Epistemic means and ends: a reply to Hofmann

How is epistemic justification related to knowledge? Is it, as widely thought, constitutive of knowledge? Is it merely a means to knowledge, or merely a means to something else, such as truth? In a recent article in this journal, Hofmann (2005, Synthese, 146(3), 357–369) addresses these questions in attempting to defend an important argument articulated by Sartwell (1992, The Journal of Philosophy, 89(4), 167–180) and reconstructed and criticized by Le Morvan (2002, Erkenntnis: An International Journal of Analytic Philosophy, 56(2), 151–168). This Sartwellian argument purported to show that, since epistemic justification is of merely instrumental value, it is not constitutive of knowledge. In this paper, I argue that Hofmann’s defense of Sartwell fails, but that its failure brings to light some important lessons concerning the nature of justification and its relationship to truth and knowledge.     

Short-distance navigation in cephalopods: a review and synthesis

This paper provides a short overview of the scientific knowledge concerning short-distance navigation in cephalopods. Studies in laboratory controlled conditions and observations in the field provide converging evidence that cephalopods use visual cues to navigate and demonstrate spatial memory. A recent study also provides the first evidence for the neural substrates underlying spatial abilities in cuttlefish. The functions of spatial cognition in cephalopods are discussed from an evolutionary standpoint.     

Ill-structured measurement designs in organizational research: implications for estimating interrater reliability

Organizational research and practice involving ratings are rife with what the authors term ill-structured measurement designs (ISMDs)--designs in which raters and ratees are neither fully crossed nor nested. This article explores the implications of ISMDs for estimating interrater reliability. The authors first provide a mock example that illustrates potential problems that ISMDs create for common reliability estimators (e.g., Pearson correlations, intraclass correlations). Next, the authors propose an alternative reliability estimator--G(q,k)--that resolves problems with traditional estimators and is equally appropriate for crossed, nested, and ill-structured designs. By using Monte Carlo simulation, the authors evaluate the accuracy of traditional reliability estimators compared with that of G(q,k) for ratings arising from ISMDs. Regardless of condition, G(q,k) yielded estimates as precise or more precise than those of traditional estimators. The advantage of G(q,k) over the traditional estimators became more pronounced with increases in the (a) overlap between the sets of raters that rated each ratee and (b) ratio of rater main effect variance to true score variance. Discussion focuses on implications of this work for organizational research and practice.     

Acculturative dissonance, ethnic identity, and youth violence

Studies suggest that the process of acculturation for immigrant youth, particularly for second-generation youth, is significantly associated with delinquency and violence. This study explored the acculturation-violence link with respect to acculturative dissonance and ethnic identity. The results revealed in a sample of 329 Chinese, Cambodian, Mien/Laotian, and Vietnamese youth that acculturative dissonance was significantly predictive of serious violence, with full mediation through peer delinquency. Ethnic identity was not significantly associated with peer delinquency or serious violence. Although acculturative dissonance and ethnic identity accounted for a small percentage of variance in violence compared with peer delinquency, it cannot be discounted as trivial. Structural equation analyses provided support for both measurement and structural invariance across the four ethnic groups, lending support for cross-cultural comparisons. The results also lend support for the inclusion of cultural factors in youth violence prevention and intervention efforts.     

Subtyping adolescents with bulimia nervosa

Cluster analyses of eating disorder patients have yielded a "dietary-depressive" subtype, typified by greater negative affect, and a "dietary" subtype, typified by dietary restraint. This study aimed to replicate these findings in an adolescent sample with bulimia nervosa (BN) from a randomized controlled trial and to examine the validity and reliability of this methodology. In the sample of BN adolescents (N=80), cluster analysis revealed a "dietary-depressive" subtype (37.5%) and a "dietary" subtype (62.5%) using the Beck Depression Inventory, Rosenberg Self-Esteem Scale and Eating Disorder Examination Restraint subscale. The "dietary-depressive" subtype compared to the "dietary" subtype was significantly more likely to: (1) report co-occurring disorders, (2) greater eating and weight concerns, and (3) less vomiting abstinence at post-treatment (all p's<.05). The cluster analysis based on "dietary" and "dietary-depressive" subtypes appeared to have concurrent validity, yielding more distinct groups than subtyping by vomiting frequency. In order to assess the reliability of the subtyping scheme, a larger sample of adolescents with mixed eating and weight disorders in an outpatient eating disorder clinic (N=149) was subtyped, yielding similar subtypes. These results support the validity and reliability of the subtyping strategy in two adolescent samples.     

Dissociated roles for the lateral and medial septum in elemental and contextual fear conditioning

Extensive evidence indicates that the septum plays a predominant role in fear learning, yet the direction of this control is still a matter of debate. Increasing data suggest that the medial (MS) and lateral septum (LS) would be differentially required in fear conditioning depending on whether a discrete conditional stimulus (CS) predicts, or not, the occurrence of an aversive unconditional stimulus (US). Here, using a tone CS-US pairing (predictive discrete CS, context in background) or unpairing (context in foreground) conditioning procedure, we show, in mice, that pretraining inactivation of the LS totally disrupted tone fear conditioning, which, otherwise, was spared by inactivation of the MS. Inactivating the LS also reduced foreground contextual fear conditioning, while sparing the higher level of conditioned freezing to the foreground (CS-US unpairing) than to the background context (CS-US pairing). In contrast, inactivation of the MS totally abolished this training-dependent level of contextual freezing. Interestingly, inactivation of the MS enhanced background contextual conditioning under the pairing condition, whereas it reduced foreground contextual conditioning under the unpairing condition. Hence, the present findings reveal a functional dissociation between the LS and the MS in Pavlovian fear conditioning depending on the predictive value of the discrete CS. While the requirement of the LS is crucial for the appropriate processing of the tone CS-US association, the MS is crucial for an appropriate processing of contextual cues as foreground or background information.     

Biphasic ERK1/2 activation in both the hippocampus and amygdala may reveal a system consolidation of contextual fear memory

There is accumulating evidences to suggest that memory consolidation in some conditions involves two waves of neuronal plastic change. Using two fear conditioning procedures in male C57BL/6J mice, we have recently shown that consolidation of the foreground contextual fear memory required two waves of ERK1/2 activation in hippocampal CA1, while consolidation of cue conditioning was only associated with the early phase of activation. The present experiment further showed that this bi-phasic pattern of ERK1/2 activation was not restricted to hippocampal CA1, but could also be observed in other fear memory-related brain areas. The unpaired conditioning procedure (context in foreground) induced two waves of ERK1/2 activation in hippocampal CA1 and CA3, as well as in the LA and BLA nuclei of the amygdala. In contrast, the paired conditioning procedure (context in background) led to a transient early phase only in hippocampal CA1 and LA. In addition, ERK1/2 phosphorylation in the hippocampus was found to correlate with that in the amygdala nuclei specifically after the unpaired procedure. Taken together, our data suggest that the observed biphasic pattern of neuronal plastic events may reflect the interplay between hippocampal and amygdala activity-dependent plasticity critical for the system consolidation of contextual fear memory.