Persuasion in the Legal Process

Evidence and Expertise

Evidence
- Gets us beyond subjective claims
- Evidence in common law trials in form of oral testimony
  - Fact finders jusdge not only what witnesses say but how
  - Sophisticated ability to judge plausability of narrative accounts and to infer meaning from speech and demeanour
- Subject to reasoning biases
  - We are poor at detecting deceit
- We long for evidence that is impartial and allows us to arrive at a greater certainty about our inferences
Expert
- Jurors as expert triers of fact
- Contemporary understanding of expertise is that it discriminates the expert from the lay person
- Expertise: a special skill, knowledge or judgement
- Expert: a person who has extensive skill or knowledge in a particular field

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Ubiquitous Expertise
- Expertise we all have (understanding natural langauge and infer meaning) or that many of us have (driving a car or texting)
- Jurors are employed for their ubiquitous expertise though juries may contain jurors with other types of expertise
Contributory Expertise
- Contributes to a specialist field
- Requires specialised training and/or experience in a given area and involves a great deal of specialist knowledge which cannot be simply communicated to the novice
Interactional Expertise
- Expertise in the language of a specialism in the abscence of expertise in its practice
- Journalists, translators but also lawyers may acquire interactional expertise without acquiring contributory expertise

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Issues of Discrimination
- Jurors are expected to have ubiquitous expertise but not contributory expertise
- Experts are allowed to be called in to assist jurors in matters involving contributory expertise outside their experience
- How do you distinguish a doctor from charlatan?
- Can novices, while remaining novices, make justified judgements about the relative credbility of rival experts?

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Constructing Expertise
- Lack of sufficient meta-expertise in both jury and judge to discriminate reliable from unreliable expertise
- Space opens for rhetorical construction of expertise
  - Putative expertise is legitimised
  - Expert status is established
  - Evidence is strategically codified
  - Conclusions are made certain
Legitimising Expertise
- Expert evidence is legitimate if:
  - It conforms to established standards in specialised field
  - It is authorised by the law
Establishing Expert Status
- Gives witness powerful ethos
- Ethos: character of speaker and character includes status
  - Status of expert witness can be used to disguide political manoeuvres
  - Linguistic experts called on to establish whether offending texts incite hatred or show traits of extremism

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Demeanour: appearance, speech style, manner
- Strongly relied on
- Poor indicator of expertise
Experience
- Better indicator than demeanour
- Without experience in technical domain, no specialist expertise
- Experience without institutional accreditation is suspicous
Credentials: occupation, qualifications, awards
- Main concious focus of rhetorical work
- Many experts exaggerate or disguise credentials

Construction of Credentials in OJ trial
- Opening speech promises
- Examination in chief

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Tension between epistemologies of science and law
- Science progresses through tentative findings
- Law demands certain conclusion
Priorities of science and law
- Scientists trained to give objective, unbiased opinion
- Experts are appointed by legal teams to win cases
Certain evidence: fingerprints, DBA, polygraph
- Certainty of fingerprints challenged

Linguistic Fingerprint
- Fingerprint used as rhetorically powerful metaphor to indicate certain evidence eg brain fingerprinting
- Linguistic fingerprint: collection of stylistic markers that leaves a unique authorial impression on a text
- Cusum Analysis
  - Cumulatively counting stylistic features across sentences

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