Semantic and subword priming during binocular suppression

Abstract

In general, stimuli that are familiar and recognizable have an advantage of predominance during binocular rivalry. Recent research has demonstrated that familiar and recognizable stimuli such as upright faces and words in a native language could break interocular suppression faster than their matched controls. In this study, a visible word prime was presented binocularly then replaced by a high-contrast dynamic noise pattern presented to one eye and either a semantically related or unrelated word was introduced to the other eye. We measured how long it took for target words to break from suppression. To investigate word-parts priming, a second experiment also included word pairs that had overlapping subword fragments. Results from both experiments consistently show that semantically related words and words that shared subword fragments were faster to gain dominance compared to unrelated words, suggesting that words, even when interocularly suppressed and invisible, can benefit from semantic and subword priming.

Fig. 1

Schematic representation of the experimental paradigms. In the experimental condition (a), the prime word was presented for 2 s to both eyes. The target word (related or unrelated to the prime) was then gradually introduced to one eye and competed with a dynamic noise pattern presented to the other eye. The contrast of the target word was linearly ramped up from 0% to 100% over 1 s, and then remained constant until the observer made a response to indicate where relative to fixation (above or below) the target word appeared. In the control condition (b), the prime word was seen by both eyes for 2 s, and then the target word was blended into the noise background with contrast gradually increased (at a slower rate than in the experimental condition). Participants viewed the words binocularly and responded to the appearance of the target word as soon as they detected it either above or below fixation.

Fig. 2

Suppression time results from Experiment 1 and Experiment 2. The left side of the figure shows the average suppression times of semantically related and unrelated words in Experiment 1, and the right side shows the average suppression times of semantically primed words, subword primed words, as well as unrelated words in Experiment 2. Results from the two experiments showed significant semantic and subword priming effects under binocular suppression. ^*, p < .05; ^**, p < .01; n.s., no significance.

Fig. 3

Detection times for the non-rivalry control conditions (Experiment 3). In the experiment, the target word was presented binocularly and was blended into the noise background. There was no significant difference in detection times between the semantically related and unrelated word pairs for the two conditions. Left: shorter ramping time (a time course of 10 s to reach full contrast); Right: longer ramping time (a time course of 20 s to reach full contrast).