Infant Controlled Habituation
Habituation is defined as a decrease in attention (e.g., of looking time) in response to the repeated exposure to an event or stimulus. If the event, or a property or feature of the event is changed, and the infant notices the change, their attention is said to “recover” in response to the novel event or stimulus.
In this infant controlled habituation program we have included the option for
including initial and final control trials. This allows the researcher to examine
whether an infant's failure to show dishabituation is a result of a failure to notice
the change in the stimulus or whether the infant became bored with the procedure
and thus failed to notice the change. These two control trials are not included
or counted as part of the habituation sequence.
After the first control trial is completed, the habituation sequence commences. The user is allowed to set the maximum individual trial length, total number of trials allowed to reach habituation, habituation criterion (as a percent decrease from the “baseline” trial average), and the look-away criterion to end an individual trial. In addition the user can specify whether they choose to include baseline trials as well as the number of baseline trials to average. The program also provides an option of what are labeled as “skipped” trials – these trials ensure that the habituation program must include a minimum number of trials prior to reaching the habituation criterion. In addition to a flexible, or user defined habituation criterion, the program allows the user to define how many consecutive trials must be below the habituation criterion before reaching habituation. The program also provides the option of including “lag” or post-habituation trials to reduce the likelihood of spontaneous regression to the mean. In addition, if the looking on the lag trials exceeds the habituation criterion the user has the option of having the program return to the habituation sequence in order to “re-habituate” the infant or to simply allow the post-habituation or lag trials potentially exceed the habituation criterion. Finally the program is also flexible in terms of the number of test trials that are included.
The program provides an output summary for the baseline trials, number of trials and time to reach habituation. Post-habituation looking, looking during the test trials, and of course an index of visual recovery. The program also provides the option of including a secondary observer. Direction of the infant’s first looks, as well as time spent on each “look” and “look-away” for trial-by-trial examination
After launching the program you will be prompted to enter the
participant’s demographic data –including age and date of participation
as the program will compute the participant’s age in days.
After initiating the first trial, and once the infant’s look away time has exceeded the user defined look-away time limit, the computer will signal (via a tone/beep) to the second experimenter that the look-away criterion has been met for that trial and they should end the trial. A 500 ms inter-trial-interval occurs before one can commence the next trial. The second or subsequent trial can be commenced following the 500 ms ITI and is indicated by a second tone (distinct from the tone that specifies the end of a trial) and the vibration of the observer’s button box (i.e., X-box controller). This alternation of end/begin tones continues from the first control trial and continues through the baseline, skipped trials (if included), and the habituation trials until the infant has reached the user defined habituation criterion and has stayed below the habituation criterion for the specified number of criterion trials. Once the habituation criterion has been met the experiment will transition to the post-habituation trials (if included otherwise the program proceeds to the test trials).
The program signals the transition to the post-habituation trials with a single tone followed by “yea” type sound. Following the presentation of the post-habituation trials – and if the post-habituation trials are less than the habituation criterion – the sound of clapping hands will indicate the program is now anticipating the presentation of the test trials.
If the “criterion re-check” option is selected the program will continue to the test trials (i.e., indicated by hand-clapping) only if the average of the post-habituation or lag trials are below the habituation criterion. If, however, the average of the post-habituation or lag trials is not below the habituation criterion the computer will signal a return to the habituation trials with a single tone followed by an explosion type sound. The program then returns to the habituation sequence, excluding baseline trials – but including the post-habituation trials - until the average of the post-habituation trials is below the habituation criterion.
Following the post-habituation or lag trials the program then records the number of test trials and the final control trial.
During the experiment, the times recorded by the primary observer and secondary observer will be displayed in the corresponding columns.
At the completion of the experiment, the program will display “End of all trials” and the “View Report” button will be enabled, and the projector can click on that button to open the report in Microsoft Excel.
The primary observer will press the “X” or blue button to start the trial and then will press and hold
down the “A” or green button while the infant is looking and lets go of the “A” button while the
infant is looking away from the event. Once the infant looks away for the user-defined look-away
criterion, the program ends the trial and controller will vibrate to let the primary observer know
the trial has ended and a new trial will be forthcoming. On subsequent trials the primary observer
presses the “X” button to start the trial and presses and holds the “A” button while the infant is
looking toward the event.
The secondary observer does not press the “X” button to start recording. Secondary observer only presses the “A” button while the infant is looking at the screen and lets go of the “A” button when the infant is looking away from the event. The secondary observer cannot initiate a trial.
Preferential Looking or Intermodal Matching
In these experiments, two different stimuli are displayed on adjacent screens for a predetermined number of trials – where each trial occurs for a specified number of seconds. This program allows users to examine infants’ visual preferences – or intersensory or intermodal matching.
After entering the participant information, defining the number of trials and trial lengths, and clicking “Begin Trial,” the software is now “running” and ready for event recording. The program will signal to end a trial with a single beep after the user defined trial time as elapsed. The program will wait 500 ms after the beep before commencing the next trial. The program will continue to run the specified number of trials until they have been completed. A trial only commences when the primary observer presses the “A” button. If the, however, the experiment must end before all trials are completed – the data for those trials that were completed are recorded and stored. After the user-defined number of trials has elapsed, the program will display “End of All Trials,” indicating the end of the experiment and will display the summary report.
The controller for the primary observer will vibrate once the “Begin Trial” button has been clicked indicating
that the experiment has commenced.
The primary observer presses the “A” or green button to start trial and presses the top left and top right buttons to indicate left and right looks. NOTE: The left button is pressed when the infant looks to the right, and the right button is pressed when the infant looks to the their left. This is done for convenience as the observer and infant often face each other separated by a partition. This feature eliminates the need for inverting or reversing the looking times.
The secondary observer does not need to press the “A” button to start a trial, but does hold the top left and top right buttons to indicate left and right looks. When the primary observer presses the “A” button to start a trial it causes the secondary observers controller to vibrate indicating they can now record the infant’s looking behavior.
- Windows Xp or Windows 7 (has not been tested on Windows 8 or Windows Vista)
- Microsoft Office 2007 Suite or above (must have Excel installed)
- 2 Xbox Controllers