Crime Details Research Articles

Single versus multiple probe blocks of P300-based concealed information tests for self-referring versus incidentally obtained information

The aim of the present study was to compare two protocols and two information types on detection of concealed knowledge. Four independent groups of subjects were run. Two were tested on probe stimuli of a self-referring (AUTO) nature and two were tested on incidentally acquired details of a mock crime (MOCK). Each pair of groups was run either in a one-probe (1PB) or multiple probe (6PB) block. In the single probe block, which was repeated three times with a different probe on each block, one probe item was randomly repeated multiple times in a Bernoulli series with frequently presented, meaningless or irrelevant items. There was also a rare target item designed to force attention to the stimulus screen. All stimulus types were of the same category within each block. In contrast, in the multiple probe (and category) block, rare probes, rare targets and frequent irrelevant items were repeatedly presented in a Bernoulli series within one block. Major results: There was a difference in task demand as measured by reaction time between the two protocols (the multiple probe protocol was more demanding), and a difference trend in P300 detection sensitivity between protocols for both information types combined in favor of the 1PB ( p < .07). With both protocols combined, there was a trend ( p < .07) favoring detection of familiar versus incidentally learned information. In terms of P300 amplitudes, both protocols showed the usual result that P300 to probes was greater than that to irrelevants. Also, as with detection rates, self-referring information was better detected in terms of Probe-Irrelevant P300 amplitude differences than mock crime information, regardless of protocol. There was no effect of time passage across the repeated blocks of the one-probe protocol. Methodological problems with the multiple probe protocol as utilized in most recent publications are discussed.

Not too ‘shy’ to help catch a thief: Recall memory of shy versus non-shy witnesses

Witness shyness was examined to determine its impact on recall accuracy in two experiments. It was hypothesized that shyness would facilitate witness accuracy, under some conditions. In Experiment 1, witnesses were asked to respond to directed recall questions probing crime event and culprit details. Non-shy and shy witnesses produced comparable accuracy rates when describing the culprit. In contrast, non-shy witnesses were more accurate when describing crime environment details than shy witnesses. In Experiment 2, arousal was manipulated and a free recall approach was used to assess recall accuracy. Under low arousal, shy witnesses were more accurate at describing the culprit than non-shy witnesses, whereas, non-shy witnesses were more accurate at describing crime details than shy witnesses. Under high arousal, differences in accuracy were not observed across shy and non-shy witnesses.

The Guilty Knowledge Test and the modified Stroop task in detection of deception: an exploratory study.

The current study tested whether a simple Stroop paradigm can be used to detect deceptive behavior. 40 university students (34 women), half of whom committed a mock crime, were administered a Guilty Knowledge Test and modified Stroop task to detect guilt or innocence. The Guilty Knowledge Test is a well-known psychophysiological detection method, which consists of multiple-choice questions about details of the crime while skin conductance is recorded. Subjects possessing guilty knowledge are expected to show enhanced differential responses to the relevant stimuli. The modified Stroop task required color-naming of colored words related to the mock crime or an irrelevant crime. Each version of the Stroop task was presented in story form. Subjects possessing guilty knowledge were expected to produce larger reaction times to the relevant version relative to the irrelevant version. The test correctly identified 100% of innocent participants and 78% of guilty participants. In contrast, Stroop interference. i.e., reaction times for irrelevant crime details subtracted from those for mock crime details, did not differentiate between the two groups, suggesting that the story form of the Stroop paradigm is not suitable for lie detection.

Abuse and Neglect of Children III: Sexual Abuse

The recent unsolved murder of a young girl in Colorado raises many issues central to our understanding of the sexual abuse of children. These issues range from the horror felt by a nation, as details of a heinous crime emerge, to uncertainty about precocious and provocative behavior of children encouraged in this behavior by parents and by society. This is the third, and last, article in a series about the abuse and neglect of children. The first two articles discuss the context of abuse and recognition of abuse. This article focuses on important aspects about the sexual abuse of children and adolescents.

Recall memory, recognition memory, and the eyewitness confidence–accuracy correlation.

Research on the eyewitness confidence-accuracy correlation assesses the degree of insight that eyewitnesses have into the accuracy of their memories. Recently, researchers have begun to consider some of the variables that may facilitate or hinder such insight. In the present study with 205 college undergraduates, a previously unexamined influence on this correlation in the context of memory for details of a simulated crime was investigated. The authors hypothesized and found that recall memory conditions (in which no alternative answers were provided ) were characterized by a higher eyewitness confidence-accuracy correlation than recognition memory conditions (in which alternative answers were provided). These findings are explained as a function of the availability of an ease-of-retrieval cue in recall memory.

Alcohol and the physiological detection of deception: arousal and memory influences.

Eighty male volunteers participated in an analogue study of the effects of alcohol intoxication at the time of a crime on the physiological detection of deception using control question and guilty knowledge techniques. Sixty-four of the subjects committed a mock crime and half of these were intoxicated during the crime. Sixteen subjects committed no crime and served as innocent controls. We found that intoxication at the time of the crime had no significant effect on polygraph test outcomes, although it did affect anticipatory arousal before the crime and subsequent memory for crime details. Manipulations designed to influence memory for crime details and arousal during the crime had differential effects for the two polygraph tests. On the guilty knowledge test, primed subjects who rehearsed specific details following the crime were more detectable than unprimed subjects. On the control question test, primed subjects were also more detectable, but only when arousal during the crime was high.

Mystery of the Slaughtered Horse

FORENSIC ENTOMOLOGY necessitates interdisciplinary cooperation with other scientific disciplines and provides an opportunity for some unusual applications of taxonomic and ecological inferences. Entomological study can be a powerful source of independent, circumstantial evidence in substantiating the details of homicides and other crimes that can not be elucidated fully with other techniques. And, in some instances, the assessment of insects collected at a site allows the only inference regarding particular conditions of death. Although forensic entomology is most often associated with contemporary homicides and other recent crime scenes, insect remains also can be vital in solving older mysteries. In 1992, we were presented with insect remains from an unusual death—the victim was a horse killed more than 400 years ago.

Violence among child molesters

Although sexual offenses against children have often been characterized as nonviolent, recent information has indicated that a subgroup of very violent offenders exists. The present study examined details of both familial and nonfamilial sexual offenses against children in order to investigate the type of offense committed, as well as the frequency of violence and aggression. Two trained raters were used to code clinical information which examined offenders’ backgrounds as well as details of crimes. Subjects consisted of all in‐patients referred to the Clarke Institute of Psychiatry over a five‐year period who were charged with a sexual offense against a child (29 incest offenders and 37 nonfamilial offenders). The two groups were similar in demographic characteristics, with the exception of the incest group being older and more frequently married. Details of the index offenses revealed that both groups of offenders had penetrated victims in over half the cases, had used physical force (such as beating) i...

Enhancement of Eyewitness Memory with the Cognitive Interview

This research evaluated an innovative interview procedure, the cognitive interview, that was designed to aid eyewitnesses recall the details of crimes. Experiment 1 was conducted to examine the success of the cognitive interview in a nonstudent population. Fifty-one nonstudent volunteers viewed police training films of simulated violent crimes and were questioned individually in interactive interviews 48 hr later by experienced law-enforcement personnel. The cognitive interview elicited significantly more correct information from the subjects than did the standard police interview, and without an accompanying increase in incorrect information or confabulation. Experiment 2 was designed to separate the cognitive interview into its constituent parts and to evaluate the success of each mnemonic. It was concluded that all four general mnemonics contained in the interview (two increasing feature overlap between encoding and retrieval contexts; two encouraging use of many retrieval paths) are useful and should be retained. The cognitive interview is a viable memory-enhancement technique that is effective, efficient, and legally acceptable.

Innocence, Information, and the Guilty Knowledge Test in the Detection of Deception

ABSTRACTThe purpose of this detection of deception experiment was to study the assumption of the Guilty Knowledge Test that subjects with guilty knowledge will be classed as guilty by the test regardless of their actual guilt or innocence. Prior to a polygraph examination, three groups of innocent subjects were given the same crime‐relevant information as members of a group guilty of a mock crime. These innocent subjects either witnessed the crime, were told the crime details, or carried out innocent activities involving crime‐relevant information. An additional group of innocent subjects had no crime‐relevant information. Analysis of the Guilty Knowledge Test results showed that the detection scores of guilty subjects were higher than those in any of the innocent groups. In fact, with the exception of the innocent activities group, the innocent informed subjects did not differ from those in the uninformed group. The major conclusion is that subjects may have crime‐relevant information and not be classed, based on the detection scores, as guilty.