Read the passage given below and solve the questions based on it.
The behavioral economics literature provides several motivations for the common observation that agents appear somewhat unwilling to deviate from their recent choices. For instance, some researchers mention the bias towards recent choices as an example of the availability bias, the ease with which instances come to mind. Similarly, others have argued that players, when indifferent between strategies, choose the most salient strategy. In combination with the so-called recency effect, this may explain why agents appear to have a preference for recent choices. The recency effect refers to the cognitive bias that results from disproportionate salience of recent stimuli or observations. Other motivations include models for agents displaying defaulting behavior or inertia, the formation of habits, the use of rules of thumb, or the locking in on certain modes or behavior due to learning by doing or, as some express it: unlearning by not doing.
In the above passage, ‘rules of thumb’ means