Results

Analyses of the data proceeded as follows. We first verified the existence of differences among the offers made by participants to the different responders.

Then, we investigated whether different constraints affected the amount of money offered by participants.

3.1.3.1 Activation of mindreading processes

On the data collected a one-way repeated measure ANOVA was carried out in order to verify whether participants made significantly different offers depending on the psychological features of each responder.

Before running the analysis the assumption of univariant normality was assessed on the offers made to each responder by getting skewness and kurtosis and dividing these by the standard errors. Both skewness and kurtosis were within the +1 to -1 range, so allowing to conclude that data were normally distributed (Marcoulides & Hershberger, 1997). Specifically, as for the offers made to Marco the skewness was -.89, whereas the kurtosis was 46; for the offers made to Grazia the skewness was – 1.05 and the kurtosis from -.53; for the offers made to Gianni the skewness value was .09 and the kurtosis .88; for the offers made to Marina the skewness value was .56 and the kurtosis value -.77.

The mean values of the sums of money that the proposers offered to each responder by collapsing the three instruction conditions are reported in Table 3.4.

Responder Mean SD Marco 5.39 2.45 Grazia 4.28 1.62 Gianni 3.69 1.67 Marina 3.68 1.86 Tab. 3.4 – Mean values of money offered to each responder

Prior to the ANOVA, the assumption of sphericity, which implies the equality of the variances of the differences between levels of the repeated measures factor, was assessed by using the Mauchly’s sphericity test. Since Mauchly’s test was significant (Mauchly's W(5) = 0.517, p <.001) then sphericity couldn’t be

assumed and, as a consequence, the Greenhouse-Geisser correction for violation of sphericity was used.

Then, the analysis of variance assuming the four responders as the levels of the independent variable was computed. It showed that offers were significantly different according to the psychological portrait of the other player (F(2.052, 114.898) = 9.61, p <.001). More precisely, contrast analyses allowed us to maintain that the amount of money offered to Marco was higher than the amounts offered to the other three responders, and that the amount offered to Grazia was higher than the amount offered to Gianni and Marina, who received mean amounts of money not significantly different each other (see Table 3.5).

Responders Mean difference F ^(1,56) P η²

Gianni – Grazia -0.588 3.888 .054 .059

Gianni – Marco -1.702 7.929 <.001 .146

Gianni –Marina 0.009 .001 .972 .001

Grazia – Marco -1.114 13.842 <.005 .194

Grazia – Marina 0.596 3.481 .067 .065

Marco – Marina 1.711 13.476 <.001 .199

Tab. 3.5 – Contrast analyses comparing each couple of responder under the mean offered amount of money

Then, the mean value of money offered to the couple of responders who were described as “acceptors” (Gianni and Marina) and to the “rejecters” (Marco and Grazia) was calculated. The acceptors and rejecters’ unified mean values were reported in Table 3.6.

Type of responder Mean SD

Acceptors 3.69 1.50 Rejecters 4.84 1.57 Tab. 3.6 – Mean values of money offered to “acceptors” and “rejecters”

By assuming the two types of responders as the levels of the independent variable a one-way repeated measure ANOVA was carried out. Results showed that offers significantly varied depending on the responders’ characterization (F(1,56) = 12.457, p <.001). Participants offered higher sum of money to those responders who were supposed to reject low offers.

Results showed that participants were able to spontaneously activate mindreading processes which permitted them to effectively differentiate their offers in order to increase the likelihood of having their offers accepted.

3.1.3.2 Influence of instruction’s type

The influence of the instruction’s type was tested both on the total amount of money offered by the proposers (collapsing the four different responders) and, then, on the offers made to each different responder. As a consequence, it was first calculated the total mean value of money offered by the proposer by collapsing the four different responders. Then, before running the analyses, the assumption of univariant normality was assessed on the total offers by getting skewness and kurtosis and dividing these by the standard errors. Skewness and kurtosis values turned out to be within the +1 to -1 range.

The assumption of homogeneous variances was tested by using Levene’s test. P-value was not statistically significant (p = .152), thus indicating that the analysis of variance was possible.

In order to compare the offers obtained under the three types of constraints, a one-way ANOVA was computed. Results are reported in Table 3.7.

Tab. 3.7 - One-way ANOVA comparing offers made under the three constraints

Results showed that offers were different under the three constraints. In particular, LSD and Newman-Keuls post-hoc tests highlighted that offers made under spontaneous and maximizing constraints were not significantly different (p = .177), whereas the offers made under the threshold constraint were significantly lower than the ones under the other constraints (p <.001).

Instruction Mean SD F(2,55) P η²

Spontaneous 4.67 1.07

Maximizing 4.30 0.93

Threshold 3.71 0.17

5.957 <.005 .181

Then, the influence of the different constraints on the offers made to each single responder was tested through four one-way ANOVAs which were carried out on the sums of money offered to each responder by distinguishing among the spontaneous, maximizing and threshold conditions. Results are reported in Table 3.8.

Responder Instruction Mean SD F(2,55) P η² Spontaneous 6.71 2.35

Maximizing 5.15 2.69 Marco

Threshold 4.02 1.30

6.983 .002 .205

Spontaneous 4.38 2.18 Maximizing 4.31 1.33

Grazia

Threshold 4.11 1.11

0.126 .882 .050

Spontaneous 3.71 1.85 Maximizing 3.78 2.12

Gianni

Threshold 3.55 0.70

0.008 .919 .030

Spontaneous 3.88 2.49 Maximizing 3.94 1.71

Marina

Threshold 3.14 0.78

1.017 .369 .130

Tab. 3.8 - One-way ANOVAs comparing offers made under the three constraints to each responder

Results showed that only in the case of Marco significant differences occurred.

In any case, also with the other players the same trend emerged: the offers were lower in the threshold condition as compared to the other two conditions, which were, except for Marco, approximately the same. It emerged that the type of instructions played a minor role in modulating the offers, with the exceptions that in the spontaneous condition some higher sums of money were offered to the character (Marco) who, working with poor and indigent people, could have driven participants to make him higher offers as compared to the other characters.

In order to verify the existence of an interaction effect between the characterization of the responders (acceptors vs. rejecters) and the type of constraints (spontaneous, maximizing, threshold) a mixed ANOVA assuming

the responders’ types as within-subjects variable and the constraints’ types as between-subjects variable. Since the assumption of sphericity (Mauchly’s W(5)=0.578, p <.001) was not verified, it was used the Greenhouse-Geisser correction for violation of sphericity. Results highlighted that the interaction between responders’ type and constraints’ type factors was not significant (F(2.000,54.000) = 1.010, p < .371). Given the absence of interaction between responders’ and constraints’ types, we were induced to conclude that participants, irrespectively of the constraints embedded in the instructions, activate relevant mindreading processes which induce them to reciprocate in a different way according to the presumed psychological features of their counterparts.

However, since it was held it necessary to identify the type of instruction that would have been employed in the next studies, we chose to use the maximizing instruction. In fact, we exclude the spontaneous instruction because it emerged that people, without any monetary gain constraint, showed an exaggerated altruistic attitude, above all toward Marco, whose life could actually induce a hyper-altruistic behaviour. On the contrary, it seemed that the threshold constraint led people to an excessive concern about money, keeping them from taking into the right account the psychological features of their opponents. So, given the importance of some type of monetary constraint, we opted for the maximizing instruction which turned out to allow people to avoid offering to the extremes, both high (spontaneous) and low (threshold) sums of money.