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At least 181 records · Page 10Linked to original sources

In defense of the signal detection interpretation of remember/know judgments.

Donaldson (1996) argued that remember/know judgments can be conceptualized within a signal detection framework by assuming that they are based on two criteria situated along a strength-of-memory decision axis. According to this model, items that exceed a high criterion receive a remember response, whereas items that only exceed a lower criterion receive a know response. Although a variety of findings have been presented in evidence against this idea, Dunn (2004) recently showed that detection theory is fully compatible with those findings. We present a variety of new results and new analyses that weigh strongly in favor of the detection interpretation. We further show that a dual-process account of recognition memory is compatible with a unidimensional detection model despite the common notion that such a model necessarily assumes a single process. The key assumption of this model is that individual recognition decisions are based on both recollection and familiarity (not on one process or the other).

Humans↗

A Signal Detection Theory analysis of the effect of chest cage restriction upon the detection of inspiratory resistive loads.

1. By the use of Signal Detection Theory techniques, resistive load detection sensitivity was estimated in six normal subjects, and compared with detection when the chest cage was strapped in the position of full expiration. 2. With chest cage restriction there was both a decrease in detection sensitivity and an increase in the willingness to report the presence of an added load to breathing. 3. This suggests that the similarity of detection in chest clamping and control previously reported was due partly to increased detection bias with chest clamping. 4. These results have implications concerning the dependence of detection on afferent information from the chest wall.

Adult↗

Signal-detection analysis of nonverbal recognition memory in dementia.

A signal-detection analysis was applied to performance on two non-verbal recognition memory tasks for 21 subjects with presumed dementia of the Alzheimer type, 19 subjects with presumed multi-infarct dementia, and 19 elderly depressed subjects. Performance was best for the depressed and worst for the Alzheimer subjects. Response bias did not differ significantly among groups. Within the depressed group, more impaired and older subjects were more conservative on one test. Correlations suggested that the sensitivity and response-bias measures may depend on the type of material used and so have limited generality.

Aged↗

Awareness of P300-related cognitive processes: a signal detection approach.

Although the P300 component of the human event-related potential is purported to indicate consciousness of an event, it is unclear which of the P300-related processes, if any, are accessible to awareness. This study explored awareness of such processes in Bernoulli series of auditory stimuli using signal detection theory and selective averaging of ERPs according to the subjects' classifications. Following targets eliciting appropriate P300 amplitudes, the subject was requested to classify his brain response as small, medium, or large, whereupon visual feedback was given about the correctness of the response. Averaging the ERPs according to the subjects' classifications showed P300 amplitudes to increase with the classification category, whereas the prestimulus and post-P300 event-related potentials were unrelated to the category. Signal detection analysis revealed non-zero sensitivity measures for the P300 amplitude categories. Although no conclusive suggestion can be made at present as to the basis of the P300 discrimination ability found here, it was possible to rule out electro-ocular and electromyographic activity, the preceding auditory stimulus, and the prior feedback given, as cues for discrimination.

Adult↗

Signal-detection analysis of recognition memory of obese subjects.

Obese and normal-weight subjects were run on a series of recognition-memory tasks with low and high meaningful CVC trigrams. Subjects received feedback or no feedback regarding the appropriateness of their answers during testing for recognition memory. A signal-detection analysis was used to examine a relatively pure index of memory (d') as compared to response-bias factors [Ln (beta)]. No significant main effect on memory of obese and control subjects was noted although a significant interaction indicated that obese subjects' memory increases over trials in a differential fashion from normal-weight individuals with poorer performance among the obese after 3 trials. Feedback facilitated memory for both groups. Analysis of response criteria [Ln (beta)] showed no significant difference between groups. Highly meaningful trigrams had a significantly lower response criterion than low meaningful trigrams and there was a significant interaction of meaningfulness by trials. An interaction of feedback by meaningfulness was also present. Advantages of using a signal-detection analysis in memory studies comparing obese and normal weight subjects are discussed. Ramifications of the present data for the internality/externality hypothesis of obesity are also discussed.

Adolescent↗

Initial storage of unfamiliar objects: examining memory stores with signal detection analyses.

The memory source(s) underlying performance of the object decision task were examined. Application of signal detection theory with independent indices of sensitivity and bias indicated that greater object decision sensitivity (possible vs. impossible object discrimination) is observed for primed than for unprimed objects and a greater bias to respond "possible" is observed for primed than for unprimed objects. To test whether a single memory store underlies the two effects, we assessed whether the two effects would be influenced in similar ways by a particular experimental manipulation. Sensitivity did not differ between processing of 180 degrees -rotated primed objects vs. un-rotated primed objects, but bias to respond "possible" differed between those conditions in predictable ways depending on the cerebral hemisphere of direct test presentations. Results support a conciliatory resolution to the debate concerning memory in this task and help to clarify properties of memory stores underlying the initial storage of unfamiliar objects.

Adult↗

Flexibility of noncompetitive avidin-biotin immunoassay: immunoassay of lutropin applied to different signal detection systems.

I adapted the noncompetitive avidin-biotin immunoassay (NABA) of lutropin (LH) for use with radiometric, fluorometric, time-resolved fluorometric, and luminometric detection systems by changing the enzyme substrate or conjugating avidin with different labels. The corresponding methods were used to determine LH in 40 urine samples, and the results were compared with those obtained by an immunoenzymometric assay (IEMA), also based on the NABA principle. Scatter plots of the results showed a linear relation with high correlation coefficients (r = 0.972-0.983), and bias plots showed good agreement between the four comparison methods and the IEMA. The results indicate that the effectiveness of the NABA of LH is independent of the signal detection system. This means good flexibility for the user in choice of instrument and signal detection system.

Avidin↗

A signal-detection theory based perspective on design of warning.

The effects of warnings are analyzed using a distributed signal-detection theory model. It is established that selectivity always increases effectiveness. The implications to optimal warning design for intermittent versus continuous hazards are discussed. The changes in the behavior of the 6 human subjects in response to changes in the warning levels are consistent with the predictions of the model.

Accident Prevention↗

Placebo application, personality, and headaches: a signal detection theory analysis of experimentally induced pain in comparison to clinical pain.

45 patients suffering from severe chronic intermittent headaches were divided into 3 groups matched for sex, and assigned to a double-blind 5-week cross-over design with 3 X 1 g/d metamizole--a mild analgesic of the pyrazolone type--a placebo, or a no-treatment control condition. For each of the 6 sessions (t0-t5) signal detection theory parameters d' and log beta for assessment of electrical pain perception and headache ratings on the preceding treatment period were obtained. At t0 all patients were examined via a personality inventory. There were no significant drug effects on headache and signal detection theory parameters, but a clear decrease of the discrimination index d' and of clinical pain over time, regardless of the mode of treatment. No relationship between pathological and experimentally induced pain could be demonstrated. There was no significant negative correlation between response bias of judgement of stimulus intensity (log beta) and neuroticism.

Adult↗

Nicotine-alcohol interactions and attentional performance on an operant visual signal detection task in female rats.

Nicotine and alcohol are very often co-used and co-abused. Thus, it is important to understand their interactions. In many ways, nicotine and alcohol have opposing effects. This can be clearly seen in terms of their effects on cognitive function. Nicotine effectively improves attention while alcohol impairs it. The current study was conducted to determine in a rat model the interaction of nicotine and alcohol on attention using an operant visual signal detection task. It is hypothesized that nicotine would reverse the alcohol-induced impairment in accuracy of performance in this task. Female Sprague-Dawley rats (N=35) were trained on a visual operant signal detection task for food reinforcement with 300 trials/session in three equal time blocks. The rats were divided into poor and good performers according to their predrug baseline performance accuracy. The first experiment examined the dose-effect function of alcohol (0, 0.375, and 0.75 g/kg i.p.) on this task. The lower alcohol dose significantly impaired percent correct rejection in the high-performing rats but not the low-performing rats. The higher alcohol dose significantly impaired percent hit performance during the first two thirds of the session in both high- and low-performing groups. The second experiment examined alcohol (0.75 g/kg i.p.) interactions with nicotine (0, 12.5, 25, and 50 microg/kg s.c.) on attentional performance. The 25 and 50 microg/kg nicotine doses caused a significant (P<.05) improvement in hit accuracy. Alcohol blocked this nicotine-induced improvement, even though at this later time it no longer had an effect of its own. In the high baseline group, the 25 microg/kg nicotine dose also caused a significant (P<.025) improvement in hit accuracy. As in Experiment 1, the high baseline group was not significantly impaired by 0.75 g/kg of alcohol. However, this alcohol dose did eliminate the nicotine-induced improvement. These results suggest that alcohol, when given alone, impairs sustained attention and blocks nicotine-induced attentional improvements even when it does not cause impairments on its own.

Animals↗

Is local myocardial contractility related to endocardial acceleration signals detected by a transvenous pacing lead?

The availability of sensors monitoring cardiac function parameters may offer many interesting new applications in cardiac pacing. A microaccelerometer sensor (BEST, Biomechanical Endocardial Sorin Transducer) located at the tip of a pacing lead (PL) has been developed by Sorin Biomedica. The signal detected by the accelerometer, peak endocardial acceleration (PEA), was shown to reflect cardiac contractility and to be related to the dP/dt signal. Whether the PEA detected by the BEST sensor in different cardiac locations is the expression of local acceleration forces or reflects the whole heart contractility has not yet been demonstrated in humans. Endocardial acceleration and PEA were evaluated in five patients (4 males, 1 female, mean age 68 years) who underwent cardiac catheterization. Sinus rhythm was present in four patients and chronic atrial fibrillation was present in one. The BEST PL was introduced through the left subclavian vein and PEA signals were recorded: (1) at the apex of the right ventricle (RV), (2) within the coronary sinus (CS), (3) at the right atrial appendage (RAA), and (4) floating in the right atrium. The PEA signals were recorded simultaneously with surface ECG, intracardiac electrograms, and RV pressure. At each recording site, PEA signals with significant amplitude were always recorded during the preejection period, during the isovolumic contraction phase, independently of the recording site and cardiac rhythm. The PEA amplitude was higher in the RV (mean value 1.32 g) and it decreased in the RAA and CS (0.75 and 0.45 g, respectively). The same behavior of PEA was observed during sinus rhythm or atrial fibrillation. The amplitude and the timing of the PEA signals detected by the BEST accelerometer were independent of the recording site and atrial rhythm; they appeared to be strictly related to the global ventricular contractility. These results suggest that the BEST could be used either as an effective sensor in closed loop pacing systems, or primarily as a diagnostic hemodynamic sensor.

Acceleration↗

Signal detection analysis of recognition memory in depressed elderly.

The purpose of this study was to examine the relationship of late-life depression to memory complaint and objective performance in a recognition memory task. Fifty-seven individuals between the ages of 58 and 88 were evaluated for depression using the Beck Depression Inventory (short form). They were then shown two stimulus lists, each consisting of high-imagery and low-imagery words. Recognition for these words was subsequently tested. Error rates and nonparametric signal detection measures were analyzed as indices of performance. Respondents gave global self-assessments of memory and, during the recognition task, also made self-ratings of performance. Depressed individuals showed more conservative response biases than nondepressed respondents, reflected in a higher false-negative error rate but a lower false-positive rate. Neither overall memory sensitivity as assessed by signal detection analysis nor self-ratings of performance were related to depression, though global memory self-ratings were. Elderly depressed individuals thus presented a pattern of greater memory complaint and unwillingness to venture responses in spite of showing small or no information-processing deficits.

Aged↗

Signal detection theory analyses of semantic priming in word recognition.

Word recognition, semantic priming, and cognitive impenetrability research have used signal detection theory (SDT) measures to separate perceptual and postperceptual processes. In the D. Norris (1986) checking model and model simulation (D. Norris, 1995), priming alters only postperceptual word decision criteria: Stimulus-related priming reduces uncertainty, increasing sensitivity; stimulus-unrelated priming increases false alarms more than hits, reducing sensitivity. This work is cited as strong evidence that criterion changes can alter perceptual sensitivity and that SDT is inappropriate for investigating complex cognitive processes. The authors' current SDT ideal observer analysis of the model demonstrates that related priming does not directly alter sensitivity and that unrelated priming increases only false-alarm rate, reducing sensitivity. This analysis provides new perspectives on SDT concepts of complex decision processing.

Humans↗

Cautiousness and hearing acuity in elderly women: a signal detection approach.

Hearing loss in elderly women was investigated with respect to measures of sensory and decision processes in an auditory signal detection task. A 1000Hz signal was used as the stimulus and a 6-point response category scale was employed. Subject biases were obtained from 6 normal hearing and 6 moderately hearing impaired elderly adults (65-76 yr). Results indicated that the subjects set a conservative criterion, regardless of hearing loss, and tended to use a binary decision process.

Aged↗

Effects of d-amphetamine and morphine on delayed discrimination: signal detection analysis and assessment of response repetition in the performance deficits.

Signal detection analysis was used to examine the effects of d-amphetamine and of morphine on delayed visual discrimination (delay intervals: 0-4-8-16 s) in male rats. The probability of response repetition in the discrete trial two-choice discrimination procedure was used as an additional behavioral measure. d-Amphetamine (0.16-0.33 mg/kg) decreased SI ( a measure of the animals' sensitivity to the discriminative stimuli) at delays between stimulus presentation and opportunity for responding of 4-16 s, and did not affect SI at the 0 s delay. Morphine (1-3 mg/kg) decreased SI at all delay conditions. d-Amphetamine, but not morphine, affected RI (a measure of the animals' bias towards responding on one lever or the other) and increased the probability of response repetition. The bias measure B inches was affected neither by d-amphetamine nor by morphine. It is concluded that d-amphetamine, but not morphine, produces a deterioration of delayed discrimination performance, probably as a result of drug-induced response perseveration. It is suggested that, under the conditions of the present study, the selective deterioration of discrimination performance after d-amphetamine at delays which are longer than 0 s may not be primarily related to a drug-induced disruption of a short-term memory mechanism, but may be related to drug effects on response output.

Animals↗

Lowered responsiveness and auditory signal detectability during depression.

Ten depressed patients were assessed on an auditory signal detection task; testing was repeated on remission. The patients' clinical state was monitored by means of the Hamilton rating scale and the Beck Depression Inventory. The task was performed under three conditions: 2 button (Yes/No); 1 button (Yes); 1 button (No). The findings indicated lower motor responsiveness during depression, consistent with Seligman's learned helplessness model. The measure of auditory sensitivity was also lowered during depression, possibly attributable to attentional disturbance. It is suggested that the lowered initiation of voluntary responses may be an important factor in the assessment of cognitive functioning during depression; such deficits may be reduced if the task does not permit the omission of a response.

Auditory Perception↗

Signal detection methods for measurement of utility in animals.

Analytic methods of signal detection theory were employed to assess the utility of reinforcers. Four pigeons were trained to detect the presence or absence of a stimulus by pecking one of two side keys in a trial-by-trial choice paradigm. The relative rate of positive reinforcement for correct choices was varied to offset the biasing effects of electric shock for incorrect right side-key choices. The effects of relative rate of reinforcement on bias were similar at all shock intensities even though the subjects' sensitivity changed during the course of the experiment. The relative rate of reinforcement required to produce equal bias was calculated and plotted against shock intensity to generate utility functions. The relative rate of reinforcement necessary to offset the bias induced by shock was an increasing function of shock intensity.

Journal Article↗

Application of the theory of signal detectability to the perception of differences in load.

In applying the theory of signal detectability to the perception of differences in load on a bicycle ergometer, the distributions of signal and noise were tested for normality and equality of variances. Two subjects cycled on a basic load of 40% of their VO2 max. Each subject operated under five different response criteria. The results showed that the assumptions of normality and equality of variance were observed in both cases.

Adult↗