# Biblatex: first names in text only for some sources - why?

I have a rather complex document using the biblatex style apa. For some sources that I cite first names appear (which I don't want, according to the APA guidelines), such as in:

\autocite{windttheoryconsciousness}


which yields

(Jennifer M. Windt & Noreika, 2011)


However

\autocite{stumbrysinductionreview}


yields

(Stumbrys, Erlacher, Schädlich, & Schredl, 2012)


These are the entries in the .bib file:

@article{windttheoryconsciousness,
title={How to integrate dreaming into a general theory of consciousness—a critical review of existing positions and suggestions for future research},
author={Jennifer M. Windt and Valdas Noreika},
journal={Consciousness and cognition},
volume={20},
number={4},
pages={1091--1107},
year=2011,
publisher={Elsevier}
}

@article{stumbrysinductionreview,
title={Induction of lucid dreams: A systematic review of evidence},
author={Tadas Stumbrys and Daniel Erlacher and Melanie Sch{\"a}dlich and Michael Schredl},
journal={Consciousness and Cognition},
volume={21},
number={3},
pages={1456--1475},
year=2012,
publisher={Elsevier}
}


I tried a minimal example, but I could not reproduce the problem (which was that first names sometimes appear and sometimes not). Therefore I can phrase my question only vaguely: What could be the difference between these sources? I noticed that sometimes the year tag was in curly brackets, but I removed them and recompiled -- still the same result in the complex document. Also, for some sources in the bib file I noticed that authors were separated by commas instead of and. Changed that and recompiled -- still the same. Both of these sources appeared for the first time in the document.

I'd appreciate any guide in solving this problem.

If two different authors have the same surname, biblatex adds the first name to identify each of them. (You may add the uniquename=false option to change this behavior.)

Ex:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@article{windttheoryconsciousness,
title={How to integrate dreaming into a general theory of consciousness—a critical review of existing positions and suggestions for future research},
author={Jennifer M. Windt and Valdas Noreika},
journal={Consciousness and cognition},
volume={20},
number={4},
pages={1091--1107},
year=2011,
publisher={Elsevier}
}

@article{windttheoryconsciousness2,
title={How to integrate dreaming into a general theory of consciousness—a critical review of existing positions and suggestions for future research},
author={Alex Windt and Valdas Noreika},
journal={Consciousness and cognition},
volume={20},
number={4},
pages={1091--1107},
year=2011,
publisher={Elsevier}
}

@article{stumbrysinductionreview,
title={Induction of lucid dreams: A systematic review of evidence},
author={Tadas Stumbrys and Daniel Erlacher and Melanie Sch{\"a}dlich and Michael Schredl},
journal={Consciousness and Cognition},
volume={21},
number={3},
pages={1456--1475},
year=2012,
publisher={Elsevier}
}
\end{filecontents*}

\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa,backend=biber]{biblatex}
\DeclareLanguageMapping{american}{american-apa}