Comprehending compass directions

Two experiments investigated the processes by which compass directions are comprehended. In both experiments, the task was as follows. A compass direction (e.g., 210 deg) was visually presented. The subject drew a representation of the direction and then pressed a key. Reaction time from onset of the stimulus to the keypress was measured. The results suggested a model of direction comprehension involving two steps: first, computing the nearest cardinal direction to the target direction, and then “rotating” from the cardinal to the target direction. Rotation could be performed equally well clockwise or counterclockwise. Additionally, north-south. tended to be comprehended faster than east-west, confirming past results that have shown an advantage of up-down over left-right in discrimination tasks.     

Learning of magnetic compass directions in pigeons

A proof of magnetic compass learning by pigeons under laboratory conditions has been attempted for decades, but all experiments have failed so far. The aim of the present study was to test whether pigeons can learn magnetic compass directions in an operant chamber if magnetic cues are presented as true spatial cues. Experimental sessions were carried out in the local geomagnetic field and in magnetic fields with matched total intensity and inclination, but different directions generated with Helmholtz-coils. Birds demonstrated successful learning with a performance level comparable to that in learning studies with magnetic anomalies. In addition, we compared the data from magnetic learning in the laboratory with performance from homing experiments in the field. The birds that were more successful in the learning experiment had vanishing bearings farther away from the home direction than the group mean at unfamiliar, but not at familiar sites. This might suggest that better learners explore unknown locations in a different way. Our findings represent the first evidence for operant magnetic compass learning in pigeons and also provide a link between behavioural data from the field and the laboratory.     

Identifying finite cardinal abstracts

Philosophical Studies - Objects appear to fall into different sorts, each with their own criteria for identity. This raises the question of whether sorts overlap. Abstractionists about...     

Bioethics policies and the compass of common morality

Even if there is a common morality, many would argue that it provides little guidance in resolving moral disputes, because universally accepted norms are both general in content and few in number. However, if we supplement common morality with commonly accepted factual beliefs and culture-specific norms and utilize coherentist reasoning, we can limit the range of acceptable answers to disputed issues. Moreover, in the arena of public policy, where one must take into account both legal and moral norms, the constraints on acceptable answers will narrow the extent of reasonable disagreement even further. A consideration of the debate over legalization of assisted dying supports this claim.

The ABC of cardinal and ordinal number representations

Numerical cognition encompasses the concepts of quantity ('how many?') and serial order ('which position?'). Yet, although numbers can convey different meanings, a recent imaging study by Fias and coworkers showed that ranking letters in the alphabet is subserved by a cortical network highly similar to that involved in judging magnitudes. In terms of neural processing, quantity and rank might just be two sides of the same coin.     

Methods for describing ordinal data with cardinal models

Several methods, both new and old, for describing ordinal data with a cardinal model are discussed in a newly developed and general context which broadens their applicability beyond their traditional use in multidimensional scaling. The relationships between the methods is investigated. It is shown that the two most commonly used methods (Guttman's rank-image principle and Kruskal's least-square monotonic transformation) are the boundary conditions of a newly proposed single parameter family of methods. An additional method is proposed which is shown to yield an equal-density model space. The commonly made distinction between “transformation” methods and “transformation-free” methods is shown to be a pseudodistinction. It is observed that all the methods can be stated as matrix operations on the model space with the conclusion that they try to optimize a linear combination of the model space.     

“无”义辩析

本文通过对“无”这个概念的不同含义的发掘 ,认为哲学史上的“无”含义有三大类型 ,第一类是万物皆有 ,而无无的“无” ;第二类是有无统一的“无” ;第三类是万物皆“空”的“无”。并从变化发展和物质存在形式二种角度探讨了有无统一的“无” ,从本原、语义、自性三种角度探讨了万物皆空的“无”。在此基础上 ,分析比较了对作为道教和西方哲学的基本概念的“无”与作为佛教基本概念的“空”的异同。     

Olfactory perception as a compass for olfactory neural maps

The mammalian brain commonly uses structural proximity to reflect proximity in stimulus and perceptual space. Objects or object features that are near each other in physical structure or perception are also near each other in the brain. This generates sensory maps. The topography of olfactory connectivity implies a rudimentary map in the olfactory epithelium, a more intricate map in the olfactory bulb, but no ordered topography is evident in piriform cortex. Currently, we are largely unable to link the ordered topography in epithelium and bulb to meaningful olfactory axes within a strong predictive framework. We argue that the path to uncovering such a predictive framework depends on systematically characterizing olfactory perception, and we describe initial efforts in this direction.     

Inducing ordinal and cardinal representations of the first five natural numbers

The prediction that the ordinal property of natural number symbols (using these symbols to represent the terms in an ordered progression) is more easily learned than the cardinal property of natural number symbols (using these symbols to represent the manyness of collections) was examined in this experiment. Preschoolers who evidenced no proficiency with either the ordinal or cardinal properties of natural number symbols were trained to acquire these properties via simple feedback. Both properties proved to be trainable. The most important findings were that the ordinal property was much easier to train than the cardinal property, ordinal training effects were more durable across a 1-week interval than cardinal training effects, and ordinal training appeared to transfer better than cardinal training.     

A new secretary problem with rank-based selection and cardinal payoffs

We present an extension of the secretary problem in which the decision maker (DM) sequentially observes up to n applicants whose values are random variables X₁,X₂,…,X_n drawn i.i.d. from a uniform distribution on [0,1]. The DM must select exactly one applicant, cannot recall released applicants, and receives a payoff of x_t, the realization of X_t, for selecting the tth applicant. For each encountered applicant, the DM only learns whether the applicant is the best so far. We prove that the optimal policy dictates skipping the first sqrt(n)-1 applicants, and then selecting the next encountered applicant whose value is a maximum.     

Defining Discrimination in the Personal/Group Discrimination Discrepancy

Members of low-status groups typically report that their group experiences more discrimination than they do personally, a phenomenon referred to as the personal/group discrimination discrepancy. It is hypothesized that manipulating the meaning of discrimination affects the personal/group discrimination discrepancy. In three studies, 301 female undergraduates (259 Whites; 42 non-Whites) from a large midwestern university read vignettes depicting discriminatory events that varied according to severity and frequency. Participants in high-frequency conditions perceived both more personal and group discrimination than low-frequency participants, and they showed smaller personal/group discrepancies. This effect was found for work-related discrimination and social sexism. Results indicate that severe and infrequent events are what people typically think of as discrimination and that using the term discrimination affects personal and group judgments. The importance of defining discrimination when investigating the personal/group discrimination discrepancy is discussed.     

Discrimination of loudness similarity

Interval and ratio scale values were derived from measures of variability in the discrimination of loudness similarity. The interval values are linearly related to interval values based on equisection judgments (Garner, 1954), cumulating jnds (Riesz, 1933), and the dispersion of absolute judgments (Gamer, 1952). Scale values based on three diverse discriminability procedures and on the method of equisection are thus in good agreement. The ratio lvalues, however, are at variance with ratio values determined by direct ratio estimations (Stevens, 1955).