PERFORMANCE IMPROVEMENTS IN UFOV \u27BRAIN TRAINING\u27 STUDIES ARE CONFOUNDED BY STIMULUS LEARNING

Computerized brain training is a multi-billion-dollar industry that makes many claims about how it is a vital tool to support optimal brain function. Researchers often use the brain as muscle metaphor to suggest that cognitive exertion strengthens the brain in the same way that physical exertion strengthens the body. The most striking findings in the field have involved transfer of training from the Useful Field of View (UFOV), sometimes categorized as speed of processing training, to subsequent tasks. Yet apart from vague appeals to neuroplasticity, no plausible mechanism of transfer has emerged. UFOV training involves an adaptive dual task to identify one stimulus and locate another. Researchers using classic visual search paradigms have long known that if the target and distractor stimuli are consistent, then stimulus learning can occur, and the UFOV is one such paradigm. We compared UFOV groups trained with similar consistently mapped (CM) stimuli, to those with changing, varied mapped (VM) stimuli and distractors, and so isolated the component of stimulus learning. These groups were then transferred to new stimuli, to show the effects of loss of the familiar stimulus advantage. Transfer to new CM stimuli following extensive practice was associated with a large performance cost for the CM-trained group (d = -1.31, t = -7.91, pbonf \u3c 0.001); smaller changes in performance were noted for VM trained participants transferred to new VM stimuli (d = -0.86, t = -4.93, pbonf \u3c 0.001). Training improvements may be driven by stimulus familiarity rather than any change in latent constructs like processing speed. Claims that improving UFOV training increases latent constructs such as processing speed or expanding an attentional field are overstated