Deciding about decision models of remember and know judgments: a reply to Murdock (2006)

B. B. Murdock (2006) has interpreted remember-know data within a decision space defined by item and associative information, the fundamental variables in his general recognition memory model TODAM (B. B. Murdock, 1982). He has related parameters of this extended model to stimulus characteristics for several classic remember-know data sets. The authors show that this accomplishment is shared by both one- and two-dimensional signal-detection-based remember-know models (J. C. Dunn, 2004; C. M. Rotello, N. A. Macmillan, & J. A. Reeder, 2004; J. T. Wixted & V. Stretch, 2004), which can be represented in this same decision space and can be related to stimulus characteristics with similar success. Murdock claims that his model, unlike its competitors, is a process model; however, the process aspects of TODAM are not used in his application, and the decision aspects are identical to a previously proposed model. Murdock's claim that one competing model (STREAK; C. M. Rotello et al., 2004) is not fully specified is shown to be false. The new model is not superior to existing ones, but comparisons among the models to date are not definitive. The authors describe several strategies that might be applied to distinguish among them.     

Vitamins E and C pretreatment prevents ovariectomy-induced memory deficits in water maze

We investigated whether the pretreatment with vitamins E (alpha-tocopherol) and C (ascorbic acid) would act on ovariectomy-induced memory deficits in Morris water maze tasks. Adult female Wistar rats were divided into three groups: (1) naive (control), (2) sham (submitted to surgery without removal of ovaries) and (3) ovariectomized. Thirty days after surgery, they were trained in the Morris water maze in order to verify ovariectomy effects both on reference and working memory tasks. Results show that ovariectomized rats presented impairment in spatial navigation in the acquisition phase, as well as in the time spent in target quadrant and in the latency to cross over the location of the platform in test session, when compared to naive and sham groups (controls), in the reference memory task. Ovariectomy did not affect performance in the working memory task. Confirming our hypothesis, ovariectomized rats pretreated for 30 days with vitamins E and C had those impairments prevented. We conclude that ovariectomy significantly impairs spatial reference learning/memory and that pretreatment with vitamins E and C prevents such effect. Assuming this experimental memory impairment might mimic, at least in part, the cognitive deficit sometimes present in the human condition of lack of reproductive hormones, our findings lend support to a novel therapeutic strategy, based on vitamins E and C, to cognitive impairments in post-menopausal women.     

Causal conditionals and counterfactuals

Causal counterfactuals e.g., 'if the ignition key had been turned then the car would have started' and causal conditionals e.g., 'if the ignition key was turned then the car started' are understood by thinking about multiple possibilities of different sorts, as shown in six experiments using converging evidence from three different types of measures. Experiments 1a and 1b showed that conditionals that comprise enabling causes, e.g., 'if the ignition key was turned then the car started' primed people to read quickly conjunctions referring to the possibility of the enabler occurring without the outcome, e.g., 'the ignition key was turned and the car did not start'. Experiments 2a and 2b showed that people paraphrased causal conditionals by using causal or temporal connectives (because, when), whereas they paraphrased causal counterfactuals by using subjunctive constructions (had…would have). Experiments 3a and 3b showed that people made different inferences from counterfactuals presented with enabling conditions compared to none. The implications of the results for alternative theories of conditionals are discussed.     

Mixing strong and weak targets provides no evidence against the unequal-variance explanation of ʐROC slope: a comment on Koen and Yonelinas (2010)

Koen and Yonelinas (2010; K&Y) reported that mixing classes of targets that had short (weak) or long (strong) study times had no impact on ?ROC slope, contradicting the predictions of the encoding variability hypothesis. We show that they actually derived their predictions from a mixture unequal-variance signal detection (UVSD) model, which assumes 2 discrete levels of strength instead of the continuous variation in learning effectiveness proposed by the encoding variability hypothesis. We demonstrated that the mixture UVSD model predicts an effect of strength mixing only when there is a large performance difference between strong and weak targets, and the strength effect observed by K&Y was too small to produce a mixing effect. Moreover, we re-analyzed their experiment along with another experiment that manipulated the strength of target items. The mixture UVSD model closely predicted the empirical mixed slopes from both experiments. The apparent misfits reported by K&Y arose because they calculated the observed slopes using the actual range of ?-transformed false-alarm rates in the data, but they computed the predicted slopes using an extended range from - 5 to 5. Because the mixed predictions follow a slightly curved ?ROC function, different ranges of scores have different linear slopes. We used the actual range in the data to compute both the observed and predicted slopes, and this eliminated the apparent deviation between them.     

Error Detection, Task Characteristics, and Some Consequences for Software Design

On a étudié la détection des erreurs par les utilisateurs d'ordinateur à partir de la théorie de l'action. On a effectué, pour des raisons de validités externe et interne, à la fois une recherche sur le terrain et deux expériences de laboratoire exploitant un traitement de texte. La problématique portait sur le taux de détection de différents types d'erreurs, l'impact de la complexité de la tâche sur la détection des erreurs et la question de la détection programmée des erreurs. Les résultats débouchent sur un meilleur taux de détection (96,5%) dans la recherche de terrain (par rapport au taux obtenu dans les expériences). Les erreurs apparaissant dans les tâches complexes étaient plus difficiles à détecter. En outre, la moitié de la totalité des erreurs pouvaient être détectées par les seuls utilisateurs. Pas plus de 22% des erreurs étaient détectées avec l'aide du système informatique. Ce sont les erreurs dans les travaux complexes que la détection aidée par le système déjouait le plus difficilement. On propose, comme application pratique, une stratégie de gestion des erreurs qui ferait appel à un processus de traitement des erreurs relevant du software.     

Measures of sensitivity based on a single hit rate and false alarm rate: The accuracy, precision, and robustness of′,A z, andA’

Signal detection theory offers several indexes of sensitivity (d’,A _z, andA’) that are appropriate for two-choice discrimination when data consist of one hit rate and one false alarm rate per condition. These measures require simplifying assumptions about how target and lure evidence is distributed. We examine three statistical properties of these indexes: accuracy (good agreement between the parameter and the sampling distribution mean), precision (small variance of the sampling distribution), and robustness (small influence of violated assumptions on accuracy). We draw several conclusions from the results. First, a variety of parameters (sample size, degree of discriminability, and magnitude of hits and false alarms) influence statistical bias in these indexes. Comparing conditions that differ in these parameters entails discrepancies that can be reduced by increasing N. Second, unequal variance of the evidence distributions produces significant bias that cannot be reduced by increasing N—a serious drawback to the use of these sensitivity indexes when variance is unknown. Finally, their relative statistical performances suggest thatA _z is preferable toA’.     

Decision Making with Uncertain Information: Learning from Women in a High Risk Breast Cancer Clinic

Patients and practitioners may believe that clinically validated laboratory tests provide definitive information. Genetic counselors know this is not always so, and the possibility of inconclusive genetic test results is often discussed in the pretest counseling session. This added discussion topic prolongs the process of genetic counseling, but if there is inadequate patient understanding, patient frustration may be high when receiving a result of uncertain significance, and patients may make decisions about subsequent medical management based on incorrect assumptions. For patients/participants in a research setting, where the clinical validity of testing may be unclear, some patients/participants may still want to use test results to influence their medical management. This paper presents findings from a qualitative study wherein 15 women from the High Risk Breast Cancer Clinic at Utah's Huntsman Cancer Institute discussed how uncertainty regarding results affected their decision making. The women were randomly selected from 3 categories--women with test results of uncertain significance; women without cancer who have a mutation; and women who are members of high-risk families, but for whom no mutation was found. Study findings will be used in future studies to better understand how to improve communication regarding uncertain results, especially in a research environment.     

The sampling distributions of Gaussian ROC statistics

For a discrimination experiment, a plot of the hit rate against the false-alarm rate--the ROC curve--summarizes performance across a range of confidence levels. In many content areas, ROCs are well described by a normal-distribution model and the z-transformed hit and false-alarm rates are approximately linearly related. We examined the sampling distributions of three parameters of this model when applied to a ratings procedure: the area under the ROC (Az), the normalized difference between the means of the underlying signal and noise distributions (da), and the slope of the ROC on z-coordinates (s). Statistical bias (the degree to which the mean of the sampling distribution differed from the true value) was trivial for Az, small but noticeable for da, and substantial for s. Variability of the sampling distributions decreased with the number of trials and was also affected by the number of response categories available to the participant and by the overall sensitivity level. Figures in the article and tables available on line can be used to construct confidence intervals around ROC statistics and to test statistical hypotheses.     

Sum-difference theory of remembering and knowing: a two-dimensional signal-detection model

In the remember-know paradigm for studying recognition memory, participants distinguish items whose presentations are episodically remembered from those that are merely familiar. A one-dimensional model postulates that remember responses are just high-confidence old judgments, but a meta-analysis of 373 experiments shows that the receiver operating characteristic (ROC) curves predicted by this model have the wrong slope. According to the new sum-difference Theory of remembering and knowing (STREAK), old items differ from new ones in both global and specific memory strength: The old-new judgment is based on a weighted sum of these dimensions, and the remember- know judgment is based on a weighted difference. STREAK accounts for the form of several novel kinds of ROC curves and for existing remember-know and item-recognition data.     

Scene perception and memory revealed by eye movements and receiver-operating characteristic analyses: does a cultural difference truly exist?

Cultural differences have been observed in scene perception and memory: Chinese participants purportedly attend to the background information more than did American participants. We investigated the influence of culture by recording eye movements during scene perception and while participants made recognition memory judgements. Real-world pictures with a focal object on a background were shown to both American and Chinese participants while their eye movements were recorded. Later, memory for the focal object in each scene was tested, and the relationship between the focal object (studied, new) and the background context (studied, new) was manipulated. Receiver-operating characteristic (ROC) curves show that both sensitivity and response bias were changed when objects were tested in new contexts. However, neither the decrease in accuracy nor the response bias shift differed with culture. The eye movement patterns were also similar across cultural groups. Both groups made longer and more fixations on the focal objects than on the contexts. The similarity of eye movement patterns and recognition memory behaviour suggests that both Americans and Chinese use the same strategies in scene perception and memory.