Figure 1.
Six plastic cups containing pieces of cookies of various dimensions: two pieces of cookie of 4×2×0.5 cm (sequence of four 4×0.5×0.5 cm - left position), two pieces of cookie of 4×0.5×0.5 cm (middle position) and two pieces of cookie of 1×0.5×0.5 cm (right position) corresponding to the combination of rewards # 4.
Table 1.
Number (#) and content of cups for each combination of rewards.
Table 2.
Evaluation of each combination of rewards following the Expected Utility Theory (δ is the risk aversion parameter), with δ = 1 (neutrality to risk).
Figure 2.
Kahneman and Tversky evaluation function for α = β = 1, λ = 2.25, and a reference point of 1.
Figure 3.
Percentage of returned items for each age according to the combination of rewards.
The bar indicates the threshold of 50% of exchange. Combinations with no common letters differ significantly at p<.05.
Table 3.
Evaluation of each combination of rewards following the Cumulative Prospect Theory (without probability distortion and loss aversion).
Table 4.
Comparisons of the mean percentage of return between the different age-groups using Tukey HSD pairwise comparison post-hoc tests.
Table 5.
Tukey HSD pairwise comparison post-hoc tests for combinations significantly differing by the mean percentage of return.
Table 6.
Influence of the probability of losing PL (getting a small piece of cookie in this trial), the probability of gaining PG (getting a large piece of cookie in this trial), and the interaction PL x PG on the exchange behaviors of children.
Table 7.
Student's t-tests on the percentage of return for each combination.
Figure 4.
Estimation of the loss aversion parameter λ, and the probability distortion parameter γ: a. Under the assumption of no probability distortion (fixing arbitrarily γ = 1, grey continuous line), 1<λ≤2; b. Under the assumption of no loss aversion (fixing arbitrarily λ = 1, grey continuous line), 0.32<γ<1; c. Acceptable values for both loss aversion and probability distortion parameters (grey area).
Figure 5.
Probability weighting function a. for γ = 0.6 (Kahneman and Tversky).
The inflexion point is close to a probability of 0.35; individuals perceive low probabilities under 0.35 higher than their actual value and high probabilities over 0.35 lower than their actual value. b. for children aged over 5 years (0.32<γ<1). For γ = 0.33, the inflexion point is close to a probability of 0.15; individuals perceive low probabilities under 0.15 higher than their actual value and high probabilities over 0.15 lower than their actual value.