Biomedical subjects

Julie Benard

Publications and source records attributed to Julie Benard.

3 recordsLinked to original sources

PubMed2006

Categorization of visual stimuli in the honeybee Apis mellifera.

Categorization refers to the classification of perceptual input into defined functional groups. We present and discuss evidence suggesting that stimulus categorization can also be found in an invertebrate, the honeybee Apis mellifera, thus underlining the generality across species of this cognitive process. Honeybees show positive transfer of appropriate responding from a trained to a novel set of visual stimuli. Such a transfer was demonstrated for specific isolated features such as symmetry or orientation, but also for assemblies (layouts) of features. Although transfer from training to novel stimuli can be achieved by stimulus generalization of the training stimuli, most of these transfer tests involved clearly distinguishable stimuli for which generalization would be reduced. Though in most cases specific experimental controls such as stimulus balance and discriminability are still required, it seems appropriate to characterize the performance of honeybees as reflecting categorization. Further experiments should address the issue of which categorization theory accounts better for the visual performances of honeybees.

Animals↗

PubMed2004

Local-feature assembling in visual pattern recognition and generalization in honeybees.

Generalization is a cognitive ability that allows similar stimuli along a given dimension to be treated as equivalents. Insects exhibit high levels of visual generalization. Honeybees trained to recognize complex visual stimuli on the basis of a single feature generalize their choice to novel stimuli sharing that common feature with the trained stimuli. The demonstration of this kind of performance has been limited to the use of a single visual feature, and the possibility that bees link different features in learning a visual pattern has been denied. Here we show that honeybees trained with a series of complex patterns sharing a common layout comprising four edge orientations remember these orientations simultaneously in their appropriate positions, and generalize their response to novel stimuli that preserve the trained layout. Honeybees also generalize their response to patterns with fewer correct orientations, depending on their match with the trained layout. Stimulation of the achromatic L-photoreceptor input is necessary for this task. The mini-brain of the honeybee can thus extract regularities in its environment and establish correspondences among correlated features. It can thus generate a large set of object descriptions from a finite set of elements.

Animals↗

PubMedDate not supplied

A test of transitive inferences in free-flying honeybees: unsuccessful performance due to memory constraints.

We asked whether honeybees, Apis mellifera, could solve a transitive inference problem. Individual free-flying bees were conditioned with four overlapping premise pairs of five visual patterns in a multiple discrimination task (A+ vs. B-, B+ vs. C-, C+ vs. D-, D+ vs. E-, where + and - indicate sucrose reward or absence of it, respectively). They were then tested with the nonadjacent pairs A vs. E and B vs. D. Preference of B to D is consistent with the use of the implicit hierarchy A > B > C > D > E. Equal choice of B and D supports choice based on the associative strength of the stimuli. The bees' choice was determined by their memory constraints: experience with the last premise pair (D+ vs. E-) predominated. In the tests, bees preferred A to E and chose equally B and D. An analysis of the performance in terms of a reward/penalty ratio showed that B had a higher associative strength than D. Thus, bees do not establish transitive inferences but, rather, guide their choices by the joint action of a recency effect and the associative strength of the stimuli. The former supports choice of D, whereas the latter supports choice of B, thus determining equal choice of B and D in the tests.

Animals↗