Temporal Order Judgment

Background

Temporal Order Judgment (TOJ) tasks measure the ability to perceive the temporal order of events. Hirsh & Sherrick (1961) showed that humans need ~20–50 ms separation to reliably judge which of two stimuli came first.

Point of Subjective Simultaneity

The Point of Subjective Simultaneity (PSS) is the SOA at which the observer responds “left first” and “right first” equally often. Ideally PSS = 0, but biases can shift it.

Just Noticeable Difference

The Just Noticeable Difference (JND) for temporal order is estimated from the psychometric function slope — a smaller JND means finer temporal resolution.

This Experiment

This experiment uses visual-only stimuli (two flashes) to avoid cross-modal timing complications.

References

Hirsh, I.J. & Sherrick, C.E. (1961). Perceived order in different sense modalities. Journal of Experimental Psychology, 62, 423–432.
Sternberg, S. & Knoll, R.L. (1973). The perception of temporal order: Fundamental issues and a general model. In S. Kornblum (Ed.), Attention and Performance IV.

Two squares will flash briefly on the left and right sides of the screen, one slightly before the other.

Judge which side flashed FIRST.

Press F if the LEFT side flashed first, J if the RIGHT side flashed first.

Sometimes the timing difference is very small — respond with your best judgment.

There are 72 trials total (~5 minutes).

Temporal Order Judgment

Your Results