The integration of continuous and discrete latent variable models: potential problems and promising opportunities

Structural equation mixture modeling (SEMM) integrates continuous and discrete latent variable models. Drawing on prior research on the relationships between continuous and discrete latent variable models, the authors identify 3 conditions that may lead to the estimation of spurious latent classes in SEMM: misspecification of the structural model, nonnormal continuous measures, and nonlinear relationships among observed and/or latent variables. When the objective of a SEMM analysis is the identification of latent classes, these conditions should be considered as alternative hypotheses and results should be interpreted cautiously. However, armed with greater knowledge about the estimation of SEMMs in practice, researchers can exploit the flexibility of the model to gain a fuller understanding of the phenomenon under study.     

Psychotherapy as Moral Encounter: A Crisis of Modern Conscience

Psychotherapy can no longer be understood as a morally neutral or value-free practice. Many have argued that psychology is implicitly and inevitably laden with moral assumptions and has a significant impact on the moral and ethical fabric of its clients and surrounding society (Browning 1987; Doherty 1995; Dueck and Reimer 2003; Kelly and Strupp 1992; Rieff 1987, 2006). In this work, the authors highlight the profound identity crises within the field of psychology around the place of morality/ethics in its theories and practices. Chronicling some of the shifts between modern and postmodern theory will allow for a meaningful engagement with this issue. The postmodern shifts in the field have left clinicians ideologically hampered in their ability to attend to the moral dimensions of their clients’ lives. In conclusion, the authors posit a virtue ethics and consider avenues of holistically and meaningfully infusing clinical practice with moral sensibilities.     

Heart Rate Reactivity in HAD and LAD Rats during Pavlovian Fear Conditioning

Recently, we reported that High-Alcohol-Drinking (HAD) rats exhibited selective deficits in active avoidance learning under alcohol-naive conditions, and that administration of moderate doses of alcohol (0.5 and 1.0 g/kg) facilitated learning in these rats (Blankenship et al., 2000; Rorick et al., 2003b). We hypothesized that the deficits resulted from excessive fear in the aversive learning context and that the anxiolytic properties of alcohol may have contributed to the improved learning that was observed after alcohol administration. This hypothesis was supported by a recent study in which prolonged freezing in HAD rats was seen after a classical fear conditioning procedure (Rorick et al., 2003a). To provide additional evidence that HAD rats indeed exhibit behaviors consistent with the expression of increased fear in aversive learning contexts, we employed a Pavlovian fear conditioning task to measure heart rate in HAD and Low-Alcohol-Drinking (LAD) rats. In this study, HAD (HAD-1 and HAD-2) and LAD (LAD-1 and LAD-2) rats were assigned to one of three pre-exposure conditions: Context Only, Context/Tone, or Sequential (Context Only followed by Context/Tone) Pre-Exposure. Following pre-exposure, fear conditioning acquisition and extinction procedures were identical for all groups. Results indicated that although no baseline differences were observed between HAD and LAD rats, HAD rats receiving Context-Only pre-exposure exhibited excessive heart rate reactivity to the tone conditional stimulus during fear conditioning acquisition, compared to LAD rats receiving the same pre-exposure conditions. These findings support the hypothesis that HAD rats exhibit behaviors consistent with increased fear in aversive learning contexts, as measured by autonomic conditioning.     

Syllabic priming effects in picture naming in French: lost in the sea!

Ferrand, Segui, and Grainger (1996) found robust syllable priming effects in picture naming latencies: Pictures primed with their initial syllable (e.g., ba for baleine [whale]) were processed faster than pictures primed with a string of letters shorter or longer than their initial syllable (e.g., bal for baleine). However, in several studies, these priming effects have not been replicated in word naming or in picture naming either in Dutch or in English (Schiller, 1998, 1999, 2000). The present study was aimed at replicating syllable priming effects in picture naming in French using a masked priming paradigm. The study employed a larger number of participants and items than were used in the Ferrand et al. (1996) study. The syllable priming effect in picture naming latencies was not replicated. Subsampling procedures were then used to examine the stability of the Ferrand et al. (1996) pattern of results in picture naming in greater detail. The syllabic priming effect in picture naming turned out to be an extremely rare event.     

Personality prototypes in eating disorders based on the Big Five model

A three factor model of personality pathology was investigated in a clinical sample of 335 female eating disordered patients. Cluster analysis of the Big Five NEO-FFI scales (Costa & McCrae, 1992) yielded three distinct personality profiles, which were consistent with previous studies: (1) a resilient/high functioning cluster with no clinical elevations on the NEO-FFI scales; (2) an undercontrolled/emotionally dysregulated cluster with elevated scores on the Neuroticism scale and low scores on Conscientiousness and Agreeableness; (3) an overcontrolled/constricted cluster showing high scores on Neuroticism and Conscientiousness and low scores on Openness to Experience. Comparing the three personality prototypes with respect to Axis I and Axis II disorders,resilients reported systematically less clinical and personality problems than both undercontrollers and overcontrollers. Compared to the latter, undercontrollers showed more impulsive personality features and behaviors. Finally, cluster membership was not clearly associated with eating disorder subtypes, suggesting that there is considerable variance in personality features and/or pathology within the various eating disorder categories.     

Biases in the perceived timing of perisaccadic perceptual and motor events

Subjects typically experience the temporal interval immediately following a saccade as longer than a comparable control interval. One explanation of this effect is that the brain antedates the perceptual onset of a saccade target to around the time of saccade initiation. This could explain the apparent continuity of visual perception across eye movements. This antedating account was tested in three experiments in which subjects made saccades of differing extents and then judged either the duration or the temporal order of key events. Postsaccadic stimuli underwent subjective temporal lengthening and had early perceived onsets. A temporally advanced awareness of saccade completion was also found, independently of antedating effects. These results provide convergent evidence supporting antedating and differentiating it from other temporal biases.     

Epistemic Intuitions and Epistemic Contextualism

In this paper I examine the way appeals to pretheoretic intuition are used to support epistemological theses in general and the thesis of epistemic contextualism in particular. After outlining the sceptical puzzle and the contextualist's resolution of that puzzle, I explore the question of whether this solution fits better with our intuitive take on the puzzle than its invariantist rivals. I distinguish two kinds of fit a theory might have with pretheoretic intuitions–accommodation and explanation, and consider whether achieving either kind of fit would be a virtue for a theory. I then examine how contextualism could best claim to accommodate and explain our intuitions, building the best case that 1 can for contextualism, but concluding that there is no reason to accept contextualism either in the way it accommodates nor the way it explains our intuitions about the sceptical puzzle.     

Immobility and supination in garter snakes (Thamnophis elegans) following handling by human predators

A common response of animals to physical restraint is tonic immobility. The authors observed the behavior of garter snakes, Thamnophis elegans, in the field to determine the frequency of immobility as a response to handling. Most snakes fled after release, but the remainder remained immobile, sometimes on their backs (supination), for up to 10 min. Immobility was seen most often in pregnant snakes, which also were more likely than other snakes not to have moved before capture. Failure to move, either before or after capture, might be a consequence of the limited locomotory ability of gravid snakes. However, the lack of observations of interactions between snakes and their natural predators impedes researchers' understanding of the antipredator value, if any, of tonic immobility.