On this page, you'll find a listing of studies that we have already completed. To view the study results, you can either click on a study in the list to go directly to its results, or simply scroll through all the studies.
Children are surrounded by many different objects in their everyday lives. Already in the first months of life, they can distinguish between real objects and pictures of objects. For example, infants know early on that they can grasp a real pacifier, whereas they cannot interact with a picture of a pacifier. In recent years, we have already found that infants as young as 7 months look longer at real objects than at pictures of these objects. Moreover, we know that this so-called "visual preference for real objects" is related to whether the infants have previously explored the objects with their hands.
A crucial difference between two- and three-dimensional objects is the presence of depth cues. Real objects contain more depth cues than pictures of the objects. For example, if we move from left to right, our field of view shifts, with nearby objects moving in the opposite direction and more distant objects moving in the same direction as our head. This effect is called motion parallax. With images, on the other hand, there is no motion parallax. When we look at an image and move sideways, the image always remains the same and the objects in it do not move.
In our project on 2D3D perception, we are currently investigating the role of motion parallax in distinguishing between real objects and their images in infants. For this purpose, we show 7- and 8-month-old infants real objects and images of these objects simultaneously and compare how long the infants look at both object formats. We show the images on iPads by using an app that simulates depth cues through motion parallax, making two-dimensional objects appear as if they were three-dimensional. We can turn this simulation on and off so that sometimes the same image contains depth cues and sometimes it does not.
Currently, we are still in the middle of data collection and are looking forward to many more participants!
Categorization of emotions across the lifespan
The goal of our study was to determine how people categorize emotional facial expressions across the lifespan. To this end, we tested children (ages 6–7), young adults (ages 20–30), and older adults (ages 65–80). We used our newly developed stimuli, which included not only dynamic facial expressions of four emotions (happy, happy-surprised, sad, and angry) but also a specific combination of a facial expression paired with a verbal expression of that specific emotion (e.g., smiling and saying “I am happy”). We wanted to determine whether the previously observed preferences for positive and negative emotions could be replicated using our different stimuli—a positivity bias in children and older adults and a negativity bias in young adults.
The study’s results show that young adults were the fastest and most accurate of all age groups, with no difference across the emotion categories. Children were faster and more accurate with positive expressions, while older adults showed a different preference depending on the emotional category—with positive expressions, they were more accurate and faster when there was no additional verbal information, whereas the opposite effect was observed with negative emotions. These findings suggest a complex, developmentally driven change in emotional perception that broadens our understanding of the perception of static and dynamic emotional expressions, as well as the influence of verbal and facial emotional expressions.
For more information, please click on the link to the following publication:
Tsenkova, N., Bahn, D., Kauschke, C., Billino, J., & Schwarzer, G. (2026). Categorization of visual and visual-verbal dynamic positive and negative expressions: a cross-sectional lifespan study. European Journal of Developmental Psychology, 1–18. https://doi.org/10.1080/17405629.2026.2693469
Childhood social-emotional development and parental stress during Covid 19
Early child development is strongly influenced by what a child experiences in his/her daily life. The ongoing Covid-19 Pandemic has a strong impact on the daily lives of many families. To examine how these changes have affected early social-emotional development, we conducted a questionnaire study.
Over the past 3 years, more than 400 families completed these questionnaires. Preliminary results suggested a persistent stress level (particularly among parents of toddlers) over the course of the pandemic. In addition, parental stress appeared to be negatively associated with social-emotional child development. To better understand the long-term effects of the pandemic, we surveyed parents again in 2024 regarding their stress level and their children’s social-emotional development. In addition, we invited a subgroup of children who have been participating in our study since the first lockdown to visit our department so that we could assess their emotional competencies in even greater detail using a standardized testing procedure (EMK 3-6). Overall, early childhood social-emotional competencies were within the age-appropriate range. Parents’ perceived stress level, however, remained significantly increased even after the pandemic.
For more information, please click on the link to the following publication:
Dillmann, J.*, Sensoy, Ö.*, & Schwarzer, G. (2022). Parental perceived stress and its consequences on early social-emotional child development during COVID-19 pandemic. Journal of Early Childhood Research.https://doi.org/10.1177%2F1476718X221083423
Perception of materials
This project is about the question of how children at the age of 6 perceive different properties of materials. In particular, we are interested in whether and how they distinguish permanently deformable materials (e.g. clay or plasticine) from elastic materials (e.g. foam). For us adults, this distinction is relatively easy because we can feel such differences with special hand grips. We would now like to find out whether children who are allowed to explore objects made of different materials with their hands can also distinguish between corresponding materials, and whether they adapt their hand movements to the properties of the materials.
For this purpose, the children are allowed to explore either an elastic or a plastic object, which looks identical, by looking at it and feeling it. Then, two visually identical objects (each elastic/plastic) are manipulated by another person and the children are allowed to watch. Afterwards, the children are asked to decide which of the two objects corresponds to the one they have previously engaged with themselves. This current study continues a series of studies with children of different ages that began some time ago. In the groups surveyed so far (11 months, 3 years, 5 years), it appears that children are not able to distinguish subtle differences in materials, such as different types of deformability until they are 5 years old. The study with the 6-year-old children is currently being collected.
Perception and processing of familiar size in infancy
The familiar size of objects describes the size that an object typically has in the real world. Hereby, the familiar size influences our thinking and our actions. For instance, to successfully grasp an object, we have to take its size into account. In a series of studies, we investigate, when infants show knowledge of the familiar size of objects and which conditions contribute to activating their knowledge. Our results demonstrate that infants as young as 7-month show knowledge of the familiar size of objects, but only when they are able to interact with the real objects. By 12 months of age, however, looking at objects is enough for activating familiar size knowledge. Moreover, we were also interested in how far infants show knowledge of the familiar size of objects when they see pictures rather than real objects. At 7 and 12 months, we found no indications for recognizing the familiar size of objects in pictures. Therefore, we are investigating in a current study, if 15-month-old children are able to recognize the familiar size of objects in pictures and how this might be connected to walking freely.
Further reading:
Sensoy, Ö., Culham, J.C., & Schwarzer, G. (2021). The Advantage of Real Objects over Matched Pictures in Infants' Processing of the Familiar Size of Objects. Infant and Child Development, 30(4); July/August 2021. https://doi.org/10.1002/icd.2234
Sensoy, Ö., Culham, J.C. & Schwarzer, G. (2020). Do infants show knowledge of the familiar size of everyday objects?. Journal of Experimental Child Psychology. Volume 195, July 2020. https://doi.org/10.1016/j.jecp.2020.104848
Perceived valence and arousal in emotional facial expressions
With our survey, we would like to investigate developmental changes occurring from an early age (6-7 years) to adulthood in terms of perceiving arousal and valence in facial expressions. The terms "arousal" and "valence" can be understood as continua of how pleasant/unpleasant a face is for the observer (valence) or to what extent the perceived face has an arousing/calming effect on the observer (arousal). These scales are a staple in emotion research and previous results have shown that children are more sensitive to positive information compared to adults which applies both to emotion words and emotional facial expressions.
We would like to further test whether this effect which was found for static facial expressions can be replicated with videos of animated, talking characters expressing different emotions.
The study’s results show that children found positive facial expressions as more positive compared to adults, which suggests a positivity bias when it comes to valence. However, we found the opposite effect for arousal where children evaluated the negative expressions as more arousing compared to adults. This points to a difference in the perception of static and dynamic expressions of emotions depending on the given task (rating valence or arousal).
For more information, please click on the link to the following publication: Tsenkova, N., Bahn, D., Kauschke, C., & Schwarzer, G. (2025). Developmental differences in perceiving arousal and valence from dynamically unfolding emotional expressions. Plos one, 20(8), e0329554. https://doi.org/10.1371/journal.pone.0329554
Speech and face processing in infancy
Speech and face processing are strongly interlinked with each other and show similar developmental trajectories in infancy. During the first year of life, infants become experts in their native language and native faces. This specialization is described as perceptual narrowing. In a series of studies, we are investigating, if speech and face processing still interact with each other beyond infancy or if both get more separated with ongoing specialization. The first results show that 5-year-olds process face identities independent of speech, however, speech processing is affected by face processing. With increasing age and in adulthood, speech and face processing seem to become largely independent of each other.
