An analysis of the intergenerational shift in behaviors in that country
In the 1990s, over 40% of Icelandic youths aged 15 to 16 reported excessive alcohol consumption. Other substances—such as cigarettes and marijuana—were also consumed at levels comparatively higher than in other European countries. However, following a series of measures adopted by the Icelandic government, this "hedonistic" youth culture changed dramatically; today, only 5% of young people in the same age group report heavy alcohol consumption, compared to 42% three decades ago. Regarding cigarettes and marijuana, the intergenerational differences in consumption are equally striking: dropping from 23% to 3% and from 17% to 7%, respectively.
https://www.espn.com.br/futebol/artigo/_/id/4306536/lado-b-da-copa-islandia-o-pais-que-usou-o-esporte-para-combater-o-alcoolismo-entre-jovens
If this remarkable behavioral shift is directly linked to the introduction of government measures aimed at fostering healthy habits—such as sports—from an early age, as well as restricting access to alcohol and other drugs, then it serves as a prime example of human plasticity. It illustrates the broader capacity to alter or change behavior—if not about a single individual, then at least within a group (it would be interesting to know the current status of the Icelandic youths who were assessed in the 1990s and reported high consumption of alcohol and other substances). It also demonstrates just how powerful an influence the environment can have on us. ...of just how socially conformist we can be... But it also shows that, even before—when "Icelandic youth" were disproportionately mired in habits harmful to physical and mental health—the situation didn't apply to the entire group; 60% (a majority) did not fall into the "bad habits" statistics... It demonstrates that even when homogenizing forces exist within certain social groups, there is a strong likelihood that at least a minority will not "follow the herd"... This also highlights the power of biology itself as an influence on behavior—perhaps the most important factor. After all, both the young person who falls into the world of addiction and the one who does not are primarily—and, I would argue, deterministically—influenced by their behavioral biology: the morphological characteristics of their brains and the hormonal makeup of their bodies, in constant interaction with the environment, these traits manifest as behavioral tendencies that may be similar or vastly different. There is no such thing as someone "from nowhere" taking up smoking while another person in the same group quits; in terms of behavior, nothing ever happens "from nowhere." There is no *blank slate* inside our heads leading us down completely random paths; the range of behaviors we can adopt is predetermined—provided we aren't born literally without brains, and given that the brains we are born are result from combinations of our parents' genetic material, which already possesses its own specific individual makeup. We are certainly born with developing brains, but never without pre-existing or predetermined elements—contrary to the notion of a blank slate waiting for experience to write upon it. Although many believe this—including supposed experts in related fields—the Icelandic experiment does not prove that human genetics or biology is entirely a product of the social and cultural environment; rather, it shows that because our biology is intrinsically plastic, it allows for a wider range of behavioral variation. Some might still argue that various individual and environmental factors operate as a chain of influences... ...can lead some or many to follow certain paths. The "anatomical structure" of multiple, highly specific causal factors leading an individual or group to adopt certain behaviors is not inherently superfluous, as it can serve to illustrate a trajectory. However, it does not support the argument—which might otherwise be used to bolster the "blank slate" hypothesis—given that intrinsic predispositions remain the most important factor. Indeed, there is a correlation between addiction and certain personality traits, such as neuroticism, as well as physiological predispositions—for instance, the capacity to tolerate high levels of alcohol in the bloodstream and how this can contribute to the establishment of a specific cycle of alcohol addiction.
Furthermore, there is another interesting fact not shown in the linked report: the crime rate in that country has not decreased significantly since the government began steering younger generations away from cigarettes, marijuana, and alcohol, as illustrated in the linked graph..below, having remained relatively constant (generally very low) from that time until the most recent years of the 2020s. This is interesting because it is common to attribute some irrationally antisocial behaviors to alcohol or drug abuse. And even though there is a logical link between behavioral changes and excessive substance use, even in that dire scenario of total surrender to addiction, intrinsic factors—such as predominant personality traits—continue to exert influence; after all, not every addict goes around mugging people or committing even graver acts, such as unprovoked violence or even homicide. This may demonstrate that certain behaviors or habits are more malleable than others, but it also suggests that this experiment is particularly well-suited to countries with populations ethnically similar to Iceland’s—such as its Scandinavian cousins—whereas populations that are culturally, psychologically, and cognitively distinct might well show different responses... Even if it could be adopted as a medium- to long-term public policy in other countries...
https://www.macrotrends.net/global-metrics/countries/isl/iceland/crime-rate-statistics
To answer the question posed in the title: the social environment certainly influences human behavior. However, behavior is never shaped solely by the environment; for the interaction to be complete, it depends first on the behavioral biology of the population or the individual. Secondly, if the "environment" is merely a set of factors determined in arbitrary and variable ways, the only true agent—and the primary one in this dynamic—is always the living being/ human being. Consequently, the most important directives and determinants originate from within that individual. Just as a human being cannot fly unaided without the necessary biological machinery and physical and mental capabilities, neither can they overcome their own limitations—specifically, the very traits that define and characterize them. For if—based on the example in the text—he lacks the psychological and even physiological predispositions to become addicted to alcohol or drugs, it is highly likely that he will not end up trapped in that problematic cycle of reward in his daily life, even if he happens to be exposed to it...
