The product type and multi-disciplinarity level of tasks may be associated with the behaviors of data searchers and their utilization of cognitive System 1 and System 2. To test these associations, a user experiment was conducted. Findings suggest that due to differences in the uncertainty of data needs and the difficulty of data evaluation, when executing tasks with intellectual products, users devote more effort to data evaluation rather than query optimization and rely more on System 2. Moreover, due to differences in knowledge complexity and the availability of data resources, when performing multi-discipline tasks, users devote more effort to query optimization and data evaluation but gain lower search performance. When performing intellectual-multi-discipline tasks, data searchers use System 1 and System 2 in a complementary way to support systematic and efficient evaluation. A task classification has been developed, offering a framework to identify behavioral and cognitive patterns linked to specific tasks.