Chapter 32 — Exercises

Work these without looking back at the chapter first; then check yourself. Items marked † have full worked solutions in the answers appendix. There are no answers in this file. Mix of recall, applied reasoning, evidence interpretation, "spot the overstatement," ethics, and a cold-case extension.

A. Recall and definitions

  1. Define eyewitness identification in one sentence, and state the single fact about it that the DNA exonerations revealed (i.e., its standing among the causes of wrongful conviction).

  2. Contrast the video-recorder model of memory with the reconstructive model. Which is correct, and why does the wrong one make jurors over-trust a confident witness?

  3. † Distinguish estimator variables from system variables. Give two examples of each, and state which kind the justice system can actually control.

  4. Name the three stages of memory (encoding, storage, retrieval) and state, in one phrase each, the kind of error that enters at each stage.

  5. Define a lineup and distinguish it from a showup. Why is a showup inherently more suggestive?

  6. Define simultaneous and sequential lineup presentation, and state the type of judgment (relative vs. absolute) each tends to invite.

  7. Define double-blind administration of a lineup, and state precisely what channel of contamination it severs.

  8. Define the confidence–accuracy relationship as the chapter actually frames it (not the folk version): under what single condition does confidence carry real information about accuracy?

  9. What is the cross-race effect, and why is it not explained by prejudice? State one reason it is considered one of the more robust findings in the field.

  10. Define weapon focus and explain why it makes armed, violent crimes — the ones society most wants solved — especially hard to identify a perpetrator in.

B. Applied reasoning

  1. † A witness saw a perpetrator for about two seconds, at night, across a parking lot, while a gun was pointed at them, and the perpetrator was of a different race than the witness. List every estimator variable present and explain why no lineup procedure, however perfect, can make this identification reliable.

  2. Explain the post-identification feedback effect: what does an administrator's "good, that's our guy" do to a witness's confidence, and to their later reports of how good a view they had? Why does this make the trial confidence misleading?

  3. A witness is not told that the perpetrator might be absent from the lineup. Explain the "pick the closest" trap this creates and how it can lead to identifying an innocent person who merely resembles the perpetrator.

  4. † Why does a simultaneous lineup invite a relative judgment, and why is that dangerous specifically when the lineup contains an innocent suspect and not the true perpetrator?

  5. Explain why recording the witness's confidence immediately and verbatim at the first identification is essential, and what is lost if the only confidence statement on record is the one given at trial.

  6. A small department has only one detective who knows the case, making a fully blind administrator impractical. Describe one blinded alternative procedure that approximates double-blind administration, and explain why it works.

  7. Explain why "fillers should match the witness's description of the perpetrator" is a more defensible rule than "fillers should resemble the suspect."

  8. Using the three-stage model, explain why a witness's rich, detailed, confident description at trial is not evidence that the original perception was good — and may in fact have been assembled after the event.

C. Evidence interpretation

  1. † Re-read Figure 32.1 ("Two ways to run the same lineup"). List the four suggestive system variables present in Version A, and for each, name the safeguard in Version B that neutralizes it.

  2. Re-read Figure 32.2 ("The same certainty, two very different values"). The witness says "maybe number 4, I only saw him for a second" at the array and "there is absolutely no doubt" at trial. Explain which statement carries evidentiary value and why the increase in certainty is not evidence of anything about the perpetrator.

  3. An identification procedure was undocumented — no record of what the administrator said, what the witness's first words were, or how confident the witness was at first. Explain why this absence is itself an evidentiary problem, and what specifically can no longer be assessed.

  4. A report states that a witness "positively and unequivocally identified the defendant." What three questions from this chapter must you ask before you can assign that statement any weight?

D. Spot the overstatement

  1. † A prosecutor argues: "The witness was certain on the stand — you could see it — so you can be certain too." Identify the specific error in this argument using the confidence–accuracy material, and rewrite the claim honestly.

  2. A detective says: "I've run hundreds of lineups and I have never once led a witness, so blind administration is unnecessary in my cases." Name the specific reason this confidence does not establish that the detective's lineups are unbiased. (Connect to Chapter 31.)

  3. A training manual claims the sequential lineup is "proven superior and should always replace the simultaneous lineup." Explain why this overstates the research, and state the chapter's actual position on the sequential/simultaneous question.

  4. An expert is asked to testify that "this particular witness's identification is wrong." Explain why a responsible eyewitness expert should decline to say that, and what they can legitimately testify to instead.

E. Ethics and reasoning

  1. † The chapter calls a sincerely mistaken witness a "second victim" of the crime. Explain what this means, why treating eyewitness error as a moral failing of the witness misunderstands it, and what that reframing implies about where reform should be directed.

  2. A jurisdiction's admissibility test once listed the witness's certainty as an indicator that a suggestive identification was nonetheless reliable. Explain the circular error this creates (the procedure corrupts both the answer and the test of the answer), and why it is a self-defeating safeguard.

  3. You are designing lineup policy for a police department. List the six best-practice safeguards from §32.4/§32.6 you would mandate, and for each, name the specific failure it prevents.

  4. Why are these reforms still unevenly adopted decades after the research, and despite a 2014 National Academy of Sciences report? Tie your answer to the parallel resistance to blind testing in Chapter 31.

F. Synthesis and validity spectrum

  1. † Explain how eyewitness identification advances at least two of the book's four themes (exclusion over proof; the validity spectrum; cognitive bias; the CSI effect cutting both ways). Name which themes and how.

  2. Place eyewitness identification on the validity spectrum (Chapter 1) relative to (a) single-source DNA and (b) the confident pattern-comparison disciplines. Justify its position by reference to its core claim and whether the confidence behind that claim has a measured basis.

  3. The Cotton/Thompson case ended when DNA excluded Ronald Cotton. Using the evidentiary asymmetry of Chapter 1 (§1.6), explain why a single DNA mismatch could overturn an identification that a jury had found overwhelming, while the identification itself could only ever include — never prove.

G. Cold-case extension

  1. † Cold Case. Using only what the neighbor's "tall stranger's truck" account establishes, write the entry you would add to the Mill Creek evidence log (Appendix I). State (a) the honest status of the lead, (b) at least three estimator variables that degrade it, (c) why "a tall stranger's truck" feels like specific evidence but contains almost none, and (d) why building (or excluding) a theory on it would repeat the Cotton/Thompson error in miniature.

  2. Cold Case extension. Suppose investigators wanted to test whether the neighbor's account could be made more reliable. Explain why, unlike the system variables of a lineup, the conditions of her observation (night, distance, brevity, hindsight) cannot be improved after the fact — and what, at most, a careful re-interview could and could not recover.

  3. Cold Case, integrative. The chapter says we "did not chase" the tall-stranger lead and instead let the physical and digital evidence carry the weight. Name two evidence types from earlier chapters that are collected under controllable, auditable conditions, and explain why the book prefers to build the case on those rather than on a confident but poorly-conditioned eyewitness account.

H. Short writing

  1. In 150–200 words, explain to a juror why a confident, sincere, weeping witness who says "I'll never forget his face" can be completely wrong — and why that is not a claim that the witness is lying.

  2. † In 150–200 words, write the two-sided honest summary of the confidence–accuracy relationship: why the naive view ("confidence proves accuracy") is wrong, why the overcorrection ("confidence means nothing, ever") is also wrong, and what reconciles them.

  3. In 150–200 words, explain how the Cotton/Thompson case illustrates every major section of this chapter at once (reconstruction, estimator variables, system variables, confidence–accuracy, reform), and why the friendship that followed matters to the reform argument.

  4. In one paragraph, explain why double-blind lineup administration and the Chapter 31 reforms (context management, blind analysis) are the same idea, and why "I have good intentions" is not, in either domain, an adequate substitute for the procedure.