Summary diagram of the observed effects of strong MPEs in contrast to weak MPEs (solid lines in orange) and their effects at the trial level (dashed lines in orange).

Associative memory task design and memory behavior.

(a) Study phase task design. (b) Match/mismatch test phase task design. (c) Behavior in the match/mismatch retrieval task: d’ (left) and RTs (right) in dark teal for strong pairings and light teal for weak pairings. Frontal theta power (d), posterior alpha power (e), and pupil diameter (f) for strong (top) and weak (bottom) trials, color coded by match/mismatch condition (blue/orange). Subplots on the left depict mean and standard error of z-scored power/size across participants. Mean and standard error of participant-level betas for the effects of Mismatch, Strength, and Mismatch x Strength are depicted on the right. Horizontal lines below beta plots indicate significant clusters (permutation-corrected; all p<0.001).

Hit and false alarm rates

Pupil components sensitive to MPEs and their relationships with frontal theta and posterior alpha.

(a) Pupil components extracted by temporal PCA with bootstrapped 95% confidence intervals. PC scores for PC3 (b) and PC4 (c) as a function of match/mismatch conditions and memory strength (middle) and as related to reaction times (right). (d) Schematic of observed relationships among frontal theta, posterior alpha, PC3 scores, and PC4 scores. Time windows over which frontal theta and posterior alpha were averaged in trial-level analyses are underlined in yellow and correspond to those displayed in Fig. 2. (e) Relationship between frontal theta cognitive control signals and attention signals in posterior alpha. (f and g) Relationships between frontal theta cognitive control signals and PC3 (f) and PC4 (g). (h and i) Relationships between posterior alpha MPE-related attention signals and PC3 (h) and PC4 (i). Quartiles and quintiles are shown for visualization purposes only; data were analyzed using continuous measures as described in the Methods.

PC3 scores as a function of Mismatch and Strength

PC3 scores as a function of Mismatch, Strength, and Memory Accuracy

PC3 scores and RTs

PC4 scores as a function of Mismatch and Strength

PC4 scores as a function of Mismatch, Strength, and Memory Accuracy

PC4 scores and RTs

Dynamics between cognitive control, attention, and arousal in response to strong MPEs.

(a) Schematic of hypothesized relationships: stronger MPEs increase attention/arousal and this effect was hypothesized to be partially explained by an increase in cognitive control. (b) A multivariate mediation analysis testing the model diagrammed in (a) with pupil PC3 as the measure of attention/arousal. (c) A multivariate mediation analysis testing the model diagrammed in (a) with posterior alpha as the measure of attention. (d) Cross-correlation analysis showing the correlation between frontal theta time series and lagged posterior alpha time series on strong MPE trials. (e) An alternative model: changes in cognitive control following MPEs may be explained by changes in attention, as assayed by posterior alpha. (f) A multivariate mediation analysis testing the model in (e), examining whether posterior alpha mediates the relationship between RTs and frontal theta. Paths in mediation models are labeled with the mean of the posterior and 95% credible intervals. Gray histograms accompanying mediation model diagrams depict the posterior distribution for the indirect effect; black points indicate posterior medians and horizontal lines indicate the 66% and 95% highest density intervals.

MPE-driven increases in frontal theta by strong MPEs enhance learning.

(a) Behavioral performance in the surprise recognition task in Experiment 1 and Experiment 2. (b) Higher frontal theta during strong MPEs is associated with a higher likelihood of subsequently remembering the probe ∼5 min later (Experiment 1). Points indicate binned values for visualization; smoothed lines reflect model estimates. (c) Trial-level regression models for frontal theta modeling the effects of Subsequent Memory, Strength, and Subsequent Memory × Strength interactions in Experiment 1.