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At least 217 records · Page 12Linked to original sources
PubMed2006

Likelihood ratio, optimal decision rules, and correct response probabilities in a signal detection theoretic, equal-variance Gaussian model of the observer in the 4IAX paradigm.

This article provides a synthetic account of the likelihood ratio, optimal decision rules, and correct response probabilities in a signal detection theoretic model of the observer in the dual-pair comparison, or four-interval AX (4IAX), paradigm. The model assumes a static sampling process, resulting in four, equal-variance normally distributed (i.e., Gaussian) observations on each trial First, a likelihood ratio equation allowing for an arbitrary degree of correlation between observations is provided. Specific solutions for the cases of independent and highly correlated observations are then derived. It is shown that these solutions, and the associated decision rules, correspond to those provided independently in earlier publications. A modified 4IAX paradigm involving, as a standard, an additional stimulus (C) located medially between the A and the B stimuli is also considered. It is shown that the optimal (static, equal-variance, Gaussian) decision model for this paradigm is unaffected by correlation between observations and is equivalent to the standard 4IAX with highly correlated observations. Finally, we consider how, under the considered (static, equal-variance, Gaussian) model, the proportion of correct responses in the different versions of the 4IAX paradigm is related to d', and a solution for the case of independent observations is provided.

Decision Making↗
PubMed2001

Some contributions of signal detection theory to the analysis of stimulus control in animals.

This paper reviews some applications of Signal Detection Theory (SDT) to the quantitative analysis of non-human animal discrimination. The basic detection model is briefly outlined and the separation of sensitivity and bias is illustrated. Several other applications and ideas are reviewed, including the rating method, some implications of signal and criterion variance, and the measurement of 'guesses' not encompassed by standard SDT. The conceptual framework and analytic tools of SDT help to clarify processes underlying stimulus control and provide direction to more complete process models.

Journal Article↗
PubMed2000

Signal detection theory in the 2AFC paradigm: attention, channel uncertainty and probability summation.

Neural implementation of classical High-Threshold Theory reveals fundamental flaws in its applicability to realistic neural systems and to the two-alternative forced-choice (2AFC) paradigm. For 2AFC, Signal Detection Theory provides a basis for accurate analysis of the observer's attentional strategy and effective degree of probability summation over attended neural channels. The resulting theory provides substantially different predictions from those of previous approximation analyses. In additive noise, attentional probability summation depends on the attentional model assumed. (1) For an ideal attentional strategy in additive noise, summation proceeds at a diminishing rate from an initial level of fourth-root summation for the first few channels. The maximum improvement asymptotes to about a factor of 4 by a million channels. (2) For a fixed attention field in additive noise, detection is highly inefficient at first and approximates fourth-root summation through the summation range. (3) In physiologically plausible root-multiplicative noise, on the other hand, attentional probability summation mimics a linear improvement in sensitivity up to about ten channels, approaching a factor of 1000 by a million channels. (4) Some noise sources, such as noise from eye movements, are fully multiplicative and would prevent threshold determination within their range of effectiveness. Such results may require reappraisal of previous interpretations of detection behavior in the 2AFC paradigm.

Attention↗
PubMed2006

Signal detection theory, the approach of choice: model-based and distribution-free measures and evaluation.

New and old methods of analyzing two-choice experiments with confidence ratings are evaluated. These include the theory of signal detectability (TSD), Luce's choice theory,nonparametric techniques based on areas under receiver-operating characteristic (ROC) functions, andmethods based on S' and omega, proposed by Balakrishnan and his colleagues. New methods for assessing the bias of a complete ROC function are proposed, together with an additional area-based measure of response bias. Area measures of both sensitivity and bias proved the most consistent. Response bias for a full ROC function was larger than bias at the cut point and also provided additional information. Participants showed voluntary control of bias for all measures except omega. Unequal variance versions of TSD and choice models gave similar fits to data, with the choice model closer to an equal variance version. Discrimination data from Balakrishnan (1999) formed the empirical test bed.

Choice Behavior↗
PubMed2004

Mask-dependent attentional cuing effects in visual signal detection: the psychometric function for contrast.

A spatial-cuing paradigm was used to test the hypothesis of Carrasco, Penpeci-Talgar, and Eckstein (2000) that the mask-dependent cuing effects found in visual signal detection by Smith (2000a) were caused by submaximal activation of the transient-orienting system. Mask-dependent cuing was found with a range of stimulus contrasts with pure peripheral cues and with the mixed central-peripheral cues of Smith (2000a), contrary to the predictions of the submaximal activation hypothesis. The use of a pedestal detection task to control spatial uncertainty showed that the cuing effect was due to signal enhancement. A model of mask-dependent cuing is described, which assumes that attention affects the rate of information accumulation from the display and that masks limit the visual persistence of the stimulus. The model correctly predicts differential mask dependencies in sensitivity for detection and discrimination and the associated patterns of response times.

Adolescent↗
PubMed2006

Repeated inhalation of toluene by rats performing a signal detection task leads to behavioral tolerance on some performance measures.

Previous work showed that trichloroethylene (TCE) impairs sustained attention as evidenced by a reduction in accuracy and elevation of response latencies in rats trained to perform a visual signal detection task (SDT). This work also showed that these effects abate during repeated exposures if rats inhale TCE while performing the SDT. The present experiment sought to determine whether toluene, another commonly-used solvent, would induce tolerance similarly if inhaled repeatedly during SDT testing. Sixteen male, Long-Evans rats were trained to perform the SDT. Upon completion of training, rats were divided into 2 groups. In Phase I, concentration-effect functions were determined for toluene (0, 1200, 1600, 2000, 2400 ppm) in both groups. Toluene reduced the proportion of correct responses [P(correct)], and increased response time (RT) and response failures. In Phase II, Group-Tol inhaled 1600 ppm toluene while Group-Air inhaled clean air during 11 daily SDT sessions. In Group-Tol the effect of toluene on P(correct) abated after 3 days, while RT remained elevated for the duration of the repeated exposures. In Phase III, toluene concentration-effect functions were re-determined for both groups. Group-Air remained impaired on all test measures, whereas for Group-Tol, toluene did not reduce P(correct), but continued to increase RT. These data confirm our previous hypothesis that animals can develop tolerance to chemical exposures that impair appetitively-motivated behaviors if that impairment leads to loss of reinforcement.

Administration, Inhalation↗
PubMed2000

The effect of shared responsibility and competition in perceptual games: a test of a cognitive game-theoretic extension of signal-detection theory.

Perceptual decisions are often made in complex social settings in which distinct observers can affect each other. To address such situations, I. Erev, D. Gopher, R. Itkin, and Y. Greenshpan (1995) proposed a formal extension of signal-detection theory and a descriptive modification of the extended theory. The current article presents 2 experiments that were designed to test these models in the context of repeated 2-person perceptual safety games. In both experiments, pairs of participants performed a simulation of an industrial-production process under distinct payoff rules. Each participant had to try to produce as much as possible while avoiding costly accidents. In line with the descriptive model's predictions, the results showed a slow adjustment to the incentive structure that can be approximated by a reinforcement learning process among different perceptual cutoff strategies. Providing players with prior information about the game had an initial effect but did not alter the pattern of the results.

Adult↗
PubMed2007

The mirror effect and mixture signal detection theory.

The mirror effect for word frequency refers to the finding that low-frequency words have higher hit rates and lower false alarm rates than high-frequency words. This result is typically interpreted in terms of conventional signal detection theory (SDT), in which case it indicates that the order of the underlying old item distributions mirrors the order of the new item distributions. However, when viewed in terms of a mixture version of SDT, the order of hits and false alarms does not necessarily imply the same order in the underlying distributions because of possible effects of mixing. A reversal in underlying distributions did not appear for fits of mixture SDT models to data from 4 experiments.

Attention↗
PubMed1996

Comparison of the BOLD- and EPISTAR-technique for functional brain imaging by using signal detection theory.

Two magnetic resonance imaging techniques, BOLD (blood oxygenation level dependent) and EPISTAR (echo-planar imaging and signal targeting with alternating radio-frequency), were compared for functional brain imaging. Ten volunteers were imaged performing a sequential finger to thumb opposition task alternating with no movement conditions. Techniques were compared using variance maps and signal detection theory (ROC analysis). True positive activation in regions of interest with expected task-dependent signal changes were computed versus false activation rates in regions in which no activation was expected. D-prime coefficients were calculated for each comparison and statistically compared using a paired t test. Activation in the perirolandic region was seen in all volunteers with both techniques. There was no significant difference for the d-prime between BOLD and EPISTAR. These results indicate that based on a different physiologic principle, EPISTAR is an alternative to BOLD to perform fMRI with similar results.

Adult↗
PubMed2005

Dissociation between judgments and outcome-expectancy measures in covariation learning: a signal detection theory approach.

A number of studies using trial-by-trial learning tasks have shown that judgments of covariation between a cue c and an outcome o deviate from normative metrics. Parameters based on trial-by-trial predictions were estimated from signal detection theory (SDT) in a standard causal learning task. Results showed that manipulations of P(c) when contingency (deltaP) was held constant did not affect participants' ability to predict the appearance of the outcome (d') but had a significant effect on response criterion (c) and numerical causal judgments. The association between criterion c and judgment was further demonstrated in 2 experiments in which the criterion was directly manipulated by linking payoffs to the predictive responses made by learners. In all cases, the more liberal the criterion c was, the higher judgments were. The results imply that the mechanisms underlying the elaboration of judgments and those involved in the elaboration of predictive responses are partially dissociable.

Attitude↗
PubMed2004

Comparison of spatial filter selectivity in surface myoelectric signal detection: influence of the volume conductor model.

Spatial filters are used for increasing selectivity in surface EMG signal detection. The study investigated the importance of the description of the volume conductor to the inference of conclusions on comparing filter selectivity from simulation analyses. A cylindrical multi-layer description of the volume conductor was used for the simulation analysis. Different anatomies were analysed with this model, and results on filter selectivity were compared. The longitudinal single (LSD), double (LDD) and normal double differential (Laplacian, NDD) filters were investigated. Largely different conclusions could be drawn when comparing filter selectivity resulting from simulations with different volume conductor models. A filter that performed best with a particular anatomy could be the poorest with another anatomy. With a bone-muscle model and superficial fibres, the ratio between peak-to-peak values of the propagating and non-propagating signal components was approximately 220% for LDD and LSD and lower than for NDD (approximately 290%). With a bone-muscle-fat-skin model, LSD performed significantly worse (150%) than both LDD and NDD, which showed similar performances (approximately 300%). Similarly, if the lateral distance of the recording was increased by 10 degrees, the signal amplitude was reduced to 2% with LSD and LDD and to 4% with NDD. With another anatomy, LSD and LDD reduced signal amplitude to 20-25%, and NDD reduced it to 4%. Similar considerations could be drawn for other selectivity indexes. Thus, modelling should be used carefully to infer conclusions on spatial selectivity and to indicate particular choices of spatial filters.

Action Potentials↗
PubMed1999

Body size perception in anorexia nervosa: a signal detection approach.

This study investigated whether individuals with anorexia nervosa (AN) visualize themselves as fatter than they are because they perceive themselves as fatter. Females with AN who overestimated their own body size judged size differences between pictures of their own body, and then again of someone else's body. Signal detection analysis of the results showed no differences in perceptual sensitivity between the AN and normal and thin control groups. No significant correlations were found between body size estimates and perceptual sensitivity. The anorexic group did, however, show a bias to report seeing "thin" differences, which was opposite to that of thin controls. Because bias differences between the groups were significant while sensitivity differences were not, it was concluded that abnormalities of body image most probably arise during reconstruction of the visual body image, rather than during perception of the body.

Adult↗
PubMed2001

Somatosensory processing in the biological relatives of schizophrenia patients: a signal detection analysis of two-point discrimination.

This study examined 2-point discrimination performance in 1 st-degree biological relatives (n = 39) of individuals with schizophrenia and normal adult control participants (n = 30) recruited from the community. They completed an objective 2-point discrimination task, adapted for use with a signal detection approach to permit separation of discriminability (i.e., sensitivity, d') from response bias/ criterion (or motivation, lnbeta). Relatives revealed poorer performance on the d' index compared with controls. The 2 groups did not differ on lnbeta, suggesting a genuine difference in sensitivity but not response bias. The sensitivity deficit might reflect decreased spatial acuity and/or impaired intensity cue processing of tactile stimuli. Poor performance on the d' index was most closely associated with 2 schizotypic features, namely "odd beliefs/magical thinking."

Adult↗
PubMed1979

Signal detection theory and pain research.

Rollman [13,14] has clearly raised important questions about the application of signal detection (TSD) procedures to the study of the perceived painfulness of stimuli. Researchers have often failed to realize that the discriminability of two usually painful stimuli need not be related to their reported painfulness. Thus indices of discrimination accuracy derived form TSD are logically (though not necessarily empirically) independent of the analgesic properties of any treatment. However, Rollman misleadingly gives the impression that he is questioning the general validity of the application of TSD to answering questions in pain research. This is not the case. Procedures derived from TSD may play an important part in answering questions of interest to pain researchers especially as Rollman has exaggerated the practical difficulties associated with TSD experiments. It must be emphasized that there is no one TSD model as Rollman often seems to imply but a variety of models [5,9]. The usefulness of any model in any situation is a matter for experiment. Rollman has certainly criticized effectively one dubious analogy to TSD procedures which pain researchers have used. That is not the same as questioning the general usefulness of TSD models.

Acoustic Stimulation↗
PubMed1979

Signal detection theory pain measures: empirical validation studies and adaptation-level effects.

Proponents of the use of signal detection theory (SDT) in the assessment of pain modulation have generally looked for changes in d' to indicate a reduction of sensory function, and a change in criterion to indicate a modification of the subject's response bias or attitudinal predisposition. In the first experiment, both assumptions failed to receive empirical verification. Discrimination d' was eqivalent before and after two strong levels of electrical current was reduced. The criterion parameter appeared to shift in a more conservative direction after the stimulus diminution. These results are used to question the validity of both detection and discrimination indices in the measurement of pain. An alternative means for describing the experimental results revealed a striking adaptation-level effect with implications for the assessment of both experimentally induced and endogenous pain. The outcome of a second experiment reinforced the adaptation-level theory interpretation of the results and provided additional evidence concerning the difficultuies in evaluating SDT parameters in studies of potential analgesics.

Discrimination, Psychological↗
PubMed2003

He said, she said: a quasi-signal detection analysis of daily interactions between close relationship partners.

In everyday life, close relationship partners enact behaviors through which they may influence each other. To understand how these exchanges affect partners, previous research has emphasized the enactors' reports, the receivers' perceptions, or the congruence of the two. We developed a strategy based on classic signal detection theory that combined elements from these three approaches in a naturalistic daily experience study. Members of 58 heterosexual dating couples reported daily on their own behaviors and their perceptions of their partners' behaviors. Results showed that an enactor's beliefs about his or her behavior and the perceiver's interpretation combined to affect daily mood and relationship satisfaction. However, different patterns of results emerged for positive and negative behaviors, such that the enactor's perspective accounted for independent effects of negative behaviors. Results show the value of simultaneously considering the perspective of both parties in social interaction.

Adult↗
PubMedDate not supplied

Imageability and word recognition in the left and right visual fields: a signal detection analysis.

Identifying the information processing constraints that determine whether or not imagery moderates visual field asymmetries is essential for constructing a dynamic model of hemispheric interaction during language processing. In this investigation, we manipulated the global experimental context in which imageable and nonimageable words were presented by contrasting mixed and blocked word lists using a lateralized lexical decision task. Signal detection analyses were employed to assess whether global stimulus context and imageability differentially affect word discriminability (d prime) and response bias (log beta) across visual fields. Both discriminability and response bias varied with imageability and stimulus context, but to a comparable extent across visual fields. This suggests that both hemispheres are sensitive to the global context in which words are presented, and can adjust processing based not only on semantic characteristics of the words themselves, but also on the variability of items in the stimulus environment.

Cognition↗
PubMed2005

An introduction to Bayesian hierarchical models with an application in the theory of signal detection.

Although many nonlinear models of cognition have been proposed in the past 50 years, there has been little consideration of corresponding statistical techniques for their analysis. In analyses with nonlinear models, unmodeled variability from the selection of items or participants may lead to asymptotically biased estimation. This asymptotic bias, in turn, renders inference problematic. We show, for example, that a signal detection analysis of recognition memory data leads to asymptotic underestimation of sensitivity. To eliminate asymptotic bias, we advocate hierarchical models in which participant variability, item variability, and measurement error are modeled simultaneously. By accounting for multiple sources of variability, hierarchical models yield consistent and accurate estimates of participant and item effects in recognition memory. This article is written in tutorial format; we provide an introduction to Bayesian statistics, hierarchical modeling, and Markov chain Monte Carlo computational techniques.

Bayes Theorem↗