What best describes insight learning?

Insight learning is characterized by a sudden realization or understanding that allows an individual to solve a problem or grasp a concept when faced with a new situation. This type of learning often involves rethinking the problem and integrating previously acquired knowledge in a novel way. The hallmark of insight learning is that the solution comes without trial-and-error and is often described as an "aha" moment, where the learner can suddenly combine elements of past experiences or knowledge to achieve a deeper understanding or to devise an effective strategy.

In contrast, the other options reflect different concepts in learning and behavior. Gradual accumulation of skills refers more to processes like skill acquisition through practice or gradual improvement rather than the sudden clarity observed in insight learning. Behavior modification through conditioning pertains to learning through rewards and punishments, highlighting a process of change rather than an immediate realization. Lastly, simple reversible changes in behavior suggest a more superficial alteration that does not encompass the profound understanding that insight learning entails.