 <!--  /* Font Definitions */  @font-face 	{font-family:"Cambria Math"; 	panose-1:2 4 5 3 5 4 6 3 2 4; 	mso-font-charset:0; 	mso-generic-font-family:roman; 	mso-font-pitch:variable; 	mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face 	{font-family:Calibri; 	panose-1:2 15 5 2 2 2 4 3 2 4; 	mso-font-charset:0; 	mso-generic-font-family:swiss; 	mso-font-pitch:variable; 	mso-font-signature:-1610611985 1073750139 0 0 159 0;}  /* Style Definitions */  p.MsoNormal, li.MsoNormal, div.MsoNormal 	{mso-style-unhide:no; 	mso-style-qformat:yes; 	mso-style-parent:""; 	margin-top:0cm; 	margin-right:0cm; 	margin-bottom:10.0pt; 	margin-left:0cm; 	line-height:115%; 	mso-pagination:widow-orphan; 	font-size:11.0pt; 	font-family:"Calibri","sans-serif"; 	mso-fareast-font-family:Calibri; 	mso-bidi-font-family:"Times New Roman"; 	mso-fareast-language:EN-US;} .MsoChpDefault 	{mso-style-type:export-only; 	mso-default-props:yes; 	font-size:10.0pt; 	mso-ansi-font-size:10.0pt; 	mso-bidi-font-size:10.0pt; 	mso-ascii-font-family:Calibri; 	mso-fareast-font-family:Calibri; 	mso-hansi-font-family:Calibri;} @page Section1 	{size:595.3pt 841.9pt; 	margin:72.0pt 72.0pt 72.0pt 72.0pt; 	mso-header-margin:35.4pt; 	mso-footer-margin:35.4pt; 	mso-paper-source:0;} div.Section1 	{page:Section1;} -->   Hi all, I’m a psychologist moving from anova to lmer for analysis of response time (and error data) from a reaction time experiment, and have a question about specifying the structure of random effects in the model. Many of the examples I am reading about involve split-plot designs where effects are nested within each other .... This is not the case here: I am using a typical repeated measures design where each subject does everything:  30 subjects judge the laterality of a hand shown on a computer screen, completing 18 trials in all combinations of the following experimental factors (Angle, 8 levels (hand shown in 8 different orientations), Laterality, 2 levels (both right and left hands shown), Condition, 3 levels (participant holds own hands in posture a,b or c).  With repeated measures ANOVA the Error structure is specified as follows   aov(percentErrors~angle*condition*laterality+Error(subject/(angle*condition*laterality)),data=errorData)     aov(meanRT~angle*condition*laterality+Error(subject/(angle*condition*laterality)),data=RTdata)     where response variables, percentErrors and meanRT, are the percentage of errors (out of 18 trials) and the mean reaction time over 18 trials     I need to move to lmer as variance is not constant across Angle and error data are bounded (0,1) so I should use the binomial family – my first pass (looking at all main effects & possible interactions) is:     lmer(cbind(numErrors,numCorrect)~angle*condition*laterality+(angle*condition*laterality|subject),family=”binomial”),data=errorData)     where numErrors+numCorrect = 18 for each subject & Angle-Laterality-Condition combination        lmer(meanRT~angle*condition*laterality+(angle*condition*laterality|subject),data=RTdata)        I am unsure if this is correct? Help is welcome, thanks - Nuala           

Nuala Brady
School of Psychology
University College Dublin
Belfield, D4
IRELAND

+353 (0)1 716 8247
nuala.brady@ucd.ie



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