Nathan Weber

Confidence-Accuracy Calibration in Absolute and Relative Face Recognition Judgments

Confidence-accuracy (CA) calibration was examined for absolute and relative face recognition judgments as well as for recognition judgments from groups of stimuli presented simultaneously or sequentially (i.e., simultaneous or sequential mini-lineups). When the effect of difficulty was controlled, absolute and relative judgments produced negligibly different CA calibration, whereas no significant difference was observed for simultaneous and sequential mini-lineups. Further, the effect of difficulty on CA calibration was equivalent across judgment and mini-lineup types. It is interesting to note that positive (i.e., old) recognition judgments demonstrated strong CA calibration whereas negative (i.e., new) judgments evidenced little or no CA association. Implications for eyewitness identification are discussed.

The effect of judgment type and confidence scale on confidence-accuracy calibration in face recognition.

Confidence-accuracy calibration was examined for both absolute (recognizing single faces as old or new) and relative (selecting which of pairs of faces is old) judgments, using both full- (0%-100%) and half-range (50%-100%) confidence scales. The half-range confidence scale demonstrated superior calibration to the full-range scale, for which a confidence-accuracy association was evident only for the upper half (i.e., 50%-100%) of the scale. Good calibration was observed for the absolute judgment conditions, but the relative judgment conditions evidenced marked underconfidence. Also, in the absolute judgment conditions, good calibration for positive recognition decisions and poorer calibration for negative decisions was observed. These results are discussed in the context of theories of confidence and accuracy in face recognition memory and also of eyewitness identification research.

The Confidence-Accuracy Relationship for Eyewitness Identification Decisions: Effects of Exposure Duration, Retention Interval, and Divided Attention

Prior research points to a meaningful confidence-accuracy (CA) relationship for positive identification decisions. However, there are theoretical grounds for expecting that different aspects of the CA relationship (calibration, resolution, and over/underconfidence) might be undermined in some circumstances. This research investigated whether the CA relationship for eyewitness identification decisions is affected by three, forensically relevant variables: exposure duration, retention interval, and divided attention at encoding. In Study 1 (N = 986), a field experiment, we examined the effects of exposure duration (5 s vs. 90 s) and retention interval (immediate testing vs. a 1-week delay) on the CA relationship. In Study 2 (N = 502), we examined the effects of attention during encoding on the CA relationship by reanalyzing data from a laboratory experiment in which participants viewed a stimulus video under full or divided attention conditions and then attempted to identify two targets from separate lineups. Across both studies, all three manipulations affected identification accuracy. The central analyses concerned the CA relation for positive identification decisions. For the manipulations of exposure duration and retention interval, overconfidence was greater in the more difficult conditions (shorter exposure; delayed testing) than the easier conditions. Only the exposure duration manipulation influenced resolution (which was better for 5 s than 90 s), and only the retention interval manipulation affected calibration (which was better for immediate testing than delayed testing). In all experimental conditions, accuracy and diagnosticity increased with confidence, particularly at the upper end of the confidence scale. Implications for theory and forensic settings are discussed.

Sex differences in pre-diagnosis concerns for children later diagnosed with autism spectrum disorder:

In the absence of intellectual impairment, girls are diagnosed with autism spectrum disorder significantly less and later than boys. This study explored potential reasons for why autism spectrum disorder may be more difficult to identify in girls, based on carer concerns during the pre-diagnosis period. Carers of 92 boys and 60 girls diagnosed with autism spectrum disorder from school age completed an online survey addressing concerns regarding the child’s development during the pre-school years (pre-diagnosis). Significant sex differences were evident in key early concerns, as well as the strategies used to navigate pre-school social situations, and the types of restricted interests. Findings suggest, from carer perspective, that girls who went on to be diagnosed with autism spectrum disorder presented differently when compared to boys, providing insight into why the diagnosis of autism spectrum disorder may be more difficult to make with cognitively able girls.

Eyewitness Recall: Regulation of Grain Size and the Role of Confidence.

Eyewitness testimony plays a critical role in Western legal systems. Three experiments extended M. Goldsmith, A. Koriat, and A. Weinberg-Eliezers (2002) framework of the regulation of grain size (precision vs. coarseness) of memory reports to eyewitness memory. In 2 experiments, the grain size of responses had a large impact on memory accuracy. Further, participants achieved a compromise between the accuracy and informativeness of their testimony by volunteering precise answers only when likely to be correct. The level of detail reported was strongly, positively related to confidence in the accuracy of the response. This highlights the importance of considering the level of detail, not just the accuracy, of eyewitness testimony.

Improving eyewitness identification accuracy by screening out those who say they don't know.

Improving eyewitness identification evidence remains a key priority for research. Basic laboratory research has consistently demonstrated that allowing participants to withhold answers about which they are unsure leads to improved accuracy. Surprisingly, this approach has not been the subject of comprehensive investigation in the eyewitness identification literature. In this article, we explored the utility of allowing uncertain witnesses to opt out of an identification decision, by providing an explicit don’t know option. Further, we contrasted the rate of use of this explicit option with the frequency that participants spontaneously withheld a decision when asked to respond in their own words. Four hundred and twenty participants witnessed a mock crime video before being presented with a showup of the perpetrator or an innocent suspect. Participants were tested either immediately or after a 3-week delay, with one of the three report options: Participants either made their choice in their own words (spontaneous report), chose between identifying and rejecting the showup (forced-report), or chose between identification, rejection and don’t know (free-report). Only 2.2% of witnesses spontaneously used a don’t know response, compared to 19.3% who used it when the option was explicit. Compared with the forced-report decisions, free-report decisions were more accurate, more diagnostic of the suspect’s guilt or innocence, and came at no cost to the number of correct decisions rendered. These data suggest that utilisation of an explicit don’t know option may be of practical value.

Phenomenological reports diagnose accuracy of eyewitness identification decisions

This study investigated whether measuring the phenomenology of eyewitness identification decisions aids evaluation of their accuracy. Witnesses (N=502) viewed a simulated crime and attempted to identify two targets from lineups. A divided attention manipulation during encoding reduced the rate of remember (R) correct identifications, but not the rates of R foil identifications or know (K) judgments in the absence of recollection (i.e., K/[1-R]). Both RK judgments and recollection ratings (a novel measure of graded recollection) distinguished correct from incorrect positive identifications. However, only recollection ratings improved accuracy evaluation after identification confidence was taken into account. These results provide evidence that RK judgments for identification decisions function in a similar way as for recognition decisions; are consistent with the notion of graded recollection; and indicate that measures of phenomenology can enhance the evaluation of identification accuracy.

How Variations in Distance Affect Eyewitness Reports and Identification Accuracy

Witnesses observe crimes at various distances and the courts have to interpret their testimony given the likely quality of witnesses’ views of events. We examined how accurately witnesses judged the distance between themselves and a target person, and how distance affected description accuracy, choosing behavior, and identification test accuracy. Over 1,300 participants were approached during normal daily activities, and asked to observe a target person at one of a number of possible distances. Under a Perception, Immediate Memory, or Delayed Memory condition, witnesses provided a brief description of the target, estimated the distance to the target, and then examined a 6-person target-present or target-absent lineup to see if they could identify the target. Errors in distance judgments were often substantial. Description accuracy was mediocre and did not vary systematically with distance. Identification choosing rates were not affected by distance, but decision accuracy declined with distance. Contrary to previous research, a 15-m viewing distance was not critical for discriminating accurate from inaccurate decisions.

Identifying the Bad Guy in a Lineup Using Confidence Judgments Under Deadline Pressure

Eyewitness-identification tests often culminate in witnesses not picking the culprit or identifying innocent suspects. We tested a radical alternative to the traditional lineup procedure used in such tests. Rather than making a positive identification, witnesses made confidence judgments under a short deadline about whether each lineup member was the culprit. We compared this deadline procedure with the traditional sequential-lineup procedure in three experiments with retention intervals ranging from 5 min to 1 week. A classification algorithm that identified confidence criteria that optimally discriminated accurate from inaccurate decisions revealed that decision accuracy was 24% to 66% higher under the deadline procedure than under the traditional procedure. Confidence profiles across lineup stimuli were more informative than were identification decisions about the likelihood that an individual witness recognized the culprit or correctly recognized that the culprit was not present. Large differences between the maximum and the next-highest confidence value signaled very high accuracy. Future support for this procedure across varied conditions would highlight a viable alternative to the problematic lineup procedures that have traditionally been used by law enforcement.

How should witnesses regulate the accuracy of their identification decisions: one step forward, two steps back?

Explorations of memory accuracy control normally contrast forced-report with free-report performance across a set of items and show a trade-off between memory quantity and accuracy. However, this memory control framework has not been tested with lineup identifications that may involve rejection of all alternatives. A large-scale (N = 439) lineup study explored regulation of identification decisions either with an initial forced-choice decision followed by free-report decision or with the reverse. Overall, initial free-report decisions provided stronger evidence of suspect guilt than forced-choice decisions, with little cost to memory quantity. The 2 response orders produced different patterns of response associated with control of accuracy. A model based on evaluation of the strength of the best candidate answer was able to provide only a partial fit to the data, suggesting that witnesses use more than simple memory strength of a candidate answer when controlling the accuracy of their responses in free report.