How to easily apply multimodal measurement during research with children
As my colleague Andrew Spink mentioned in a previous blog post, researchers today are not only using observations to study behavior, but they are complementing their toolbox with a wide range of other measurement tools. For example, tools to measure pupil reactions, blood pulse, blood volume, skin conductance, heart rate, and brain activity will greatly increase the insights you gain during research when you combine this with video-based observation.
Assessing social skills or emotional empathy in children
For example, when social skills are the topics of your research and you want to study how infants and parents respond to emotions of others, their pupil sizes will tell you something about the physiological arousal while they observe other people. Eye-tracking data can be used to measure the pupil reactions .
Or, to provide insights into infants’ responses to sociomoral scenes, especially infants who do not use spoken words yet, neuroimaging techniques such as electroencephalography (EEG) better explain the nature of the mental processes. Several studies used this technique to find out if there were differences in antisocial versus prosocial interactions by investigating the frontal alpha power while the infants viewed helping and hindering scenarios [2,3].
Gathering multiple data streams
Another example is measuring autonomic nervous system activity using data acquisition software. The research team of Palser used ECG, GSR, and respiratory measurement tools to investigate resting parasympathetic nervous system activity in children with dyslexia — a reading disorder — and its relationship to autonomic and behavioral responding to others’ emotions . These components were measured:
- Physiological data
- Cardiac activity | inter-beat interval (IBI)
- Respiration | respiratory cycle time and respiratory sinus arrhythmia (RSA)
- Electrodermal activity (EDA) | skin conductance level (SCL)
- Emotional facial behavior
- Emotional reactivity
- Emotion regulation
In such an experiment, a participant must be connected to a lot of equipment before the test can start.
Tips and tricks when working with children
As a researcher who works with children, you probably face quite a few challenges. A child can get fussy during or following testing. He or she can suddenly pull the EEG cap off the head, refuses to sit still, or gets distracted.
How do you handle this kind of situations, or better, how can you prevent them from happening?
I asked my colleague Patrick Zimmerman for advice, since he is an experienced trainer and human behavior consultant.
What to do before the actual experiment starts?
Before you can start a test, it is important that you carry out some test runs to make sure all equipment is working properly. On the day of the test, allow yourself sufficient time to do a final check of the equipment and make sure everything is ready to go when the first participant arrives.
Check if all cables are plugged in properly and if the software is standby.
When a participant arrives at your lab, take the time to welcome and to make the child feel comfortable. Of course, before a test, each participant should be fully informed about the measurements and must give consent for participating in the test and having their behavior recorded. In case of young children, the parents must give consent.
How to make it run as smoothly as possible
Making participants feel comfortable and explain to them what will happen before, during, and after a test, is even more important when working with children. It helps if the experimental room is (temporarily) designed with bright colors or objects that makes it feel more like a playroom than a lab.
Sometimes it is useful to have one of the parents present to make the child feel more at ease. The downside could be that the parent gets involved in the test even if he or she is not supposed to. Therefore, it is important to instruct the parent clearly what to do and what not to do during a test as well.
How to deal with invasive measurement tools
Of course, it can happen that young participants are not comfortable with some of the more invasive measurements, for example, electrodes on their body or a cap for measurement of brain activity. In this case, it is important that you explain to them, in simple language, what the equipment entails and what they can expect to happen. Let them know they cannot do anything wrong, and that it’s okay if any wires are pulled loose.
Also, inform them that they won't feel any pain or other discomfort. Let them know if they might hear noises. Reassure them about all this and tell them to warn you if they feel uncomfortable. Obviously, it helps if one of the parents is there to make tit easier for them.
When you work with children, it is likely that some measurements fail due to the child’s behavior. Be prepared for this and recruit some more children than you actually need for answering your research questions.
Pay attention to the time spend
A test for children should be designed in such a way that it takes into account the attention span of children. Thus, no long boring tests, but regular breaks to bring back attention to the test.
Tip: give them a reward during this short break and/or play a quick game, such as throwing/rolling a ball to each other. Take a moment to do something completely different before returning the full attention to the test itself.
Of course, it should be noted in the acquired data when breaks take place to have the most accurate possible data during data selection and analysis.
To be able to perform this analysis properly, it is important that all data streams are synchronized. How do you handle that?
How to make data synchronization easier
Making sure participants feel at ease is one thing, but equally important is data synchronization. The whole point of carrying out multimodal measurements, e.g. combining behavioral, video, facial expression, and physiological data, is that you want to look at the relationship between different types of data.
For this it is vital that different data streams are recorded synchronously or can be easily (preferably automatically) synchronized after data acquisition. Part of a Noldus Lab is a communication protocol that serves as a central time keeper, controlled from our annotation and data integration suite, and central engine The Observer XT. This ensures that behavioral, facial expression, physiological, and video data are recorded simultaneously and synchronously.
If you have other equipment in your lab, which cannot be connected to the Noldus time keeper protocol, the time stamps in the exported data can be used in the import step into The Observer XT to manually synchronize it with other data.
In the end, the synchronized data set yields more insights into the response of your participants.
In the joint webinar How to integrate psychophysiological & behavioral data using both Noldus and BIOPAC tools we dive deeper into the benefits of integrating data seamlessly. Watch this webinar on-demand at your convenience to learn more.
 Aktar, E.; Nimphy, C.A.; Kret, M.E.; Pérez-Edgar, K.; Bögels, S.M. & Raijmakers, M.E.J. (2021). Pupil responses to dynamic negative facial expressions of emotion in infants and parents. Developmental Psychobiology, 63 (7), https://doi.org/10.1002/dev.22190
 Cowell, J. M. & Decety, J. (2015). Precursors to morality in development as a complex interplay between neural, socioenvironmental, and behavioral facets. Proceedings of the National Academy of Sciences, 112 (41), 12657-12662. https://doi.org/10.1073/pnas.1508832112
 Tan, E. & Hamlin, K. (2021). Infants’ Neural Responses to Helping and Hindering Scenarios. https://doi.org/10.31219/osf.io/nuxwv
 Palser, E.R.; Morris, N.A.; Roy, A.R.K.; Holley, S.R.; Veziris, C.R.; Watson, C.; Deleon, J.; Miller, Z.A.; Miller, B.L.; Gorno-Tempini, M.L. & Sturm, V.E. (2021). Children with developmental dyslexia show elevated parasympathetic nervous system activity at rest and greater cardiac deceleration during an empathy task. Biological Psychology, 166. https://doi.org/10.1016/j.biopsycho.2021.108203.