Paul Conti

Social isolation has a detrimental impact on human well-being and health.

"And we know that it's not good to have too little, right? That isolation isn't good for us." (said at 0:20:00)

Extensive meta-analytic evidence from large prospective cohort studies confirms that social isolation has a substantial detrimental impact on human health and well-being. Meta-analyses demonstrate that social isolation is robustly associated with increased risks of all-cause mortality (approximately 29% to 32% increased risk), cardiovascular disease mortality, cancer mortality, and various adverse mental and physical health outcomes (including depression, cognitive decline, and chronic conditions).

• supports: Loneliness and social isolation as risk factors for mortality: a meta-analytic review. (Perspectives on psychological science : a journal of the Association for Psychological Science 2015)

  "Across studies in which several possible confounds were statistically controlled for, the weighted average effect sizes were as follows: social isolation odds ratio (OR) = 1.29, loneliness OR = 1.26, and living alone OR = 1.32, corresponding to an average of 29%, 26%, and 32% increased likelihood of mortality, respectively." (abstract, results, passage verified)

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• supports: Potential impact of physical distancing on physical and mental health: a rapid narrative u… (BMJ open 2021)

  "The results suggest that lack of social connection is associated with chronic physical symptoms, frailty, coronary heart disease, malnutrition, hospital readmission, reduced vaccine uptake, early mortality, depression, social anxiety, psychosis, cognitive impairment in later life and suicidal ideation." (abstract, results, passage verified)

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• supports: A systematic review and meta-analysis of 90 cohort studies of social isolation, loneliness… (Nature human behaviour 2023)

  "Here we show that, in the general population, both social isolation and loneliness were significantly associated with an increased risk of all-cause mortality (pooled effect size for social isolation, 1.32; 95% confidence interval (CI), 1.26 to 1.39; P < 0.001) and cancer mortality (pooled effect size for social isolation, 1.24; 95% CI, 1.19 to 1.28; P < 0.001). Social isolation also increased the risk of CVD mortality (1.34; 95% CI, 1.25 to 1.44; P < 0.001)." (abstract, results, passage verified)

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Writing down thoughts or speaking them out loud recruits distinct cognitive and error-checking brain processes compared to purely internal thought.

"And and when we take the thought process outside of us, so if we write the words down or if we say the words, we say the words to another person, then we're bringing different brain processes online, different error-checking processes online." (said at 0:30:40)

Cognitive neuroscience and psycholinguistic research support the claim that overt expression (speaking out loud or externalizing language) engages distinct error-monitoring and neural feedback mechanisms compared to covert/internal thought. Studies investigating self-monitoring during overt versus covert speech demonstrate that externalized output recruits external auditory/sensory feedback loops and widespread performance-monitoring networks (including the anterior cingulate cortex, supplementary motor area, insula, and sensory-motor regions) to detect and correct errors in real time, distinct from internal-only monitoring circuits.

• supports: Neural correlates of verbal feedback processing: an fMRI study employing overt speech. (Human brain mapping 2007)

  "The results show that auditory feedback processing involves a network of different areas related to general performance monitoring and speech-motor control. These include the cingulate cortex and the bilateral insula, supplementary motor area, bilateral motor areas, cerebellum, thalamus and basal ganglia. Our findings suggest that the anterior cingulate cortex, which is often implicated in error-processing and conflict-monitoring, is also engaged in ongoing speech monitoring." (abstract, results, passage verified)

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• supports: Self-Monitoring in Speaking: In Defense of a Comprehension-Based Account. (Journal of cognition 2020)

  "According to the comprehension-based account proposed by Levelt, Roelofs, and Meyer (1999) and Roelofs (2004), speakers detect errors by using their speech comprehension system for the monitoring of overt as well as inner speech. According to the production-based account of Nozari, Dell, and Schwartz (2011), speakers may use their comprehension system for external monitoring but error detection in internal monitoring is based on the amount of conflict within the speech production system, assessed by the anterior cingulate cortex (ACC)." (abstract, background, passage verified)

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Severe psychological trauma causes lasting changes in brain function.

"And the presence of trauma, of real trauma that overwhelms our coping skills and leaves our brain function different going forward, it does make it harder, right? To achieve these things" (said at 1:22:20)

A large meta-analysis of 83 task-based fMRI studies (N = 5,242) demonstrated that exposure to severe adversity and psychological trauma is associated with enduring alterations in brain function, notably hyperreactivity in the amygdala and decreased reactivity in the prefrontal cortex across emotional, cognitive, and reward-processing tasks.

• supports: Adverse Life Experiences and Brain Function: A Meta-Analysis of Functional Magnetic Resona… (JAMA network open 2023)

  "Adversity exposure was associated with higher amygdala reactivity (familywise error rate corrected at P < .001; x-axis = 22; y-axis = -4; z-axis = -17) and lower prefrontal cortical reactivity (familywise error rate corrected at P < .001; x-axis = 10; y-axis = 60; z-axis = 10) across a range of task domains. These altered responses were only observed in studies that used adult participants and were clearest among those who had been exposed to severe threat and trauma." (abstract, results)

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