fixDur {eyeRead}

Fixation Duration

Description

Calculates the fixation durations for the passes (Hyönä, Lorch, and Rinck, 2003; Hyönä, and Lorch, 2004) or the AOI's

Usage

fixDur(data, fixTime, passes, AOI = NULL)

Arguments

data

A data frame containing fixation information of an eye tracing experiment and the coded passes. Each row indicates a fixation.

fixTime

The name or number of the column containing the time per fixation.

passes

The name or number of the column containing the coded passes.

AOI

The name or number of the column in data containing the name of the area of interest (AOI) that was fixated.

Details

This function is a wrapper for aggregate

The function will only return the fixation duration of the values in the passes column. The passes column is the vector returned by the link{codePasses} function. It is also possible to provide the column name of the column containing the AOI's if you require the fixation durations for the AOI's only. The column of which the name or number is passed to passes,will be converted to a factor if it is not yet the case.

You can provide the names of the AOI's to AOI_label and indicate if rereading passes were coded in rereading. This ensures that the output contains all types of passes for each AOI, even if they did not occur. In that case the value in the output will be 0.

Value

A data frame with the following columns If the AOI column is provided to passes: $AOI: containing the AOI names $duration: containing the aggregated durations

If the passes column is provided to passes and there is no rereading: $AOI: containing the AOI names $FirstPass: containing the aggregated first pass durations $SecondPass: containing the aggregated second pass durations

If the passes column is provided to passes and there is rereading: $AOI: containing the AOI names $FirstPassForward: containing the aggregated first pass forward durations $FirstPassRereading: containing the aggregated first pass rereading durations $SecondPass: containing the aggregated second pass durations

The result will be in the same unit as the duration input.

If the data contains fixations that were outside the AOI, the first line of the results will contain the total fixation duration outside the AOI's.

References

Hyönä, J., Lorch, R. F., & Rinck, M. (2003). Eye movement measures to study global text processing. In J. Hyönä, R. Radach, & H. Deubel (Eds.), The mind's eye: cognitive and applied aspects of eye movement research (pp. 313-334). Amsterdam: Elsevier Science.

Hyönä, J., & Lorch, R. F. (2004). Effects of topic headings on text processing: evidence from adult readers’ eye fixation patterns. Learning and Instruction, 14, 131-152. doi:10.1016/j.learninstruc.2004.01.001

See Also

aggregate, by, tapply

Examples

  data( SimData )
                         
  ### This function compiles fixation durations
  ## for first and second passes
  # when the column name is given
  fixDur( data = SimData, fixTime = "fixTime", 
          passes = "passes" )
          
  # and when column number is given
  fixDur( data = SimData, fixTime = 8, passes = 9 )
  
  ## for forward and rereading passes
  fixDur( data = SimData, fixTime = "fixTime",
          passes = "passesReread" )
          
  ## and for AOI's
  fixDur( data = SimData, fixTime = "fixTime", 
          passes = "AOI" )