Observing responses in rats: Support for the secondary reinforcement hypothesis

Rats' lever presses on a retractable lever earned brief presentations of discriminative stimuli signalling periods in which responding on an alternative lever was either non-reinforced (extinction) or reinforced on a random ratio schedule. The predictions of two theoretical accounts of this behaviour were tested by studying the effects of omitting either the stimulus signalling the reinforced or that signalling the non-reinforced schedule component. Under these conditions rats' behaviour is determined by the conditioned, affective properties of the stimuli rather than by their purely informational properties.     

Persistent alterations in biological profiles in women with abuse histories: influence of premenstrual dysphoric disorder.

OBJECTIVE: To examine dysregulation in biological measures associated with histories of abuse in women and whether women with premenstrual dysphoric disorder (PMDD) differ in their dysregulation. DESIGN: Twenty-five women meeting prospective criteria for PMDD and 42 non-PMDD controls underwent structured interview to determine abuse histories and lifetime Axis I diagnoses, excluding those with current Axis I disorders or using medications. MAJOR OUTCOME MEASURES: Plasma cortisol and norepinephrine (NE), heart rate (HR), blood pressure (BP), and vascular resistance index (VRI) were assessed at rest and in response to mental stress. RESULTS: A greater proportion of PMDD women had prior abuse compared with non-PMDD women. Regardless of PMDD status, all abused women had lower plasma NE and higher HRs and tended to have lower plasma cortisol at rest and during stress. Abused women also reported more severe daily emotional and physical symptoms. Greater VRI and BP at rest and during stress were seen only in PMDD women with abuse. CONCLUSION: There is persistent dysregulation in stress-responsive systems in all abused women that cannot be accounted for by current psychiatric illness or medications, and PMDD women may be differentially more vulnerable to the impact of abuse on measures reflecting alpha-adrenergic receptor function.     

Binocular cues in the perception of distance of a point source of light

The ability to make egocentric distance estimates of a single point source of light, seen in darkness and without the cues of changing size and luminance, was investigated in sixteen observers. The attenuation required to maintain constant luminance, when the target was viewed from different distances, was shown to follow the inverse square law providing the angle subtended by the light was less than 20 s arc. Distance changes were also simulated by means of a split mirror which produced vergence cues, or by test lenses to provide accommodation cues. Over the range 0.5 to 9.2 m distance estimates were surprisingly accurate, although there was some overestimation of near and underestimation of far distances. Most observers made good judgements when only convergence cues were varied, whereas no observers made consistently good judgements when only accommodation cues were varied. The difficulties are discussed in terms of the accommodation-convergence link. When distance was simulated by changing convergence and accommodation cues, estimates were not as good as when real distance was changed. Since good estimates were made with brief target exposures, these judgements were not based on subsequent convergence or accommodation changes. It is suggested that the metric or reference against which the apparently absolute judgements were made was the efferent demand signal associated with a 'resting' position of convergence in darkness.     

Rabbi and Magister: Overlapping intellectual models of the twelfth-century renaissance

Elka Klein’s writings have illuminated reciprocal and distinctive characteristics of the social and intellectual lives of Jewry in Iberia and by comparison Northern Europe during the High Middle Ages. This article honors her insights, by comparing the development of biblical hermeneutics at the Abbey of St. Victor in Paris and in the writings of Abraham ibn Ezra. Hugh of St. Victor’s introduction to the study of Scripture, Didascalicon, provides a program for the individual student to integrate all branches of human knowledge into the search for Divine Wisdom that may be found only in Scripture. The innovation in Hugh’s program is the emphasis on the “literal” or “historical” sense of Scripture as the solid basis for the development of theological study. Grammar and rhetoric were stepping stones that led the young theologians to higher levels of Divine Wisdom. The introduction to Abraham ibn Ezra’s commentary on the Pentateuch constitutes a parallel point of orientation for twelfth-century Jewish readers. A close reading of ibn Ezra’s prologue maps the hermeneutical approaches that different communities – Christian, rabbinic Jewish, and Karaite – utilized in their expositions of the Pentateuch. After critiquing each community, ibn Ezra offers his own approach that builds an overall framework for correct interpretation on the foundation of grammar and the rabbinic oral tradition. From this perspective, the article demonstrates that during this period Jews and Christians, both in Iberia and Northern Europe, focused on harmonizing reason and revelation. Both communities used grammar as the primary criterion for evaluating the accumulation of traditional sources. Both approaches intended to develop students, who were capable of understanding that “reason is the angel that mediates between God and humanity.”     

Bidirectional Familial Influences in Dietary Behavior Test of a Model of Campaign Influences

Using both cross-sectional and longitudinal data spanning a decade, this article analyzes how dietary behavior of household children and adults (N = 576 households) was affected by the Stanford Five-City Project (FCP). Tests of a three-part, cumulative model of bidirectional influences within the family, which conceptualizes household members as sources of influence on each other and subject to influence by an external agent, were supported. Children and adults were influenced by both each other and the FCP campaign in changing and maintaining health behaviors. This article demonstrates that public health campaigns can be made more effective if they conceptualize both children and adults as potential sources of influence. The long-term effectiveness of such efforts can be enhanced by encouraging families, as opposed to individuals, to change health behaviors.