To describe how different variables contribute to psychological aging throughout human life, we trained DNNs on MIDUS 1 age group subsamples (25-39, 40-64, 65-75 years). These models contained the same 50 features as PsychoAge and Subjage, but their relative importance was not constant. In other words, a variable’s contribution to psychological aging was not static and its influence may vary with time.
First, we explored important variables (top-25 mean normalized PFI and DFS scores) shared by all age-group specific clocks to define the psychological aging core – features that significantly shift throughout one’s lifespan ( Table 2 ). Core features that determined the chronological aspect of psychological aging in MIDUS 1 contained neuroticism, seeing the community as a source of comfort and defining the lower boundary of male middle age. These features are expected to have life-long trends that let DNNs tell an old and a young person apart. Personality traits that were rendered important for human perception of age included aspirations scale, extraversion, openness, being career-oriented, and the prevalence of the positive reappraisal coping mechanism. Changes in these traits are expected to drive the internal psychological clock in humans of all ages.
Table 2
Effort put in life overall; Lower aspirations; Forcefulness; Current opinion about contributing to the well-being of others. Live for today; Persists in goal striving; Positive re-appraisal; Highest level of education; Current opinion about health. Now taking prescription medications for blood pressure; Marital status; Headaches frequency (30 days); Body mass index; Define age when men enter middle age; Community is a source of comfort; Neuroticism; Conscientiousness; Opinion about control of life in general; Define age women enter middle age; Mental health (self-evaluated); Sex life expectations in 10 years; Health locus of control others; Highest level of education; Contributing to the well-being of others in 10 years; Chronic conditions (12 months). Effort put in contributing to the well-being of others in 10 years; Opinion about life in general; Effort put in health; Neuroticism. Body mass index; Lower aspirations; Extraversion; Rate work situation in 10 years; Effort put in work; Positive reappraisal.
A series of DNNs was trained using samples from specific age groups (25-39, 40-64, 65-75 years) to inspect which features get recognized as important only within these groups. Features used by any model are the same 50 features as in SubjAge and PsychoAge; unique important features are defined as the features present in the top-25 importance list for only one aging clock. MAE stands for Mean Absolute Error See Supplementary Table 2 for a more detailed report.
Define age women enter middle age; Middle age upper limit (male); Current opinion about work situation; Contributing to the well-being of others in 10 years; Made unique contributions to society; Current opinion about life overall; Current over life in general at present; Current opinion about sexual aspects of life
The psychological core defines what aspects of human personality are constantly evolving and thus qualify as lifelong markers of https://kissbridesdate.com/no/honduranske-bruder/ psychological aging. But some features may quickly shift in a certain life period and be important for measuring psychological aging in this period only. These variables are called uniquely important in Table 2 . They identify which aspects of psycho-social life change the most reliably within an age group and thus get assigned higher importance within the corresponding age predictor.
To illustrate, agency is a uniquely important feature for accurate chronological age estimation in elderly people. This does not mean that being more or less willing to shape one’s own life is a trait only seen (or uniquely lacking) in the elderly. Most probably, agency was considered important in this age group, since people experience a major shift in this psychological attribute while going from 65 to 75 years. The DNN may have learned this possibly non-linear pattern to move a person closer to the upper or the lower boundary. In contrast, younger people may maintain more consistent agency throughout their lives, which makes DNNs seek aging-related patterns in other features.