Distractor effect on the latent inhibition of conditioned flavor aversion in rats

Using a conditioned flavor aversion procedure with rats as subjects, the effect of the addition of a distractor stimulus on the magnitude of the latent inhibition effect was examined. Experiment 1 showed that latent inhibition to vinegar was attenuated by the addition of sucrose during preexposure. On the other hand, sucrose added during conditioning to vinegar did not attenuate latent inhibition. It was also found that the degree of latent inhibition to the vinegar-sucrose compound solution was less when vinegar alone was preexposed (i.e., when sucrose was added only during conditioning) than when the compound solution was preexposed (i.e., when sucrose was added both during preexposure and during conditioning). Experiment 2 gave similar results but with sucrose assigned as the target flavor and vinegar as the distractor. These findings are in full agreement with the generalization decrement account of latent inhibition.     

Constrained maximum likelihood estimation of two-level covariance structure model via EM type algorithms

In this paper, the constrained maximum likelihood estimation of a two-level covariance structure model with unbalanced designs is considered. The two-level model is reformulated as a single-level model by treating the group level latent random vectors as hypothetical missing-data. Then, the popular EM algorithm is extended to obtain the constrained maximum likelihood estimates. For general nonlinear constraints, the multiplier method is used at theM-step to find the constrained minimum of the conditional expectation. An accelerated EM gradient procedure is derived to handle linear constraints. The empirical performance of the proposed EM type algorithms is illustrated by some artifical and real examples.This research was supported by a Hong Kong UCG Earmarked Grant, CUHK 4026/97H. We are greatly indebted to D.E. Morisky and J.A. Stein for the use of their AIDS data in our example. We also thank the Editor, two anonymous reviewers, W.Y. Poon and H.T. Zhu for constructive suggestions and comments in improving the paper. The assistance of Michael K.H. Leung and Esther L.S. Tam is gratefully acknowledged.     

Every Finitely Reducible Logic has the Finite Model Property with Respect to the Class of ♦-Formulae

In this paper a unified framework for dealing with a broad family of propositional multimodal logics is developed. The key tools for presentation of the logics are the notions of closure relation operation and monotonous relation operation. The two classes of logics: FiRe-logics (finitely reducible logics) and LaFiRe-logics (FiRe-logics with local agreement of accessibility relations) are introduced within the proposed framework. Further classes of logics can be handled indirectly by means of suitable translations. It is shown that the logics from these classes have the finite model property with respect to the class of -formulae, i.e. each -formula has a -model iff it has a finite -model. Roughly speaking, a -formula is logically equivalent to a formula in negative normal form without occurrences of modal operators with necessity force. In the proof we introduce a substantial modification of Claudio Cerrato's filtration technique that has been originally designed for graded modal logics. The main core of the proof consists in building adequate restrictions of models while preserving the semantics of the operators used to build terms indexing the modal operators.     

Effects of practice and task constraints on stiffness and friction functions in biological movements

A dynamical model of the movements of the platform of a ski-simulator was derived from experimental data, using the graphical and statistical methods developed by Beek and Beek (Beek, P. J., & Beek, W. J. (1988). Human Movement Science, 7, 301–342). The data were collected in an experiment in which both amplitude and practice were manipulated. The data were filtered and further reduced to normalised cycles that were averaged within and across subjects. Graphical methods were applied to these averaged normalised cycles to determine the stiffness and friction terms to be included in the model. The relative contribution of each term was assessed by means of multiple regression. The model, which included cubic and quintic Duffing terms and one or two dissipative Van der Pol terms, accounted on average for 99.2% of the variance. The exact parameter setting of the model differed considerably across subjects. For one subject, a qualitatively different model, including Rayleigh instead of Van der Pol terms, provided a better account of the data. Systematic changes of the coefficients in the model, related to amplitude and the duration of practice, were evident.     

The role of posttraumatic fear and social support in the relationship between trauma severity and posttraumatic growth among adolescent survivors of the Yaan earthquake

Middle school students in Lushan county (N = 315) were assessed 6 months after the Yaan earthquake using a trauma severity questionnaire, a posttraumatic fear questionnaire, a social support questionnaire and a posttraumatic growth inventory to examine the effects of posttraumatic fear and social support in the relationship between trauma severity and posttraumatic growth (PTG). The results showed that posttraumatic fear mediated the relationship between trauma severity and PTG, and social support moderated the relationship between posttraumatic fear and PTG. These findings suggested that trauma severity could be positively associated with PTG in a direct way or in an indirect way through posttraumatic fear. Moreover, posttraumatic fear had a positive relation to PTG under the condition of high social support level, whereas the relation was non‐significant when the level of social support was low. These results were discussed in terms of their implications for adolescents after trauma.     

The Treatment Planning of Experienced Counselors: A Qualitative Examination

Using consensual qualitative research, the authors examined the treatment planning process of experienced counselors (N = 9). The data analysis resulted in 4 domains: assessment steps, clinical impressions, treatment factors, and treatment strategies. These domains describe the process used by experienced counselors in making clinical decisions and offer insight into the nature of clinical expertise and the need for further research on treatment planning.     

Subtypes of severe psychological distress among US Air Force remote warriors: A latent class analysis

US Air Force remote warrior personnel include a range of military personnel composed of remotely piloted aircraft aircrew, intelligence operators, and cyber warfare operators. Job duties in these professions entail long work hours, rotating shifts, and regular engagement in combat operations. Although research has identified a number of factors correlated with elevated burnout and emotional distress in this population, little is known about the unique needs of discrete subgroups of distressed personnel. In a sample of 7,550 US Air Force remote warriors, results of latent class analysis yielded four distinct classes. Three of the four reported moderately elevated burnout and job dissatisfaction but differed with respect to demographics and development career stage. The fourth group reported significantly higher levels of emotional distress, burnout, job dissatisfaction, and problems in living. This latter group was comparable to the mid-career group with respect to demographics, although this group had much lower levels of responsibility and indicators of career advancement. Results suggest that, among remote warrior personnel, there are several subtypes of elevated emotional distress. Prevention and intervention strategies that are matched to each subtype may yield better occupational and mental health outcomes than universal, “one size fits all” strategies.     

Wisdom at the end of life: Hospice patients’ reflections on the meaning of life and death

The processes of aging and confronting mortality are often accompanied by unique psychological challenges. From the perspective of positive psychology, such challenges can yield opportunities for growth, including increased wisdom. This qualitative study explored 15 terminally ill hospice patients’ perspectives on wisdom, the dying process, and the meaning of life using consensual qualitative research methods. Most participants cited humility as a key component of wisdom, emphasizing that “Wisdom is when we realize ‘I don’t really know much’.” Other components of wisdom included self-knowledge, rationality, experiential learning, listening to and learning from others, and sharing knowledge with others. Participants also suggested that the process of facing illness and death presents opportunities for positive growth, including changing priorities and learning to appreciate life more fully in the present moment. In considering the sources of meaning in their lives, participants emphasized relational connections, personal growth, spirituality, vocational fulfilment, and living a full life. Participants also shared their reflections on important past experiences and regrets. Lastly, participants offered advice to others based on their experiences facing illness and mortality. Implications for psychological care of the dying and future research are discussed.     

Using finite mixture of GLMs to explore variability in children's flexibility in a task-switching paradigm

The present study illustrates the usefulness of finite mixture of generalized linear models (GLMs) to examine variability in cognitive strategies during childhood. More precisely, it addresses this variability in set-shifting situations where task-goal updating is endogenously driven. In a task-switching paradigm 5–6-year-olds had to switch between color- and shape-matching rules as a function of a predetermined, predictable task sequence. A finite mixture of GLMs was fitted to explore individual differences in performance. The statistical model revealed five response profiles, defined by accuracy and response times. These response profiles likely correspond to different cognitive strategies with varying efficiency and differential relations to working memory capacity (assessed by backward digit span). These results illustrate the heuristic value of statistical modeling to reveal the behavioral and cognitive variability in the temporal dynamics of children's cognitive functioning.     

A calibration explanation of serial position effects in evaluative judgments

Judges often evaluate stimulus series on dimensions for which no physical scale exists; for example, when judging academic ability in oral examinations. We propose that judges deal with this problem by calibrating an internal judgment scale that maps stimulus input onto available judgment categories. This calibration process implies serial position effects: Judges should initially avoid extreme categories, because using extreme categories reduces judgmental degrees of freedom, thereby increasing the possibility of internal consistency violations. In four experiments, we show that judgments become indeed more extreme later in a series of judgments. Judges evaluated the same good (poor) performances more positive (negative) at the end of a sequence compared to the beginning. Judges’ expertise did not prevent the effect, but allowing end-of-sequence judgments reduced serial position effects. We discuss the implications and possible remedies of these calibration effects on judgment extremity.