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Biomedical subjects

A A Smirnova

Publications and source records attributed to A A Smirnova.

31 records · Page 2Linked to original sources
PubMedDate not supplied

[Prototype symbolization in hooded crows].

The ability in prototype symbolization was studied in four crows trained in matching concept. The experimental approach was characterized by the absence of direct training providing an association between the pictured arrays and Arabic numerals. Experimental sessions were divided into demonstrative and test phases. In the demonstrative phases, the sample and the reinforced stimulus belonged to the same category: if the sample was a pictured array, the reinforced stimulus was also the pictured array, if the sample was a numeral, the reinforced stimulus was likewise a numeral. Matching-to-sample competence was sufficient to perform this task successfully. In case of a correct choice a crow received some mealworms, their number was equal to the number of items in the pictured array or the Arabic numeral. In the test phases, the sample and the comparison stimuli were of different categories. If the sample was a pictured array, the comparison stimuli were numerals; if the sample was a numeral, the comparisons were the pictured arrays. Such tests required the birds to choose a numeric symbol corresponding to the pictured array or to choose the array of pictured items numerically equal to the Arabic symbol. All four crows performed this task successfully. Birds were able to set up a correspondence between the Arabic numeral from 1 to 4 and the number of elements in pictured arrays by way of mental juxtaposition of the earlier received information. Similar experiments showed that crows are likely to be able to perform mental operations with numerals analogous to simple arithmetic addition.

Animal Communication↗
PubMedDate not supplied

[Analysis of the effect of a training regime for the correct choice of matched learning in gray crows].

It was shown that a large set of training stimuli promotes abstract concept learning. These experiments were designed to assess whether an application of a large set of training stimuli would facilitate matching learning in crows. Four hooded crows were trained with a set of 72 unique combinations of stimuli in two-alternative simultaneous matching tasks with stimuli of three different categories: achromatic color (white, light-grey, dark-grey, and black), shape (Arabic numerals from 1 to 4 used as visual shapes only), and number of elements (heterogeneous graphic arrays from 1 to 4 items). Although the performance of all crows was significantly above chance (p < 0.01) in some 72-trial blocks, birds were unable to establish matching and to reach the criterion of learning 80% correct or better over 72 consecutive trials) in 5184 trials. Thus, the modified training procedure was less efficient than the training technique previously used (successive cyclic repetition of three small sets of training stimuli), which allowed four of six crows to acquire the matching rule after 1780, 2360, 3830, and 5260 trials [4,9].

Animals↗
PubMedDate not supplied

[Conditioning of gray crows (Corvus cornix L.) in a "giant" eight-arm radial maze].

Twelve adult hooded crows (Corvus cornix) were trained to perform a standard radial-maze task in a giant eight-arm outdoor radial maze constructed at the "Chistyi les" Biological Station (Tver oblast) for comparative investigations of spatial memory in birds and mammals. The maze consists of a central part of 250 cm diameter, and has arms of 650 cm length, 170 cm height and 80 cm width. The examined hooded crows showed good task performance. Errors (repeated visits to empty arms) were few in number and were predominantly connected with the tendency to avoid arms close to an observer.

Animals↗
PubMedDate not supplied

[Numerousness judgement in hooded crows: generalization by the "more than" concept].

Four carrion crows were trained to choose the greater array from pairs of numerousness discriminanda in the range of 1-12. In the process of training all irrelevant attributes of the arrays (geometric form, size and color of elements, patterns of distribution) were varied. Several control procedures were employed to make extraneous cues unlikely. In particular, in order to preclude the use of cumulative area or other magnitude cues the ratio of cumulative area of elements to their number was varied (in a half of presentations the greater array consisted of bigger elements while the lesser array consisted of smaller elements and in the other half the greater array consisted of smaller elements while the lesser array consisted of bigger elements). All the crows demonstrated high accuracy of comparisons (75.3 +/- 2.4%). Correct performance dominated also under conditions with minimal difference between the compared arrays. It was concluded that these crows were able to compare the arrays in the range of 1-12 by numerosity itself. When arrays in the new range of 10-20 were presented all the crows demonstrated successful transfer of acquired reaction without any additional training (71.5 +/- 2.3%). However, when the ratio of cumulative area of elements to their number varied only two of the four crows performed successfully (71.9 +/- 3.6). Taken together these data suggest that crows are capable of forming the concept "more than" based on numerical discrimination up to 20.

Animals↗
PubMedDate not supplied

[Teaching hooded crows (Corvus cornix L.) the abstract rule of choice by the matching/oddity of the sample].

Six hooded crows (Corvus cornix) were trained in alternative simultaneous matching-to-sample and oddity-from-sample tasks with visual stimuli. Bird's ability to acquire the abstract same/different concept was investigated. For this purpose three stimulus sets of the following categories were used: color (black and white cards), shape (Arabic numerals "1" and "2"), and numerousness (heterogeneous arrays of 1 or 2 elements). These three sets were used for training successively and repeatedly; each time the stimulus set was changed for the next one after the criterion (80% correct or better over 30 successive trials) was reached with the previous one. The training procedure was repeated until the criterion could be reached for each of the three stimulus sets within the initial 30-50 trials. After that, the abstractness of the rule acquired by birds was tested. First, the "partial" transfer tests were conducted, which consisted in presentation of novel stimuli with familiar ones (numerals and arrays in the range from 1 to 4). At the final stage, only sets of novel numerals and arrays in the range from 5 to 8 were presented. The crows demonstrated successful transfer in all of these tests, including the test with absolutely novel stimuli (in the first 24 presentations: min 75.0%, p < 0.02; max 83.3%, p < 0.01). The level of correct choices did not differ from the baseline (p > 0.05). This allows us to conclude that birds are capable for formation of the abstract same/different concept.

Analysis of Variance↗