PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Signal Detection, Psychological”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources

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↗

Schizophrenic deficits in the processing of context. A test of a theoretical model.

BACKGROUND: Schizophrenic patients show various deficits in cognitive functions that have been difficult to understand in terms of a common unifying hypothesis. Previously described neural network models of cognitive tasks suggest that several schizophrenic performance deficits may be related to a single function-an impairment in maintaining contextual information over time and in using that information to inhibit inappropriate responses. METHODS: We tested first-episode schizophrenic patients and patients later in the course of their illness on a new variant of the Continuous Performance Test designed specifically to elicit deficits in the processing of contextual information. RESULTS: Unmedicated schizophrenic patients showed a deterioration of their signal detection performance that followed the pattern predicted by the context hypothesis, ie, they responded inappropriately when correct responding required the maintenance of context information over time to inhibit the expression of a habitual response. This deficit correlated with positive symptoms. The results also suggested that the deficit may be worse in unmedicated patients who have had a longer course of illness. Medicated patients showed a more diffuse performance deficit. CONCLUSIONS: These results support the view that a single deficit in the processing of context information may underlie various cognitive impairments observed in schizophrenia. They also suggest that such an impairment is associated with positive rather than negative symptoms, and that it may worsen with the course of the illness as in the kraepelinian view of schizophrenia.

Adult↗

Decision rules for recognition memory confidence judgments.

According to the standard signal-detection model of recognition memory, confidence judgments for recognition responses are reached in much the same way that old-new decisions are reached (i.e., on the basis of criteria situated along the strength-of-evidence axis). The question investigated here is how the confidence criteria shift when recognition accuracy is manipulated across conditions. Although several theories assume that the old-new decision criterion shifts when recognition accuracy changes, less is known about how the confidence criteria move. An analysis of data previously reported by R. Ratcliff, G. McKoon, and M. Tindall (1994) and some new data reported here suggest that the confidence criteria fan out on the decision axis as d' decreases. This result is qualitatively consistent with the predictions of a likelihood ratio model, although the data did not support the stronger quantitative predictions of this account.

Adult↗

Fuzziness of nonverbal courtship communication unblurred by motion energy detection.

A new method for the assessment of qualitative description of nonverbal behavior (automatic movie analysis) is introduced. This model-free method does not use any assumptions on the structure and organization of nonverbal behavior. Cross-cultural comparison (Germany, Japan) of unobtrusively filmed initial interactions between 2 opposite-sex strangers revealed no consistent courtship repertoire of directly observable behavior categories. Furthermore, an extensive analysis of gaze behavior and speech revealed differences between the countries but also showed no consistent relation to interest. Motion energy detection demonstrated in both cultures that female movement quality score (number of movements, duration, size, speed, and complexity) covaries with female interest. This effect is in concordance with the theory that in early stages of interactions manipulative efforts occur in order to avoid possible deception in high-risk situations.

Adolescent↗

A signal detection model predicts the effects of set size on visual search accuracy for feature, conjunction, triple conjunction, and disjunction displays.

Recently, quantitative models based on signal detection theory have been successfully applied to the prediction of human accuracy in visual search for a target that differs from distractors along a single attribute (feature search). The present paper extends these models for visual search accuracy to multidimensional search displays in which the target differs from the distractors along more than one feature dimension (conjunction, disjunction, and triple conjunction displays). The model assumes that each element in the display elicits a noisy representation for each of the relevant feature dimensions. The observer combines the representations across feature dimensions to obtain a single decision variable, and the stimulus with the maximum value determines the response. The model accurately predicts human experimental data on visual search accuracy in conjunctions and disjunctions of contrast and orientation. The model accounts for performance degradation without resorting to a limited-capacity spatially localized and temporally serial mechanism by which to bind information across feature dimensions.

Adult↗

Selective visual attention ensures constancy of sensory representations: testing the influence of perceptual load and spatial competition.

We report findings from several variants of a psychophysical experiment using an acceleration detection task in which we tested predictions derived from recent neurophysiological data obtained from monkey area MT. The task was designed as a Posner paradigm and required subjects to detect the speed-up of a moving bar, cued with 75% validity. Displays varied according to number of simultaneously presented objects, spatial distance, and difficulty of the task. All data obtained under different levels of competition with multiple objects were compared to a corresponding condition, in which only a single moving bar was presented in the absence of any interfering distracter object. For attended objects, subjects did not show any difference in their ability to detect accelerations, regardless of the strength of inter-object competition or spatial distance. This finding was consistent in all of the experiments, and was even obtained when the acceleration was made hardly detectable. In contrast, increasing competitive interactions either by enhancing number of objects or spatial proximity resulted in strong reduction of performance for non-attended objects. The findings support current noise reduction models and suggest that attention adjusts neuronal processing to ensure a constant sensory representation of the attended object as if this object was the only one in the scene.

Adult↗

Perceptual learning in contrast detection: presence and cost of shifts in response criteria.

Contemporary theoretical accounts of perceptual learning typically assume that observers are either unbiased or stably biased across the course of learning. However, standard methods for estimating thresholds, as they are typically used, do not allow this assumption to be tested. We present an approach that allows for this test specific to perceptual learning for contrast detection. We show that reliable decreases in detection thresholds and increases in hit rates are not uniformly accompanied by reliable increases in sensitivity (d'), but are regularly accompanied by reliable liberal shifts in response criteria (c). In addition, we estimate the extent to which sensitivity could have increased in the absence of these liberal shifts. The results pose a challenge to the assumption that perceptual learning has limited or no impact on response criteria.

Adult↗

Involvement of the mediodorsal thalamic nucleus in mediating recollection and familiarity.

The mediodorsal (MD) thalamic nucleus is thought to play an important role in memory processes. Distinct hippocampal-thalamic-prefrontal connections have been described as the potential neural substrate for both, recollection and familiarity. The aim of this study was to investigate whether the MD is part of the circuits underlying these two memory components. We assessed the effects of ischemic thalamic lesions with or without MD involvement on performance in a word list discrimination task and standard tests of memory and executive function. Estimates of recollection and familiarity were derived using the dual-process signal-detection model (DPSD). The results revealed impairments in both, recollection and familiarity, after unilateral thalamic damage, with recollection being more affected than familiarity. There were no significant differences in the memory performance of patients with MD lesions compared to patients with ventrolateral-thalamic lesions except for familiarity estimates, which were lower for the latter group. Lesions involving the MD led to recollection deficits, although inspection of individual cases suggested a decrease in both memory components after damage in the medial part of this nucleus. Executive dysfunction was associated with lateral MD lesions and also ventrolateral-thalamic damage. The findings suggest that MD contributes to recollection, with some preliminary evidence of a contribution of the medial MD to familiarity. The small sample size does, however, not yet allow any clear conclusions in this regard. Since damage in the ventrolateral thalamus leads to memory and executive dysfunction, further research is needed to elucidate the role of this thalamic region in cognition.

Brain Ischemia↗

Crime scene staging and its detection.

Crime scene staging is a recognized phenomenon within the criminal justice field. This article defines the occurrence for staging, identifies the motives for staging, and identifies the act that precipitated the staging. It reports the results of an exploratory survey of 20 well-versed and highly trained law enforcement officers' experience with staging in fatal and nonfatal incidents, and it reports the most commonly observed forms of crime scene staging. Investigative strategies and indicators of staging are also presented.

Attention↗

Aging and individual differences in rapid two-choice decisions.

The effects of aging on performance were examined in signal detection, letter discrimination, brightness discrimination, and recognition memory, with each subject tested on all four tasks. Ratcliff's (1978) diffusion model was fit to the data for each subject for each task, and it provided a good account of accuracy and the distributions of correct and error response times. The model's analysis of the components of processing showed that aging had three main effects: The nondecision components of processing were slower and the decision criteria were more conservative for 60- to 74-year-old and 75- to 85-year-old subjects than for college students, but the quality of the evidence on which decisions were based was as good for the older subjects as for college students on some of the tasks. Individual differences among subjects in components of processing tended to be preserved across the tasks, as was shown by strong correlations across the tasks in the parameters of the model that represent the components of processing. For example, if the evidence on which a subject's decisions were based was good in one task, it tended to be good in all four tasks.

Aged↗

The effects of practice on object-based, location-based, and static-display inhibition of return.

We report two experiments that examine the effects of practice on object-based, location-based, and static-display inhibition of return (IOR). The results are clear: All three effects get smaller with practice. These findings are at odds with the results of Müller and von Mühlenen (1996), who failed to observe object-based IOR and detected no effect of practice on static-display IOR. However, their subjects were more practiced than ours prior to data collection. We suggest, therefore, that the reducing effect of practice on IOR have occurred in their unrecorded practice sessions. We also discuss a two-process model in which IOR is seen as the net effect of underlying inhibitory and excitatory processes. In such models (e.g., Solomon & Corbit, 1974), practice often results in a reduction of the net effect of the two processes.

Adolescent↗

Challenges in real-life emotion annotation and machine learning based detection.

Since the early studies of human behavior, emotion has attracted the interest of researchers in many disciplines of Neurosciences and Psychology. More recently, it is a growing field of research in computer science and machine learning. We are exploring how the expression of emotion is perceived by listeners and how to represent and automatically detect a subject's emotional state in speech. In contrast with most previous studies, conducted on artificial data with archetypal emotions, this paper addresses some of the challenges faced when studying real-life non-basic emotions. We present a new annotation scheme allowing the annotation of emotion mixtures. Our studies of real-life spoken dialogs from two call center services reveal the presence of many blended emotions, dependent on the dialog context. Several classification methods (SVM, decision trees) are compared to identify relevant emotional states from prosodic, disfluency and lexical cues extracted from the real-life spoken human-human interactions.

Artificial Intelligence↗

Discrimination of complex patterns: orientation information is integrated across spatial scale; spatial-frequency and contrast information are not.

Real-world objects are complex, containing information at multiple orientations and spatial scales. It is well established that at initial cortical stages of processing, local information about an image is separately represented at multiple spatial scales. However, it is not yet established how these early representations are later integrated across scale to signal useful information about complex stimulus features, such as edges and textures. In the studies reported here, we investigate the scale-integration processes involved in distinguishing among complex patterns. We use a concurrent-response paradigm in which observers simultaneously judge two components of compound gratings that differ widely in spatial frequency. In different experiments, each component takes one of two slightly different values along the dimensions of spatial frequency, contrast, or orientation. Using analyses developed within the framework of a multivariate extension of signal-detection theory, we ask how information about the frequency, contrast, or orientation of the components is or is not integrated across the two grating components. Our techniques permit us to isolate and identify interactions due to excitatory or inhibitory processes from effects due to noise, and to separately assess any attentional limitations that might occur in processing. Results indicate that orientation information is fully integrated across spatial scales within a limited orientation band and that decisions are based entirely on the summed information. Information about spatial frequency and contrast is not summed over spatial scale; cross-scale results show sensory independence. However, our results suggest that observers cannot simultaneously use information about frequency or contrast when it is presented at different spatial scales. Our results provide direct evidence for the existence of a higher-level summing circuit tailored to signal information about orientation. The properties of this mechanism differ substantially from edge-detector mechanisms proposed by Marr and others.

Female↗

The ironies of vehicle feedback in car design.

Car drivers show an acute sensitivity towards vehicle feedback, with most normal drivers able to detect 'the difference in vehicle feel of a medium-size saloon car with and without a fairly heavy passenger in the rear seat' (Joy and Hartley 1953-54). The irony is that this level of sensitivity stands in contrast to the significant changes in vehicle 'feel' accompanying modern trends in automotive design, such as drive-by-wire and increased automation. The aim of this paper is to move the debate from the anecdotal to the scientific level. This is achieved by using the Brunel University driving simulator to replicate some of these trends and changes by presenting (or removing) different forms of non-visual vehicle feedback, and measuring resultant driver situational awareness (SA) using a probe-recall method. The findings confirm that vehicle feedback plays a key role in coupling the driver to the dynamics of their environment (Moray 2004), with the role of auditory feedback particularly prominent. As a contrast, drivers in the study also rated their self-perceived levels of SA and a concerning dissociation occurred between the two sets of results. Despite the large changes in vehicle feedback presented in the simulator, and the measured changes in SA, drivers appeared to have little self-awareness of these changes. Most worryingly, drivers demonstrated little awareness of diminished SA. The issues surrounding vehicle feedback are therefore similar to the classic problems and ironies studied in aviation and automation, and highlight the role that ergonomics can also play within the domain of contemporary vehicle design.

Automation↗

Age differences in noise and variability of isometric force production.

This study examined whether age-related improvements observed in the motor performance of children result from a reduction of noise in the output of the sensori-motor system. Children ages 6, 8, and 10 years and young adults (N = 48, 12 per group) performed continuous, constant isometric force contractions with the index finger at four different force levels with and without visual feedback. The results revealed that: (a) performance improved with increases in age, (b) the force output signal exhibited increased irregularity and a more broadband frequency profile with increases in age under conditions with feedback, and (c) there were no age differences in the irregularity of the force signal and smaller age differences in the frequency profiles under conditions without feedback. It is proposed that the age-related enhancements in performance throughout childhood are primarily due to a more appropriate mapping of the organization of the sensori-motor system to the task constraints rather than to reduction of system noise.

Adolescent↗

The effect of gender in the perception of elder physical abuse in court.

Two experiments investigated mock jurors' perceptions of elder abuse (EA) in a physical assault case. In Experiment 1, participants read a fictional criminal trial summary of a physical assault case in which the alleged victim was 66, 76, or 86 years old. In Experiment 2, the age of the alleged victim was 76 years old, but the gender of the alleged victim and the gender of the defendant were crossed. The results of the experiments showed that women believed the alleged victim more and rendered a guilty verdict more often than men. Overall, the alleged victim was believed more than the defendant regardless of the age of the alleged victim, and most verdicts were guilty. These results are discussed in terms of the factors that affect perceptions of alleged victims of EA in court.

Aged↗

An empirical test of the behaviour analysis interview.

The present experiment is the first empirical test of the Behaviour Analysis Interview (BAI), an interview technique developed by F. E. Inbau, J. E. Reid, J. P. Buckley, & B. C. Jayne (2001) designed to evoke different verbal and non-verbal responses from liars and truth-tellers. Inbau et al. expect liars to be less helpful than truth-tellers in investigations and to exhibit more nervous behaviours. Just the opposite predictions, however, follow from the deception literature, which notes that liars take their credibility less for granted and are therefore more aware of their responses and their impact on others. This suggests that liars' answers should be more helpful than truth-tellers' answers, and liars' non-verbal responses should appear more relaxed than truth-tellers' non-verbal responses. In the present experiment, 40 participants (undergraduate students) lied or told the truth about an event during a BAI interview. The interviews were coded according to Inbau et al.'s guidelines. The results showed that, compared to liars, truth-tellers (a) were more naive and evasive when explaining the purpose of the interview, and (b) were less likely to name someone who they felt certain did not commit the crime. Truth-tellers also exhibited more nervous behaviours. The results were consistent with the predictions of the deception literature, and directly opposed to the predictions of BAI.

Adolescent↗

Effects of stimulus-stimulus compatibility and stimulus-response compatibility on response inhibition.

Previous studies demonstrated that interference control in stimulus-stimulus compatibility tasks slowed down stopping in the stop signal task (e.g., Kramer, A. F., Humphrey, D. G., Larish, J. F., Logan, G. D., & Strayer, D. L. (1994). Aging and inhibition: beyond a unitary view of inhibitory processing in attention. psychology and aging, 9, 491-512). In the present study, the impact of stimulus-stimulus compatibility and stimulus-response compatibility on response inhibition is further investigated. In Experiment 1, the stop signal task was combined with a traditional horizontal Simon task and with a vertical variant. For both dimensions, stopping responses was prolonged in incompatible trials, but only when the previous trial was compatible. In Experiment 2, the Simon task was combined with a spatial Stroop task in order to compare the effects of stimulus-stimulus and stimulus-response compatibility. The results demonstrated that both types of compatibility influenced stopping in a similar way. These findings are in favor of the hypothesis that response inhibition in the stop signal task and interference control in conflict tasks rely on similar mechanisms.

Attention↗