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.

No description available.

No description available.

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...

As online technology continues to progress, the modes of communication through which content can be shared have exponentially grown. These include advances in navigational options for presenting information and news online. Though the listicle has been around for centuries, the internet has proliferated its growth, as content producers rely on its structure as a vehicle for sharing information. This research shows that in the case of listicles, format had no direct effect on recall, however, participants who had a greater interest in the content showed significantly higher levels of memory sensitivity. This critical finding suggests that news outlets and content producers should concern themselves with ensuring that their content is interesting and relevant to their audience more so than worrying about whether the listicle is in clickable or scrollable form. This first attempt to examine listicles by comparing their navigational difference in terms of recall performance lays a framework for future research on listicles.

Previous solutions for the the Law of Categorical Judgment with category boundary variability have either constrained the standard deviations of the category boundaries in some way or have violated the assumptions of the scaling model. In the current work, a fully Bayesian Markov chain Monte Carlo solution for the Law of Categorical Judgment is given that estimates all model parameters (i.e. scale values, category boundaries, and the associated standard deviations). The importance of measuring category boundary standard deviations is discussed in the context of previous research in signal detection theory, which gives evidence of interindividual variability in how respondents perceive category boundaries and even intraindividual variability in how a respondent perceives category boundaries across trials. Although the measurement of category boundary standard deviations appears to be important for describing the way respondents perceive category boundaries on the latent scale, the inclusion of category boundary standard deviations in the scaling model exposes an inconsistency between the model and the rating method. Namely, with category boundary variability, the scaling model suggests that a respondent could experience disordinal category boundaries on a given trial. However, the idea that a respondent actually experiences disordinal category boundaries seems unlikely. The discrepancy between the assumptions of the scaling model and the way responses are made at the individual level indicates that the assumptions of the model will likely not be met. Therefore, the current work examined how well model parameters could be estimated when the assumptions of the model were violated in various ways as a consequence of disordinal category boundary perceptions. A parameter recovery study examined the effect of model violations on estimation accuracy by comparing estimates obtained from three response processes that violated the assumptions of the model with estimates obtained from a novel response process that did not violate the assumptions of the model. Results suggest all parameters in the Law of Categorical Judgment can be estimated reasonably well when these particular model violations occur, albeit to a lesser degree of accuracy than when the assumptions of the model are met.

This thesis investigates the relationships between performance, workload, and situation awareness at varying levels of automation. The relationships observed in this study are compared to a description put forth to formalize the conventional interpretation of the trade-off between the benefits of automation during routine operation and the costs under conditions of automation failure. The original work stipulated that this “routine-failure trade-off” is likely a simplification affected by contextual factors. This work therefore aimed to i) provide empirical evidence to support or refute the trade-off and ii) to identify possible extenuating factors. The results generally supported the routine-failure trade-off, and considered in light of the functional structure of the task suggested that the relationships between goals and individual functions specific to a given task seem to affect the overall costs and benefits of automation through the mechanism of selective reliance. Further work is required to validate the findings of this study.