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No description available.

Signal detection theory (SDT) provides a theoretical framework for describing performance on decision making tasks, and fuzzy signal detection theory (FSDT) extends this description to include tasks in which there are levels of uncertainty regarding the categorization of stimulus events. Specifically, FSDT can be used to quantify the degree to which an event is 'signal-like', i.e., the degree to which a stimulus event can be characterized by both signal and non-signal properties. For instance, an improvised explosive device (IED) poses little threat when missing key elements of its assembly (a stimulus of low, but not zero, signal strength) whereas the threat is greater when all elements necessary to ignite the device are present (a stimulus of high signal strength). This research develops a link between key individual cognitive (i.e., spatial orientation and visualization) and personality (i.e., extroversion, conscientiousness, and neuroticism) differences among observers to performance on a fuzzy signal detection task, in which the items to be detected (IEDs) are presented in various states of assembly. That is, this research relates individual difference measures to task performance, uses FSDT in target detection, and provides application of the theory to vigilance tasks. In two experiments, participants viewed pictures of IEDs, not all of which are assembled or include key components, and categorize them using a fuzzy rating scale (no threat, low threat potential, moderate threat potential, or definite threat). In both experiments, there were significant interactions between the stimulus threat level category and the variability of images within each category. The results of the first experiment indicated that spatial and mechanical ability were stronger predictors of performance when the signal was ambiguous than when individuals viewed stimuli in which the signal was fully absent or fully present (and, thus, less ambiguous). The second study showed that the length of time a stimulus is viewed is greatest when the signal strength is low and there is ambiguity regarding the threat level of the stimulus. In addition, response times were substantially longer in study 2 than in study 1, although patterns of performance accuracy, as measured by the sensitivity index d', were similar across the two experiments. Together, the experiments indicate that individuals take longer to evaluate a potential threat as less critical, than to identify either an absence of threat or a high degree of threat and that spatial and mechanical ability assist decision making when the threat level is unclear. These results can be used to increase the efficiency of employees working in threat-detection positions, such as luggage screeners, provides an exemplar of use of FSDT, and contributes to the understanding of human decision making.

Source memory is our ability to relate central information (the “item”) to the context (the “source”) in which it was learned or experienced. People are often highly confident in their source judgements even when this information is incorrectly recalled. Past work has aimed to explain why source errors made with high confidence occur with a framework called the Converging Criteria (CC) account. The CC account posits that item memory can interact with source memory by altering decision criteria as item confidence increases, increasing the probability of a high confidence source judgement. This prediction differs from alternate models, like the Fixed Criteria (FC) account, where decision criteria are not expected to change with item confidence. The current study not only tests the implications of the CC account, but contrasts it to the predictions of the FC account relative to item memory, item confidence, and source discriminability, using existing data from 12 recognition memory experiments. We use a Bayesian Hierarchical model to estimate a key metric called the Item Confidence Effect (ICE) - the change in the proportion of source errors made with high confidence as item confidence increases. Results show a positive ICE, demonstrating that the proportion of source errors made with high confidence increases with item confidence, as predicted by the CC account. In the context of memory, this evidence shows that decision processes can influence behavior, regardless if evidence in memory supports it or not.

Prior work has demonstrated that the sequential presentation of lineup members in eyewitness lineups can result in undesirable position effects. For example, some studies have shown that placing the suspect in later positions increases discriminability. However, the evidence for this late-position discriminability advantage is mixed and the processes by which the discriminability increase occurs are unclear. However, one theory in particular, diagnostic feature detection theory (DFDT) explicitly predicts a late-position discriminability increase. According to DFDT, because shared features across lineup members cannot be used as reliable recognition cues to guide identification, discounting these features from consideration improves recognition. In sequential lineups, when the suspect is in a later position, witnesses are exposed to more of these shared features and are expected to benefit from discounting. By contrast, when the suspect is in an earlier position, witnesses are exposed to fewer shared features, and hence do not have the same advantage under the assumptions of the DFDT framework. One reason for the mixed evidence across the literature might be due to variation in suspect-filler similarity relationship between lineup members across studies, which we expected would moderate late-position memory effects. With the above in mind, the primary goals of the present work were: (1) testing for position effects at different levels of suspect-filler (SF) similarity, which might help elucidate conflicting evidence from prior work, and (2) testing DFDT mechanisms by simultaneously manipulating both innocent-suspect-perpetrator (IS-P) similarity and SF similarity. We found no evidence for late-position increases in discriminability as predicted by DFDT; however, participants were more conservative in later positions, especially when SF similarity was low. Discriminability was most strongly influenced by IS-P similarity, and was maximized when both SF and IS-P similarity was low. Implications for theories of eyewitness memory, practical implications for policy recommendations, and future directions are discussed.

Fifty-two college-aged observers participated in an experiment assessing color memory via a PowerPoint '97 computer display program which varied one of the three dimensions of hue, saturation and lightness at a time. Consistent with previous research, errors were greater for the lightness conditions followed by saturation, and least for hue conditions Additionally, a signal detection analysis indicated that d-prime was greatest for the hue conditions, less for saturation and lowest for lightness conditions. There were also significant but unpredicted differences in response criterion which may reflect task difficulty. Scores on the Vividness of Visual Imagery Questionnaire (Marks, 1973) were, in general, not correlated with performance on these color memory tasks, inconsistent with previous research. The role of complexity of neuronal circuitry, the significance for opponent-process, trichromatic and retinex color vision theories and the relationship to Sokolov's model of color memory were discussed. Also, it was concluded that investigators of color memory using a computer display are well-advised to calibrate the monitor with a colorimeter because the internal computer units may be unreliable indexes of changes in hue, saturation and lightness. / Ph. D.

Given the continuing deployment of total quality control and total quality management initiatives by organizations, employees have seen changes in their work environment. Furthermore, the impact of downsizing has resulted in operators becoming responsible for the quality of their own processes. This study tested the impact of various display alternatives of control chart data on decision performance and mental workload.  The control charts were shown as multiple two dimensional displays, a composite two dimensional display, and a composite three dimensional perspective display. Multiple two dimensional displays were found to have significantly higher decision accuracy and decision confidence ratings than either composite displays. No significant difference in decision accuracy and decision confidence ratings was found among the composite displays. The type of display did not have a significant effect on decision time. Mental workload was also found to be significantly affected by the type of display used. Multiple two dimensional displays imposed significantly lower levels of mental workload than either composite display. No significant difference in mental workload was found among the composite displays. These results indicated that multiple two dimensional displays should be used when control chart data from multiple processes must be displayed. / Master of Science

Every day we are exposed to huge amounts of visual stimuli (scenes). However, i tis not yet clear how accurately these scenes are stored and remembered, and what is the role of detail relative to the memory for the whole image. More specifically, to what extent the details are remembered and to what extent we extrapolate the unseen content from the presented details. We used fragmented scenes (broken to 4x4 grids) to investigate this question. Fragmented scenes were composed of three different theme categories (indoor, natural, man-made), each with different number of presented patches (3, 5 and 8). Our main research question is, whether there is any relationship between the number of presented patches and the ability to recognize which patches were presented and which were not (but still patches from the same photograph). In analysis we focus on Signal Detection Theory characteristics, mainly memory sensitivity (d') and bias. We run two experiments and in both the highest scores for (d') were for 3 patches (Exp.1: d'(n3) = 0,67; Exp.2: d'(n3) = 0,66) with bias towards negative answers (Exp.1: c(n3) = 0,27; Exp.2: c(n3) = 0,16). For 5 and 8 patches the (d') was lower (Exp.1: d'(n5) = 0,35; d'(n8) = 0,34; Exp.2: d'(n5) = 0,39; d'(n8) = 0,41) and in the same time bias was towards positive answers...