Cross-modal plasticity in the deaf enhances processing of masked stimuli in the visual modality

Abstract

Compensatory changes as a result of auditory deprivation in the deaf lead to higher visual processing skills. In two experiments, we explored if such brain plasticity in the deaf modulates processing of masked stimuli in the visual modality. Deaf and normal-hearing participants responded to targets either voluntarily or by instruction. Masked primes related to the response were presented briefly before the targets at the center and the periphery. In Experiment 1, targets appeared only at the foveal region whereas, in Experiment 2, they appeared both at the fovea and the periphery. The deaf showed higher sensitivity to masked primes in both the experiments. They chose the primed response more often and also were faster during congruent responses compared to the normal hearing. These results suggest that neuroplasticity in the deaf modulates how they perceive and use information with reduced visibility for action selection and execution.

Reward Influences Masked Free-Choice Priming

“…The control experiment replicated free-choice and forced-choice priming effects observed in several previous studies (eg., Kiesel et al, 2006;Prasad et al, 2017). The masked primes lead to higher proportion of congruent choices (on free-choice trials) and faster response times on congruent trials (on free-and forced-choice trials).…”

“…In this study, our interest was to examine whether free-choice priming is susceptible to influences by reward-learning. We adapted the masked priming design from Prasad et al (2017) where the numbers "1" and "2" were presented as primes. The same numbers were presented as targets on forced-choice trials where participants pressed either "A" or "L" depending on the target.…”

“…Throughout the trial, stimuli were presented in the center of the screen (Figure 1). The design was adapted from Prasad et al (2017). Each trial in the reward session began with a fixation screen for 1,000 ms followed by a prime (the digit "1" or "2" in Times New Roman, pt.…”

“…But more recently, these views have changed and paved the way for more refined theories which allow for executive control over unconscious processing (Kiefer, 2012;Ansorge et al, 2014). This is demonstrated specifically by studies that show that current task-goals (Ansorge and Neumann, 2005;Kiefer and Martens, 2010;Schmidt and Schmidt, 2010), different forms of attentional selection (Naccache et al, 2002;Ansorge et al, 2009Ansorge et al, , 2010 and individual differences in attention and perception (Pohl et al, 2014;Prasad et al, 2017) modulate the extent of priming effects when the primes remain almost invisible. While the role of attention in masked priming has been studied using traditionally defined forms of exogenous and endogenous attention (Sumner et al, 2006;Ansorge et al, 2009Ansorge et al, , 2010, the role of newer forms of attentional control such as reward has not been examined.…”

“…In a free-choice variant of this paradigm pioneered by Schlaghecken and Eimer (2004), a neutral symbol not associated with any response (eg., a double-headed arrow) is presented as the target on some trials (followed by the primes) and the participants are asked to choose either of the responses (left or right key) on their own. In such a task scenario, participants tend to choose the response associated with the prime presented on that trial, even when they are supposed to be choosing "freely" (Kiesel et al, 2006;O'Connor and Neill, 2011;Ocampo, 2015;Prasad et al, 2017). These free-choice priming effects suggest that the primes trigger the associated response making the participants biased toward the primed-responses even when participants freely choose a response.…”