Estimating the Stature of an Ancient North Andean Population From Articular Breadths and Diaphyseal Diameters: An Extension of Anzellini and Toyne (2020).

Every 40 s, a life is lost due to suicide (). Suicidal thoughts and behaviors (STB) are one of the leading causes of death worldwide that have devastating impacts on individuals, families, and societies. STB occurs from adolescence (), especially in the context of mood disorders, for example, major depressive disorder (MDD), anxiety disorder (AD), and bipolar disorder (BD) (). Despite the progress made during the last 50 years in identifying risk factors () and developing preventive strategies (), the death rate from STB has not declined (). The limited comprehension of cognitive and affective mechanisms creates a substantial gap in pinpointing targets for early prediction, screening, detection, and intervention in cases of suicidal thoughts. Understanding what is impaired in STB patients’ decision process would be key to preventing STB, for example through cognitive behavioral therapy (; ). Although meta-analyses have shown increased risk behavior in patients with STB across different risk domains (for a short summary, see ; ; ; ), the underlying cognitive computational mechanism is still unknown. Specifically, some studies found heightened loss aversion in STB in the context of the balloon analog risk task and the gambling task (; ), while others observed the opposite pattern using the Iowa gambling task (). Although all these results aligned with their hypotheses (for a short summary, see ), this contradictory evidence may originate from the use of underspecified models. A growing literature indeed shows that risky behavior can be far better explained after adding value-insensitive approach and avoidance components to prospect theory (; ), that is by including a decision bias in favor of the highest gain (approach) and another decision bias against the lowest loss (avoidance), above and beyond options value difference. This class of models highlights the important role of value-insensitive motivational components in decision making in addition to risk attitude-driven valuation (e.g., loss/risk aversion) (). Importantly, STB has been proposed in theoretical work to result from an abnormal motivational system (; ; ; ), but no direct evidence supports such proposals. Therefore, investigating motivational components may facilitate understanding why STB is associated with increased risk-taking behavior. We therefore hypothesized that heightened approach motivation, or weakened avoidance motivation, would account for increased risk behavior in STB. While suicide is a decision process per se, atypical mood dynamics have been thought to be at the core of STB. Contemporary theories of suicide converge on the idea that STB is initially caused by low mood experience. The interpersonal theory of suicide proposes that suicidal desire arises when people simultaneously feel socially disconnected (thwarted belongingness) and like a burden on others (perceived burdensomeness), experiences that are tightly linked to chronically low mood (). The motivational–volitional model () and the three-step theory (; ) similarly emphasize that when negative mood and feelings of defeat or entrapment are experienced as inescapable, they can give rise to suicidal ideation, and that the progression from ideation to suicide attempts depends on additional factors such as reduced fear of death, increased pain tolerance, and a tendency to act impulsively under intense affect. Some official organizations, for example, National Institute of Mental Health, have also listed mood problems as warning signals (). Interestingly, within the framework of decision making under uncertainty, gambling on lotteries with a revealed outcome has been found to induce high mood variance (), providing an opportunity to assess the relationship between deficient mood and increased gambling decisions in STB. Specifically, in a gambling task with momentary mood ratings (also referred to as happiness or subjective well-being), where participants were asked to make decisions between certain vs. gamble options (2 possible outcomes, 50% probability for each), found that mood was sensitive to certain rewards (CR), reward expectation (EV), and reward prediction error (RPE; the difference between experienced and expected outcome) (). Although mood is thought to persist for hours, days, or even weeks (; ; ; ), momentary mood, measured over the timescale in the laboratory setting, represents the accumulation of the impact of multiple events at the scale of minutes (; ; ; ; ; ; ). Momentary mood external validity is demonstrated, for example, through its association with depression symptoms (). Mood is different from emotions, which reflect immediate affective reactivity and are more transient (e.g., from surprise to fear) (; ; ; ). Here, we investigated which mood computational components (among CR, EV, and RPE) are associated with STB. We expect the mood response to gambling-related quantities (EV and RPE) to be higher in STB compared to the control groups. In contrast, ri