Procedural structures

Procedurals commands are used to define the event sequence of an experiment. The ERTS script language supports three levels to define the event flow: Session, Block, and Trial.

Procedural                                Experimental Structure
Level
                                        S

Session      ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄█▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
             ▌              ▐              ▐     ▐              ▐
             ▌              ▐              ▐     ▐              ▐
             ▌                             ▐     ▐
Block        ▌              Ba             ▐     ▐              Bb
             ▌                             ▐     ▐
             ▌              │              ▐     ▐              │
             ▌      ┌─────┬─┴──···───┐     ▐     ▐      ┌─────┬─┴──···───┐
             ▌      │     │          │     ▐     ▐      │     │          │
             ▌      │     │          │     ▐     ▐      │     │          │

Trial        Ia    Ta1   Ta2   ... TaN    P     Ib    Tb1   Tb2   ... TbN

S: Session,        B: Block,        T: Trial,        I: Instruction,        P: Pause

Trials consist of a sequence of low level events that control presentation and response registration. Trials can be packaged into a block which can be executed in random order. The highest structural level is a Session which is a sequence of single trials or blocks.