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.

Reliability of an isometric test for measuring the strength of the hip abductors and adductors

This study aimed to measure the reliability of a test for measuring the strength and strength imbalance of the hip abductors and adductors, using isokinetic equipment adapted for isometric testing. Thirteen healthy, physically active male individuals took part in the research. Two unilateral isometric tests were undertaken using a load cell attached to an adapted abductor bench machine: a hip abduction test and hip adduction test. Tests consisted of two maximum voluntary isometric contractions made for six seconds with a break of one minute between each. The following dynamic variables were measured: maximum force, mean force, rate of force development for each limb (right and left), and the existence of asymmetries between the limbs. For statistical analysis, the t-test, intraclass correlation coefficient (ICC), and standard error of measurement (SEM) were applied. Results: The methodology utilized for the evaluation of the hip abductors and adductors did not show reliability in most of the parameters researched, with the ICC neither sufficient or low, and the retest performance higher than the test (p < 0.05). The applied test was not reliable for assessing strength and strength imbalances of hip abductors and adductors in most of the parameters investigated. These results indicate that the hip joints, more precisely, the abductor and adductor muscles, are complex structures to be assessed. They need to be previously familiarized with the proposed exercise, as their performance does not occur habitually. It is recommended to develop new tests in order to measure hip abduction and adduction strength adding a prior familiarization procedure.

Positive, but not negative, facial expressions facilitate 3-month-olds’ recognition of an individual face

The current study examined whether and how the presence of a positive or a negative emotional expression may affect the face recognition process at 3 months of age. Using a familiarization procedure, Experiment 1 demonstrated that positive (i.e., happiness), but not negative (i.e., fear and anger) facial expressions facilitate infants’ ability to recognize an individual face. Experiment 2 showed that the advantage of positive over negative facial expressions is driven by the processing of salient features inherent in the happy expression, rather than by the processing of the configural information conveyed by the entire happy face. Overall, these results support the presence of a mutual interaction between face identity and emotion recognition.

The Influence of Familiarity on Judgments of Treated Speech

Three groups of 10 naive listeners transcribed sentences produced by a dysarthric speaker. The first group (Control) transcribed sentences that the speaker read in her customary manner. A second group (Treatment) transcribed the same sentences; however, the speaker produced them while implementing a breath-group strategy that she had learned in speech treatment. A final group of listeners (Familiarization) also transcribed the sentences that were produced by the speaker as she implemented the breath-group strategy. However, this Familiarization group first listened to an audiotape of the speaker reading aloud a paragraph as they followed along with a written script. This was regarded as a familiarization procedure. Statistical analysis revealed that the Familiarization group outperformed the Treatment group, which in turn outperformed the Control group. Potential perceptual benefits resulting from the familiarization procedure are discussed, along with clinical implications.