Probability of being correct with 1 of M orthogonal signals.
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Attention↗
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Results for “Probability Learning”
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Probability inequalities for testing separate activation models of divided attention.
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Arousal↗
Manipulating the disengage operation of covert visual spatial attention.
Processes of covert visual spatial attention have been closely linked to the programming of saccadic eye movements. In particular, it has been hypothesized that the reduction in saccadic latency that occurs in the gap paradigm is due to the prior disengagement of covert visual spatial attention. This explanation has received considerable criticism. No study as yet as attempted to demonstrate a facilitation of the disengagement of attention from a covertly attended object. If such facilitation were possible, it would support the hypothesis that the predisengagement of covert attention is necessary for the generation of express saccades. In two experiments using covert orienting of visual attention tasks (COVAT), with a high probability that targets would appear contralateral to the cued location, we attempted to facilitate the disengagement of covert attention by extinguishing peripheral cues prior to the appearance of targets. We hypothesized that the gap between cue offset and target onset would facilitate disengagement of attention from a covertly attended object. For both experiments, responses to targets appearing after a gap were slower than were responses in the no-gap condition. These results suggest that the prior offset of a covertly attended object does not facilitate the disengagement of attention.
Adolescent↗
The influence of adaptation and stochastic fluctuations on spontaneous perceptual changes for bistable stimuli.
Spontaneous perceptual change was studied by measuring the probabilities of the first two spontaneous pattern switches as a function of time following the onset of a bistable apparent quartet for which either horizontal or vertical motion is perceived. Contrary to the classical satiation hypothesis (Köhler & Wallach, 1944), differential time-dependent adaptation of the perceived compared with the unperceived motion directions was not necessary to account for the first spontaneous switch. In addition, adaptation of the perceived motion accompanied by recovery from adaptation of the unperceived motion was not necessary to account for the increased probability of the second spontaneous switch. It was concluded that regardless of possible adaptation effects, stochastic fluctuations are necessary for the actual reversal of activation levels that produces the spontaneous switch. When the difference in detector activation is reduced by differential adaptation of competing motion detectors (or by the occurrence of a prior spontaneous pattern change), smaller stochastic fluctuations are sufficient to reverse the relative activation of competing detectors. Thus, adaptation can increase the probability of spontaneous switches without directly causing them.
Adaptation, Ocular↗
Effects of amount of attention allocated to the location of visual stimulus pairs on perception of simultaneity.
This study was examined whether a change in the amount of attention equally allocated to two locations affects judgments of the simultaneity or successiveness of stimuli presented at those locations. Observers were cued to expect two brief flashes either to the left and right of fixation or above and below fixation. Stimulus onset asynchrony was randomly varied. On a small proportion of trials, the stimuli appeared at the unexpected locations. Observers were more likely to report the stimuli as simultaneous when they appeared in the unexpected locations. A model proposed to account for the data assumes that a brief stimulus event is represented by a probability distribution reflecting the uncertainty in determining the time of the event's occurrence, and two events are judged to be simultaneous if they are perceived to fall within some critical temporal interval, c, which is a function of the amount of attention allocated to the task.
Adult↗
The psychological side of Hempel's paradox of confirmation.
People often test hypotheses about two variables (X and Y), each with two levels (e.g., X1 and X2). When testing "If X1, then Y1," observing the conjunction of X1 and Y1 is overwhelmingly perceived as more supportive than observing the conjunction of X2 and Y2, although both observations support the hypothesis. Normatively, the X2&Y2 observation provides stronger support than the X1&Y1 observation if the former is rarer. Because participants in laboratory settings typically test hypotheses they are unfamiliar with, previous research has not examined whether participants are sensitive to the rarity of observations. The experiment reported here showed that participants were sensitive to rarity, even judging a rare X2&Y2 observation more supportive than a common X1&Y1 observation under certain conditions. Furthermore, participants' default strategy of judging X1&Y1 observations more informative might be generally adaptive because hypotheses usually regard rare events.
Adult↗
Properties of inductive reasoning.
This paper reviews the main psychological phenomena of inductive reasoning, covering 25 years of experimental and model-based research, in particular addressing four questions. First, what makes a case or event generalizable to other cases? Second, what makes a set of cases generalizable? Third, what makes a property or predicate projectable? Fourth, how do psychological models of induction address these results? The key results in inductive reasoning are outlined, and several recent models, including a new Bayesian account, are evaluated with respect to these results. In addition, future directions for experimental and model-based work are proposed.
Adult↗
Estimating the frequency of nonevents: the role of recollection failure in false recognition.
Participants studied lists of multiply presented converging associates (e.g., bed, dream, pillow, etc.) and were timed as they estimated how often they saw list items, related foils (e.g., blanket), and nonpresented critical items (SLEEP). Average number of repetitions (few [3] vs. many [6]) and repetition variability (fixed vs. variable) were manipulated between subjects. Participants responded more slowly to critical items (3.18 sec) than to list items (2.45 sec) or foils (2.22 sec). In addition, critical-item judgments of frequency (JOFs) were about as large as list-item JOFs, and false recognition (i.e., nonzero JOFs) of critical items was most likely in the few-fixed condition (96%) and least likely in the many-fixed condition (74%). These findings suggest that people can use recollection failure--the absence of an anticipated recollective experience, coupled with strong familiarity--to distinguish critical items from list items and that recollection failure is weighted most heavily when people expect familiar probes to access episodic information.
Adult↗
Decision time, subjective probability, and task difficulty.
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Cognition↗
Typicality and reasoning fallacies.
The work of Tversky and Kahneman on intuitive probability judgment leads to the following prediction: The judged probability that an instance belongs to a category is an increasing function of the typicality of the instance in the category. To test this prediction, subjects in Experiment 1 read a description of a person (e.g., "Linda is 31, bright, ... outspoken") followed by a category. Some subjects rated how typical the person was of the category, while others rated the probability that the person belonged to that category. For categories like bank teller and feminist bank teller: (1) subjects rated the person as more typical of the conjunctive category (a conjunction effect); (2) subjects rated it more probable that the person belonged to the conjunctive category (a conjunction fallacy); and (3) the magnitudes of the conjunction effect and fallacy were highly correlated. Experiment 2 documents an inclusion fallacy, wherein subjects judge, for example, "All bank tellers are conservative" to be more probable than "All feminist bank tellers are conservative." In Experiment 3, results parallel to those of Experiment 1 were obtained with respect to the inclusion fallacy.
Concept Formation↗
Tracing the footsteps of Sherlock Holmes: cognitive representations of hypothesis testing.
A well-documented phenomenon in opinion-revision literature is subjects' failure to revise probability estimates for an exhaustive set of mutually exclusive hypotheses in a complementary manner. However, prior research has not addressed the question of whether such behavior simply represents a misunderstanding of mathematical rules, or whether it is a consequence of a cognitive representation of hypotheses that is at odds with the Bayesian notion of a set relationship. Two alternatives to the Bayesian representation, a belief system (Shafer, 1976) and a system of independent hypotheses, were proposed, and three experiments were conducted to examine cognitive representations of hypothesis sets in the testing of multiple competing hypotheses. Subjects were given brief murder mysteries to solve and allowed to request various types of information about the suspects; after having received each new piece of information, subjects rated each suspect's probability of being the murderer. Presence and timing of suspect eliminations were varied in the first two experiments; the final experiment involved the varying of percentages of clues that referred to more than one suspect (for example, all of the female suspects). The noncomplementarity of opinion revisions remained a strong phenomenon in all conditions. Information-search data refuted the idea that subjects represented hypotheses as a Bayesian set; further study of the independent hypotheses theory and Shaferian belief functions as descriptive models is encouraged.
Adult↗
[An examination on the relationship between elaboration and to-be-elaborated items in human memory].
Two experiments were designed to examine the relationship between elaboration and to-be-elaborated items in paired-associate learning. In the first task of both experiments, 20 subjects were presented with a sequence of 32 noun words to be elaborated, and instructed either to generate sentences or to produce associates. In second task, the subjects were asked to remember pairs of words either incidentally (Exp. I) or intentionally (Exp. II). The first word of the pairs, referred to as the context word, was used later as a cue for cued recall, while the second word, as the target word, was to be recalled. Three different types of pairs were constructed: (i) C pairs, in which the context word was elaborated and the target word was not, (ii) T pairs, in which the target word was elaborated and the context word was not, and (iii) CT pairs, in which both words were elaborated. Subjects who generated sentences remembered the items better than subjects who produced associations. Both T and CT pairs were more recalled than C pairs, while there was no difference in recall between T and CT pairs. The results suggest that the type of to-be-elaborated items is an important factor in elaborative process.
Adult↗
[Confidence and accuracy of mental judgments].
Problems consisted of two categories of questions, of general knowledge and forecasting future events. Given each question, the subjects chose a more likely answer from the given two alternatives, rated their own confidence on the correctness of the choice, and then, assessed the hit-rate of the classmates. The major result is as follows. The difference between average confidence and average hit-rate was small, namely, calibration was good, for problems of both general knowledge and familiar future events. On the other hand, calibration was poor for problems of accidental future events. In other words, the more available knowledge, the better calibration is. In discussion we proposed "a model of retrieval and generation", which could explain our results for the problems of general knowledge. Results for problems of future events suggest that the subjects possibly used a certain model to make their probability judgments. On the basis of our results and with our discussion, we found the phenomenon that people believe themselves to make mental judgments better than the average. We call the phenomenon "self-superiority phenomenon".
Adult↗
Effect of the verbal instruction on the late positive wave P3 of auditory evoked potentials in human subjects.
The changes in the late positive wave P3 of the averaged evoked potentials (AEP) are studied under conditions when: (a) only high tones were presented requiring no motor response; (b) only low tones were presented requiring motor response; (c) the subject was instructed that the two types of tones will be presented in random order with a definite probability (50%:50% or 25%:75%, or conversely 75%:25%) requiring motor response only to the low tones. In fact, however, only high tones were presented to which no motor response was required (pseudo-mixed series). It has been established that under the effect of the verbal instruction used, the P3 wave of the AEP of the pseudo-mixed series increased at the beginning of the series, and thereafter the P3 "behaviour" was different with the different subjects: (1) In some of them P3 persisted until the presentation of a definite number of signals (different for the individual subjects) and afterwards it disappeared; (2) In some others P3 now increased now disappeared in a manner different for the different subjects; (3) Subjects in which P3 remained pronounced throughout the entire series; they also "heard" low tones. All these changes in P3 did not depend on the probability characteristics of the pseudo-mixed series ascribed by the instruction. The dependence of the late positive wave P3 on the processes of probability prediction in the human brain functioning, and on the changes in the arousal, is discussed.
Acoustic Stimulation↗
The attainment of formal operations: a comparison of probability concepts in deaf and hearing adolescents.
In a series of six experiments deaf and hearing adolescents were compared on attainment of formal operations in Piaget's theory as represented by performance on probability problems. Performance of deaf subjects provided a desirable control comparison, since their knowledge of probability concepts was most likely acquired outside school classrooms. The probability problems were usually binary choice situations that required no verbalizations and were designed to illuminate strategies, as well as to indicate conceptual stage. Two experiments, one a long-term training study of over two years' duration, used supplementary preadolescent subject groups. Most of the hearing adolescents and many of the deaf adolescents attained the formal operatory level for probability concepts according to the criteria described by Piaget and Inheldermtheir criteria can be criticized, however, as insufficiently demanding, although they do point up the difficulty of defining the place of computational abilities in formal operationsmresults from several experiments suggested a second and higher level of formal operatory attainment around the ages of 14 to 15. Further theoretical insights were obtained regarding the implicit rules that frequently appeared to guide subjects' choices; a surprising variety of strategies were reported. Analysis of choice tendendies showed consistent avoidance of calculations and selection of the choice with the greatest absolute rather than relative frequency (or area) even when these strategies produced systematic errors. Subjects were generally unable to combine probability information from two different sources. In the long-term training experiment spontaneous improvement was shown by children at formal operatory ages even without training, but not by younger children. Deaf adolescents performed as well as hearing adolescents on easy problems, but they made more errors on several types of more difficult problems; Deaf adolescents were also less consistent than the hearing in use of rules, and in several experiments they showed a two- to three-year performance lag.
Achievement↗
Coherent probability from incoherent judgment.
People often have knowledge about the chances of events but are unable to express their knowledge in the form of coherent probabilities. This study proposed to correct incoherent judgment via an optimization procedure that seeks the (coherent) probability distribution nearest to a judge's estimates of chance. This method was applied to the chances of simple and complex meteorological events, as estimated by college undergraduates. No judge responded coherently, but the optimization method found close (coherent) approximations to their estimates. Moreover, the approximations were reliably more accurate than the original estimates, as measured by the quadratic scoring rule. Methods for correcting incoherence facilitate the analysis of expected utility and allow human judgment to be more easily exploited in the construction of expert systems.
Adult↗
DECISION-THEORETIC AND EMPIRICAL INVESTIGATION OF SOME PROBABILISTIC DISCRIMINATION LEARNING SITUATIONS. ESD-TDR-64-192.
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Decision Making↗
Hospital waste management and it's probable health effect: a lesson learned from Bangladesh.
A study was conducted to evaluate the current status of hospital waste management (HWM) in Bangladesh. The aim is to recognize the health effect of the existing practice, to determine the awareness level of doctors and nurses about hospital waste, to identify the weaknesses, and to provide suggestions for improvement. Hospital staff, waste pickers, and local residents were interviewed while in depth field observation, which included sample collection and laboratory analysis was also conducted. Through this investigation, it has been quite evident that a satisfactory hospital waste management system in government hospitals and several private clinics is severely lacking. At present, Bangladesh has no rigorous laws or regulation, which are enforced in this area. The waste is generally dumped together in a public place such as the hospital surroundings, the roadside or City Corporation dustbin. Many doctors and nurses are not fully aware about what constitutes as medical waste. Health care workers have only a basic understanding of health care and do not perceive handling or disposal of medial waste as a hazardous work. Laboratory analysis shows existing contamination of infectious agents in the environment. Some staff members interviewed were suffering from various kinds of infectious diseases such as viral hepatitis B/C, typhoid, skin disease/allergy, diarrhea, dysentery, tuberculosis, and malaria. During field observation it was discovered that improved HWM systems have only recently been introduced in a small number of private hospitals and clinics, some of which could be used as references to formulate guidelines for reaching the optimal at the national level. The study indicates that there is a need to improve the handling and disposal methods of hospital waste in almost all the available medical facilities. There are a few NGOs that have started awareness building and training on waste management for selected hospital staff and NGO officials. Based on the analysis of the situation, several suggestions and recommendations have been made to aid in the development of a waste management system.
Bangladesh↗