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.     

Different responses in two strains of chickens (<Emphasis Type="Italic">Gallus gallus</Emphasis>) in a magnetic orientation test

Previous studies demonstrated that layer strain domestic chicks bred for egg production can orient using directional cues from the magnetic field; here we report that chicks from a broiler strain bred for meat production do not use magnetic cues for orientation. We imprinted both strains of chicken on a red ball and subsequently trained them in a featureless testing arena. Between rewarded trials in the geomagnetic field, we inserted unrewarded tests under the following conditions: (1) in the geomagnetic field, (2) in a magnetic field with North shifted by 90 degrees and (3) in a magnetic field with the inclination inverted. The layer chicks made a correct axial response in 75-80% of the tests, shifting their choices following a rotation of magnetic North. Chicks of the broiler strain, in contrast, performed at chance level with between 47 and 60% of choices on the correct axis. This difference between the strains does not appear to be due to substantial strain differences in motivation to perform the task. It therefore appears possible that the selection of the broiler strain has led to the elimination of the specific ability to respond to magnetic cues in the test situation.     

Sun compass orientation in seed-caching corvids: its role in spatial memory

The role of sun compass orientation in spatial memory of Clark’s nutcrackers, Nucifraga columbiana, and pinyon jays, Gymnorhinus cyanocephalus, was studied in a series of cache recovery experiments. Birds were tested in an octagonal outdoor aviary with sand-filled cups inserted in the floor. For caching, only 12 such cups in a 90° sector were available, while for recovery 4–7 days later all 48 cups in the entire aviary were open. In control tests, the birds concentrated their search activity in the sector where they had cached. When their internal clock was shifted 6 h between caching and recovery, pinyon jays shifted their search activity to the 90° adjacent sector, as predicted if the sun compass was used. Clark’s nutcrackers did not respond to the first clock-shift; however, they, too, shifted their search activity after a second clock-shift back to normal. This suggests that the sun compass is a component of spatial memory in both species. Clark’s nutcrackers, however, seem to rely on their sun compass to a lesser degree than pinyon jays or the previously studied scrub jays. A comparison of the findings indicates that the role of the sun in spatial memory might reflect differences in habitat and ecology of the three corvid species. Received: 18 February 1999 / Accepted after revision: 17 September 1999     

The Renewal of Dewey – Trends in the Nineties

This article proposes that the `renewal' of Dewey might contributeto filling the gap between the pedagogical commitment tocontingency and plurality and the fact that the pedagogicaltradition, until now, has neutralized contingency and deniedits systematic meaning for education. Therefore, the maintraits of the `renewal of Dewey' are shown in thework of some Dewey scholars who, critically and creatively,reconstruct Dewey in the mirror of poststructural, communicational and constructive theory developments.Following Dewey, these researches balance the objectiveevaluation of Dewey's work by a deliberate and overtpursuit of their own intentions and (pre-)selections by the scholars.Intersubjectivity and communication are key concepts in thisrenewal of pragmatism rejecting the subject-centered philosophy of consciousness, the traditional westernepistemology and metaphysics. The turn to the philosophicalpriority of the unforeseeable also leads to anunderstanding of action as an essentialfocus. In this context Dewey's pragmatistic view of radical democracy is received as a non-foundationaltheory and the concept of consensus is criticized.The scholars clarify that the boundaries of the subjectare broadened by communicative destabilization.At the end of the article it is asked what the renewal-dimensions mean for education locatedin the public sphere.     

Different responses of two strains of chickens to different training procedures for magnetic directions

In previous conditioning experiments training domestic chickens to magnetic directions, a brown strain solved the task, whereas a white strain seemed unable to do so (Freire et al. Anim Cogn 11:547–552, 2008). To test whether this was possibly caused by loss of magnetic compass orientation in the white chickens, we analyzed the distribution of cryptochrome 1a, the candidate receptor molecule mediating magnetic compass information, in the retinae of Lohmann Browns and White Leghorns and found no difference between the two strains. Yet, subsequent training experiments replicated the former findings: Lohmann Browns used the magnetic field to find an imprinting stimulus hidden behind the screen in a specific magnetic direction, whereas White Leghorns did not solve the task. However, when we altered the training method by training also in a magnetic field with North shifted to geographic East and including a punishment for incorrect choices, the performance of White Leghorns improved to a significant preference for the expected directions. The Lohmann Browns, on the other hand, seemed frightened and chose randomly. Our results thus demonstrate the crucial role of the training method for conditioning to magnetic stimuli, with differences found even between strains of the same species.     

The renewal of dewey — trends in the nineties

This article proposes that the ‘renewal’ of Dewey might contribute to filling the gap between the pedagogical commitment to contingency and plurality and the fact that the pedagogical tradition, until now, has neutralized contingency and denied its systematic meaning for education. Therefore, the main traits of the ‘renewal of Dewey’ are shown in the work of some Dewey scholars who, critically and creatively, reconstruct Dewey in the mirror of poststructural, communicational and constructive theory developments. Following Dewey, these researches balance the objective evaluation of Dewey’s work by a deliberate and overt pursuit of their own intentions and (pre-)selections by the scholars. Intersubjectivity and communication are key concepts in this renewal of pragmatism rejecting the subject-centered philosophy of consciousness, the traditional western epistemology and metaphysics. The turn to the philosophical priority of the unforeseeable also leads to an understanding of action as an essential focus. In this context Dewey’s pragmatistic view of radical democracy is received as a non-foundational theory and the concept of consensus is criticized. The scholars clarify that the boundaries of the subject are broadened by communicative destabilization. At the end of the article it is asked what the renewal-dimensions mean for education located in the public sphere.