The study conducted by researchers at University of California, Irvine (UCI) in US implies that when mothers are nurturing their infants, numerous everyday interruptions - even those as seemingly harmless as phone calls and text messages - can have a long-lasting impact.
The researchers studied the emotional outcomes of adolescent rats reared in either calm or chaotic environments and used mathematical approaches to analyse the mothers' nurturing behaviours.
Specifically, in one environment, the mothers displayed 'chopped up' and unpredictable behaviours.
During adolescence, their offspring exhibited little interest in sweet foods or peer play, two independent measures of the ability to experience pleasure. Known as anhedonia, the inability to feel happy is often a harbinger of later depression.
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The study shows that consistent rhythms and patterns of maternal care seem to be crucially important for the developing brain, which needs predictable and continuous stimuli to ensure the growth of robust neuron networks.
Because cellphones have become so ubiquitous and users have become so accustomed to frequently checking and utilising them, the findings are highly relevant to today's mothers and babies, and tomorrow's adolescents and adults, researchers said.
"It is known that vulnerability to emotional disorders, such as depression, derives from interactions between our genes and the environment, especially during sensitive developmental periods," said Tallie Z Baram from UCI.
"It is not how much maternal care that influences adolescent behaviour but the avoidance of fragmented and unpredictable care that is crucial. We might wish to turn off the mobile phone when caring for baby and be predictable and consistent," Baram added.
If infants are not sufficiently exposed to such reliable patterns, their pleasure systems do not mature properly, provoking anhedonia.
The findings were published in the journal Translational Psychiatry.