Estimating the frequency of everyday events

In two experiments, subjects recorded the frequency of occurrence of 12 classes of events each week for 3 months. During a final test they estimated frequency of occurrence of events either under time restrictions (Experiment 1) or difference priming instructions (Experiment 2). They also made (metamemory) estimates of the accuracy of their estimates. Time restrictions during an initial estimate did not affect the accuracy of frequency or metamemory estimation but a second estimate did increase accuracy. Priming instructions affected accuracy of metamemory estimates as well as the accuracy of estimates for high-frequency events. Metamemory error increased with event frequency.     

Estimating stimuli from contrasting categories: truncation due to boundaries

In this article, the authors present and test a formal model that holds that people use information about category boundaries in estimating inexactly represented stimuli. Boundaries restrict stimuli that are category members to fall within a particular range. This model posits that people increase the average accuracy of stimulus estimates by integrating fine-grain values with boundary information, eliminating extreme responses. The authors present 4 experiments in which people estimated sizes of squares from 2 adjacent or partially overlapping stimulus sets. When stimuli from the 2 sets were paired in presentation, people formed relative size categories, truncating their estimates at the boundaries of these categories. Truncation at the boundary of separation between the categories led to exaggeration of differences between stimuli that cross categories. Yet truncated values are shown to be more accurate on average than unadjusted values.     

Estimating the probability of negative events

How well we are attuned to the statistics of our environment is a fundamental question in understanding human behaviour. It seems particularly important to be able to provide accurate assessments of the probability with which negative events occur so as to guide rational choice of preventative actions. One question that arises here is whether or not our probability estimates for negative events are systematically biased by their severity. In a minimal experimental context involving an unambiguous, objective representation of probability, we found that participants judged a controllable event as more likely to occur when its utility was extremely negative than when it was more neutral. A decision-theoretic explanation based on loss function asymmetries is advanced which supports the claim that probability estimates are not intrinsically biased by utilities.     

What children infer from social categories

Children hold the belief that social categories have essences. We investigated what kinds of properties children feel licensed to infer about a person based on social category membership. Seventy-two 4-6-year-olds were introduced to novel social categories defined as having one internal - psychological or biological - and one external - behavioral or physical - property. For half of the participants, the internal property was described as causing the external one; for the others, no causal relationship between properties was mentioned. Children were asked to choose as a novel exemplar of a category one with only the internal or only the external property. Children inferred that exemplars had a psychological property irrespective of causal status, but they inferred the presence of a biological property only when described as causal. Children did not draw systematic inferences regarding either of the two external properties. These findings indicate that children treat psychological and causal properties as central - and perhaps essential - to human kinds.     

Learning abstract relations from using categories

When people learn categories, the importance of the features and relations in the category representation reflects both their diagnosticity for classification and their relevance to the use of the category. In earlier work in which the influence of category use on the representation has been shown, only cases in which the features and relations were simple, observable, and very specific were examined. Learners may begin to understand the underlying similarities of category members by using the categories. In the four experiments presented here, learners applied a simple category-specific formula to category members. The test results showed that the learners had incorporated relations among features from this use, including cases in which the relations were abstract. This learning occurred even though the relations were actually not predictive of category membership but just perceived to be so as a function of the use.     

Fact and fantasy: The effects of internally generated events on the apparent frequency of externally generated events

As John Locke pointed out, there are at least two sources of the contents of the mind: events that occur in the world and events that originate in the mind. Memory, as a record of experience, should contain information from both sources. The present studies investigated memory for the frequency of externally and internally generated events. Individual items were presented to subjects varying numbers of times and tested varying numbers of times. Later, subjects were asked to estimate the frequency of both types of events. Experiment 1 showed that internally generated events influenced the judged frequency of externally generated events and vice versa. The first of these was called the IFE effect and the second the IFI effect. Experiment 2 indicated that the IFE effect was greater when tests consisted of overt, as compared to covert, recall trials. The results were discussed in terms of a model for storing and using occurrence information which would account for both our ability to discriminate between and our tendency to confuse internally and externally generated memory representations.     

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 non-presented 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 userecollection 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.     

Estimating item parameters and latent ability when responses are scored in two or more nominal categories

A multivariate logistic latent trait model for items scored in two or more nominal categories is proposed. Statistical methods based on the model provide 1) estimation of two item parameters for each response alternative of each multiple choice item and 2) recovery of information from wrong responses when estimating latent ability. An application to a large sample of data for twenty vocabulary items shows excellent fit of the model according to a chi-square criterion. Item and test information curves are compared for estimation of ability assuming multiple category and dichotomous scoring of these items. Multiple scoring proves substantially more precise for subjects of less than median ability, and about equally precise for subjects above the median.Preparation of this paper was supported in part by N.S.F. Grant GS-2900.     

Category norm data and relationships with lexical frequency and typicality within verb semantic categories

The aim of the present study was to expand the scope of category norm and typicality data to include verbs for use when investigating semantic memory in fields such as linguistics, psychology, and aphasiology. Two experiments were conducted. In the first, participants were asked to list verbs within 10 semantic categories (e.g. breaking, cleaning, cooking, etc.) and 10 noun categories (e.g. animals, fruit, tools, etc.). In the second experiment, participants were asked to rate the typicality of verbs within 8 of the previously investigated verb categories. Although participants listed fewer verbs in verb categories than nouns in noun categories, the overall patterns with regard to correlation analyses between production frequency, mean rank of responses, lexical frequency, and typicality were consistent with those observed in noun categories. These patterns are also consistent with those observed in previous research. Potential similarities and differences between nouns and verbs, as well as future applications of such data, are discussed.     

Estimating the polychoric correlation from misclassified data

Many variables that are used in social and behavioural science research are ordinal categorical or polytomous variables. When more than one polytomous variable is involved in an analysis, observations are classified in a contingency table, and a commonly used statistic for describing the association between two variables is the polychoric correlation. This paper investigates the estimation of the polychoric correlation when the data set consists of misclassified observations. Two approaches for estimating the polychoric correlation have been developed. One assumes that the probabilities in relation to misclassification are known, and the other uses a double sampling scheme to obtain information on misclassification. A parameter estimation procedure is developed, and statistical properties for the estimates are discussed. The practicability and applicability of the proposed approaches are illustrated by analysing data sets that are based on real and generated data. Excel programmes with visual basic for application (VBA) have been developed to compute the estimate of the polychoric correlation and its standard error. The use of the structural equation modelling programme Mx to find parameter estimates in the double sampling scheme is discussed.     

Ideals, central tendency, and frequency of instantiation as determinants of graded structure in categories

Three possible determinants of graded structure (typicality) were observed in common taxonomic categories and goal-derived categories: (1) an exemplar's similarity to ideals associated with goals its category serves; (2) an exemplar's similarity to the central tendency of its category (family resemblance); and (3) an exemplar's frequency of instantiation (people's subjective estimates of how often it is encountered as a category member). Experiment 1 found that central tendency did not predict graded structure in goal-derived categories, although it did predict graded structure in common taxonomic categories. Ideals and frequency of instantiation predicted graded structure in both category types to sizeable and equal extents. A fourth possible determinant--familiarity--did not predict typicality in either common taxonomic or goal-derived categories. Experiment 2 demonstrated that both central tendency and ideals causally determine graded structure, and work showing that frequency causally determines graded structure is discussed. Experiment 2 also demonstrated that the determinants of a particular category's graded structure can change with context. Whereas ideals may determine a category's graded structure in one context, central tendency may determine a different graded structure in another. It is proposed that graded structures do not reflect invariant structures associated with categories but instead reflect people's dynamic ability to construct concepts.     

Depression and the frequency and strength of pleasant events: Exploration of the Staats-Heiby theory

An analysis derived from the paradigmatic behaviorism theory of depression was applied to the Pleasant Events Schedule. The PES combines measurement of frequency and intensity of pleasant events, while paradigmatic behavioral analysis indicates these involve different independent variables. Results showed that different subtypes could be isolated by differentiating these variables, subtypes that would differently predict for depression. The findings have implications for understanding, diagnosing, and treating depression.     

Functional categories in agrammatism: evidence from Greek

The aim of this study is twofold. First, to investigate the use of functional categories by two Greek agrammatic aphasics. Second, to discuss the implications of our findings for the characterization of the deficit in agrammatism. The functional categories under investigation were the following: definite and indefinite articles, personal pronouns, aspect, tense, subject-verb agreement, wh-pronouns, complementizers and the mood marker na (=to). Based on data collected through different methods, it is argued that the deficit in agrammatism cannot be described in terms of a structural account but rather by means of difficulties in the implementation of grammatical knowledge.     

Tonal frequency shifts and gaps in acoustic stimulation as reflex-modifying events

When a relatively weak signal, such as a mild tone, precedes an intense reflex-eliciting stimulus by an appropriate interval (about 100 msec), the amplitude of the elicited reaction is often reduced. It was found that in student volunteers a brief gap in a steady pure tone that occurred 150 msec prior to a mild tap to the glabella (the flat region between the eyebrows) could inhibit the eyeblink elicited by the tap. It was also found that a shift in tonal frequency across a gap in a tone was more inhibitory than a gap with no frequency shift, but it was no more inhibitory than the onset of the short second tone alone. The final study determined the minimum amount of frequency shift required to produce an additional inhibitory effect above that of a gap alone. The findings are discussed in terms of various aspects of sensory processing.     

Emotion words and categories: evidence from lexical decision

We examined the categorical nature of emotion word recognition. Positive, negative, and neutral words were presented in lexical decision tasks. Word frequency was additionally manipulated. In Experiment 1, “positive” and “negative” categories of words were implicitly indicated by the blocked design employed. A significant emotion–frequency interaction was obtained, replicating past research. While positive words consistently elicited faster responses than neutral words, only low frequency negative words demonstrated a similar advantage. In Experiments 2a and 2b, explicit categories (“positive,” “negative,” and “household” items) were specified to participants. Positive words again elicited faster responses than did neutral words. Responses to negative words, however, were no different than those to neutral words, regardless of their frequency. The overall pattern of effects indicates that positive words are always facilitated, frequency plays a greater role in the recognition of negative words, and a “negative” category represents a somewhat disparate set of emotions. These results support the notion that emotion word processing may be moderated by distinct systems.     

Intersexuality and the categories of sex

Operations on intersexuals indicate that the sex of a person is based on more than biology. Expectations about proper gender activities furnish the frameworks through which certain features and combinations of features are understood to be fundamental to bodies and to comprise their sex. Yet, we can ask whether this interpretation is either coherent or consistent with our fuller conceptions of ourselves. Is there a point to interpreting a person as a sex?