Do 15-month-old infants prefer helpers? A replication of Hamlin et al. (2007)

Hamlin et al. found in 2007 that preverbal infants displayed a preference for helpers over hinderers. The robustness of this finding and the conditions under which infant sociomoral evaluation can be elicited has since been debated. Here, we conducted a replication of the original study, in which we tested 14- to 16-month-olds using a familiarization procedure with three-dimensional animated video stimuli. Unlike previous replication attempts, ours uniquely benefited from detailed procedural advice by Hamlin. In contrast with the original results, only 16 out of 32 infants (50%) in our study reached for the helper; thus, we were not able to replicate the findings. A possible reason for this failure is that infants’ preference for prosocial agents may not be reliably elicited with the procedure and stimuli adopted. Alternatively, the effect size of infants’ preference may be smaller than originally estimated. The study addresses ongoing methodological debates on the replicability of influential findings in infant cognition

Giving, but not taking, actions are spontaneously represented as social interactions: evidence from modulation of lower alpha oscillations

Unlike taking, which can be redescribed in non-social and object-directed terms, acts of giving are invariably expressed across languages in a three-argument structure relating agent, patient, and object. Developmental evidence suggests this difference in the syntactic entailment of the patient role to be rooted in a prelinguistic understanding of giving as a patient-directed, hence obligatorily social, action. We hypothesized that minimal cues of possession transfer, known to induce this interpretation in preverbal infants, should similarly encourage adults to perceive the patient of giving, but not taking, actions as integral participant of the observed event, even without cues of overt involvement in the transfer. To test this hypothesis, we measured a known electrophysiological correlate of action understanding (the suppression of alpha-band oscillations) during the observation of giving and taking events, under the assumption that the functional grouping of agent and patient should have induced greater suppression that the representation of individual object-directed actions. As predicted, the observation of giving produced stronger lower alpha suppression than superficially similar acts of object disposal, whereas no difference emerged between taking from an animate patient or an inanimate target. These results suggest that the participants spontaneously represented giving, but not kinematically identical taking actions, as social interactions, and crucially restricted this interpretation to transfer events featuring animate patients. This evidence gives empirical traction to the idea that such asymmetry, rather than being an interpretive propensity circumscribed to the first year of life, is attributable to an ontogenetically stable system dedicated to the efficient identification of interactions based on active transfer

Preparazione e applicazioni sintetiche di monoacetali di succinaldeidi

Synthetic methods for the preparation of substituted succinaldehyde monoacetals are reviewed and the use of these compounds as intermediates in several synthetic processes is reported

Studio sulla sintesi dell'acido (R) (S)-2, 3, 3-trimetilbutanoico

The authors report a synthetic study on the syntheis of 2, 3, 3-trimethylbutanoic acid which they prepared by ten different synthetic procedures and compare their results with the ones available in the literature on the preparation of the title compound

Learning in and about opaque worlds

We argue that direct active teaching in humans exhibits at least two properties (open-endedness and content opacity) that make the recognition of teaching episodes without ostension untenable. Thus, while we welcome Kline's functional approach to the analysis of teaching, we think that she ignores important features of the socio-environmental niche in which human teaching likely evolved

Minimal cues of possession transfer compel infants to ascribe the goal of giving

Human infants’ readiness to interpret impoverished object-transfer events as acts of giving suggests the existence of a dedicated action schema for identifying interactions based on active object transfer. Here we investigated the sensitivity of this giving schema by testing whether 15-month-olds would interpret the displacement of an object as an agent’s goal even if it could be dismissed as side effect of a different goal. Across two looking-time experiments, we showed that, when the displacement only resulted in a change of object location, infants expected the agent to pursue the other goal. However, when the same change of location resulted in a transfer of object possession, infants reliably adopted this outcome as the agent’s goal. The interpretive shift that the mere presence of a potential recipient induced is testament to the infants’ susceptibility to cues of benefit delivery: an action efficiently causing a transfer of object possession appeared sufficient to induce the interpretation of goal-directed giving even if the transfer was carried out without any interaction between Giver and Givee and was embedded in an event affording an alternative goal interpretation

Facilitation of object encoding in infants by the observation of giving

We propose that humans are prepared to interpret giving as a diagnostic cue of reciprocal-exchange relations from infancy. A prediction following from this hypothesis is that infants will represent the identity of an object they see being given, because this information is critical for evaluating potential future reciprocation. Across three looking-time experiments we tested whether the observation of a transfer action induces 12-month-olds to encode the identity of a single object handled by an agent. We found that infants encoded the object identity when the agent gave the object (Experiment 1), but not when she took it (Experiment 2), despite being able to represent the goal of both actions (Experiments 1 and 3). Consistent with our hypothesis, these results suggest that the infants’ representation of giving comprises information necessary for comparing the value of transferred goods across sharing episodes

Structural asymmetries in the representation of giving and taking events

Across languages, GIVE and TAKE verbs have different syntactic requirements: GIVE mandates a patient argument to be made explicit in the clause structure, whereas TAKE does not. Experimental evidence suggests that this asymmetry is rooted in prelinguistic assumptions about the minimal number of event participants that each action entails. The present study provides corroborating evidence for this proposal by investigating whether the observation of giving and taking actions modulates the inclusion of patients in the represented event. Participants were shown events featuring an agent (A) transferring an object to, or collecting it from, an animate target (B) or an inanimate target (a rock), and their sensitivity to changes in pair composition (AB vs. AC) and action role (AB vs. BA) was measured. Change sensitivity was affected by the type of target approached when the agent transferred the object (Experiment 1), but not when she collected it (Experiment 2), or when an outside force carried out the transfer (Experiment 3). Although these object-displacing actions could be equally interpreted as interactive (i.e., directed towards B), this construal was adopted only when B could be perceived as putative patient of a giving action. This evidence buttresses the proposal that structural asymmetries in giving and taking, as reflected in their syntactic requirements, may originate from prelinguistic assumptions about the minimal event participants required for each action to be teleologically well-formed

Statistical treatment of looking-time data

Looking times (LTs) are frequently measured in empirical research on infant cognition. We analyzed the statistical distribution of LTs across participants in order to develop recommendations for their treatment in infancy research. Our analyses focused on a common within-subject experimental design, in which longer looking to novel or unexpected stimuli is predicted. We analyzed data from two sources: an in-house set of LTs that included data from individual participants (47 experiments, 1584 observations), and a representative set of published papers reporting group-level LT statistics (149 experiments from 33 papers). We established that LTs are log-normally distributed across participants, and therefore should always be log-transformed before parametric statistical analyses. We estimated the typical size of significant effects in LT studies, which allowed us to make recommendations about setting sample sizes. We show how our estimate of the distribution of effect sizes of LT studies can be used to design experiments to be analyzed by Bayesian statistics, where the experimenter is required to determine in advance the predicted effect size rather than the sample size. We demonstrate the robustness of this method in both sets of LT experiments.This work was supported by an Advanced Investigator Grant (OSTREFCOM) from the European Research Council