Research indicates human couple attachments provide the greatest relational brain and behavioral coordinated task synchrony and the greatest feelings of support.
Written by Brett J. Weiss
01-24-2021

Human attachments drive the efficient performance of social goals like rowing a boat, cutting wood for a fire, or lifting water from a well with limited and time-sensitive resources. Our unmatched abilities to coordinate these tasks has led to our supremacy among animal kingdom species. Research has shown that biobehavioral synchrony – the emergence of neural and behavioral rhythms happening at the same time – between people facilitate social coordination. Questions remain, though, about how specific types of human attachments shape social goal-directed biobehavioral synchrony.
Feldman and colleagues from Israel published a study in NeuroImage that compared biobehavioral synchrony between male-female couples, best friends, and strangers in manual task coordination and an empathy-eliciting task. Their results showed couples have the highest neural and behavioral synchrony with the fastest and most accurate manual task performance. Couples showed the highest behavioral synchrony and lowest brain synchrony in the empathy task, with the opposite true for strangers who had higher brain synchrony and lower behavioral synchrony. Overall, their results support that couple attachments may provide greater survival benefits than other types of relationships.
Measuring Brain Rhythms
Feldman and colleagues measured brain rhythms called alpha, beta, and gamma waves in their study. Neuroscientific theory posits that alpha waves are involved in constructing predictions of the consequences of behavior, beta waves in the brain’s monitoring of prediction accuracy, and gamma waves implicated in reorganizing predictions via incoming sensory information. Feldman and colleagues placed electrodes – conductors through which electricity enters and leaves a test subject – on the scalps of couples, pairs of best friends, and pairs of strangers to monitor behavior and brain activity in manual task coordination and empathy-eliciting scenarios. Their goal was to monitor performance and biobehavioral synchrony as these parameters relate to the human attachments.
Behavioral Coordination and Empathy-Eliciting Tasks
The manual coordination task, also called a motor task, used an “Etch A Sketch” with two knobs, one drawing lines up to down and the other drawing lines left to right. The paired couples, friends, and strangers could communicate with each other while drawing an “X” and a “house.”
The pairs from the three different human attachments in the study also engaged in an empathy-eliciting task where they shared distressing or troubling personal events. Following the task, participants rated how comfortable they were and how empathic, supportive, and helpful their partner was.

Couples Have Highest Biobehavioral Synchrony with Best Task Performance and Accuracy
Assessments of the manual coordination task indicated couples had the highest degree of biobehavioral synchrony along with the fastest and most accurate performance. Feldman and colleagues referred to the couples’ enhanced neural and behavioral synchrony-induced performance as linkage – where brain-behavior synchrony drives the best performance speed and accuracy.


Elevated Behavioral Synchrony and Empathic Benefits for Couples
The empathy-eliciting task analysis indicated that couples exhibit the greatest behavioral synchrony and offer the most support but have lower brain synchrony than friends and strangers. This may be due to complementarity – greater behavioral synchrony combined with looser physiological coupling – occurring when two people in a relationship sync behaviorally over time. When couples become familiar and comfortable with each other’s behaviors, less neural synchrony is required to predict the partner’s behavior for subsequent behavioral syncing. The brain uses less synchronization energy while still providing the highest degree of “felt support.”


Cohabitating Couples Have Optimal Brain-Behavior Balance
“Our tasks tapped the two prototypical social-collaborative acts utilized across human evolution: the capacity to collaborate in the planning and execution of complex motor tasks and the ability to emotionally resonate and emphatically share others’ misfortunes and joys,” stated the scientists in their publication. “We found that during natural social exchanges interbrain processes are pervasive, sustained by behavioral coordination, and are shaped by attachment and bonds toward efficient performance of survival-related social goals. Overall, our results show that in both tasks, cohabitating partners employed the most efficient two-brain-two-behavior balance toward best performance, detailing how attachment bonds shape interbrain processes.”
Couples Attachments Promote Survival Benefits
Long-term couples’ relationships afford optimum biobehavioral synchronization for coordinated manual task performance. Moreover, couples use less cognitive energy as shown with less neural synchronization and greater behavioral synchrony resulting in higher “felt support” in empathy tasks. Evolutionarily speaking, this provides evidence for couples forming advantageous relationships contributing to enhanced task coordination, emotional, and subsequent survival benefits.
Story Source
Djalovski A, Dumas G, Kinreich S, Feldman R. Human attachments shape interbrain synchrony toward efficient performance of social goals. Neuroimage. 2021 Feb 1;226:117600. doi: 10.1016/j.neuroimage.2020.117600. Epub 2020 Nov 27. PMID: 33249213.