styles and its influence on future aggression was done by Goodman, Bartlett, and Stroh (2013) in Lebanon, United States. The results indicated that children who perceived their parents as caring reported fewer tendencies of aggressive acts.
A study conducted by Williams and Kennedy (2012) in America further supported the findings that parent-child attachment affects aggression levels by examining bullying behaviors and victimization. In another study by Parens (2012) in Lebanon the results indicated that a negative relationship existed; if a person had a secure attachment, then he/she had less aggressive behavior. Ryngala (2013) reported that secure attachment predicted lower levels of internalizing (R2 = .172, F(l, 29) = 6.153, p= .02). Ojedokun, Ogungbamila and Kehinde (2015) finding suggested that students who perceived their parents as caring reported fewer tendencies to perpetrate aggressive acts. According to Kindsvatter and Desmond (2013), secure attachment in young children is associated with the attention received from the mother to fulfill the child's needs. This scenario suggested that secure attachment is a more positive form of attachment between the child and caregiver. Ooi, Ang, Fung and Cai (2015) found that the quality of parent–child attachment significantly predicted parent-rated aggression, social stress and self-esteem. Higher quality of parent–child attachment was associated with lower levels of parent-rated aggression, lower levels of social stress and higher levels of self esteem.
While most reviewed studies were qualitative, they lacked quantitative aspects hence, the present study adopting the mixed method approach that enabled analysis of both qualitative and quantitative data. In addition, most reviewed studies were conducted on females but they lacked findings from males hence the present study was conducted on both males and females to fill the gaps in the literature. In addition, most of the reviewed studies were conducted on single parents especially mothers hence the present study was conducted on both parents to fill the gaps in the literature.
The relational aggressive tendencies among pre-schoolers in Nyakach sub-county of Kenya is of great concern. However, there are previous studies, particularly in Kenya, that have focused on other factors that influence learner behavior, like teacher attitude and parental state of mind, many pre-schoolers still behave below average according to the national expectation. Furthermore, scarce literature is available on the contributions on learner aggressive tendencies which could be inadequate. Based on this, the study was geared towards establishing the relationship between parent-child attachment types and relational aggression among pre-schoolers in Nyakach Sub- County, Kenya.
The hypothesis was stated as follows:
There is no statistically significant relationship between secure attachment and relational aggression among pre-schoolers

2. Research Methodology

A research design is the arrangement of conditions for collection and analysis of data in a manner that aims to combine relevance to the research purpose with economy in procedure (Kothari, 2011). It is a plan, structure and strategy of investigation conceived so as to obtain answers to research questions. The study adopted Concurrent triangulation design within the mixed method approach. The design converges or merges quantitative and qualitative data in order to provide a comprehensive analysis of the research problem. In this design, the investigator typically collects both forms of data at roughly the same time and then integrates the information in the interpretation of the overall results (Creswell, 2014). The target population was 2,214 participants. The study adopted purposive sampling to sample teachers, learners and the sub-county coordinator for EC and simple random to sample the parents. The sample size for the study therefore consisted of 40 pre-school teachers, (30% of 131) 348 pre-schoolers (30% of 1159), 277 parents (30% of 923) and 1 Sub county coordinator hence a sample size of 666 respondents.
The data collection instruments were structured questionnaires, which generated quantitative data and interview schedules and document analysis which sought to elicit in-depth information for qualitative data. Items to measure parent-child attachment type and relational aggression were adapted from Attachment Questionnaire (AQ) previously used by Kerns (2009) and Relational Aggression Questionnaire (RAQ) by Crick (2006). They were suitable because previously adopted to study Parent-Child Attachment and Monitoring in Middle Childhood and Relational Aggression among adolescents. In using the questionnaires for this study, the items were rephrased specifically to align to Kenyan educational context to ensure that the parents understand the survey items and respond appropriately. Using the parents responses based on a five point scales of; Strongly Agree (5), Agree (4), Undecided (3), Disagree (2) or Strongly Disagree (1), a sixty five itemed Likert-scaled questionnaire which explored the parents’ views on the attachment type and relational aggression tendencies was adopted. Validity was ensured by expert judgment from university supervisors from Jaramogi Oginga Odinga University of Science and Technology. Cronbach Alpha was used establish reliability and all the subscales met the recommended threshold. Trustworthiness of qualitative data was ensured by use of multiple sources of data. Descriptive statistics, Pearson correlation and linear regression were used to analyze quantitative data. The Qualitative data was analyzed using Thematic Analysis Approach.

3. Findings and Discussion

The purpose of the study was to find out the relationship between Secure Parent-child Attachment Type as a Determinant of Relational Aggression among Pre-schoolers in Nyakach Sub-County, Kenya.
The hypothesis was stated as follows:
There is no statistically significant relationship between secure attachment and relational aggression among pre-schoolers
To establish whether there was any statistically significant influence of Secure Parent-child Attachment Type on Relational Aggression, the researcher computed abivariate Pearson’s Product-Moment Coefficient of Correlation between the scores of the two variables. The SPSS output Table 1 shows the correlation results.
Table 1. Correlation between Secure Attachment and Relational Aggression
From the results presented in table 1, the output indicated a significant (n=68; r = -.827; p < 0.05) fairly strong negative correlation between secure attachment and relational aggression among pre-schoolers. Therefore, given that the p-value was less than .05, the null hypothesis which stated that “There is no statistically significant relationship between secure attachment and relational aggression among pre-schoolers” was rejected. It is therefore concluded that there is significant negative relationship between parent-child secure attachment relationship and relational aggression among pre-schoolers, with more parent-child secure attachment associated to less relational aggression among the preschool children.
This finding implies that a preschool child who enjoys a secure attachment with her or his parent would less likely have aggressive tendencies towards other people or his/her peers. This finding suggests that secure attachment prevent the occurrence of aggression among preschool children. This finding agreed with Goodman et al (2013) and Erdem (2017) both who found that children who perceived their parents as caring reported fewer tendencies of aggressive acts. However, the same finding was in disagreement with Richards (2014) which showed that no significant association was established between secure parenting and children’s aggression. Qualitative data obtained from the teachers seemed to corroborate this finding. It emerged for instance, that learners who perceived their parents as responsive and available were calm and less aggressive.
The sub county coordinator for Early Childhood had this to say:
“These parents love their children for who they are and never spend all the time trying to correct them instead try to prepare their children for the future” (SCCEC)
Data from the observation checklist records indicated that parent’s love was observed in the children level of Politeness and love they showed fellow learners in class. This served as an important strategy in classroom interaction since it had important roles in the communication and interaction between teachers and learners thus reducing the aggressive tendencies brought about by lack of communication.
However to estimate the level of influence of secure attachment on relational aggression, a coefficient of determination was computed. This was done using regression analysis and the results were presented in Table 2.
Table 2. Model Summary on Regression Analysis of Parent-Child Secure Attachment on Relational Aggression among Pre-schoolers
The model shows that parent-child secure attachment accounted for 68.4% (R2=.684) of the variation in level of relational aggressiveness in preschool learners in Nyakach Sub-County. This was a respectable amount of effect by only one determinant on the dependent variable. The finding of the study reveals that level of parent-child secure attachment statistically significantly predict the relational aggressiveness among preschoolers, meaning that information on the level of parent-child secure attachment could be used to significantly predict the level of aggressiveness among preschoolers as Parens (2012) study in Lebanon indicated that a negative relationship existed between secure attachment and relational aggression.

4. Conclusions and Recommendations

The study sought to investigate secure parent-child attachment type as a determinant of relational aggression among per-schoolers in Nyakach Sub-County, Kenya. From the above discussion, it can be concluded that parents should practice secure parent-child attachment in their homes with their young children. Thus, children who experience nurturing behavior from their parents such as warmness have a tendency to be less aggressive in their interpersonal relationships with others. The Ministry of Education should develop structured programmes of educating parents on how to relate and respond to the needs of their children and practice secure parent-child attachment. This will help parents develop positive attitude and improve on their emotional and psychological well-being. This is because the study reported that some of the parents accepted that they do not relate well with their children.


[1]  Ainsworth, M. (1990). 'Epilogue' in Attachment in the Preschool Years, ed. M.T. Greenberg, D. Ciccheti & E.M. Cummings. Chicago, IL: Chicago University Press, pp. 463–488.
[2]  Ainsworth, MD, Blehar M, Waters E, & Wall S (1978). Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale NJ: Lawrence Erlbaum Associates.
[3]  Ainsworth, M (1967). Infancy in Uganda: Infant Care and the Growth of Love. Baltimore: Johns Hopkins University Press Bowlby, J (1971) [1969], Attachment and Loss, Vol. 1. Attachment (Pelican ed.), London: Penguin Books.
[4]  Ainsworth MD (1969). "Object relations, dependency, and attachment: a theoretical review of the infant-mother relationship". Child Development. Blackwell Publishing, 34.932-937.
[5]  Ainsworth, M. D. & Bell, S. M. (1970). Main M (1979). "The "ultimate" causation of some infant attachment phenomena". Behavioral and Brain Sciences. 9(10): 3588–3598.
[6]  Aronoff, J. (2012). Parental Nurturance in the Standard Cross-Cultural Sample: Theory, Coding, and Scores. Cross-Cultural Research. 12(5), 463-481.
[7]  Bell, S. (2010). "The development of the concept of the object as related to infant-mother attachment.". Child Development. 52, 268-276.
[8]  Berlin LJ, Cassidy J, & Appleyard K. (2008). "The Influence of Early Attachments on Other Relationships". In Cassidy J, Shaver PR. Handbook of Attachment: Theory, Research and Clinical Applications. New York and London.
[9]  Bowlby J (1973). Separation: Anger and Anxiety. Attachment and loss. Vol. 2. London: Hogarth.
[10]  Bowlby, J (1980). Attachment and Loss, London: Penguin, p. 45.
[11]  Bryant, J. H., Bryant, N. H., Williams, S., Ndambuki, R.N., & Erwin, P. C. (2012).
[12]  Addressing Social Determinants of Health by Integrating Assessment of Caregiver-Child Attachment into Community Based Primary Health Care in Urban Kenya. International Journal for Environmental Research in Public Health. 9(10): 3588–3598.
[13]  Creswell, J. W et al (2014). Research design: qualitative, quantitative, and mixed methods approach. Handbook of mixed methods in social and behavioral research (pp-209-240) Thousand Oaks, Calfornia: SAGE Publications.
[14]  Cole, S. & Anderson, S. (2016). Family Interaction and the Development of Aggression in Adolescents: The Experiences of Students and Administrators. American International Journal of Contemporary Research Vol. 6, No. 4,12-23.
[15]  Goodman, G., Stroh, M., & Bartlett, R. (2013). Mothers’ borderline features and children’s disorganized attachment representations as predictors of children’s externalizing behavior. American Psychological Association, 30(1), 16-36.
[16]  Greenberg, M. T., Speltz, M. L., Deklyen, M., & Endriga, M. C. (2012). Attachment security in preschoolers with and without externalizing behavior problems: A replication. Development and Psychopathology. Vol, 3(4), 413-430.
[17]  Howe, D. (2011). Attachment across the lifecourse. London: Palgrave, p.13.
[18]  Kerns, K. A., Schlegelmilch, A., Morgan, T. A., & Abraham, M. M. (2005). Assessing attachment in middle childhood. In Kerns, K. A., & Richardson, R. A. (Eds.), Attachment in middle childhood (pp. 46-70). New York: Guilford Press.
[19]  Karega, M. (2014). Relationship between perceived parental nurturance and problem behaviours among secondary school students in selected counties in Kenya. Retrieved on 2nd May 2016 from
[20]  Kayastha, P. (2010). Security of attachment in children and adolescents. Bangalore: Elsevier B.V.
[21]  Kothari, C. R. (2011). Research Methodology. Methods and Techniques. 2nd revised edition. New Age International (p) Ltd, Publisher.
[22]  LeVine, R. A., & LeVine B. B. (2007). Nyansongo: A Gusii community in Kenya. In B. B. Whiting (Ed.), Six cultures: Studies of child rearing (pp. 14–202). New York: John Wiley.
[23]  Maximo, S., Sabrina Nastassja & G. Loy (2014). Bullying Among High School Students as Influenced by Parent-Child Attachment and Parenting Styles. Philippine Journal of Psychology, 2014, 47(2), 125-152.
[24]  Mercer, J (2006). Understanding Attachment: Parenting, child care, and emotional development. Westport, CT: Praeger Publishers.
[25]  Olukayode, A. A. (2014). Psycho-Social Predictors of Pro-Social Behavior among a Sample of Nigerian Undergraduates. European Scientific Journal vol.10, No.2 ISSN: 1857 – 7881.
[26]  Ooi, Y., Ang, R. P., Fung, D. S., Wong, G., & Cai, Y. (2015). The impact of parent-child attachment on aggression, social stress and self-esteem. School Psychology International, 27(5), 552-566.
[27]  Ostrov, J. M. (2010). Deception and subtypes of aggression during early childhood Journal of Experimental Child Psychology, 93, 322-336.
[28]  Ostrov, J. M., Woods, K. E., Jansen, E. A., Casas, J. F., & Crick, N. R. (2004). An observational study of delivered and received aggression, gender, and social- psychological adjustment in preschool: “This White Crayon Doesn’t Work . . .” Early Childhood Research Quarterly, 19, 355-371. doi: 10.1016/j.ecresq.2004.04.009.
[29]  Parens, H. (2012). Attachment, aggression, and the prevention of malignant prejudice. Psychoanalytic Inquiry, 32, 171-185.
[30]  Rozita, A. (2016). Mother-infant Attachment Styles as a Predictor of Aggression. Journal of Midwifery and Reproductive Health. 2016; 4(1): 506-512.
[31]  Schacter, D.L. (2009). Psychology, Second Edition. New York: Worth Publishers.
[32]  Tomlison M, Cooper, C.J & Murray, K. Child Development 2005 sep-oct.
[33]  Waters, E. (2005). Defining and assessing individual differences in attachment relationships: Q-methodology and the organization of behavior in infancy and early childhood. Monographs of the Society for Research in Child Development, 50(1-2), 41-65.
[34]  Williams, K., & Kennedy, J. (2012). Bullying behaviors and attachment styles. North American Journal of Psychology, 14(2), 321-338.