227,336 research outputs found
Preference reversal in quantum decision theory
We consider the psychological effect of preference reversal and show that it
finds a natural explanation in the frame of quantum decision theory. When
people choose between lotteries with non-negative payoffs, they prefer a more
certain lottery because of uncertainty aversion. But when people evaluate
lottery prices, e.g. for selling to others the right to play them, they do this
more rationally, being less subject to behavioral biases. This difference can
be explained by the presence of the attraction factors entering the expression
of quantum probabilities. Only the existence of attraction factors can explain
why, considering two lotteries with close utility factors, a decision maker
prefers one of them when choosing, but evaluates higher the other one when
pricing. We derive a general quantitative criterion for the preference reversal
to occur that relates the utilities of the two lotteries to the attraction
factors under choosing versus pricing and test successfully its application on
experiments by Tversky et al. We also show that the planning paradox can be
treated as a kind of preference reversal.Comment: Latex file, 15 page
The 'Cheerios effect'
Objects that float at the interface between a liquid and a gas interact
because of interfacial deformation and the effect of gravity. We highlight the
crucial role of buoyancy in this interaction, which, for small particles,
prevails over the capillary suction that is often assumed to be the dominant
effect. We emphasize this point using a simple classroom demonstration, and
then derive the physical conditions leading to mutual attraction or repulsion.
We also quantify the force of interaction in some particular instances and
present a simple dynamical model of this interaction. The results obtained from
this model are then validated by comparison to experimental results for the
mutual attraction of two identical spherical particles. We conclude by looking
at some of the applications of the effect that can be found in the natural and
manmade worlds.Comment: 10 pages, 12 figures. (Typos in eqs 7 and 8 corrected
Effectiveness of synthetic versus natural human volatiles as attractants for Anopheles gambiae (Diptera: Culicidae) sensu stricto
Females of the African malaria vector, Anopheles gambiae Giles sensu stricto, use human volatiles to find their blood-host. Previous work has shown that ammonia, lactic acid, and aliphatic carboxylic acids significantly affect host orientation and attraction of this species, In the current study, these compounds were tested for their attractiveness relative to human emanations in vivo and in vitro. Emanations from a human hand, incubated sweat, and foot skin residues on a nylon sock were significantly attractive when tested against clean air. In a dual-choice test, foot skin residues were significantly more attractive than emanations from a human hand in vivo. Ammonia alone attracted more mosquitoes than fresh or incubated sweat, However, the odor of a human hand or of foot skin residues were more attractive than ammonia. A known attractive blend of ammonia with lactic acid and carboxylic acids was less effective than natural foot odorants, The results demonstrate that the synthetic blend based on skin odor is attractive for An. gambiae, but that in a choice situation in vitro natural skin odors are still preferred by the mosquito. Differences in volatile organic compound abundances between a worn sock and the synthetic blend may have resulted in stronger attraction to the sock. This suggests that candidate attractants should be evaluated with consideration of the strength of natural odorant sources, The data furthermore suggest that additional unidentified compounds from the human foot are involved in the host-seeking behavior of this mosquito species
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