scholarly journals Honeybees (Apis mellifera) exhibit flexible visual search strategies for vertical targets presented at various heights

F1000Research ◽  
2015 ◽  
Vol 3 ◽  
pp. 174 ◽  
Author(s):  
Linde Morawetz ◽  
Lars Chittka ◽  
Johannes Spaethe

When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can increase their detection ability of objects in search scenarios when targets appear frequently or exclusively in the dorsal area of the visual field. We trained individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the experimental phase, but bees increased their search performance significantly after a few foraging bouts: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. A variety of possible mechanisms underlying this behavioural adaptation, for example spatial attention, are discussed.

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 174 ◽  
Author(s):  
Linde Morawetz ◽  
Lars Chittka ◽  
Johannes Spaethe

When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can use alternative search mechanisms such as spatial attention, which allows flexible focusing on different areas of the visual field. We asked individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the test phase, but bees increased their search performance significantly after a few learning trials: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. Different possible mechanisms of this behavioural adaptation are discussed.


Author(s):  
Thomas Z. Strybel ◽  
Jan M. Boucher ◽  
Greg E. Fujawa ◽  
Craig S. Volp

The effectiveness of auditory spatial cues in visual search performance was examined in three experiments. Auditory spatial cues are more effective than abrupt visual onsets when the target appears in the peripheral visual field or when the contrast of the target is degraded. The duration of the auditory spatial cue did not affect search performance.


Author(s):  
Dorothy M. Johnston

This study was made to investigate the relationship between the size of visual fields of observers and time required to locate targets on static displays. The findings, which indicate that people with large visual fields can find targets more rapidly than observers with small fields, have practical selection and training application. Equations are presented which can be used to determine search time that can be expected as a function of the size of the visual field of the observer and the apparent size of the area being searched.


2017 ◽  
Vol 40 ◽  
Author(s):  
Hermann J. Müller ◽  
Heinrich René Liesefeld ◽  
Rani Moran ◽  
Marius Usher

AbstractThis commentary focuses on two related, open questions in Hulleman & Olivers' (H&O's) proposal: (1) the nature of the parallel attentive process that determines target presence within, and thus presumably the size of, the functional visual field, and (2) how the pre-attentive guidance mechanism must be conceived to also account for search performance in tasks that afford no reliable target-based guidance.


Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5390
Author(s):  
Mahdieh Kazemimoghadam ◽  
Nicholas P. Fey

Intent recognition in lower-limb assistive devices typically relies on neuromechanical sensing of an affected limb acquired through embedded device sensors. It remains unknown whether signals from more widespread sources such as the contralateral leg and torso positively influence intent recognition, and how specific locomotor tasks that place high demands on the neuromuscular system, such as changes of direction, contribute to intent recognition. In this study, we evaluated the performances of signals from varying mechanical modalities (accelerographic, gyroscopic, and joint angles) and locations (the trailing leg, leading leg and torso) during straight walking, changes of direction (cuts), and cuts to stair ascent with varying task anticipation. Biomechanical information from the torso demonstrated poor performance across all conditions. Unilateral (the trailing or leading leg) joint angle data provided the highest accuracy. Surprisingly, neither the fusion of unilateral and torso data nor the combination of multiple signal modalities improved recognition. For these fused modality data, similar trends but with diminished accuracy rates were reported during unanticipated conditions. Finally, for datasets that achieved a relatively accurate (≥90%) recognition of unanticipated tasks, these levels of recognition were achieved after the mid-swing of the trailing/transitioning leg, prior to a subsequent heel strike. These findings suggest that mechanical sensing of the legs and torso for the recognition of straight-line and transient locomotion can be implemented in a relatively flexible manner (i.e., signal modality, and from the leading or trailing legs) and, importantly, suggest that more widespread sensing is not always optimal.


Author(s):  
Douglas Welling ◽  
Dean Edwards ◽  
Mike Anderson

Current underwater crawling vehicles could benefit by using rotating head sonar data to avoid collisions with obstacles. We have developed and optimized a fuzzy logic controller using software for simulation of an underwater environment. The optimization results show near an order of magnitude increase in performance over both straight line and lawnmower search patterns with relatively small changes in the system parameters. The fuzzy logic controller has the capability of navigating a crawler safely and quickly between mission specific points.


2021 ◽  
Author(s):  
Daniel Fortin-Guichard ◽  
Rianne Ravensbergen ◽  
Kai Krabben ◽  
Peter M. Allen ◽  
David L. Mann

Abstract Paralympic swimmers with vision impairment (VI) currently compete in one of three classes depending on their visual acuity (VA) and/or visual field. However, there is no evidence to suggest that a three-class system is the most legitimate approach for classification in swimming, or that the tests of VA and visual field are the most suitable. An evidence-based approach is required to establish the relationship between visual function and performance in the sport. Therefore, the aim of this study was to establish the relationship between visual function and performance in VI swimming. The swimming performance of 45 elite VI swimmers was evaluated during international competitions by measuring the total race time, start time, clean swim velocity, ability to swim in a straight line, turn time and finish time. Visual function was measured using a test battery that included VA, contrast sensitivity, light sensitivity, depth perception, visual search, and motion perception. Results revealed that VA was the best predictor of total race time, though the relationship was not linear. Decision-tree analysis suggested that only two classes were necessary for legitimate competition in VI swimming, with a single cut-off between 2.6–3.5 logMAR. No further significant association remained between visual function and performance in either of the two resulting classes. Results suggest that legitimate competition in VI swimming requires one class for partially sighted and another for functionally blind athletes.


Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 117-117
Author(s):  
F W Cornelissen ◽  
A C Kooijman ◽  
H I A Ditvoorst ◽  
E Eppink

We examined search performance throughout the functional visual field. This has been shown to be an important determinant for performance in daily life tasks. We were interested to see how aging affects performance and whether we could find evidence for compensatory strategies in subjects with visual field defects. The task was to localise a target (C) among 24 distractors (O) and identify the direction of its gap. Subjects were allowed to make eye movements. Using a staircase procedure, performed separately at each of the 25 possible target positions, we determined the stimulus presentation time necessary to reach criterion performance. This method has the advantage over more common reaction time experiments that it is not affected by speed - accuracy trade-offs. Seven young (age 22 – 28 years) and seven old (age 58 – 78 years) subjects with normal vision participated. In addition, we tested older subjects with visual field defects (central defects and hemianopia). Our results show significant ( p<0.0001) age-related differences in the presentation time required for criterion performance. In addition, we found a significant ( p<0.0001) interaction between age and target eccentricity, with the largest age-related decline in performance occurring for targets on or near the initial fixation point, and smaller changes occurring for targets further away from this point. Age and target eccentricity turned out to be the main predictors for search performance. We conclude that age significantly affects search performance, but the extent depends on the distance from the initial fixation point. Our results therefore suggest that aging does not equally affect all stages in visual processing. Not surprisingly, field defects influence search performance, but we also found evidence for compensatory strategies.


2015 ◽  
Vol 78 (2) ◽  
pp. 85-95 ◽  
Author(s):  
Matthew Smith ◽  
Callum D Mole ◽  
Georgios K Kountouriotis ◽  
Catharine Chisholm ◽  
Bipin Bhakta ◽  
...  

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