Visual Working Memory Task Results and Discussion

Supplementary Material

There was a significant difference between the target rate in the OSM (69.6%) and VWM

(86.5%) tasks, (t(28) = -5.98, p < .001, d = -1.11), indicating that object-substitution masking was effective in reducing the threshold of awareness.

For the VWM task, a non-directional paired-samples t-test was conducted for each parameter between each memory-matching condition (matching and non-matching; see Figure

S1). There was a significant main effect of memory matching condition on guess rate, [t(28) =

2.30, p = .029, d = 0.427], non-target error rate, [t(28) = -2.455, p = .021, d = -0.456], and standard deviation, [t(28) = -2.213, p = .035, d = -0.411]. Participants made more guesses in the matching condition (M = .115, SD = .126), than in the non-matching condition (M = .092, SD = .

105). They made more non-target errors in the non-matching condition (M = .046, SD = .065) than in the matching condition (M = .018, SD = .030). Finally, participants were more precise in the matching condition (M = 15.27, SD = 3.12) than in the non-matching condition (M = 16.71

SD = 4.03). Target response rate did not differ significantly between the two conditions, t(28) = 0.683, p = .500, d = 0.127.

a b 1 20 * Match ) 18 0.9 s e s e e 0.8 r 16 s Non-Match g n e

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0.1 S 2 0 0 Guess NTE Target Match Non-Match Response Parameter Memory-Matching Condition Figure S1. (a) Response proportions and (b) SD for each memory matching condition in the VWM task. Within-subjects error bars represent ± 95% CI, * p < .05.

In the memory task, the significant difference in non-target error rate between the matching and non-matching conditions suggests that the masked perceptual target may have been interfering with memory performance on a small number of trials (i.e., reporting the perceptual target when the VWM item was not successfully remembered). This difference is not surprising, as distractors presented during the delay period of working memory tasks have been shown to affect performance (McNab & Dolan, 2014). However, this effect was restricted to a small proportion of trials (~5%). Moreover, participants with NTEs that exceeded 3 SDs above the mean in any of the conditions were excluded from all analyses (N = 5). Importantly, the change in guess rate without a change in target rate suggests that the increased non-target errors did not affect the proportion of trials on which the participants correctly recalled the target item, but instead only occurred on those trials in which the participants may have otherwise reported a guess response.

The significant increase in precision (decrease in SD) in memory-matching trials is also perhaps not surprising, as previous studies have shown that even recalling a target item from memory multiple times can lead to an increase in precision (LaRocque, Eichenbaum, Starrett,

Rose, Emrich & Postle, 2015). Thus, being exposed to the target in both the memory and perceptual phases of the task likely led to an increase in precision. However this does not appear to reflect a response bias on behalf of the participants, as there was no significant change in the proportion of trials in which the participants correctly reported the target.

References

LaRocque, J. J., Eichenbaum, A. S., Starrett, M. J., Rose, N. S., Emrich, S. M., & Postle, B. R.

(2015). The short-and long-term fates of memory items retained outside the focus of

attention. Memory & cognition, 43(3), 453-468.

McNab, F., & Dolan, R. J. (2014). Dissociating distractor-filtering at encoding and during

maintenance. Journal of Experimental Psychology: Human Perception and Performance,

40(3), 960.