6-Month-Old Infants’ Sensitivity to Contingency in a Variant of the Mobile Paradigm With Proximal Stimulation Studied at Fine Temporal Resolution in the Laboratory

Abstract

Infants’ ability to monitor “sensorimotor contingencies,” i.e., the sensory effects of their own actions, is an important mechanism underlying learning. One method that has been used to investigate this is the “mobile paradigm,” in which a mobile above an infant’s crib is activated by motion of one of the infant’s limbs. Although successfully used in numerous experiments performed in infants’ homes to investigate memory and other types of learning, the paradigm seems less robust for demonstrating sensitivity to sensorimotor contingencies when used in the laboratory. One purpose of the present work was to show that certain changes to the mobile paradigm would make it easier for infants to show their sensitivity to the contingency in the lab. In particular, we used proximal stimulation on infants’ wrists instead of the usual mobile, and our stimulation was coincident with the limbs that caused it. Our stimulation was either on or off, i.e., not modulated by the amount the infant moved. Finally, we used a “shaping” procedure to help the infant discover the contingency. In addition to these changes in the paradigm, by analyzing infants’ limb activity at 10-s resolution instead of the usual 1-min resolution, we were able to show that infants’ sensitivity to the contingency became apparent already within the first minute of establishment of the contingency. Finally, we showed how two alternate measures of sensitivity to contingency based on probability of repeated movements and on “stop and go” motion strategies may be of interest for future work.

Methodological integrity assessment in the mobile paradigm literature: A lesson for understanding opportunistic use of researcher degrees of freedom in psychology

“…We believe that developing new methodological protocols without using learning criteria is particularly essential to evaluating whether memory findings reflect the true state of the world. In recent years, some studies developed alternative operational definitions of learning such as a movement burst at the beginning of the extinction phase (Zaadnoordijk et al, 2018(Zaadnoordijk et al, , 2020 and response differentiation between the limbs (Popescu et al, 2021). These studies, without using particular selection criteria, demonstrated that young infants can learn sensorimotor contingencies.…”

“…This created a unique way of measuring memory in the mobile paradigm that is different from the other paradigms measuring memory (e.g., deferred imitation, Meltzoff, 1985; preferential looking, Robinson & Pascalis, 2004; habituation, Fantz, 1965). Nevertheless, it is also important to note that newer versions of the mobile paradigm used alternative methodological approaches (e.g., alternative operational definitions of learning, Popescu et al, 2021; Zaadnoordijk et al, 2018, 2020). This unique methodological approach of the traditional methodological protocol makes it interesting to examine how these methodological choices affect the reliability of the results.…”

“…This design choice has resulted in exclusion of 15% of infants on average from the mobile paradigm studies, reaching as high as 30% (Gerhardstein et al, 2012; Gulya et al, 1998) and even 50% in some cases (Tiernan & Angulo‐Barroso, 2008; Watanabe & Taga, 2009). In the literature, where the mobile paradigm was used outside of memory development domain, there are studies in which the threshold for learning criterion was lowered (e.g., 1.2 times of baseline, Watanabe & Taga, 2006), in other cases this selection criterion was not used at all (Popescu et al, 2021; Zaadnoordijk et al, 2020).…”