according to Stephens, when are learning behaviors expected to evolve?

To get the answer to when learning behaviors are expected to evolve according to Stephens, you would need to refer to a source or research conducted by this individual. Here's a step-by-step guide on how to find this information:

1. Start by searching for any available publications or research papers authored by Stephens. This can be done using online academic databases (e.g., Google Scholar, PubMed), university library resources, or even general internet searches.

2. Specify the subject area or field of study related to learning behaviors. This will help narrow down the results and increase the chances of finding relevant information.

3. After obtaining the publications or research papers by Stephens, carefully read through the texts to locate any information related to the evolution of learning behaviors. Look for specific sections or passages where this topic is addressed.

4. Take note of any statements or findings made by Stephens about the timing or circumstances in which learning behaviors are expected to evolve. Look for any patterns or recurring themes that might provide insights into this question.

5. Lastly, compile the information found and summarize the findings regarding when learning behaviors are expected to evolve according to Stephens.

Remember that the answer to your question will ultimately depend on the specific views and research evidence presented by Stephens, so it's important to refer to his work for accurate and reliable information.