Stat: Four in 10 Americans say technology has improved their lives most in the past 50 years.

Story: To end 2018, we look ahead at the promise of new technologies, which also bring challenges for societies. To understand the issues, we speak to Arati Prabhakar, former director of the Defense Advanced Research Projects Agency. From artificial intelligence to neurotechnology, she notes the "dazzling" new capabilities emerging and the thorny considerations they bring.