WRITTEN BY: Sally Phillips, Ph.D. Candidate at School of Law, Birmingham City University, United Kingdom.
Sally Phillips is a second-year Ph.D. student with the law school at Birmingham City University, UK. Her research focus is on the intersection of science and law, particularly in cases concerning Shaken Baby Syndrome/Abusive Head Trauma. Coming from a background in Criminology and Forensic Studies with a firm foundation in the natural sciences, she has a great interest in the use of science in criminal prosecutions and the judicial response to this complex juncture of disciplines.
The ‘traditional hypothesis’ of “Shaken Baby Syndrome” (SBS) surmises that if a child were to present with a brain bleed and bleeding behind the eyes, but was absent a history of accidental trauma, then that child had likely been violently shaken. Despite extensive scientific research, this hypothesis remains subject to significant criticism which suggests the underpinning science is uncertain and that some SBS diagnoses may be inaccurate. This debate has generated tensions amongst medical professionals and in criminal proceedings involving medical evidence of the diagnosis. In the UK, in 2016, neuropathologist Dr. Waney Squier had her medical licence revoked (and subsequently reinstated on appeal, with a 3-year ban on testifying), for her part as a defense expert in SBS cases. Additionally, convictions have been overturned and charges dropped in prosecutions in both the US and England and Wales, due to perceived uncertainty in SBS. Despite similarities in criminal justice processes in these two jurisdictions, their response to this alleged uncertainty has differed. To put these responses into context, a closer look at the science is warranted.
A review of relevant scientific literature highlights five areas of significant debate. These areas are reflected in US and English case law, as key points of contention between defense and prosecution. First, is the important question of what level of force is sufficient to produce the SBS-associated injuries. Although, some argue that an individual cannot shake a baby hard enough to harm it, most accept that shaking is a dangerous practice. Experiments using animals, dummies and computational models continue to better simulate a live infant, but so far no certain answer can be given about exact levels of force needed to cause SBS (Nadarasa et al., 2014).
Second, the possibility of a period where the child appears ‘fine’ after shaking, has been discussed. The defendant in SBS cases will almost always be the individual with the child when they became symptomatic (known as collapse), so the possibility of this ‘lucid interval’ raises the question of potential alternative perpetrators who have cared for the child in the days or hours leading up to collapse. However, the evidence suggests lengthy, non-symptomatic, lucid intervals are extremely rare (Arbogast et al, 2005).
Third are theories that suggest an innocent explanation for just one SBS symptom, of which there are many. Although a child is unlikely to have three innocent explanations for the three individual symptoms, this is a possibility which needs to be ruled out in each case. Many natural diseases and accidental injuries have potential to cause injuries that appear to mimic those seen in SBS. However, these are often testable and distinguishable if investigated thoroughly (Jenny, 2014).
The fourth category of uncertainty is closely related to the third – the possibility that a single innocent explanation triggered all three symptoms. Events such as severe coughing, seizures or forceful vomiting have been considered in the literature. Aside from a few case reports, these theories are presently unsubstantiated. It is for this reason that the fifth category of debate is key. This is whether diagnostic procedures are adhered to closely enough to effectively apply current scientific knowledge clinically, preventing misdiagnoses. The standardisation and efficacy of proper diagnostics cannot be underestimated when cases of potential SBS are brought to physicians.
This evolving and uncertain science does not fit harmoniously with the rigid, process-driven attitude of criminal justice. More technologically-aware juries expect scientific evidence in criminal trials, and lawyers perceive a need for increasingly captivating and certain science in order to obtain convictions. These expectations and perceptions may stem from knowledge of examples where science, such as DNA technology, has been invaluable in prosecutions. However, often science and law are not congruent. This has been attributed to differing approaches of law and science to finding ‘truth’ (Jasanoff, 2005). While science builds corroboratively to generate evidence that can be generalized and expanded upon, law is concerned with conclusive end-points in the narrow context of a particular case. In science, an inconclusive result is unsatisfactory, but does not carry the same consequences as in criminal proceedings, where a conviction must be conclusive “beyond reasonable doubt.”
The practical consequences of this tension, is that when experts testify in criminal cases, their language and reasoning may not be translating accurately to judges, lawyers and juries. For example, the phrase, “reasonable degree of medical certainty” is a common one in expert medical testimony, but is not used in normal clinical practice. There is evidence to suggest that experts understand and use this phrase to describe a different level of certainty, with some believing it to be close to 100%, while others see it as 50% or more (Gena, 2007). Faulty translations like this, can be misleading for a jury and only exacerbate the areas of uncertainty in SBS.
The Case Law
In the US, the judiciary has employed avoidance techniques in response to much scientific debate. A strict adherence to finality interests and legal process often trumps any substantive examination of contentious scientific evidence. Trial judges are charged with assessing reliability of expert testimony under Daubert v. Merrell Dow Pharm., 509 U.S. 579 (1993). Daubert’s criteria was carefully considered by the Law Commission in England and Wales (Law Commission, 2011). However, as the Law Commission noted, there is still significant confusion and inconsistency if and/or when Daubert is applied. Daubert urges courts to take a more active role in dealing with science, but there is clear discomfort when it comes to applying the guidelines in a way which involves a thorough examination of scientific concepts.
Review of the US appellate opinions reveals increased awareness of scientific issues in SBS cases. However, when it comes to a critical examination, judges will focus on legal frameworks, but pay little attention to the application of them to SBS. A range of arguments are used to dis-apply reliability frameworks, such as Daubert, leaving SBS testimony to enter court un-examined. Judgement of reliability is often left to the jury, as judges will conclude that flaws in expert testimony go to the weight, not admissibility of the evidence. Appeals will often focus on procedural claims, allowing the judiciary to bypass critical scientific examination in favour of procedural analysis. Cases which confront the science head-on are few and far between, and often overruled.
In England and Wales, courts have made more concerted attempts to address the problem. Extensive opinions, such as R v Harris and Others  EWCA Crim 1980 and R v Henderson and Others  EWCA Crim 1269, probe deeper into SBS and this has resulted in specific CPS guidelines being issued for cases of Non-Accidental Head Injury (a broader term for SBS). These guidelines caution against the bringing of prosecutions solely based upon SBS injuries, and advise that other supporting evidence such as broken bones, bruises or confessions be present before a case is prosecuted. There is also guidance in place by way of the Criminal Procedure Rules and Practice Directions, which list factors that may render expert testimony reliable.
The courts should not be expected to ultimately resolve the current scientific debate in SBS; however, they cannot ignore the issue altogether. Stakeholders across the scientific and legal communities must develop and apply guidelines that keep unreliable science from entering the courtroom. A failure to do so will continue to result in wrongful convictions.
References and Further Reading:
- Arbogast, K., Margulies, S. & Christian, C., Initial Neurologic Presentation in Young Children Sustaining Inflicted and Unintentional Fatal Head Injuries, 116 Pediatrics 180 (2005).
- Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993).
- Gena, M., Shaken Baby Syndrome: Medical Uncertainty Casts Doubt on Convictions, 2007 Wisconsin Law Review 701.
- Jasanoff, S., Law’s Knowledge: Science for Justice in Legal Settings, 95 American Journal of Public Health s49 (2005).
- Jenny, C., Alternate Theories of Causation in Abusive Head Trauma: What the Science Tells Us, 44 Pediatric Radiology 543 (2014).
- Law Commission, Expert Evidence in Criminal Proceedings in England and Wales (Law Com. No. 325) (2011).
- Nadarasa, J., Deck, C., Meyer, F., Willinger, R. & Raul, J., Update on Injury Mechanisms in Abusive Head Trauma – Shaken Baby Syndrome, 44 Pediatric Radiology 565 (2014).
- R v Harris and Others,  EWCA Crim 1980.
- R v Henderson and Others  EWCA Crim 1269.