Reducing age differences in the retrieval of verbatim and gist representations: Encoding manipulations.

Aging causes changes in episodic memory. While the ability to remember the general idea or gist of past episodes is relatively preserved from the effects of aging, the ability to remember the verbatim details of these episodes declines. The aim of the present study was to examine whether age-related differences in the quality of episodic representations could be reduced by manipulations of information encoding. Two experiments were conducted with younger adults (NExp.1 = 32, NExp.2 = 31, 18-27 years old) and older adults (NExp.1 = 31, NExp.2 = 30, 54-81 years old) in which either the retrieval of gist representations of studied items was facilitated by presenting items that could be grouped within the same category (Exp. 1) or the retrieval of verbatim details of studied items was facilitated by presenting the same items repeatedly (Exp. 2). Both manipulations proved effective in increasing retrieval of either gist or verbatim representations in a recognition task in younger and older adults. Increasing gist retrieval improved correct recognition performance for both younger and older adults but also led the latter to make more recognition errors. Increasing verbatim retrieval improved correct recognition performance for both younger and older adults, and the gain was greater for older adults. These findings support the notion that age-related changes in episodic memory can be explained by changes in the specificity of representations and suggest that simple encoding manipulations could improve episodic memory in older adults.

Risky-Choice Framing Effects Result Partly From Mismatched Option Descriptions in Gains and Losses.

Textbook psychology holds that people usually prefer a certain option over a risky one when options are framed as gains but prefer the opposite when options are framed as losses. However, this pattern can be amplified, eliminated, or reversed depending on whether option descriptions include only positive information (e.g., "200 people will be saved"), only negative information (e.g., "400 people will not be saved"), or both. Previous studies suggest that framing effects arise only when option descriptions are mismatched across frames. Using online and student samples (Ns = 906 and 521), we investigated 81 framing-effect variants created from matched and mismatched pairs of 18 option descriptions (nine in each frame). Description valence or gist explained substantial variation in risk preferences (prospect theory does not predict such variation), but a considerable framing effect remained in our balanced design. Risky-choice framing effects appear to be partly-but not completely-the result of mismatched comparisons.

Effects of emotional ambiguity and emotional intensity on true and false memory.

Whereas the effects of emotional intensity (the perceived strength of an item's valence or arousal) have long been studied in true- and false-memory research, emotional ambiguity (the uncertainty that attaches to perceived emotional intensity) has only been studied recently. Available evidence suggests that emotional ambiguity has reliable effects on true memory that are distinct from those of emotional intensity. However, those findings are mostly restricted to recall, and the effects of emotional ambiguity on false memory remain unexplored. The current study addressed both limitations by measuring the effects of emotional ambiguity and emotional intensity on true and false recognition. In two experiments, we manipulated valence ambiguity and valence intensity (Experiment 1) and arousal ambiguity and arousal intensity (Experiment 2) of Deese/Roediger/McDermott lists. Multiple linear regression analyses were conducted for Experiment 1, Experiment 2, and the combined data of the experiments to separate the effects of emotional ambiguity and emotional intensity. Our results showed that both valence ambiguity and arousal ambiguity improved true recognition, and the effects of valence ambiguity remained robust even when controlling for valence intensity, arousal intensity, and arousal ambiguity. More importantly, for both valence and arousal, there was an interaction between ambiguity and intensity in false memory. Specifically, we found that valence ambiguity increased false recognition with positive valence, while arousal ambiguity amplified the effect of arousal intensity on false recognition. Our results are discussed in the context of the emotional ambiguity hypothesis and fuzzy-trace theory.

Making decisions one drink at a time and the "just one drink" effect: A fuzzy-trace theory model of harmful drinking.

BACKGROUND: Understanding the decision factors that drive harmful alcohol use among young adults is of practical and theoretical importance. We apply fuzzy-trace theory (FTT) to investigate a potential danger that may arise from the arguably correct notion that a single drink carries no meaningful risk. Decisions that are mentally represented as one drink at a time could contribute to excessive drinking. METHODS: College students (N = 351) made a series of decisions to take or decline eight hypothetical drinks presented one at a time. Outcome measures included each decision, recent alcohol consumption (weekly drinks, peak blood alcohol content, and binges), and alcohol-related harms (scores on the Brief Young Adult Alcohol Consequences Questionnaire and Alcohol Use Disorders Identification Test). Linear regression models predicted each outcome from sex, perceived risk of a single drink, perceived risk of heavy drinking, perceived consequences of drinking, and general health-related risk sensitivity. RESULTS: Consistent with FTT, decisions to have a first drink and up to four additional drinks in short succession were each associated with lower perceived risk of one drink-a "just-one drink" effect-independent of perceived risks of heavy drinking, perceived consequences of drinking, and general risk sensitivity. Similarly, all measures of recent alcohol consumption and consequent harms were associated with perceived risk of one drink. Participants reporting "zero risk" of a single drink had worse outcomes on all measures than those reporting at least "low risk." CONCLUSIONS: Results are consistent with the theoretically informed premise that consumption decisions are typically made one drink at a time rather than by deciding the total number of drinks to be consumed in a sitting. When decisions about alcohol use proceed one drink at a time, a perception of zero risk in a single drink may contribute to heavy drinking.

"It's Not Literally True, But You Get the Gist:" How nuanced understandings of truth encourage people to condone and spread misinformation.

People have a more-nuanced view of misinformation than the binary distinction between "fake news" and "real news" implies. We distinguish between the truth of a statement's verbatim details (i.e., the specific, literal information) and its gist (i.e., the general, overarching meaning), and suggest that people tolerate and intentionally spread misinformation in part because they believe its gist. That is, even when they recognize a claim as literally false, they may judge it as morally acceptable to spread because they believe it is true "in spirit." Prior knowledge, partisanship, and imagination increase belief in the gist. We argue that partisan conflict about the morality of spreading misinformation hinges on disagreements not only about facts but also about gists.

To risk or not: The impact of socioeconomic status on preschoolers' risky decision-making for gains and losses.

Disparities in socioeconomic status (SES) may affect individuals' risk preferences, which have important developmental consequences across the lifespan. Yet, previous research has shown inconsistent associations between SES and risky decision-making, and little is known about how this link develops from a young age. The current research is among the first to examine how SES influences preschoolers' risky decisions in both gain and loss frames. Across two studies, children aged 5 to 6 years (total N = 309, 154 boys) were asked to choose between certain and risky options. The risky option was more advantageous, equal to, or less advantageous than the certain option. Study 1 revealed that in the loss frame, high-SES children (n = 84, 44 boys) chose more risky options and were more sensitive to the expected value compared to low-SES children (n = 78, 42 boys), especially when the risk was more advantageous. However, this SES difference was not significant in the gain frame. Supporting the potential causal link between SES and risky decision-making, Study 2 further found that experimentally increasing low-SES children's (n = 68, 30 boys) status by providing additional resources increased their risk-seeking behavior in the loss frame. Overall, our findings suggest an interaction between environmental cues (gain vs. loss) and early life circumstances (SES) in shaping children's risk preferences. RESEARCH HIGHLIGHTS: This research is among the first to examine how school backgrounds and experimentally manipulated SES influence preschoolers' risk preferences in gain and loss frames. Children were more risk-seeking for losses than for gains; this framing effect was stronger in higher-SES than lower-SES children. Lower-SES children exhibited fewer risk-seeking behaviors and decreased sensitivity to the expected value of options for losses, but not for gains. A temporary boost in SES increased children's risk-seeking behavior, but not sensitivity to expected values.

Providing the Gist of Medical Expertise in the Context of Laws, Rules, and Guidelines: Fuzzy-Trace Theory's Alternative Approach to Improve Patient Communication.

Current guidelines and regulatory frameworks create a dilemma that threatens the effectiveness of much needed communication between patients and medical providers: How can patients be presented with detailed facts without creating cognitive "overload"? We explain how this is a false dichotomy and illustrate, using three examples, how fuzzy-trace theory offers a third way of informing patients.

Forgetting of specific and gist visual associative episodic memory representations across time.

Associative binding between components of an episode is vulnerable to forgetting across time. We investigated whether these forgetting effects on inter-item associative memory occur only at specific or also at gist levels of representation. In two experiments, young adult participants (n = 90, and 86, respectively) encoded face-scene pairs and were then tested either immediately after encoding or following a 24-hour delay. Tests featured conjoint recognition judgments, in which participants were tasked with discriminating intact pairs from highly similar foils, less similar foils, and completely dissimilar foils. In both experiments, the 24-hour delay resulted in deficits in specific memory for face-scene pairs, as measured using multinomial-processing-tree analyses. In Experiment 1, gist memory was not affected by the 24-hour delay, but when associative memory was strengthened through pair repetition (Experiment 2), deficits in gist memory following a 24-hour delay were observed. Results suggest that specific representations of associations in episodic memory, and under some conditions gist representations, as well, are susceptible to forgetting across time.

Can degrading information about patient symptoms in vignettes alter clinical reasoning in paramedics and paramedic students? An experimental application of fuzzy trace theory.

BACKGROUND: Research has shown paramedics form rapid intuitive impressions on first, meeting a patient and these impressions subsequently affected their clinical reasoning. We report an experiment where theory-based interventions are developed with the goal of reducing reliance on intuitive reasoning by paramedics and paramedic students in simulated patients. METHOD: Australian paramedics (n = 213; 49% female) and paramedicine students (n = 83; 55% female) attending paramedic conferences completed a 2 × 2 fully between participants experiment. They saw a written clinical vignette designed to be representative of Acute Coronary Syndrome (ACS) in which key clinical information was precise or degraded (stimulus), they then either chose the single most likely diagnosis from a list, or ranked competing diagnoses (response). Outcome variables were diagnostic rate and response time. RESULTS: There were no differences in the proportion of participants choosing ACS across the four stimulus-response conditions (0.75 [0.65, 0.84] vs 0.79 [0.68, 0.87] vs, 0.78 [0.65, 0.87] vs 0.72 [0.59, 0.82], p = 0.42) CONCLUSION: This is the first study attempting to experimentally examine clinical reasoning in paramedics using a theory-based intervention. Neither of the interventions tested succeeded in altering measures of clinical reasoning. Similar to previous research on physicians, paramedic reasoning appears robust to manipulation.

Do colored cells in risk matrices affect decision-making and risk perception? Insights from randomized controlled studies.

Risk matrices communicate the likelihood and potential impact of risks and are often used to inform decision-making around risk mitigations. The merits and demerits of risk matrices in general have been discussed extensively, yet little attention has been paid to the potential influence of color in risk matrices on their users. We draw from fuzzy-trace theory and hypothesize that when color is present, individuals are likely to place greater value on reducing risks that cross color boundaries (i.e., the boundary-crossing effect), leading to sub-optimal decision making. In two randomized controlled studies, employing forced-choice and willingness-to-pay measures to investigate the boundary-crossing effect in two different color formats for risk matrices, we find preliminary evidence to support our hypotheses that color can influence decision making. The evidence also suggests that the boundary-crossing effect is only present in, or is stronger for, higher numeracy individuals. We therefore recommend that designers should consider avoiding color in risk matrices, particularly in situations where these are likely to be used by highly numerate individuals, if the communication goal is to inform in an unbiased way.

Understanding the landscape of web-based medical misinformation about vaccination.

Given the high rates of vaccine hesitancy, web-based medical misinformation about vaccination is a serious issue. We sought to understand the nature of Google searches leading to medical misinformation about vaccination, and guided by fuzzy-trace theory, the characteristics of misinformation pages related to comprehension, inference-making, and medical decision-making. We collected data from web pages presenting vaccination information. We assessed whether web pages presented medical misinformation, had an overarching gist, used narrative, and employed emotional appeals. We used Search Engine Optimization tools to determine the number of backlinks from other web pages, monthly Google traffic, and Google Keywords. We used Coh-Metrix to measure readability and Gist Inference Scores (GIS). For medical misinformation web pages, Google traffic and backlinks were heavily skewed with means of 138.8 visitors/month and 805 backlinks per page. Medical misinformation pages were significantly more likely than other vaccine pages to have backlinks from other pages, and significantly less likely to receive at least one visitor from Google searches per month. The top Google searches leading to medical misinformation were "the truth about vaccinations," "dangers of vaccination," and "pro con vaccines." Most frequently, pages challenged vaccine safety, with 32.7% having an overarching gist, 7.7% presenting narratives, and 17.3% making emotional appeals. Emotional appeals were significantly more common with medical misinformation than other high-traffic vaccination pages. Misinformation pages had a mean readability grade level of 11.5, and a mean GIS of - 0.234. Low GIS scores are a likely barrier to understanding gist, and are the "Achilles' heel" of misinformation pages.

How does attribute ambiguity improve memory?

The memory effects of semantic attributes (e.g., concreteness, familiarity, valence) have long been studied by manipulating their average perceived intensities, as quantified in word rating norms. The semantic ambiguity hypothesis specifies that the uncertainty as well as the intensity of semantic attributes is processed when words are encoded. Testing that hypothesis requires a normed measure of ambiguity, so that ambiguity and intensity can be manipulated independently. The standard deviation (SD) of intensity ratings has been used for that purpose, which has produced three characteristic ambiguity effects. Owing to the recency of such research, fundamental questions remain about the validity of this method of measuring ambiguity and about its process-level effects on memory. In a validity experiment, we found that the rating SDs of six semantic attributes (arousal, concreteness, familiarity, meaningfulness, negative valence, positive valence) passed tests of concurrent and predictive validity. In three memory experiments, we found that manipulating rating SDs had a specific effect on retrieval: It influenced subjects' ability to use reconstructive retrieval to recall words. That pattern was predicted by the current theoretical explanation of how ambiguity benefits memory.

Individual differences in numerical representations of risk in health decision making: A fuzzy-trace theory approach.

Fuzzy-trace theory predicts that decisionmakers process numerical information about risk at multiple levels in parallel: the simplest level, nominal (categorical some-none) gist, and at more fine-grained levels, involving relative comparison (ordinal less-more gist) and exact quantities (verbatim representations). However, little is known about how individual differences in these numerical representations relate to judgments and decisions, especially involving health tradeoffs and relative risks. To investigate these differences, we administered measures of categorical and ordinal gist representations of number, objective numeracy, and intelligence in two studies (Ns = 978 and 956). In both studies, categorical and ordinal gist representations of number predicted risk judgments and decisions beyond objective numeracy and intelligence. Participants with higher scores in categorical gist were more likely to choose options to avoid cancer recurrence risks; those who were higher in ordinal gist of numbers were more likely to discriminate relative risk of skin cancer; and those with higher scores in objective numeracy were more likely to choose options that were numerically superior overall in terms of relative risk of skin cancer and of genetic risks of breast cancer (e.g., lower numerical probability of cancer). Results support parallel-processing models that assume multiple representations of numerical information about risk, which vary in precision, and illustrate how individual differences in numerical representations are relevant to tradeoffs and risk comparisons in health decisions. These representations cannot be reduced to one another and explain psychological variations in risk processing that go beyond low versus high levels of objective numeracy.

Gist Representations and Decision-Making Processes Affecting Antibiotic Prescribing for Children with Acute Otitis Media.

Objective. To test the predictions of fuzzy-trace theory regarding pediatric clinicians' decision-making processes and risk perceptions about antibiotics for children with acute otitis media (AOM). Methods. We conducted an online survey experiment administered to a sample of 260 pediatric clinicians. We measured their risk perceptions and prescribing decisions across 3 hypothetical AOM treatment scenarios. Participants were asked to choose among the following options: prescribe antibiotics immediately, watchful waiting ("hedging"), or not prescribing antibiotics. Results. We identified 4 gists based on prior literature: 1) "why not take a risk?" 2) "antibiotics might not help but can hurt," 3) "antibiotics do not have harmful side effects," and 4) "antibiotics might have harmful side effects." All 4 gists predicted risky choice (P < 0.001), and gist endorsements varied significantly between scenarios when antibiotics were indicated, F(2, 255) = 8.53, P < 0.001; F(2, 255) = 5.14, P < .01; and F(2, 255) = 3.56, P < 0.05 for the first 3 factors, respectively. In a logistic regression, more experienced clinicians were less likely to hedge (B = -0.05; P < 0.01). Conclusion. As predicted by fuzzy-trace theory, pediatric clinicians' prescription decisions are associated with gist representations, which are distinct from verbatim risk estimates. Implications. Antibiotic stewardship programs can benefit by communicating the appropriate gists to clinicians who prescribe antibiotics for pediatric patients. Highlights: We found clinicians' antibiotic prescription decisions were driven by gist representations of antibiotic risks for a given hypothetical patient scenario, and clinicians' gist representations and verbatim risk estimates about antibiotic-related risks were distinct from each other.We showed that the effect of patient scenarios on clinicians' antibiotic prescription decisions was mediated by clinicians' gist representations.Less experienced clinicians tend to "hedge" in their antibiotic prescription decisions compared with more experienced clinicians.The broader impact of our study is that antibiotic stewardship programs can benefit by communicating the appropriate gists to clinicians who prescribe antibiotics for pediatric patients, rather than solely focusing on closing potential knowledge deficits of the clinicians.

Accelerating Psychological Science With Metastudies: A Demonstration Using the Risky-Choice Framing Effect.

A metastudy is a set of many tiny studies (microstudies) created from a much larger collection of possibilities. Metastudies can yield many of the benefits of time-consuming replications and meta-analyses but more efficiently and with greater attention to generalizability and the causal effects of moderators. Statistical precision and power are higher than in studies with the same total sample size but with fewer conditions and more participants per condition. In this article, we describe metastudies and their benefits, demonstrate how to conduct a metastudy using the well-known risky-choice framing effect as an example, and report on the generalizability of that effect. In three metastudies (total N = 2,338), the framing effect generalized well across most of the potential moderators tested, as was expected. Surprisingly, however, the effect was up to twice as large when the certain option was replaced with a slightly risky option; prospect theory predicts the opposite, and fuzzy-trace theory predicts no difference. Metastudies provide a relatively quick and not-so-painful way of examining an effect's generalizability without waiting for a meta-analysis. Both individual labs and multilab networks are encouraged to shift from traditional studies to metastudies.

Adapting a Theoretically-Based intervention for underserved clinical populations at increased risk for hereditary Cancer: Lessons learned from the BRCA-Gist experience.

Background: Minorities at increased risk for Hereditary Breast and Ovarian Cancer (HBOC) frequently have low awareness and use of genetic counseling and testing (GCT). Making sure that evidence-based interventions (EBIs) reach minorities is key to reduce disparities. BRCA-Gist is a theory-informed EBI that has been proven to be efficacious in mostly non-Hispanic White non-clinical populations. We conducted formative work to inform adaptations of BRCA-Gist for use in clinical settings with at-risk diverse women. Methods: Genetic counselors (n = 20) were recruited nationally; at-risk Latinas and Blacks (n = 21) were recruited in Washington DC and Virginia. They completed the BRCA-Gist EBI between April 2018 - September 2019. Participants completed an acceptability scale and an interview to provide suggestions about implementation adaptations. T-tests for independent samples compared acceptability between at-risk women and genetic counselors. The Consensual Qualitative Research Framework was used to code adaptation suggestions. Suggested adaptations were discussed by a multidisciplinary team to integrate fidelity and adaptation considerations. Results: At-risk women had a significantly higher acceptability (M = 4.17, SD = 0.47 vs. M = 3.24, SD = 0.64; p = 0.000; scale 1-5) and satisfaction scores (M = 8.3, SD = 1.3 vs. M = 4.2, SD = 2.0; p = 0.000; scale 1-10) than genetic counselors. Genetic counselors and at-risk women suggested contextual (e.g. format) and content (e.g. shortening) adaptations to enhance the fit of BRCA-Gist for diverse clinical populations. Conclusions: Findings illustrate the process of integrating fidelity and adaptation considerations to ensure that EBIs retain their core components while enhancing the fit to minoritized clinical populations. Future studies will test the efficacy of the adapted BRCA-Gist in a Randomized Controlled Trial.

Supporting Health and Medical Decision Making: Findings and Insights from Fuzzy-Trace Theory.

HIGHLIGHTS: Fuzzy-trace theory (FTT) supports practical approaches to improving health and medicine.FTT differs in important respects from other theories of decision making, which has implications for how to help patients, providers, and health communicators.Gist mental representations emphasize categorical distinctions, reflect understanding in context, and help cue values relevant to health and patient care.Understanding the science behind theory is crucial for evidence-based medicine.

Numeracy and the Motivational Mind: The Power of Numeric Self-efficacy.

BACKGROUND: Objective numeracy appears to support better medical decisions and health outcomes. The more numerate generally understand and use numbers more and make better medical decisions, including more informed medical choices. Numeric self-efficacy-an aspect of subjective numeracy that is also known as numeric confidence-also relates to decision making via emotional reactions to and inferences from experienced difficulty with numbers and via persistence linked with numeric comprehension and healthier behaviors over time. Furthermore, it moderates the effects of objective numeracy on medical outcomes. PURPOSE: We briefly review the numeracy and decision-making literature and then summarize more recent literature on 3 separable effects of numeric self-efficacy. Although dual-process theories can account for the generally superior decision making of the highly numerate, they have neglected effects of numeric self-efficacy. We discuss implications for medical decision-making (MDM) research and practice. Finally, we propose a modification to dual-process theories, adding a "motivational mind" to integrate the effects of numeric self-efficacy on decision-making processes (i.e., inferences from experienced difficulty with numbers, greater persistence, and greater use of objective-numeracy skills) important to high-quality MDM. CONCLUSIONS: The power of numeric self-efficacy (confidence) has been little considered in MDM, but many medical decisions and behaviors require persistence to be successful over time (e.g., comprehension, medical-recommendation adherence). Including numeric self-efficacy in research and theorizing will increase understanding of MDM and promote development of better decision interventions. HIGHLIGHTS: Research demonstrates that objective numeracy supports better medical decisions and health outcomes.The power of numeric self-efficacy (aka numeric confidence) has been little considered but appears critical to emotional reactions and inferences that patients and others make when encountering numeric information (e.g., in decision aids) and to greater persistence in medical decision-making tasks involving numbers.The present article proposes a novel modification to dual-process theory to account for newer findings and to describe how numeracy mechanisms can be better understood.Because being able to adapt interventions to improve medical decisions depends in part on having a good theory, future research should incorporate numeric self-efficacy into medical decision-making theories and interventions.

Novel Approaches and Cognitive Neuroscience Perspectives on False Memory and Deception.

The DRM (Deese-Roediger-McDermott) paradigm produces robust false memories of non-presented critical words. After studying a thematic word list (e.g., bed, rest, and pillow) participants falsely remember the critical item "sleep." We report two false memory experiments. Study One introduces a novel use of the lexical decision task (LDT) to prime critical words. Participants see two letter-strings and make timed responses indicating whether they are both words. The word pairs Night-Bed and Dream-Thweeb both prime "sleep" but only one pair contains two words. Our primary purpose is to introduce this new methodology via two pilot experiments. The results, considered preliminary, are promising as they indicate that participants were as likely to recognize critical words (false memories) and presented words (true memories) just as when studying thematic lists. Study Two actually employs the standard DRM lists so that semantic priming is in play there as well. The second study, however, uses functional near-infrared spectroscopy (fNIRS) to measure activity in the prefrontal cortex during a DRM task which includes a deception phase where participants intentionally lie about critical lures. False and true memories occurred at high levels and activated many of the same brain regions but, compared to true memories, cortical activity was higher for false memories and lies. Accuracy findings are accompanied by confidence and reaction time results. Both investigations suggest that it is difficult to distinguish accurate from inaccurate memories. We explain results in terms of activation-monitoring theory and Fuzzy Trace Theory. We provide real world implications and suggest extending the present research to varying age groups and special populations. A nagging question has not been satisfactorily answered: Could neural pathways exist that signal the presence of false memories and lies? Answering this question will require imaging experiments that focus on regions of distinction such as the anterior prefrontal cortex.

Fluency and confidence predict paramedic diagnostic intuition: An experimental study of applied dual-process theory.

INTRODUCTION: We report an experiment using Australian paramedics (n = 64) and Australian paramedicine undergraduates (n = 44), on the processes underlying the formation of an intuitive diagnostic impression, based on limited dispatch information. Previous research has signalled roles for objective likelihood of the disease, subjective typicality of the disease, and the ease with which the diagnosis comes to mind (answer fluency) as important in impression formation. METHOD: Participants completed four brief written clinical vignettes under time pressure and with a concurrent navigation task to simulate conditions faced by paramedics prior to meeting a patient. Diagnostic impression, confidence and subjective typicality of the vignette were self-reported while answer fluency was measured. The vignettes varied the objective likelihood of a diagnosis of Acute Coronary Syndrome (ACS), a condition often encountered by paramedics. RESULTS: Likelihood, answer fluency, self-reported typicality and confidence predicted the impression but there was no effect of experience. Students and experienced paramedics had comparable accuracy and performance. CONCLUSION: The results support a role for answer fluency and confidence in forming that impression. We have shown it is possible to experimentally manipulate various factors associated with paramedic diagnostic impressions. These experimental methods can form the basis for additional studies into paramedic decision making.