Kinship and Prosocial Behaviour Preregistration


A reanalysis of data from DeBruine (2002) Facial Resemblance Enhances Trust, PRSLB.


Hypothesis 1: self_pref

Cues of kinship will increase prosocial behaviour. Cues of kinship will be manipulated by morphed facial self-resemblance. Prosocial behaviour will be measured by responses in the trust game. The prediction is that the number of trusting AND/OR reciprocating moves will be greater to self morphs than to other morphs.


  • trust_lowbound is confirmed if analysis trust yields[1]>0
  • trust_highbound is confirmed if analysis trust yields[2]>0.2
  • recip_lowbound is confirmed if analysis recip yields[1]>0
  • recip_highbound is confirmed if analysis recip yields[2]>0.2



The hypothesis is corroborated if the 97.5% CI lower bound is greater than 0 and the 97.5% CI upper bound is greater than 0.2 (the SESOI) for either the trust or reciprocation moves.

(trust_lowbound & trust_highbound) | (recip_lowbound & recip_highbound)

The hypothesis is falsified if the 97.5% CI upper bound is smaller than 0.2 (the SESOI) for both trust and reciprocation.

!trust_highbound & !recip_highbound

All other patterns of results are inconclusive.


Analysis 1: trust

    t.test(kin$trust_self, kin$trust_other, paired = TRUE, conf.level = 0.975)

Analysis 2: recip

    t.test(kin$recip_self, kin$recip_other, paired = TRUE, conf.level = 0.975)