Halliday & Matthiessen (2014: 352):
From a transitive point of view, in these initiating structures there is a feature of cause added. This is also possible with (i) mental clauses and with (ii) relational ones.
(i) Corresponding to the initiating structure in material clauses, we find an inducing structure in mental clauses; for example, remind can be interpreted as ‘induce to remember’
(ii) Corresponding to the initiating structure in material clauses, we find attributed and assigned structures in relational clause. As we have seen, for the transitive analysis we have to recognize the additional functions of Attributor and Assigner; but from the ergative point of view, these clauses simply add a feature of agency.