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The civil-law applications of forensic-psychological capacity assessment: testamentary capacity under Banks v. Goodfellow 1870 (understand nature of act, extent of estate, claims of those who might benefit, absence of insane delusion) and its modern UK reaffirmation in Sharp v. Adam 2006; marriage capacity under Sec 12 Hindu Marriage Act 1955 + the *Asha Qureshi v. Afaq Qureshi* 2002 frame; contract capacity (the Indian Contract Act 1872 § 11-12); the dedicated capacity-assessment instruments (MacCAT-T for treatment-decision capacity, MacCAT-CR for research consent, ACE Assessment of Capacity to Consent to Treatment); the modern UK Mental Capacity Act 2005 five-step process.
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Most forensic psychologists encounter capacity in the criminal context first: fitness to plead, competence to stand trial, criminal responsibility. But the largest volume of capacity work by practising forensic psychologists worldwide sits in the civil sphere, where questions about an individual's ability to make legally valid decisions arise at some of the most consequential moments of a person's life: writing a will, entering a marriage, signing a contract, consenting to medical treatment, managing property, or appointing someone to make decisions on their behalf.
Civil capacity cases share a structural feature that makes them distinctive from criminal ones: they are almost always decided retrospectively, after the act in question has already been performed. The will has already been signed, the marriage has already been solemnised, the contract has already been executed. The forensic psychologist is not assessing a person's present capacity to perform a future act; they are reconstructing whether a specific individual had the requisite mental functioning at a specific past moment to make a particular kind of decision.
The legal standards for civil capacity differ between jurisdictions, and they differ between types of decision within a single jurisdiction. Testamentary capacity (making a will) has its own doctrinal test in English and Indian law dating back to the Victorian era. Marriage capacity is governed by different statutory and case-law standards. Contract capacity has its own framework. The Mental Capacity Act 2005 in England and Wales introduced a unified, functional approach that applies across most civil decisions and has influenced capacity law in other common-law jurisdictions. India has no equivalent comprehensive statute; capacity for civil acts is instead distributed across several different pieces of substantive law.
This topic covers these frameworks, the forensic-psychology assessment methodology for each, and the instruments available for structured capacity evaluation. It should be read alongside the Forensic Medicine M9 topic on forensic psychiatry, which covers the clinical-treatment and sectioning dimensions of mental incapacity; this topic owns the civil-law and capacity-assessment layers.
*A four-part test articulated by Sir Alexander Cockburn in 1870 has survived 150 years of medical advances and countless will challenges; its durability tells us something about what legal capacity is actually measuring.*
The dominant legal standard for testamentary capacity in the common-law world was set out in Banks v. Goodfellow (1870, LR 5 QB 549) by Sir Alexander Cockburn CJ. John Banks suffered from paranoid delusions involving a deceased man named Featherstone Alexander and was intermittently troubled by the belief that devils followed him. He nonetheless executed a valid will leaving his estate to his niece. The court upheld the will, articulating the four elements required for testamentary capacity.
The Banks v. Goodfellow test. A testator must: (1) understand the nature of making a will and its effects; (2) understand the extent of the property being disposed of; (3) understand the claims of those who might reasonably expect to benefit from the estate (natural objects of the testator's bounty); and (4) not be suffering from any disorder of the mind that poisons the testator's affections, perverts their sense of right, or prevents the exercise of their natural faculties in disposing of their property. The fourth element is sometimes called the "insane delusion" prong: a delusion that affects the testamentary act invalidates the will, even if the testator satisfies the other three prongs. Banks satisfied prongs one through three; his delusions, though real, did not affect his disposal of property.
Reaffirmation in Sharp v. Adam (2006, EWCA Civ 449). The Court of Appeal in Sharp v. Adam reaffirmed the Banks test as the governing standard in England and Wales and clarified that the question of capacity is a matter of law for the court to decide on the evidence as a whole, not a question for the medical or psychological expert. The expert's role is to provide evidence about the deceased's mental functioning at the relevant time; the court determines whether that functioning meets the legal test. This distinction between the expert's role (factual opinion on mental state) and the court's role (legal determination of capacity) is essential for the forensic psychologist drafting a testamentary capacity report: the report should address the four Banks criteria in terms of mental functioning, not conclude that the person "did" or "did not" have testamentary capacity, which is the court's determination.
Retrospective assessment challenges. In most testamentary capacity disputes, the testator is dead. The assessment is therefore entirely retrospective, based on medical records, psychiatric notes, GP records, hospital correspondence, witness accounts from those who observed the testator around the time of the will, and the will itself and its surrounding solicitor notes. The "golden rule" in English trust and probate practice, articulated in Kenward v. Adams (1975), requires the solicitor taking instructions for a will from an elderly or seriously ill testator to arrange for a medical assessment of capacity at the time of execution, and to retain a contemporaneous record. Where this was done, the forensic psychologist has direct contemporaneous evidence to work with; where it was not done (which is the majority of cases), the retrospective reconstruction depends on the quality of the available records.
India: Indian Succession Act 1925 and Hindu Undivided Families. In India, testamentary capacity for persons governed by the Indian Succession Act 1925 (principally non-Hindus and Hindus who have opted out of Hindu personal law for succession purposes) is assessed against criteria substantially similar to the Banks test. The Indian courts have adopted the Banks framework in numerous decisions. For Hindus dying intestate, succession is governed by the Hindu Succession Act 1956, which does not require testamentary capacity to be proven for intestate distributions. For testamentary dispositions by Hindus, the Indian Succession Act § 59 requires sound mind as a precondition for a valid will, with "sound mind" being applied with reference to the Banks criteria in case law. The Bombay and Madras High Courts have each produced substantial case law on this, drawing on the Banks framework while adapting it to Indian probate practice.
Australian and Canadian dimensions. Australian courts apply the Banks test directly, as it remains the common-law standard in all state and territory jurisdictions. The Victorian Court of Appeal in Re Estate of Mann (2019) reaffirmed the Banks test and provided guidance on the degree of cognitive impairment that is consistent with testamentary capacity. In Canada, all provinces except Quebec (which applies civil-law capacity concepts) apply the Banks framework through a combination of statutory succession law and common-law capacity doctrine.
*The law asks whether a person understood what they were agreeing to; the forensic psychologist must translate 'understanding' into measurable cognitive and emotional functioning.*
Marriage capacity is assessed using different legal standards and instruments from testamentary capacity, reflecting the different nature of the decision. Marriage is a status, not a transaction; it creates ongoing mutual obligations and rights that a one-time transactional test inadequately captures.
India: Hindu Marriage Act 1955 § 12. Under the Hindu Marriage Act 1955, a marriage is voidable (not void) under § 12(1)(b) if the consent of the petitioner was obtained by force or fraud or was not free consent because the petitioner was of unsound mind at the time of the marriage. Section 12(1)(c) extends this to marriages where, though neither party was of unsound mind, one party was mentally deficient or was subject to recurrent attacks of insanity. The distinction between void and voidable is significant: a voidable marriage remains valid until a court annuls it on petition, while a void marriage is a nullity from the outset.
The case of Asha Qureshi v. Afaq Qureshi (2002, Allahabad High Court) addressed marriage capacity under the Muslim Personal Law (Shariat) Application Act 1937, applying analogous principles: the court examined whether the petitioner had the mental capacity to understand the nature and consequences of the nikah at the time it was performed. Indian courts across religious personal laws have applied a functional understanding test analogous to (though not always cited directly from) the Banks framework.
England and Wales: The Mental Capacity Act 2005 and Re DMM. Before the MCA 2005, English marriage capacity was assessed under the common-law test articulated in cases including Re Bennett (1987) and In re K (1988): the person must be capable of understanding the nature of the act of marriage and the duties and responsibilities that normally attach to it. The MCA 2005 § 2 establishes that a person lacks capacity if, at the material time, they are unable to make a decision for themselves in relation to a matter because of an impairment of, or a disturbance in the functioning of, the mind or brain. The functional test under the MCA requires assessment of whether the person can understand, retain, use or weigh, and communicate information relevant to the specific decision.
The case of Re DMM (2017, EWCOP) is a significant Court of Protection decision on marriage capacity under the MCA framework: the court held that the relevant information for the marriage decision includes understanding that marriage is a contract that creates legal obligations, the ability to understand the consequences of marriage (including property implications, the legal status of children born in marriage, and the implications for existing relationships), and the capacity to communicate a decision. The Court of Protection's evolving case law on marriage capacity is particularly relevant in cases involving adults with learning disabilities, dementia, or traumatic brain injury.
The forced-marriage dimension. In the UK, the Forced Marriage (Civil Protection) Act 2007 and the Anti-Social Behaviour, Crime and Policing Act 2014 (which criminalised forced marriage in England and Wales) created a framework for protecting people lacking capacity from being married without their valid consent. The forensic psychologist assessing capacity in a suspected forced-marriage context must address both the general question of capacity and the specific question of whether the person's apparent consent was genuinely free and informed or was the product of coercion or incapacity.
*The Indian law disqualifies persons of unsound mind from valid contract formation; the threshold for 'unsound mind' in the contract context is calibrated differently from the threshold in the criminal context.*
The capacity to enter a binding contract is the most economically significant aspect of civil capacity, and the law has developed its standards with commercial as well as welfare considerations in mind.
Indian Contract Act 1872 §§ 11-12. Section 11 of the Indian Contract Act 1872 specifies that every person is competent to contract who is of the age of majority, is of sound mind for the purposes of contracting, and is not disqualified from contracting by any law to which they are subject. Section 12 defines "sound mind for the purposes of making a contract": a person is said to be of sound mind for the purpose of making a contract if, at the time of making it, they are capable of understanding it and of forming a rational judgement as to its effect upon their interests. The crucial provision is the further sentence: "A person who is usually of unsound mind, but occasionally of sound mind, may make a contract when they are of sound mind."
This "lucid intervals" doctrine means that a person with a cyclical or episodic mental disorder (bipolar disorder during a euthymic phase, schizophrenia in remission) may validly enter a contract during a period of adequate mental functioning, even if they would lack capacity at other times. The forensic psychologist assessing contract capacity in India must therefore assess the temporal question: was the person in a lucid interval at the time of the contract? This requires examination of contemporaneous clinical records, medication compliance records, and the observations of witnesses who interacted with the person around the time of the transaction.
English and Australian law. In England and Wales, the contract capacity position is governed by a combination of common law and the MCA 2005. At common law, a contract made by a person of unsound mind is voidable at their option if the other party knew of the incapacity (Imperial Loan Co. v. Stone [1892]). The MCA 2005 does not directly address contract capacity but its functional test (inability to understand, retain, use or weigh, or communicate information relevant to the decision) has been applied by courts to commercial transaction capacity. Australian state contract law follows the English common-law position: contracts with those of unsound mind are voidable, not void, and the requirement of the other party's knowledge of the incapacity remains.
Undue influence and capacity in practice. In probate, contract, and gift challenges, the question of capacity is frequently intertwined with a claim of undue influence. A person may have borderline capacity to understand a transaction while being simultaneously vulnerable to pressure from a carer, family member, or advisor. The forensic psychologist must be alert to the distinction between a capacity opinion (did this person meet the legal threshold for understanding?) and an undue-influence analysis (was this person's will so overborne by another's that their consent was not truly their own?). The two are separate legal concepts but often overlap clinically in cases involving elderly or cognitively impaired individuals.
*The MCA 2005 does not presume incapacity; it presumes capacity and places the burden on whoever asserts otherwise; a principle that has required systematic adjustment in how capacity is assessed and documented.*
The Mental Capacity Act 2005 in England and Wales came into force in October 2007 and fundamentally reordered the law of civil capacity in that jurisdiction. Its core principles have influenced capacity law in several other jurisdictions and its functional approach has become the de facto international standard for capacity assessment methodology.
The five key principles. Section 1 of the MCA 2005 sets out five statutory principles: (1) a person must be assumed to have capacity unless it is established otherwise; (2) a person is not to be treated as unable to make a decision unless all practicable steps to help them do so have been taken without success; (3) a person is not to be treated as unable to make a decision merely because the decision appears unwise; (4) acts done or decisions made for or on behalf of a person who lacks capacity must be done or made in their best interests; and (5) such acts and decisions must be the least restrictive of the person's rights and freedom of action.
Principles 1 and 3 are the most significant for forensic psychology practice. Principle 1 reverses what had been the practical assumption in many medical and legal settings that cognitively impaired individuals lacked capacity unless demonstrated otherwise; the burden now lies on the person asserting incapacity to establish it. Principle 3 prevents a "welfare override": a decision to sell a house to fund gambling, or to marry someone of whom family disapproves, cannot be treated as evidence of incapacity simply because others consider it unwise. The person's right to make bad decisions is protected as part of personal autonomy.
The functional test. Sections 2 and 3 of the MCA set out the test. A person lacks capacity if they are unable to make a decision for themselves because of an impairment or disturbance in the functioning of their mind or brain (the diagnostic threshold). They are unable to make a decision if they cannot (a) understand information relevant to the decision, (b) retain that information, (c) use or weigh that information as part of the decision-making process, or (d) communicate their decision. Each of these is assessed in relation to the specific decision to be made, not globally. A person may have capacity for some decisions but not others.
Scotland, Canada, and the wider influence. Scotland's Adults with Incapacity (Scotland) Act 2000 preceded the MCA and introduced a similar functional approach, with a "principles" section requiring that interventions must benefit the person, be the least restrictive available, and take account of the person's wishes. Canada has a patchwork of provincial legislation: Ontario's Substitute Decisions Act 1992, British Columbia's Adult Guardianship Act 1996, and Alberta's Personal Directives Act 1996 all adopt functional capacity tests, though the specific formulations vary. The MCA 2005's influence is visible in capacity legislation adopted in Ireland (Assisted Decision-Making Capacity Act 2015, commenced 2023) and in reforms proposed in Australia under the ALRC's 2014 report on equality, capacity, and disability.
*Structured instruments do not determine capacity. Courts and tribunals determine capacity. But they provide a documented, reproducible basis for the expert opinion that courts rely on.*
Several structured instruments have been developed for capacity assessment across specific domains. The MacArthur group produced the most widely validated series, and their instruments are used in North American, European, and, increasingly, Asian forensic and clinical settings.
MacCAT-T (MacArthur Competence Assessment Tool-Treatment). The MacCAT-T assesses capacity to consent to medical treatment. It addresses the person's ability to understand disclosed information about their condition and proposed treatment, appreciate the significance of that information for their own situation, reason about treatment options, and express a consistent choice. It takes approximately 15-20 minutes to administer and produces four scale scores. Its validation sample was North American, and normative data for Indian and East Asian populations are not available, which limits its direct application in Indian legal proceedings.
MacCAT-CR (MacArthur Competence Assessment Tool-Clinical Research). The MacCAT-CR parallels the MacCAT-T but addresses capacity to consent to research participation. Given the increasing inclusion of psychiatric populations in clinical trials, particularly in India through CTRI-registered trials, this instrument is relevant to the ethics of research consent in forensic and clinical-psychiatric populations.
ACE (Assessment of Capacity for Everyday Decision-Making). The ACE is designed for assessment of capacity for financial and other everyday decisions, making it more directly relevant to testamentary and contract capacity assessment than the MacCAT series. It uses a semi-structured interview format with decisions from the specific domains relevant to the individual being assessed.
The Testamentary Capacity Assessment (TCA). The TCA, developed by Shulman, Hull, and Cohen, is a structured interview specifically designed for retrospective and prospective assessment of testamentary capacity against the Banks criteria. It operationalises each of the four Banks elements into assessable interview domains. Its psychometric properties have been evaluated in elderly populations with dementia, and it has been cited in UK probate proceedings.
Cognistat and the MoCA in retrospective assessment. For retrospective assessments, the forensic psychologist works from records rather than direct examination. Cognitive test scores from contemporaneous medical records (the Montreal Cognitive Assessment, the Mini-Mental State Examination, the Addenbrooke's Cognitive Examination) provide objective evidence about cognitive functioning at the material time. The forensic psychologist's task is to translate these scores and clinical observations into an opinion about capacity as defined by the applicable legal standard, not to provide a clinical diagnosis of dementia or capacity in isolation from the legal framework.
*The civil capacity report is a translation document: it converts clinical observations about mental functioning into an opinion about a legal criterion the clinician did not invent.*
The forensic psychologist drafting a civil capacity report for use in legal proceedings must observe a different discipline from the one that applies to a criminal-responsibility or risk-assessment report. The structural differences are practical and important.
Define the legal standard first. The report must specify, at the outset, which legal standard applies to the question being assessed. Testamentary capacity in England is Banks v. Goodfellow; testamentary capacity in India is Indian Succession Act § 59 as applied by case law; marriage capacity in India is Hindu Marriage Act § 12 as applied by the relevant court. The forensic psychologist who writes a capacity report without naming the legal standard leaves the reader unable to evaluate whether the assessment addressed the right criteria.
Address each criterion separately. Each criterion in the applicable legal standard should be addressed by a separate section of the report. For the Banks test, this means separate analysis of whether the person understood the nature of making a will, the extent of their property, the claims of those who might benefit, and whether any mental disorder poisoned their affections or perverted their judgement. For the MCA 2005, this means separate analysis of whether the person could understand, retain, use or weigh, and communicate information relevant to the decision.
Distinguish present from retrospective capacity. In most civil capacity cases, the expert is conducting a retrospective assessment. The report must state clearly whether it is addressing past capacity (the state of the person at the time of the act in question) or present capacity. Where the assessment is retrospective, the basis must be identified: what records were reviewed, what contemporaneous observations are available, and what is the estimated reliability of the retrospective reconstruction.
Avoid the ultimate issue. In English and Australian proceedings, the expert should state a clinical opinion on mental functioning against each element of the legal test but avoid the ultimate-issue statement ("this person did/did not have testamentary capacity"). In Indian proceedings, BSA 2023 § 39 requires the expert to state the basis of the opinion and any limitations; the conclusory language should be calibrated to what the evidence actually supports. In US proceedings, the Daubert obligation requires the expert to state the methodology, the known error rate, and the degree of confidence.
Acknowledge uncertainty. Retrospective capacity assessment is inherently uncertain. Medical records are incomplete; witnesses have motivations; cognitive test scores do not map precisely to legal criteria. The report must acknowledge these sources of uncertainty explicitly, not minimize them to produce a more decisive-sounding conclusion. A report that overstates certainty will be demolished on cross-examination; a report that honestly quantifies uncertainty and explains the reasoning will be more likely to survive scrutiny.
John was 78 years old when he made a will leaving his estate to a carer rather than to his adult children. He had been diagnosed with mild cognitive impairment six months earlier. The adult children challenge the will on the basis of lack of testamentary capacity. Under the Banks v. Goodfellow standard, which element is most directly engaged by evidence that he held a paranoid belief that his children were poisoning him and that this belief was the reason he excluded them?
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