When is it too late to learn another language?

It is never too late to learn another language; adults quite advanced in years have learned to speak another tongue. However, recent research indicates that there seems to be a "window of opportunity" during which the brain is particularly receptive to learning language. Children above the age of 7 have a much harder time learning a new language, and may never reach the level of fluency that a native speaker acquires.

Which is more influential, genetics or environment?

This is one of those thorny issues that keeps coming up, but has no definitive answer. There is plenty of evidence that indicates that children are born with genetically-determined temperaments that shape a child's response to the world. However, it is also the case that these traits in turn change the way the world responds to them, creating an endless feedback loop. For example, aggression is a trait with a strong genetic component. Yet aggressive children tend to elicit rejection from their peers. This creates a social environment that gives rise to even more aggression. How can we separate out a lifetime of differential treatment from the influence of genes? We have to content ourselves with the answer that both play an important role, and that the relationship between the two is complex.

How have research and theory on aging changed to adjust for the fact that the average life-span is increasing?

As a larger proportion of our lives occurs after retirement age, psychologists are adjusting their thinking about old age. While previous theorizing about aging assumed that people withdrew and deteriorated as they aged, current research on aging takes a different stance: rather than starting from the assumption that their abilities decline, psychologists are discovering the ways in which the elderly maintain their abilities. We now know that cognitive and memory impairments are by no means inevitable; elderly people who stay active and stimulated maintain these abilities as well as their happiness and involvement with life.

Do people continue to develop after they reach physical maturity?

While the most outward and dramatic developmental changes occur between birth and adolescence, humans never stop changing as they continue through the rest of the life cycle. From the peak of physical health in young adulthood, through the shifting roles and responsibilities of middle adulthood, to the bodily slow-down associated with aging, people continually make social, emotional, and physical adjustments.