A recent study published in the journal Behaviour Research and Therapy has shed light on how humans react differently to threats compared to rewards. The researchers found that people tend to respond more intensely and quickly to negative or threatening images than to positive or rewarding ones. This phenomenon, referred to as “negativity effects,” was particularly pronounced in women compared to men.
The study was motivated by the desire to better understand why humans often react more strongly to threats than to rewards. Evolutionary theories suggest that it is more crucial for survival to respond to threats, as ignoring a danger could result in harm or death. While rewards are important, missing an occasional positive experience is less likely to be life-threatening. The study aimed to explore this evolutionary perspective by examining how people’s emotions fluctuate in response to different types of stimuli, and how these reactions might relate to susceptibility to anxiety disorders.
“An emerging literature highlights the dynamic (quickly varying) nature of emotional reactions and their regulation. We developed an ‘affectometer’ (now called the Dynamic Affect Reactivity Task or DART) that allows us to assess emotional reactions with a great deal of temporal precision, in response to affective images,” said study author Michael D. Robinson, a professor of psychology at North Dakota State University.
“We have published a number of papers using this technology. For example, Irvin et al. (in press) show that, even after equating pleasant and unpleasant images for arousal and extremity, people still tend to have faster and stronger reactions to unpleasant stimuli. We link this to evolutionary perspectives on emotion (basically, the idea that responding to any particular threat is more mandatory, for survival, than responding to any particular reward). In another paper, Robinson et al. (in press) showed that people with higher levels of general mental ability display more muted emotional reactions.”
“In the present case, we wanted to use the DART’s negativity effects (particularly with regard to peak, slope, and prototypical patterning) to see whether the dynamic emotional probe can be used to understand individual differences in proneness to anxiety and threat. We used sex differences as the model because women tend to be more threat-reactive than men and score higher in anxiety and its disorders.”
The researchers conducted a series of three experiments with a combined total of 375 participants, aimed at exploring how individuals react emotionally to positive (appetitive) versus negative (aversive) stimuli. The participants were primarily undergraduate students from a Midwestern university in the United States.
Each participant was placed in a private room with a personal computer to ensure focused and uninterrupted participation. The core of the experimental procedure was the Dynamic Affect Reactivity Task, which required participants to continuously rate their emotional state in response to a series of images.
The images were selected from the Nencki Affective Picture System and the International Affective Picture System, which are standardized sets of images known to elicit strong emotional reactions. These images included both appetitive images (e.g., happy people, children playing) and aversive images (e.g., car crashes, rotten food). Importantly, the images were equated for arousal and extremity to ensure that any differences in participants’ reactions were due to the positive or negative nature of the images rather than their overall intensity.
Participants used a vertical rating bar displayed on a computer screen to indicate their emotional state. The bar was labeled “very unpleasant” on one end, “very pleasant” on the other, and “baseline feelings” in the middle. Participants were instructed to press the up or down arrows on the keyboard to move a cursor along the rating bar, continuously indicating how they felt in response to each image. For some participants, pleasant reactions were mapped to the up arrow, while for others, they were mapped to the down arrow, ensuring that the task’s design did not bias the results.
The researchers quantified several key parameters from the participants’ responses. They measured the onset time (how quickly a reaction began after the image was presented), peak intensity (the maximum emotional response during the image presentation), and the slope of the reaction (how quickly the emotional intensity changed over time). Additionally, they calculated the prototypicality of the reaction, which indicated how closely a participant’s response matched a typical reaction pattern averaged across all participants.
Robinson and his colleagues found that participants’ emotional reactions to aversive images began more quickly than their reactions to appetitive images. This rapid onset of negative reactions supports the evolutionary theory that humans are hardwired to detect and respond to potential threats swiftly, which is crucial for survival.
The peak intensity of emotional responses was also higher for aversive images compared to appetitive ones. This means that not only do negative reactions start faster, but they also reach a higher level of emotional intensity.
Additionally, the slope of emotional change was steeper for aversive images. This finding aligns with the idea that humans need to quickly ramp up their emotional response to threats to prepare for appropriate actions, such as fight or flight.
“The negative emotion system is more reactive than the positive emotion system is,” Robinson told PsyPost. “That is, we are predisposed to negative emotional reactivity. Threat sensitivity varies by individuals, though, and probes of the present type can be used to understand the micro-momentary processes that might contribute to anxiety and fear over the long term.”
Another critical finding was that negative reactions were more prototypical than positive reactions. In other words, reactions to aversive images were more uniform and consistent, suggesting a more automatic and possibly hardwired response mechanism to threats.
“We really like the ‘prototype’ measure,” Robinson said. “Basically, we are able to correlate an individual emotional reaction with a prototype for that stimulus. The higher the correlation, the more prototypic, or invariant, the reaction seems to be. Negative emotional reactions tend to be more prototypical across individuals than positive emotional reactions.”
Sex differences were another notable aspect of the findings. The study showed that women had quicker onset times, higher peak intensities, and steeper slopes in their emotional responses to aversive images than men, on average. This aligns with the higher prevalence of anxiety and fear-related disorders among women.
“We show that women do tend to have stronger negativity effects than men, which suggests that the paradigm can be used to understand the sorts of individual differences that have been emphasized in the anxiety literature,” Robinson explained.
The findings of this study have important implications for understanding and treating anxiety disorders. By identifying individuals with heightened threat sensitivity, clinicians might better predict who is at risk for anxiety-related conditions.
For example, the DART “could be used to assess variations in the ‘acute threat’ mechanisms that may predispose people to anxiety symptoms and disorders,” Robinson explained.
The research provides robust evidence for the existence of negativity effects in emotional reactivity. But as with any study, there are limitations. The sample primarily consisted of young adults from a university setting, which may not be representative of the general population. Future research could include a more diverse age range and explore how these findings apply to older adults.
Additionally, the study focused on sex differences without delving into the underlying causes, which could include hormonal, genetic, and sociocultural factors. Further research is needed to unpack these influences and understand how they contribute to the observed differences in threat sensitivity.
“We would like to increase the clinical relevance of this research,” Robinson said. “This would be done by focusing on clinical symptomology, longitudinal predictions, and responses to treatment.”
“We live our lives in dynamic terms and it is nice to have a model of the dynamic nature of emotional reactions,” he added.
The study, “Threat sensitivity in emotion dynamics: Negativity effects and sex differences,” was authored by Michael D. Robinson, Roberta L. Irvin, and Muhammad R. Asad.
