Grid vs subcutaneously delivered shock in escape schedules with guinea pigs

Guinea pigs were trained by use of titrated negative-reinforcement procedures to escape electric shock on ratio schedules. With one group of Ss, shock was delivered through the grid floor of the chamber. Another group had electrodes implanted subcutaneously, closing a circuit between the back of the neck and near the tail bone. The subcutaneous group was also run with grid-shock escape. Results indicate that grid-delivered shock is more effective and efficient than is shock delivered through implanted electrodes.     

A titration procedure for generating escape behavior

In a grid-shock escape paradigm using time-out as reinforcement, both fixed-ratio and variable-interval performances were established directly from a continuous reinforcement schedule with rats and guinea pigs. A procedure was developed that employed a stepwise decrease in reinforcement time for all responses except the terminal response. Acquisition and long-term maintenance data were obtained from Ss trained on this titrated negative-reinforcement procedure.     

Serial killers,spiders and cybersex: Social and survival information bias in the transmission of urban legends

This study uses urban legends to examine the effects of the social information bias and survival information bias on cultural transmission across three phases of transmission: the choose‐to‐receive phase, the encode‐and‐retrieve phase, and the choose‐to‐transmit phase. In line with previous research into content biases, a linear transmission chain design with 60 participants aged 18–52 was used to examine the encode‐and‐retrieve phase, while participants were asked to rank their interest in reading the story behind a headline and passing a story on for the other two phases. Legends which contained social information (Social Type), legends which contained survival information (Survival Type), and legends which contained both forms of information (Combined Type) were all recalled with significantly greater accuracy than control material, while Social and Combined Type legends were recalled with significantly greater accuracy than Survival Type legends. In another study with 30 participants aged 18–22, no significant differences were found between legend types in either the choose‐to‐receive phase or the choose‐to‐transmit phase.     

Dynamic visuomotor synchronization: Quantification of predictive timing

When a moving target is tracked visually, spatial and temporal predictions are used to circumvent the neural delay required for the visuomotor processing. In particular, the internally generated predictions must be synchronized with the external stimulus during continuous tracking. We examined the utility of a circular visual-tracking paradigm for assessment of predictive timing, using normal human subjects. Disruptions of gaze–target synchronization were associated with anticipatory saccades that caused the gaze to be temporarily ahead of the target along the circular trajectory. These anticipatory saccades indicated preserved spatial prediction but suggested impaired predictive timing. We quantified gaze–target synchronization with several indices, whose distributions across subjects were such that instances of extremely poor performance were identifiable outside the margin of error determined by test–retest measures. Because predictive timing is an important element of attention functioning, the visual-tracking paradigm and dynamic synchronization indices described here may be useful for attention assessment.     

A second generation nonlinear factor analysis

Nonlinear common factor models with polynomial regression functions, including interaction terms, are fitted by simultaneously estimating the factor loadings and common factor scores, using maximum-likelihood-ratio and ordinary-least-squares methods. A Monte Carlo study gives support to a conjecture about the form of the distribution of the likelihood-ratio criterion.The research reported in this paper was partly supported by Natural Sciences and Engineering Research Grant No. A6346.     

Concerning Paul Edwards' “Heidegger on Death”: A Criticism

For Husserl, noetics is the most fundamental science and the centrepiece of a phenomenological epistemology. Since in his major works Husserl does not develop noetics systematically but uses its main ideas and achievements often in apparent isolation without clarifying their systematic unity, the significance of noetics is often overlooked. Although Husserl has repeatedly stressed the importance of a phenomenological epistemology, what the concrete theses of such an undertaking are supposed to be often remains obscure. We shall see that the best way to clarify this is by providing a detailed account of Husserl’s noetics as it is developed in Husserl’s lecture courses “Introduction to Logic and Theory of Knowledge” (1906/07) and “Logic and General Theory of Science” (1917/18). This is the main aim of the present paper. We will shed light on the significance, systematic unity, and concrete theses of noetics. Furthermore, I shall show in what way the main theses of noetics are present in Husserl’s other works, even if the term noetics does not even occur. Finally, we will see that some basic ideas of Husserl’s noetics play an important role in current analytic epistemology and we will indicate how a phenomenological epistemology could enrich current debates.     

Chronic stress prior to hippocampal stroke enhances post-stroke spatial deficits in the ziggurat task

Stress is one of the most important variables to determine recovery following stroke. We have previously reported that post-stroke exposure to either stress or corticosterone (CORT) alleviates hippocampal ischemic outcome. The present experiment expands previous findings by investigating the influence of exposure to stress prior to ischemic event. Rats received either daily restraint stress (1h/day; 16 consecutive days) or CORT (0.5mg/kg; 16 consecutive days) prior to focal ischemic stroke in the hippocampus induced by bilateral injection of endothelin-1 (ET-1). All experimental groups were then tested in the ziggurat task, a new task for spatial cognition. The stress+stroke group showed significant deficits in both hippocampal structure and function. No deleterious effect of pre-stroke exposure to CORT was found in the CORT+stroke group. Our results indicate that a history of chronic stress sensitizes hippocampal cells to the damaging consequences of focal ischemia. The opposing effects of CORT-related experiences in this study not only reflect the diversity of glucocorticoid actions in the stress response, but also provide evidence that elevated CORT in the absence of emotional disturbance is not sufficient to produce hippocampal deficit.