The article by John T. Cacioppo and Louise C. Hawkley explores the impact of perceived social isolation, or loneliness, on cognitive performance and overall health. Social isolation, a condition characterized by chronic distress and a lack of redeeming features, is a significant risk factor for cognitive decline and various health issues in both animals and humans. Research indicates that loneliness is associated with poorer cognitive performance, faster cognitive decline, poorer executive functioning, more negative emotions, heightened sensitivity to social threats, and a confirmatory bias in social cognition. These cognitive and emotional changes can further contribute to social isolation, creating a vicious cycle. The authors highlight that human social processes, once considered incidental to learning and cognition, are now recognized as integral to the evolution of the neocortex and various aspects of human cognition. Studies show that loneliness impairs learning and cognitive abilities, particularly in executive functioning, which involves controlling attention, cognition, emotion, and behavior to meet social standards or personal goals. Experimental manipulations of loneliness have shown that it can impair attentional regulation, self-regulation, and executive functioning, leading to poorer emotional regulation and more negative social interactions. Loneliness also affects social cognition, making individuals more hypervigilant for social threats and more likely to construe their social world as threatening. This can lead to a cycle where negative social expectations and interactions reinforce each other, further isolating individuals. Additionally, loneliness is contagious within social networks, spreading through direct and indirect contact, and can reduce social ties and social cohesion. The article concludes by emphasizing the need to understand the biological and cognitive mechanisms underlying the association between loneliness and cognition, and to develop effective interventions to reduce perceived social isolation and promote healthy social connections.The article by John T. Cacioppo and Louise C. Hawkley explores the impact of perceived social isolation, or loneliness, on cognitive performance and overall health. Social isolation, a condition characterized by chronic distress and a lack of redeeming features, is a significant risk factor for cognitive decline and various health issues in both animals and humans. Research indicates that loneliness is associated with poorer cognitive performance, faster cognitive decline, poorer executive functioning, more negative emotions, heightened sensitivity to social threats, and a confirmatory bias in social cognition. These cognitive and emotional changes can further contribute to social isolation, creating a vicious cycle. The authors highlight that human social processes, once considered incidental to learning and cognition, are now recognized as integral to the evolution of the neocortex and various aspects of human cognition. Studies show that loneliness impairs learning and cognitive abilities, particularly in executive functioning, which involves controlling attention, cognition, emotion, and behavior to meet social standards or personal goals. Experimental manipulations of loneliness have shown that it can impair attentional regulation, self-regulation, and executive functioning, leading to poorer emotional regulation and more negative social interactions. Loneliness also affects social cognition, making individuals more hypervigilant for social threats and more likely to construe their social world as threatening. This can lead to a cycle where negative social expectations and interactions reinforce each other, further isolating individuals. Additionally, loneliness is contagious within social networks, spreading through direct and indirect contact, and can reduce social ties and social cohesion. The article concludes by emphasizing the need to understand the biological and cognitive mechanisms underlying the association between loneliness and cognition, and to develop effective interventions to reduce perceived social isolation and promote healthy social connections.