Complete the summary below using words from the passage.
Write ONE WORD ONLY for each answer.

Neuromarketing can provide valuable information on attitudes to particular [1]. It may be more reliable than surveys, where people can be [2] or focus groups, where they may be influenced by others. It also allows researchers to identify the subject’s [3] thought patterns. However, some people are concerned that it could lead to problems such as an increase in disease among [4].