The reaction to frustration of middle- and lower-class children.
Explore the source record for details and available documents.
Child↗
SEARCH · PubMed Health
Results for “Probability Learning”
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.
Orienting of attention in deafferented patients.
Visual attentional processes were compared in two deafferented patients and 11 normal subjects. Two consecutive stimuli were presented in rapid succession in one of two locations. A peripheral cue first oriented attention to one location where a response was requested. After 100 msec, a second response was required at either the same or opposite location (valid vs invalid cue). Four probabilities of valid cue occurrence were presented: 100, 80, 50 and 20%. Results showed (1) faster reaction times for the second response on cued than on uncued signals; (2) greater attentional effects with increased cue probability; (3) smaller attentional effects in patients. These findings suggest that the patients adopted a cost-minimizing strategy.
Adult↗
Detection and discrimination of simple and complex patterns at low spatial frequencies.
Explore the source record for details and available documents.
Discrimination, Psychological↗
Emotional memory systems in the brain.
The neural mechanisms of emotion and memory have long been thought to reside side by side, if not in overlapping structures, of the limbic system. However, the limbic system concept is no longer acceptable as an account of the neural basis of memory or emotion and is being replaced with specific circuit accounts of specific emotional and memory processes. Emotional memory, a special category of memory involving the implicit (probably unconscious) learning and storage of information about the emotional significance of events, is modeled in rodent experiments using aversive classical conditioning techniques. The neural system underlying emotional memory critically involves the amygdala and structures with which it is connected. Afferent inputs from sensory processing areas of the thalamus and cortex mediate emotional learning in situations involving specific sensory cues, whereas learning about the emotional significance of more general, contextual cues involves projections to the amygdala from the hippocampal formation. Within the amygdala, the lateral nucleus (AL) is the sensory interface and the central nucleus the linkage with motor systems involved in the control of species-typical emotional behaviors and autonomic responses. Studies of cellular mechanisms in these pathways have focused on the direct relay to the lateral amygdala from the auditory thalamus. These studies show that single cells in AL respond to both conditioned stimulus and unconditioned stimulus inputs, leading to the notion that AL might be a critical site of sensory-sensory integration in emotional learning. The thalamo-amygdala pathway also exhibits long-term potentiation, a form of synaptic plasticity that might underlie the emotional learning functions of the circuit. The thalamo-amygdala pathway contains and uses the amino acid glutamate in synaptic transmission, suggesting the possibility that an amino-acid mediated form of synaptic plasticity is involved in the emotional learning functions of the pathway. We are thus well on the way to a systems level and a cellular understanding of at least one form of emotional learning and memory.
Animals↗
Amplitude variations in P300 component due to unpredictable stepwise change of stimulus probability.
The present study investigates whether the amplitude of the P300 in 'normal' subjects adapts to unexpected changes in global stimulus probability. The adaptation level (AL) metrics (in terms of Helson's [1964] theory) was applied to explain the variations in the P300 amplitude. In an oddball paradigm the probability of the deviant tone (target 1000 Hz, 80 dB, 50 ms) occurring randomly in a train of standard ones (non-target 1100 Hz, 80 dB, 50 ms) was changed in a stepwise way from 0.5 to 0.3 and then to 0.1 in 3 blocks without interruption of the stimulus presentation. Two experiments were performed. In the first one the subjects did not receive any prior information about the changes in the stimulus probability, whereas in the second experiment they were aware of such changes. The task always required the subject to silently count the deviants. EEG was recorded monopolarly from Fz, Cz and Pz in a total of 15 subjects. The block averaged P300 increased monotonically with probability, the increase being larger in Expt. II. In contrast to the block averaged P300, the variations in the P300 amplitude following the abrupt change in probability showed a non-linear dependency. On the basis of the AL a simulation of the time course of the P300 variations with probability was performed and a clear similarity between the simulated P300 and the experimental data was found. Some properties of the AL model are discussed.
Acoustic Stimulation↗
Dissociation of intake adjustments to sustained and day-to-day changes in food caloric density.
Rats were subjected to day-to-day changes in food caloric density superimposed on a sustained (average) change above or below the basal value. This was done by giving them a different diet every day, so that caloric density gradually increased from a basal value. By repeating this procedure the caloric density varied in a sinusoidal pattern above or below the basal value. Short-term compensatory changes in food intake followed a reversed and delayed sinusoidal pattern (compared to that of caloric density), and achieved only an incomplete compensation of caloric intake. On the other hand, long-term changes in the average food intake led to a complete compensation of the average caloric intake for the high-calorie diets. The low-calorie diets produced a marked body weight loss, although these rats maintained the partly compensatory responses to the day-to-day changes in caloric density; that is, food intake decreased when the caloric density of the diet increased to the basal value, overriding any effect of body weight loss. It is concluded that short-term and long-term controls of food intake are relatively independent of each other and that the short-term control determines the daily caloric intake, with a delay that probably indicates learning processes, while the long-term control is determining the average caloric intake over a period of several days, accounting for a more or less complete compensation of caloric density changes.
Analysis of Variance↗
Differential conditioning of electrodermal responses: effects of performing a masking task during the interstimulus and intertrial intervals.
Explore the source record for details and available documents.
Adolescent↗
Channel probability and Nd: an event-related potential sign of attention strategies.
Event-related potentials were recorded in a two-channel selective attention paradigm designed to assess the effects of channel probability on processing negativity. For channel probabilities of 70% or greater, the subtraction Nd for standard tones was greatly reduced or absent. This change was due to apparent processing negativity in the waveform of the irrelevant standards at high channel probabilities. Deviant long tones showed similar early Nds to standard tones, and also developed late attention-related negativity commencing at about 500 ms from stimulus onset. It was concluded that there was no evidence that processing negativity to the relevant tones, defined as a negative component associated with selective attention, is affected by channel probability. Changes in Nd amplitude as the channel probabilities became more unequal were attributed to changes in strategies used by subjects, which primarily altered ERPs associated with the irrelevant tones.
Adult↗
Stimulus probability and motor response in young and old adults: an ERP study.
The effects of responding hand and stimulus probability were investigated in young and old subjects in an RT task in which both rare and frequent stimuli required a response. It was found that the effect of stimulus probability was less pronounced in old subjects than in young, and that the latency of P3 was longer in the elderly, although their RTs were not different from young subjects. ERPs for right hand responses were larger than for left hand responses; this difference was discernible already in the P2 and N2 peaks of the ERP. A tentative explanation is offered for these large and unexpected hand differences. An interpretation in terms of an age-related decrease in resources is proposed for the increased P3 latency and the decreased probability effect on P3 amplitude in old subjects.
Adolescent↗
Time effects on event-related brain potentials and vigilance performance.
A review of the literature showed that in vigilance or oddball tasks, changes over time in event-related potentials (ERPs) and performance measures often seem to be unrelated, but a number of studies had some shortcomings. In the present study a visual vigilance experiment was carried out, in which single-trial ERPs and performance data of 40 males were obtained. A relationship between time trends in behavioral and ERP measures was found: an early P3 amplitude and response latency (RT) showed an inversely varying relation over time. Analysis of covariance showed that the two linear trends tap the same aspect of processing: both trends became insignificant when adjusted for common variance. A negative correlation between mean values of P3 amplitude and RT rather than for change scores has been observed in previous studies, but has been ignored in the literature. However, correlations with RT have also been reported for other ERP deflections. Although there were several correlations between mean scores, most time-induced changes in ERP parameters appeared to be unrelated to worsening performance, for which several explanations are advanced. The ERP results do not support the hypothesis that a decrement in performance is caused by increasing difficulty discriminating targets from nontargets. A gradual decline in effort or resources allocated to the task might be an alternative explanation of performance deterioration. However, an effort-hypothesis cannot easily be tested. Effort is often invoked post hoc, and has previously been associated with many ERP components. The relationship between ERPs and the signal detection measures "sensitivity" d' and "response bias" beta is discussed.
Adolescent↗
Cognitive load as a determinant of the dimensionality of the electroencephalogram: a replication study.
A sequel study to that reported by Gregson, Britton, Campbell and Gates (1990), partially replicating and extending findings which relate estimates of the dimensionality of the EEG to the complexity of task load in a visual scanning task, is described. The correlation dimensionality D2 of the attractor was computed using a variant of the Grassberger-Procaccia algorithm, and was shown to change in the expected direction, increasing as the task became more complicated. The effects are slight but consistent, and may be attenuated by nonstationarity over time, and by idiosyncratic factors. The results are numerically and qualitatively compatible with other recent reported studies, and support an interpretation linking brain dynamics to implied cognitive processes.
Adult↗
On the relationship between background EEG and the P300 event-related potential.
Background EEG was recorded from 24 subjects under eyes open/closed conditions for 5 min. The P3(00) event-related brain potential (ERP) was elicited with auditory stimuli when eyes were open/closed in the same subjects. Target stimulus probability was manipulated (0.20, 0.40, 0.60, 0.80) in different blocks under each eyes open/closed condition. Spectral analysis indicated that EEG power between 8 and 12 Hz demonstrated a similar scalp distribution as the P3 component of the ERP for the electrode sites employed. Spectral power and mean frequency were modestly correlated with P3 amplitude and peak latency primarily in the slower EEG bands, with associations observed across probability conditions and often strongest when target stimulus probability was .20. The results suggest that differences between individuals for EEG variation may contribute to P3 component variability, especially at the parietal recording site and under low target stimulus probability conditions when the P3 is largest and most stable.
Adolescent↗
Pathological gambling treated with cognitive behavior therapy: a case report.
A novel approach to the cognitive behavioral treatment of pathological gambling is described. The approach is based on the hypothesis that biased information may form the basis of the rules governing gambling behavior. The treatment focused on modifying assumptions and beliefs underlying the gambling behavior of a 47-year-old male with a 26-year gambling history. Based on a 6-month follow-up, the intervention successfully reduced the frequency of the client's gambling behavior from 10 times per month in the 3 years prior to treatment to three total times in the 6-month follow-up period.
Alcoholism↗
Objectives to direct the training of emergency medicine residents in off-service rotations: plastic surgery.
This is the fourth article in a continuing series on objectives for emergency medicine training; plastic surgery objectives will be presented. Plastic surgery topics overlap many in emergency medicine. Specific behaviorally based objectives for mastery of skills in plastic surgery are outlined. Specific references are provided for additional information and reinforcement in skill mastery. The basic concepts of plastic surgery are probably best learned by observation and supervised performance. Specific objectives provide guidance and direction for the didactic as well as the supervised experiences in skill mastery. These objectives provide a structure for systematically learning and mastering the content presented on a plastic surgical rotation or experience in emergency medicine training.
Education↗
Taking advice, using information and knowing what you are doing.
Subjective descriptions of judgment policies have been found to be imperfect. This could be because subjective weights are obtained on just a single occasion after all judgments have been completed. It could also be because people have tended to state their perception of an ideal way of responding rather than their perception of how they actually responded. Finally, it could be because they experience difficulty in relating variation in stimulus dimensions to variation in quite different response dimensions. In our task, people made sales forecasts on the basis of four pieces of information. They also stated the weight they placed on each one and the weight they should have placed on it. The means of weights stated on each trial were more appropriate than those stated at the end of all trials. Stated actual weights were very similar to stated ideal weights. Weights were more appropriate when forecasts and cues varied along the same dimension than when they did not. Thus, our results are consistent with the view that all three factors affect people's ability to provide subjective descriptions of their judgment policies.
Adult↗
Probability ratings in claustrophobic patients and normal controls.
Forty-nine DSM-IV diagnosed claustrophobics and 49 sex- and age-matched community controls, without any current or past psychiatric disorder, were asked to estimate the probability that three types if events would occur if they were in the described situations. The events were claustrophobic, generally negative, and positive in nature. The results showed that claustrophobics significantly overestimated the probability of events they specifically feared, i.e. the claustrophobic events, while there was no difference between the groups regarding generally negative events and positive events. This finding remained when the higher scores for claustrophobics on the Claustrophobia scale and the Anxiety Sensitivity Index were covaried out. The conclusion that can be drawn is that claustrophobics' probability ratings are characterized by distortions that are specifically connected to anxiety-arousing events and not negative events in general. The hypothesis is proposed that this may be explained by an exaggerated use of simplified rules-of-thumb for probability estimations that build on availability in memory, simulation, and representativity.
Adult↗
Solving probabilistic and statistical problems: a matter of information structure and question form.
Is the human mind inherently unable to reason probabilistically, or is it able to do so only when problems tap into a module for reasoning about natural frequencies? We suggest an alternative possibility: naive individuals are able to reason probabilistically when they can rely on a representation of subsets of chances or frequencies. We predicted that naive individuals solve conditional probability problems if they can infer conditional probabilities from the subset relations in their representation of the problems, and if the question put to them makes it easy to consider the appropriate subsets. The results of seven studies corroborated these predictions: when the form of the question and the structure of the problem were framed so as to activate intuitive principles based on subset relations, naive individuals solved problems, whether they were stated in terms of probabilities or frequencies. Otherwise, they failed with both sorts of information. The results contravene the frequentist hypothesis and the evolutionary account of probabilistic reasoning.
Adult↗
Gigerenzer's normative critique of Kahneman and Tversky.
Gigerenzer has argued that it may be inappropriate to characterize some of the biases identified by Kahneman and Tversky as "errors" or "fallacies," for three reasons: (a) according to frequentists, no norms are appropriate for single-case judgments because single-case probabilities are meaningless; (b) even if single-case probabilities make sense, they need not be governed by statistical norms because such norms are "content-blind" and can conflict with conversational norms; (c) conflicting statistical norms exist. I try to clear up certain misunderstandings that may have hindered progress in this debate. Gigerenzer's main point turns out to be far less extreme than the position of "normative agnosticism" attributed to him by Kahneman and Tversky: Gigerenzer is not denying that norms appropriate for single-case judgments exist, but is rather complaining that the existence and the nature of such norms have been dogmatically assumed by the heuristics and biases literature. In response to this complaint I argue that single-case probabilities (a) make sense and (b) are governed by probabilistic norms, and that (c) the existence of conflicting statistical norms may be less widespread and less damaging than Gigerenzer thinks.
Bias↗