Condition and Item Trigger Matching

The join key

EyeSort tracks trial context between configured start and end codes. Inside each trial it extracts numeric identifiers from recognized condition and item events, then creates a condition_item key such as 211_42.

Step 2 uses that key to select one IA row. Step 3 uses condition_number plus item_number to copy optional columns. The IA condition and item columns must therefore contain numeric values that correspond to the event triggers.

Matching behavior

Exact trigger text is accepted. Numeric-only configuration values may match the numeric portion of an event marker, and item ranges such as S1:S112 are expanded. Case-insensitive and optional leading-$ matching applies to IA column names, not to arbitrary reinterpretation of trigger identities.

Common failure modes

• condition/item events occur outside the configured trial boundaries;
• one key is missing before fixation events begin;
• IA values are nonnumeric or duplicated unexpectedly;
• configured triggers omit codes present in some participants;
• EEG keys have no IA row, or IA rows are never represented in EEG.

Check missing_text_file_keys, unused_text_file_keys, trigger match counts, and complete-key counts in EEG.eyesort_step2_diagnostics. Resolve key mismatches before interpreting region or label counts.