首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
Vogel JS  Hurford DP  Smith JV  Cole A 《Adolescence》2003,38(149):57-74
The literature suggests that smokers are more likely to be depressed, while people who are depressed are more likely to smoke. The purpose of the present study was to determine the strength of the relationship between smoking, depression, intention to smoke, and several psychosocial and environmental factors. The participants (98 high school and college students aged 16 to 19 years) completed a paper-and-pencil questionnaire consisting of the Multiscore Depression Inventory (MDI) and items regarding smoking behavior as well as psychosocial and environmental factors. Correlation, stepwise regression, and discriminant analyses were then conducted. It was found that participants were more likely to smoke if their parents smoked, if their scores on the MDI indicated instrumental helplessness and social isolation/withdrawal, or if they were older. Participants were more likely to state intention to smoke in the future if they had MDI scores indicating instrumental helplessness, if they were older, if their parents smoked, if their MDI scores indicated social intro-version, or if they resided with a guardian. Participants were also more likely to have smoked for more years if their parents smoked or if their scores on the MDI indicated instrumental helplessness. Further, participants were more likely to have scores on the MDI indicative of higher depression levels if they had low grades or if their parents smoked.  相似文献   

2.
Formal definitions are given of the following intuitive concepts: (a) A model is quantitatively testable if its predictions are highly precise and narrow. (b) A model is identifiable if the values of its parameters can be ascertained from empirical observations. (c) A model is redundant if the values of some parameters can be deduced from others or if the values of some observables can be deduced from others. Various rules of thumb for nonredundant models are examined. The Counting Rule states that a model is quantitatively testable if and only if it has fewer parameters than observables. This rule can be safely applied only to identifiable models. If a model is unidentifiable, one must apply a generalization of the Counting Rule known as the Jacobian Rule. This rule states that a model is quantitatively testable if and only if the maximum rank (i.e., the number of linearly independent columns) of its Jacobian matrix (i.e., the matrix of partial derivatives of the function that maps parameter values to the predicted values of observables) is smaller than the number of observables. The Identifiability Rule states that a model is identifiable if and only if the maximum rank of its Jacobian matrix equals the number of parameters. The conclusions provided by these rules are only presumptive. To reach definitive conclusions, additional analyses must be performed. To illustrate the foregoing, the quantitative testability and identifiability of linear models and of discrete-state models are analyzed. Copyright 2000 Academic Press.  相似文献   

3.
In a matching-to-sample context, pigeons were taught two conditional discriminations according to one of three equivalence paradigms: train if A, then select B and if B, then select C; train if B, then A and if B, then C; or train if A, then B and if C, then B. Test trials without reinforcement revealed that the conditional relations did not satisfy the symmetrical and transitive properties of an equivalence relation. Apparently, only specific if... then relations were learned. Contrary to Kendall's (1983) findings, and probably as a consequence of procedural differences, none of the pigeons in the present experiment were observed to emit mediating behavior during the transitivity probe trials. The absence of symmetry and transitivity may be related to the individual stimuli not being reflexive. Behavioral techniques other than the commonly used matching-to-sample technique might better succeed in avoiding unintended stimulus control in the study of the formation of stimulus classes.  相似文献   

4.
Aim: This research article contributes to the debate on the value and limitation of the use of spiritual strategies, like prayer, in counselling (Foskett & Lynch, 2001) by disseminating the insights that were gained from a qualitative study of mainstream counsellors whose work includes prayer. Method: Participants were 19 British Association for Counselling and Psychotherapy (BACP)‐accredited and Churches Ministerial Counselling Service (CMCS)‐approved counsellors who use prayer in their practice. They were interviewed, and the data were analysed using Interpretative Phenomenological Analysis. Results: The data reveal that counsellors who use prayer are aware that ethical problems may be encountered: if prayer changes the way that the counsellor is perceived; when using prayer with issues of psychopathology; if the counsellor uses prayer to impose faith on a client; when being professionally held to account; if prayer is used for avoidance or as a defence; if prayer is used to enhance the counsellor's power; if prayer is not part of the client's agenda; if prayer is used routinely; if prayer cannot be challenged; if there is a cultural pressure to pray; and if the prayer method is not matched to the client – but that their concern over potential ethical issues is not of sufficient strength to override their therapeutic use of prayer if facilitated with due care.  相似文献   

5.
B. H. Slater 《Ratio》1996,9(1):47-55
Two uses of ‘if are discussed which do not involve conditions. The first is illustrated in the example ‘If he's here, I don't see him’, the second in ‘He's not a dunce, if a trifle stupid’. A third non-conditional use, cognate with the first is also mentioned: it would be illustrated in the example ‘If he's a Dutchman, I'll eat my hat’. It is argued that recent attempts to formulate a logic of conditionals have distorted our understanding of ‘if, by ignoring these uses, sometimes deliberately. Specifically, as a result, many arguments involving ‘if have been misjudged as invalid, because the expectation has been that ‘if expresses a condition. It is suggested that the traditional analysis of ‘necessary and sufficient conditions’ in terms of ‘if and only if, is partly to blame for these misunderstandings. And the proper understanding of ‘if’ which emerges shows it is quite fully captured in the propositional calculus.  相似文献   

6.
This paper uses the notion of Galois-connection to examine the relation between valuation-spaces and logics. Every valuation-space gives rise to a logic, and every logic gives rise to a valuation space, where the resulting pair of functions form a Galois-connection, and the composite functions are closure-operators. A valuation-space (resp., logic) is said to be complete precisely if it is Galois-closed. Two theorems are proven. A logic is complete if and only if it is reflexive and transitive. A valuation-space is complete if and only if it is closed under formation of super-valuations.  相似文献   

7.
The aim of this study was to test the predictions of the current theories of reasoning about the comprehension of conditional statements. We used two types of conditional statement that are logically equivalent: if p then q and p only if q . The model theory of reasoning considers that these conditional forms differ in their initial meaning, because the negative contingency is considered only in the p only if q form. Mental-rule theories maintain that the interpretation of p only if q depends on a rephrasing of the statement as: if not q then not p . Alternatively, a directional bias may explain the differences between if p then q and p only if q . We report three experiments that demonstrate the existence of a directional bias in the comprehension of the conditionals. The results were not predicted by either the mental-rules theories or the model theory; they could, however, be easily assimilated by the model theory.  相似文献   

8.
Research has shown that if equality is violated in public‐good dilemmas, group members react with more anger if another group member (a follower), rather than if the leader violates equality. The present research argued that people's personality—particularly, need for emotion—moderates group members’ reactions if equality is violated by either the leader or a follower. Results revealed that group members low in need for emotion reacted with more anger and were more inclined to exclude the violator if this person was a follower, rather than the leader of the group. Group members high in need for emotion, however, reacted with more anger and wished to exclude the violator more if this person was the leader, rather than a follower.  相似文献   

9.
Dissimilarity is a function that assigns to every pair of stimuli a nonnegative number vanishing if and only if two stimuli are identical, and that satisfies the following two conditions called the intrinsic uniform continuity and the chain property, respectively: it is uniformly continuous with respect to the uniformity it induces, and, given a set of stimulus chains (finite sequences of stimuli), the dissimilarity between their initial and terminal elements converges to zero if the chains’ length (the sum of the dissimilarities between their successive elements) converges to zero. The four properties axiomatizing this notion are shown to be mutually independent. Any conventional, symmetric metric is a dissimilarity function. A quasimetric (satisfying all metric axioms except for symmetry) is a dissimilarity function if and only if it is symmetric in the small. It is proposed to reserve the term metric (not necessarily symmetric) for such quasimetrics. A real-valued binary function satisfies the chain property if and only if whenever its value is sufficiently small it majorates some quasimetric and converges to zero whenever this quasimetric does. The function is a dissimilarity function if, in addition, this quasimetric is a metric with respect to which the function is uniformly continuous.  相似文献   

10.
Unless reasoning     
We report the results of two experiments investigating conditional inferences from conditional unless assertions, such as Juan is not in León unless Nuria is in Madrid. Experiments 1 and 2 check Fillenbaum's hypothesis about the semantic similarity of unless with if not and only if assertions; both also examine inferential endorsements (Experiment 1) and endorsements and latencies (Experiment 2) of the four logically equivalent conditional formulations: if A then B, if not-B then not-A, A only if B and notA unless B. The results of these experiments show the similarity of unless and only if confirming that the representation of both conditionals from the outset probably include two possibilities directionally oriented from B to A; results also confirm the especial difficulty of unless assertions. The implications of the results are discussed in the context of recent psychological and linguistic theories of the meaning of unless.  相似文献   

11.
The intuitive notion behind the usual semantics of most systems of modal logic is that of ‘possible worlds’. Loosely speaking, an expression is necessary if and only if it holds in all possible worlds; it is possible if and only if it holds in some possible world. Of course, contradictory expressions turn out to hold in no possible worlds, and logically true expressions turn out to hold in every possible world. A method is presented for transforming standard modal systems into systems of modal logic for impossible worlds. To each possible world there corresponds an impossible world such that an expression holds in the impossible world if and only if it does not hold in the possible world. One can then talk about such worlds quite consistently, and there seems to be no logical reason for excluding them from consideration.  相似文献   

12.
The ‘watched pot’ phenomenon — the lengthening of duration experience when one is attentively and perhaps impatiently waiting for some event to occur — was studied in three experiments. In them, each observer attended for a duration of 270 sec to a liquid-containing beaker on an electrical burner. Observers who were told that the experiment concerned time perception (prospective paradigm) reproduced the duration as longer than those told that it concerned visual perception (retrospective paradigm). In the prospective paradigm, reproductions were longer if the liquid did not boil than if it did, and an interruption (task-unrelated questioning) shortened reproductions if the liquid did not boil but had no effect if it did. In the retrospective paradigm, if there was boiling or questioning or both, reproductions were longer than if there was neither. Results have implications for hypotheses about duration experience.  相似文献   

13.
In this article, I articulate and respond to an epistemological challenge to meta‐normative realism. The challenge has it that, if realism about the normative is correct, and if evolutionary forces have significantly influenced our normative judgments, then it would be a remarkable coincidence if the content of the normative facts and our normative judgments were aligned. I criticize David Enoch's recent attempt to meet this challenge, but provide an alternative response that is structurally similar. I argue that if realism is correct, then it would be remarkable if the content of our normative judgments and the normative facts were not significantly aligned.  相似文献   

14.
Traditional approaches to epistemology have sought, unsuccessfully, to define knowledge in terms of justification. I follow Timothy Williamson in arguing that this is misconceived and that we should take knowledge as our fundamental epistemological notion. We can then characterise justification as a certain sort of approximation to knowledge. A judgement is justified if and only if the reason (if there is one) for a failure to know is to be found outside the subject's mental states; that is, justified judging is possible knowing (where one world accessible from another if and only if they are identical with regard to a subject's antecedent mental states and judgement forming processes). This view is explained and defended.  相似文献   

15.
The results of three experiments suggest that a memory trace for an event is not altered by witnessing similar events, but that postevents can interfere with its retrieval. On an immediate recall test, details from an original story (e.g. wrench) were recalled less often if a subsequent story mentioned a ‘screwdriver’ than if it did not. The interference effect occurred if people were asked to recall details fromboth stories (tool —— ——), but not if people were asked to recall primarily from the first story. Thus, the interference effect in immediate recall was averted if the target trace could be activated selectively (Experiments 1a and 1b). A more general interference effect was found after a day. Fewer targets from the original story were recalled if the second story was presented just before the test than if both stories occurred a day earlier. Thus, the second story interfered with recall only if it emphasized contextual retrieval cues that did not match the trace for the targets (Experiment 2). Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

16.
Rogerson  Susan  Butchart  Sam 《Studia Logica》2002,71(1):119-132
In his paper [6], Greg Restall conjectured that a logic supports a naïve comprehension scheme if and only if it is robustly contraction free, that is, if and only if no contracting connective is definable in terms of the primitive connectives of the logic. In this paper, we present infinitely many counterexamples to Restall's conjecture, in the form of purely implicational logics which are robustly contraction free, but which trivialize naïve comprehension.  相似文献   

17.
Three studies investigated conditions in which perceivers view dispositions and situations as interactive, rather than independent, causal forces when making judgments about another's personality. Study 1 showed that perceivers associated 5 common trait terms (e.g., friendly and shy) with characteristic if...then... (if situation a, then the person does x, but if situation b, then the person does y) personality signatures. Study 2 demonstrated that perceivers used information about a target's stable if...then... signature to infer the target's motives and traits; dispositional judgments were mediated by inferences about the target's motivations. Study 3 tested whether perceivers draw on if...then... signatures when making judgments about Big Five trait dimensions. Together, the findings indicate that perceivers take account of person-situation interactions (reflected in if...then... signatures) in everyday explanations of social behavior and personality dispositions. Boundary conditions are also discussed.  相似文献   

18.
Peter Murphy 《Erkenntnis》2006,65(3):365-383
This paper looks at an argument strategy for assessing the epistemic closure principle. This is the principle that says knowledge is closed under known entailment; or (roughly) if S knows p and S knows that p entails q, then S knows that q. The strategy in question looks to the individual conditions on knowledge to see if they are closed. According to one conjecture, if all the individual conditions are closed, then so too is knowledge. I give a deductive argument for this conjecture. According to a second conjecture, if one (or more) condition is not closed, then neither is knowledge. I give an inductive argument for this conjecture. In sum, I defend the strategy by defending the claim that knowledge is closed if, and only if, all the conditions on knowledge are closed. After making my case, I look at what this means for the debate over whether knowledge is closed.  相似文献   

19.
Timothy Williamson has argued that in the debate on modal ontology, the familiar distinction between actualism and possibilism should be replaced by a distinction between positions he calls contingentism and necessitism. He has also argued in favor of necessitism, using results on quantified modal logic with plurally interpreted second-order quantifiers showing that necessitists can draw distinctions contingentists cannot draw. Some of these results are similar to well-known results on the relative expressivity of quantified modal logics with so-called inner and outer quantifiers. The present paper deals with these issues in the context of quantified modal logics with generalized quantifiers. Its main aim is to establish two results for such a logic: Firstly, contingentists can draw the distinctions necessitists can draw if and only if the logic with inner quantifiers is at least as expressive as the logic with outer quantifiers, and necessitists can draw the distinctions contingentists can draw if and only if the logic with outer quantifiers is at least as expressive as the logic with inner quantifiers. Secondly, the former two items are the case if and only if all of the generalized quantifiers are first-order definable, and the latter two items are the case if and only if first-order logic with these generalized quantifiers relativizes.  相似文献   

20.
For various nonnormal distributions, the power of the Student t test can be increased if continuous measures are transformed to ranks before the test is performed. The power of the test can also be increased almost as much and, even more for some distributions, if measures are replaced by dichotomous variables with the values 0 and 1, instead of ranks. Similarly, the power of a significance test of correlation can be increased if scores are transformed to ranks, that is, with the use of the Spearman rank correlation method. Power can also be increased almost as much and in some cases even more if dichotomous variables are introduced, that is, if the phi coefficient is used as a measure of correlation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号