How do we respond to threats in our environment?
Responding to threat quickly and efficiently is critical for survival. Indeed, when faced with the approach of a slithering snake or a dangerous drop-off, delays in responding can be costly, perhaps even deadly. But how do we learn what is safe and what is dangerous? How do we detect and respond to potential threats—dangerous animals, aggressive people, infectious diseases—in the world around us?
Because of the significant reproductive benefit associated with rapid identification of threatening stimuli, the most prominent theories propose that humans have evolved psychological mechanisms that facilitate the detection and subsequent avoidance of potential threat. These mechanisms are thought to detect cues in the environment that signal the presence of threat, and initiate cognitive and emotional responses that lead to avoidance behavior. For example, researchers have proposed that humans possess an evolved fear module that is activated upon contact with recurrent, widespread, and evolutionarily relevant threats like snakes, spiders, and threatening conspecifics; activation of this module is automatic, and leads to rapid detection and rapid fear learning for threatening stimuli. Behavioral immune system theory proposes that a similar set of mechanisms evolved to detect the presence of pathogens or infectious illness, automatically activating disgust responses that result in avoidance behavior. Although these and other similar theories differ in their specifics, they all assume that humans possess a specialized set of mechanisms for threat detection and avoidance that are universal, early emerging, and stable across individuals. However, until recently, very little developmental research had addressed this topic.
Our research program investigates human behavioral responses to emotionally valenced stimuli—specifically to negative or threatening stimuli—and the mechanisms guiding the development of these responses. In one line of research, we found that humans perceive the presence of threatening stimuli very quickly, and that rapid detection begins in infancy. However, these biases can be learned, they can change over the course of development, and may reflect a broad spectrum of individual differences. Further, in a second line of research, we found that avoidance responses to threats do not develop until later in childhood, and are dependent on learning. Our current work builds on these findings to ask whether early perceptual biases for threat contribute to maladaptive avoidance behaviors, such as those associated with the development of fear and anxiety, and how children learn adaptive avoidance responses, such as avoidance of contagious people or contaminated objects. Altogether, our findings suggest that human threat responses are not singular or automatic: They are differential and complex, supporting flexible developmental trajectories based on both experience and context. By continuing to develop procedures that measure threat responses developmentally, and by establishing the developmental time course of these behaviors, we hope to create a broader theoretical framework for understanding how early developing biases for threat interact with everyday experience to create both adaptive and maladaptive patterns of responding.
Do we detect threats faster than other things?
In one project, we have sought to examine whether emotional or threatening stimuli are detected more quickly than neutral stimuli. In the basic experimental set-up, children and adults view 3 x 3 matrices of colorful photographs on a touch-screen monitor and are asked to find targets on the screen by touching them. In one line of experiments, we have found that infants, young children and adults detect fear-relevant or threatening stimuli like snakes and spiders, more quickly than several categories of neutral stimuli, such as frogs, caterpillars, cockroaches, flowers, and mushrooms (LoBue & DeLoache, 2008, 2010; LoBue, 2010). In another line of experiments, we have also found that infants, children, and adults detect threatening facial expressions (angry, fearful) more quickly than non-threatening ones (sad, happy, neutral) (LoBue & DeLoache, 2009; LoBue, 2009). Thus it appears that we do indeed perceive emotional or threatening stimuli more quickly than neutral stimuli.
Despite these consistent results, it is still unclear how or why these stimuli are so salient at such an early age. In one ongoing project, we are examining how perception, cognition, and emotion contribute to threat detection. In some experiments, we use simple stimuli to study how low-level perceptual cues, cognitions or knowledge about a stimulus’ threatening properties, and an individual’s emotional state each contribute and interact to facilitate the rapid detection of biological threats, such as snakes and spiders (LoBue, 2014; LoBue & DeLoache, 2011; LoBue & Larson, 2010). We are also examining how cognitive and emotional cues might guide the detection of neutral stimuli. Using an eye-tracker, we are hoping to present a more detailed analysis of the strategies that both adults and children use to detect threatening stimuli, and how perceptual, cognitive, and emotional cues might change patterns of visual detection (LoBue, Matthews, Harvey, & Stark, 2014).
Relatedly, we are also examining the developmental trajectories of attentional biases for threat over the course of infancy and early childhood to determine whether early attentional biases for social threats play a causal role in the development of anxiety-related avoidance behaviors. Indeed, attention is a process by which infants themselves select the input they receive. If infants rapidly and preferentially attend to threatening or negative social information, this negative information may play a role in shaping their expectations about social situations, and ultimately, their social behavior. We have already observed that between the ages of 2 and 5, shy, or temperamentally fearful children more rapidly attend to social threats (i.e., angry faces) when compared to non-shy children (e.g., LoBue & Pérez-Edgar, 2014). In an ongoing collaboration with Kristin Buss and Koraly Pérez-Edger from Penn State University and Andy Field from the University of Sussex, we have developed several eye-tracking tasks that enable us for the first time to capture core components of attention in infants and toddlers, focusing on the relations between attention and negative affect (LoBue et al., 2017; Morales et al., 2017; Pérez-Edgar et al., 2017). We are employing a multi-method longitudinal approach, collecting data at five time points (4, 8, 12, 18, and 24 months) using our new eye tracking tasks coupled with a rich behavioral battery to measure negative affect. We will also assess known biomarkers (i.e., resting electroencephalogram [EEG] activity, and respiratory sinus arrhythmia [RSA] during challenge), and parental characteristics (e.g., anxiety, depression, psychosocial stressors) known to increase risk for anxiety. Ultimately, we will use these variables to predict behavioral inhibition, or social withdrawal—the most significant known predictor of social anxiety—at age 2.
How do children learn to avoid threatening stimuli?
Several evolutionary theories of threat responses assume early onset of avoidance behaviors, perhaps even from the very first encounter with specific threats. However, research from our lab points to a much longer developmental trajectory for avoidance behaviors to non-social threats, with no clear signs of snake and spider avoidance, for example, in preschool-aged children. In fact, our data suggest that children might even like snakes and spiders: During a free play session, we found that 18- to 36-month-olds spent just as much time interacting with a live snake and tarantula as they did with a hamster and a fish. Instead of actively avoiding snakes and spiders, children demonstrated an avid interest in all the live animals, interacting with them longer than with a set of highly attractive toys (LoBue, Bloom Pickard, Sherman, Axford, & DeLoache, 2013).
Because young children do not spontaneously avoid threats like snakes and spiders, it is critically important to understand both how they develop avoidance responses to various threats, and why avoidance behaviors are more likely to develop for some stimuli over others. Indeed, snake and spider fears are more common than fears of other biological threats like bears and sharks, and manmade threats, like guns and knives, which are arguably all more threatening in Western countries than snakes and spiders. In another ongoing project, we aim to investigate several unanswered questions about a variety of threats, including: 1.) What developmental trajectories characterize the acquisition of avoidance responses to specific threats? 2.) How are avoidance responses for threatening stimuli learned throughout development, and what types of information (e.g., vicarious conditioning, negative verbal information) most effectively promote learning? 3.) What role do specific psychological processes (e.g., heightened attention, physiological arousal) play in privileging learning about some threats over others?
Although snakes and spiders are indeed threatening to humans in some parts of the world, there are other stimuli that present more every day threats to humans more broadly. In a new ongoing project, we are expanding previous research on the perception of threatening predators and social threats to examining how children behave in the presence of a biological threat, or contagious illness. Young children are exposed to a countless number of germs everyday—in the air or on surfaces they encounter (e.g., floor and objects), on their toys, and on the floors that they play on. With more opportunities to contact germs and a less developed immune system, children are particularly vulnerable to getting sick. Researchers have shown a continued interest in what children know about illness. Using verbal reports and child interviews, researchers report that around the age of 5, children are beginning to reason about illness and contagion. However, although having knowledge about how we get sick is clearly important for development, knowing about illness does not necessarily translate to behaving adaptively when confronted with it.
One of our current projects focuses on how children behave when faced with the possibility of getting sick. We recently published the first study examining when children spontaneously avoid contact with sick individuals and contaminated objects. We invited 4- to 7-year-old children to play with two experimenters—one of whom was “sick” and the other who was not—and the toys each experimenter touched. Afterward, we assessed children’s knowledge of contagion. Overall, children avoided proximity to and contact with the sick experimenter and her toys, but only 6- and 7-year-olds performed above chance. However, the most relevant factor in determining avoidance behavior was not age but the ability to make accurate predictions about whether someone will get sick based on prior events (Blacker & LoBue, 2016). Importantly, this pattern of results suggests that younger children can also avoid a sick experimenter and her toys given the appropriate knowledge. We are now beginning to examine other factors that lead to early illness avoidance, and whether providing younger children (3- to 5-year-olds) with different kinds of information about illness transmission will lead to increases in knowledge and behavioral avoidance of contaminated objects.
The Child Affective Facial Expression Set (CAFE)
Emotional development is one of the largest and most productive areas of psychological research. For decades, researchers have been fascinated by how humans respond to, detect, and interpret facial expressions. Most research on face perception has relied on controlled stimulus sets of adults posing various facial expressions. Together, there are over 80 facial expression sets freely available for use in research (www.face-rec.org/databases). Although these sets provide an easy, controlled way of examining responses to human facial expressions, they are limited in that they only represent emotional expressions in one specific group, namely Caucasian adults. At the Child Study Center, we are currently working on a new stimulus set of emotional facial expressions into the domain of research on emotional development—The Child Affective Facial Expression set (CAFE). The CAFE set is unique and significant to the field for several reasons. Primarily, instead of featuring photographs of adults posing various facial expressions, it features photographs of 2- to 8-year-old children. To date, very few stimulus sets feature children posing facial expressions, and none have featured children as young as preschool age. The stimulus set is also racially and ethnically diverse, featuring Caucasian, African American, Asian, Latino (Hispanic), and South Asian (Indian / Bangladeshi / Pakistani) children. In an NSF funded project, we recently validated the CAFE set and it is currently available for free to the scientific community (LoBue & Thrasher, 2015). We are currently working on expanding the CAFE set to include older children, adults, and dynamic (video) displays.
For more information on the CAFE set, visit the CAFE page.
The Rutgers Mobile Maker Center (MMC)
Photo by Elizabeth Lapidow
In collaboration with Elizabeth Bonawitz and Pat Shafto, we are currently working to build the Rutgers-Newark Mobile Maker Center (MMC), a fully mobile lab that can be brought to local science museums, parks, play centers, zoos, and libraries to study children’s learning and to bring science directly to the community. The Rutgers-Newark MMC is now fully constructed, and we hope to use it to collect data for the very first time this fall. For more information on the MMC, visit the MMC's website.