68.25 There is clear evidence that children differ from adults in their capacity to make decisions. It is not clear, however, at what age an individual should be regarded as having the capacity to make a decision regarding his or her personal information. The following provides an overview of the research on the issue.
Ages of development
68.26 There is a general consensus in the literature on child development that the capacity of children to make voluntary and rational decisions increases with both age and the development of cognitive skills. Decision making is a skill that develops over time together with the development of certain cognitive skills, including the capacity for logical thought, the ability to understand cause and effect, and the analysis of consequences of decisions. Jean Piaget, a leading child psychologist, identified four stages of cognitive development through which all children pass and the typical ages at which this development occurs. It is during the fourth stage—the ‘formal operations’ period—that a child demonstrates adult-like thinking abilities such as a comprehension of abstract logic, a capacity to reason, the use of deductive and inductive reasoning, making of intelligent choices, and the ability to hypothesise.
68.27 Piaget’s typology, including the allocation of typical ages at which certain developments occur, resonates with research about the decision-making capacities of children. In her examination of the capacity of minors to provide voluntary consent to medical treatment, Dr Tara Kuther noted:
During the adolescent years, minors become better able to consider information and opinions from diverse sources, and capable of owning their judgements. Between the ages of 15 and 17, most adolescents become capable of providing voluntary consent that is not unduly influenced by others.
68.28 Kuther also discusses the way in which children exercise more independence in making decisions as they become older. In particular she notes:
Young children tend to view authority figures such as physicians and parents as legitimate and powerful, and are likely to comply with their requests because of differences in perceived social power. With increasing age, authority figures tend to be viewed as cooperative and orientated toward promoting social welfare; adolescents are more likely to question demands that seem unreasonable and are less susceptible to coercive influence.
68.29 Many commentators argue that young people that have reached a certain age have the same capacity as adults to make decisions. The area that has received the most attention is the capacity of an individual to consent to medical treatment. In a study comparing the competency of individuals aged 9, 14, 18 and 21 to make informed decisions about medical treatment, Dr Lois Weithorn and Dr Susan Campbell found that, in general, 14 year olds demonstrated the same level of competence as those aged 18 years and over. The researchers used four standards of competency to test the making of hypothetical medical decisions: evidence of choice; reasonable outcome; rational reasons; and understanding. Weithorn and Campbell noted that while nine year olds were less competent to make a rational decision, even they were able to comprehend the basics of what is required of them when they are asked to state a preference for treatment.
68.30 Based on her research, Kuther suggests that young people aged 15 can make decisions concerning medical treatment; Sarah Ramsey suggests the age is somewhere between 14 and 16 years of age.
68.31 Although the evidence suggests that decision-making abilities are linked to age, the evidence also suggests that it is not possible to identify an age above which all children are competent to make decisions and below which all children are not competent.
Brain development and psychosocial factors
68.32 In addition to the more traditional child development research, there is a growing body of research into the brain development of adolescents and the relationship between brain development and the capacity of adolescents to make decisions. This research does not necessarily contradict the earlier research on the stages of child development, but adds an additional element to the understanding of the process and outcomes of decision making by adolescents.
68.33 The frontal lobe of the brain is responsible for functions such as organising thoughts, setting priorities, planning and making judgments. Scientists have discovered that the frontal lobe undergoes significant change during adolescence, in which it produces a significant amount of ‘grey matter’ (the brain tissue responsible for thinking) and then undergoes a period in which it rapidly thins or ‘prunes’ the grey matter and develops ‘white matter’ (the brain tissue responsible for making the brain operate precisely and efficiently). The research suggests that the frontal lobe, and therefore an individual’s decision-making capacity, has not reached full maturity until some time in a person’s early twenties.
68.34 Other research looking at how different parts of the brain interrelate has led researchers to conclude that adolescents rely more heavily than adults on the parts of the brain that react to emotion than on the (more logical) frontal lobe, possibly because the frontal lobe is still maturing. As a result, it has been suggested that adolescents allow their emotional responses to situations to determine their course of action and do not fully evaluate the consequences of a particular course of action before commencing it. One study has shown that age differences in decision making and judgment become most apparent when the decisions of adolescents in emotionally charged or highly social situations are compared with the decisions of adults in similar situations. For example, it has been found that adolescents take more risks when in the presence of their peers than do adults.
68.35 While some have cautioned against jumping to conclusions about adolescent decision-making capacity based on the latest brain research, the findings and suggestions are consistent with a review of the studies by Elizabeth Cauffman and Professor Laurence Steinberg on the susceptibility of adolescents to influence. Cauffman and Steinberg identify three themes that emerge from research on age difference in decision-making priorities:
in comparison to adults, adolescents view long-term consequences as less important than short-term consequences;
‘sensation seeking’ is a higher priority for adolescents than it is for adults; and
social status among peers is an important factor for many adolescents.
68.36 Cauffman and Steinberg argue that the big difference between decision making by individuals under the age of 18 and adults is that psychosocial factors can influence the use of cognitive skills by young people during the decision-making process. Three components make up these psychosocial factors:
responsibility, including health autonomy, clarity of identity and self-reliance;
perspective, which is the ‘ability to acknowledge the complexity of a situation and see it as part of a broader context’; and
temperance, which is the ‘ability to limit impulsive and emotional decision making, to evaluate situations thoroughly before acting … and to avoid decision-making extremes’.
68.37 This is not to suggest that adolescents are unable to make decisions on their own. The results of the research are consistent, however, with the approach that stresses that an individual’s capacity to make a decision cannot be determined by age alone. It also depends on: the maturity of the individual; his or her social development, including his or her relational style with authority and cultural and religious background; and his or her sense of self. Importantly, an individual’s capacity to make a decision also depends on the particular decision that needs to be made, its complexity and the gravity of the consequences. This makes an adolescent’s maturity of judgment for making a decision highly situation-specific. In the context of making medical decisions, Assistant Professor Leanne Bunney has noted:
merely because a child may not have the capacity to make decisions in one area does not necessarily imply that he or she would be unable to make decisions in relation to other treatment.
Evolving capacity and the need for individual assessment
68.38 The research suggests, therefore, that the capacity of a child or young person to make a decision is evolving and dependent on a number of considerations relevant to the individual and the particular decision. As discussed above, this understanding of capacity is reflected in art 5 of CROC.
68.39 An individual approach to assessing the capacity of a child or young person has been adopted in case law. The House of Lords decision in Gillick v West Norfolk and Wisbech AHA (Gillick), and the High Court of Australia decision in Department of Health and Community Services (NT) v JWB (‘Re Marion’), reflect the concept of evolving capacities and the need for individual assessment. In Re Marion, Deane J stated that:
the legal capacity of a young person to make decisions for herself or himself is not susceptible of precise abstract definition. Pending the attainment of full adulthood, legal capacity varies according to the gravity of the particular matter and the maturity and understanding of the particular young person.
68.40 The words of Deane J, and the individual approach to assessing capacity of a minor, were adopted by the Full Court of the Family Court of Australia in B and B v Minister for Immigration and Multicultural and Indigenous Affairs, which considered the capacity of a minor voluntarily to terminate migration detention. Unlike the Gillick approach, however, which requires a positive inquiry as to the capacity of a minor to make a particular decision, it has been argued that the Court’s approach in B and B suggests that capacity is presupposed in some matters, although may be found to be lacking due to certain factors. The Courtlisted a number of factors, which, in its opinion, may affect the competence of a child. These include ‘isolation, English language skills, schooling, access to resources and administrative barriers’. Age was considered to be just one factor to take into consideration. This approach has not as yet been followed in other cases.
Assisting children and young people to make decisions
68.41 In addition to developing decision-making abilities with age, children also develop the capacity to make decisions by being involved in decision-making processes. Dr Mary Ann McCabe argues that ‘children’s preferences and capacity for involvement in medical decision making will be heavily influenced by their prior experience with taking responsibility in decisions’. McCabe suggests that such experience includes children making different types of decisions in their everyday lives, such as the time they will go to bed.
68.42 Some researchers argue that children have the ability to comprehend difficult concepts that are important for making decisions when the concepts are presented to them in ways that are ‘developmentally appropriate’. Nigel Thomas and Claire O’Kane argue that, unless the views of children are sought in ways that enable them to use their competence, children may erroneously be considered incompetent.
 See, eg, T Kuther, ‘Medical Decision-Making and Minors: Issues of Consent and Assent’ (2003) 38 Adolescence 343, 349.
 Ibid, 348. A child’s competency, however, may not necessarily increase in direct relation to his or her age: S Ramsey, ‘Representation of the Child in Protection Proceedings: The Determination of Decision-Making Capacity’ (1983–1984) 17 Family Law Quarterly 287, 315.
 D Singer and T Revenson, A Piaget Primer: How A Child Thinks (revised ed, 1996), 20–26. The four stages and typical ages associated with the stages are: the ‘sensory motor’ period (birth to two years of age); ‘pre-operational’ period (two to seven years of age); ‘concrete operations’ period (seven to 11 years of age); and ‘formal operations’ period (11 to 15 years of age).
 S Ramsey, ‘Representation of the Child in Protection Proceedings: The Determination of Decision-Making Capacity’ (1983–1984) 17 Family Law Quarterly 287, 312–313.
 T Kuther, ‘Medical Decision-Making and Minors: Issues of Consent and Assent’ (2003) 38 Adolescence 343, 348, citing C Lewis, ‘Minors’ Competence to Consent to Abortion’ (1987) 42 American Psychologist 84 and T Grisso and L Vierling, ‘Minors’ Consent to Treatment: A Developmental Perspective’ (1978) Professional Psychology 412.
 T Kuther, ‘Medical Decision-Making and Minors: Issues of Consent and Assent’ (2003) 38 Adolescence 343, 347, citing W Damon, ‘Measurement and Social Development’ (1977) 6(4) Counselling Psychologist 13 and R Thompson, ‘Vulnerability in Research: A Developmental Perspective on Research Risk’ (1990) 61 Child Development 1.
 L Weithorn and S Campbell, ‘The Competency of Children and Adolescents to Make Informed Treatment Decisions’ (1982) 53 Child Development 1589.
 The four hypothetical dilemmas were diabetes, epilepsy, depression and enuresis.
 Weithorn and Campbell cautioned, however, that their findings are limited in so far as their subjects were ‘normal, white, healthy individuals of higher intelligence and middle-class background and that the situations they considered were hypothetical’: L Weithorn and S Campbell, ‘The Competency of Children and Adolescents to Make Informed Treatment Decisions’ (1982) 53 Child Development 1589, 1596.
 T Kuther, ‘Medical Decision-Making and Minors: Issues of Consent and Assent’ (2003) 38 Adolescence 343, 350.
 S Ramsey, ‘Representation of the Child in Protection Proceedings: The Determination of Decision-Making Capacity’ (1983–1984) 17 Family Law Quarterly 287, 314.
 C Wallis and K Dell, ‘What Makes Teens Tick’, Time Magazine (online), 10 May 2004, <www.time.com>; J Fagan, ‘Adolescents, Maturity, and the Law’, The American Prospect (online), 14 August 2005, <www.prospect.org>; A Ortiz, Adolescence, Brain Development and Legal Culpability (2004) Juvenile Justice Center—American Bar Association, 2, citing E Sowell et al, ‘In Vivo Evidence for Post-Adolescent Brain Maturation in Frontal and Striatal Regions’ (1999) 2 Nature Neuroscience 10 and E Sowell et al, ‘Mapping continued Brain Growth and Gray Matter Density Reduction in Dorsal Frontal Cortex: Inverse Relationships During Post-Adolescent Brain Maturation’ (2001) 21 Journal of Neuroscience 22.
 A Ortiz, Adolescence, Brain Development and Legal Culpability (2004) Juvenile Justice Center—American Bar Association, 2. See also L Bowman, New Research Shows Stark Differences in Teen Brains (2004) Death Penalty Information Center <www.deathpenaltyinfo.org> at 10 April 2008, 1.
 D Yurgelun-Todd, Inside the Teenage Brain: Interview (2002) Public Broadcasting Services <www.pbs.org/wgbh/pages/frontline/shows/teenbrain/interviews/todd.html> at 10 April 2008.
 A Ortiz, Adolescence, Brain Development and Legal Culpability (2004) Juvenile Justice Center—American Bar Association, 2; J Fagan, ‘Adolescents, Maturity, and the Law’, The American Prospect (online), 14 August 2005, <www.prospect.org>.
 C Wallis and K Dell, ‘What Makes Teens Tick’, Time Magazine (online), 10 May 2004, <www.
 Inside the Teenage Brain: Introduction (2002) Public Broadcasting Service <www.pbs.org/wgbh/
pages/frontline/shows/teenbrain/etc/synopsis.html> at 10 April 2008.
 E Cauffman and L Steinberg, ‘The Cognitive and Affective Influences on Adolescent Decision-Making’ (1995) 68 Temple Law Review 1763, 1772–1773.
 Ibid, 1770.
 Ibid, 1764.
 M McCabe, ‘Involving Children and Adolescents in Medical Decision Making: Developmental and Clinical Consideration’ (1996) 21 Journal of Paediatric Psychology 505.
 L Weiss Roberts, ‘Informed Consent and the Capacity for Voluntarism’ (2002) 159 American Journal of Psychiatry 705.
 R Ludbrook, ‘Children and the Political Process’ (1996) 2 Australian Journal of Human Rights 278, 376; P Tuohy, ‘Children’s Consent to Medical Treatment’ (2001) New Zealand Law Journal 253.
 E Cauffman and L Steinberg, ‘The Cognitive and Affective Influences on Adolescent Decision-Making’ (1995) 68 Temple Law Review 1763, 1775.
 L Bunney, ‘The Capacity of Competent Minors to Consent to and Refuse Medical Treatment’ (1997) 5 Journal of Law and Medicine 52, 56.
 Gillick v West Norfolk and Wisbech AHA  AC 112; Department of Health and Community Services (NT) v JWB (1992) 175 CLR 218.
 Department of Health and Community Services (NT) v JWB (1992) 175 CLR 218, 293.
 B and B v Minister for Immigration and Multicultural and Indigenous Affairs (2003) 199 ALR 604, . The children involved in the case were aged 5, 9, 11, 12 and 14, and were detained with their parents who were appealing the refusal of their claim for refugee status.
 J Morss, ‘But for the Barriers: Significant Extensions to Children’s Capacity’ (2004) 11 Psychiatry, Psychology and Law 319, 319. The High Court of Australia overturned the Full Court of the Family Court’s decision concerning its jurisdiction over the welfare of children detained under the Migration Act 1948 (Cth); however the Full Court of the Family Court’s discussion of capacity was not considered by the High Court: see Minister for Immigration and Multicultural and Indigenous Affairs v B and B (2004) 219 CLR 365.
 B and B v Minister for Immigration and Multicultural and Indigenous Affairs (2003) 199 ALR 604, .
 M McCabe, ‘Involving Children and Adolescents in Medical Decision Making: Developmental and Clinical Consideration’ (1996) 21 Journal of Paediatric Psychology 505 and R Ludbrook, ‘Children and the Political Process’ (1996) 2 Australian Journal of Human Rights 278.
 M McCabe, ‘Involving Children and Adolescents in Medical Decision Making: Developmental and Clinical Consideration’ (1996) 21 Journal of Paediatric Psychology 505, 510.
 Ibid, 510.
 T Kuther, ‘Medical Decision-Making and Minors: Issues of Consent and Assent’ (2003) 38 Adolescence 343, 347; N Thomas and C O’Kane, ‘Discovering What Children Think: Connections Between Research and Practice’ (2000) 30 British Journal of Social Work 819.
 N Thomas and C O’Kane, ‘Discovering What Children Think: Connections Between Research and Practice’ (2000) 30 British Journal of Social Work 819, 831.