Before conducting the experiment, the researcher must obtain written consent from all participants.

consent 是名词，意思是"同意、许可"，指正式或官方的允许或批准。这个词来自拉丁语 consentire，由 con-（一起）和 sentire（感觉）组成，字面意思是"共同感受"，引申为"达成一致意见"。