Optimal cache search depends on precision of spatial memory and pilfering, but what if that knowledge is not perfect?

Pfuhl, Gerit; Tjelmeland, Håkon; Molden, S.; Biegler, Robert

doi:10.1016/j.anbehav.2009.06.014

Cited by 6 publications

(13 citation statements)

References 26 publications

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“…Therefore, if the target had not been found within the search area, it was certain that the target was not within that area. These two assumptions are consistent with those in our mathematical analysis (Pfuhl et al, 2009). If the probability of detecting the target when coming across it is low, or navigation inaccurate, other search patterns may be preferable (Wehner & Srinivasan, 1981).…”

Section: Materials and Proceduressupporting

confidence: 75%

“…A quantitative analysis of the relationship between estimated precision and optimal search radius is presented in Pfuhl et al (2009). The following boundary conditions apply: If knowledge of the cache location is extremely precise-for example, the cache is almost certain to be within the area of a single probe-then such a single probe without finding the cache constitutes good evidence that the cache has been pilfered, even if the a priori probability of pilfering is very low.…”

Section: When To Stop a Search: Cache Retrievalmentioning

confidence: 99%

“…Many decision processes benefit from taking into account the variance inherent in a representation (Pfuhl, Tjelmeland, & Biegler, 2011;Pfuhl, Tjelmeland, Molden, & Biegler, 2009). However, theoretical benefits do not guarantee widespread use of estimates of precision.…”

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confidence: 99%

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Do adjustments in search behavior depend on the precision of spatial memory?

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Various forms of uncertainty are important for decision making. How aware are we of the precision of knowledge, and how accessible it is? In three experiments, an assessment of the precision of spatial memory was needed to make optimal decisions. First, we examined search strategies in a search task in which the most efficient strategy was to head to one side of the target by a margin depending on the precision of spatial information, the "where to start" task. We found that nine out of of our 20 human subjects adapted the margin according to precision. Second, we let the subjects search for the location of a sample picture. On one-third of the trials, the target was not present, making it a "when to stop searching" task. We found that the subjects did not adjust their investment in search according to their precision. In the third experiment, we looked at whether there was transfer between the two tasks. Subjects who had been reminded of the relevance of uncertainty by the "where to start" task increased their search effort more in the "when to stop searching" task. Thus, the results show that the use of information about precision is not automatic, but can be triggered.

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Section: Materials and Proceduressupporting

confidence: 75%

Section: When To Stop a Search: Cache Retrievalmentioning

confidence: 99%

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Do adjustments in search behavior depend on the precision of spatial memory?

et al. 2012

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“…It is only possible to define optimal behaviour if the optimality model takes into account the limits of available information. Then one may quantify the possible gains from estimating the various forms of uncertainty (Stephens 1989;Dall et al 2005;Koops 2004;Pfuhl et al 2009). …”

Section: General Conclusionmentioning

confidence: 99%

Precision and Reliability in Animal Navigation

2010

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Uncertainty plays an important role in several navigational computations. Navigation typically depends on multiple sources of information, and different navigational systems may operate both in parallel and in combination. The optimal combination of information from different sources must take into account the uncertainty of that information. We distinguish between two types of spatial uncertainty, precision, and reliability. Precision is the inverse variance of the probability distribution that describes the information a cue contributes to an organism's knowledge of its location. Reliability is the probability of the cue being correctly identified, or the probability of a cue being related to a target location. We argue that in most environments, precision and reliability are negatively correlated. In case of cue conflict, precision and reliability must be traded off against each other. We offer a quantitative description of optimal behaviour. Knowledge of uncertainty is also needed to optimally determine the point where a search should start when an organism has more precise spatial information in one of the spatial dimensions. We show that if there is any cost to travel, it is advantageous to head off to one side of the most likely target location and head toward the target. The magnitude of the optimal offset depends on both travel cost and search cost.

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“…The causes of food‐caching behaviour have received a great deal of attention from the perspective of animal cognition (e.g. Heinrich & Pepper 1998; Brotons 2000; Bugnyar & Kotrschal 2002; Emery, Dally & Clayton 2004; Dally, Clayton & Emery 2006; Hopewell & Leaver 2008; Pfuhl et al. 2009).…”

Section: Introductionmentioning

confidence: 99%

Linking seed dispersal to cache protection strategies

Muñoz

Bonal

2011

Journal of Ecology

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Summary1. The spatial distribution of dispersed seeds results from the combined action of the caching strategies followed by different granivores. Hence, it is essential to study the factors that influence seed predation and caching decisions to achieve a better understanding of the dispersal process. 2. In this study, we document how seed dispersal and the spatial patterns of natural recruitment are linked to the strategies used by granivores to protect their cached seeds from pilferage. We present a theoretical model showing that those strategies may convey benefits for both seed cachers and plants.3. We studied the relationships among seed production, seed predation ⁄ caching, cache pilferage and plant recruitment in a savanna-like landscape of oaks dispersed by scatter-hoarding rodents. 4. Our results show that acorn-dispersing rodents were concentrated under the canopies of scattered oaks, where the theft of cached acorns increased by 77% as compared to that of the surrounding open landscape. Acorns were thus cached selectively in the open areas to reduce pilferage; in fact, none of the few seeds cached beneath tree canopies survived predation by granivores (pilferage + recovery). Meanwhile, some acorns cached in the surrounding open areas were neither pilfered nor recovered and then recruited successfully. Accordingly, natural recruitment of newly emerged seedlings was higher outside than under canopies, suggesting that rodent caching strategies have direct implications for the directed dispersal of oaks. 5. Synthesis. The spatial patterns of seed dispersal shape the fitness of both the plant because they influence dispersal and recruitment efficiency, and the granivores that cache and predate its seeds because they influence their foraging efficiency. Cache protection strategies reduce pilferage significantly and enhance seed recovery rates by the cache owner. At the same time, more seeds remain dispersed and unrecovered. Thus, cache protection strategies can provide net benefits to the plant in terms of effective directed dispersal.

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Optimal cache search depends on precision of spatial memory and pilfering, but what if that knowledge is not perfect?

Cited by 6 publications

References 26 publications

Do adjustments in search behavior depend on the precision of spatial memory?

Do adjustments in search behavior depend on the precision of spatial memory?

Precision and Reliability in Animal Navigation

Linking seed dispersal to cache protection strategies

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