Programmer/web developer for psychology project

We are looking to hire a web developer for the following project. We need help in designing a dot-probe task ([login to view URL]). This is an example of a dot probe task: [login to view URL] The program will be similar to the one above but with the following differences/additions: - This task is a program consisting of a number of trials where a pair of stimuli (1 threatening, 1 neutral) are presented on a screen for a set period of time, and the user then has to tell the program on which side of the screen either the threatening or neutral stimuli appeared. There will be a set of stimuli and the program will randomly display different stimuli combinations which will change with every new trial. - The program should be designed to be able to present either pairs of words or pairs of images. - The set from which the stimuli pairs are pulled, and various other parameters such as speed and number of trials, should be easy for our staff to modify on our own without additional assistance from the programmer once this job assignment has been completed. - The dot probe task must be accessible online. - We will need to collect and store information about user input such as reaction time and accuracy. - Participants will complete this task once a day for 8 days. Ideally, the program would be able to randomize participants to one of two versions of the dot probe (each with slightly different parameters) and keep track of the participant ID, which group the participants were assigned to, and how many times they have already completed the task, as they move through the study. - The ability to connect participant IDs to their IDs on [login to view URL] to complete follow-up measures would be a plus.