quick data check

Sample size: N = 45.

Sanity check for behavioral performance (across low, high, and very high load):

  • min number of hits (could be 0) : 96
  • max number of hits (could be 288) : 288
  • min number of false alarms (could be 0) : 0
  • max number of false alarms (could be 892) : 144

Note that hits are correct responses between 200 and 1000 ms after target onset (defined in ASSR_study2_process_beh.R)
False alarms are responses at other times: 1152 + 7*4 (initial trials) - 288 (trial after a target) = 892.

hit rates

Simple hit rates (%) were as follows:

  • low load = 93.4
  • high load = 70.01
  • very high load = 78.16

table

Conditions are no, lo, hi, vh (very high)
Differences: loMhi refers to lo minus hi
dpr: signal detection index d´
RTms: reaction time to hits (in ms)
pcu: partial credit unit score of working memory capacity
vP3: visual P3 to targets (vs. nontargets)
LL and UL refer to the 95% confidence interval (from two-tailed t tests)

Variable Mean LL UL N
dprlo 4.249 3.951 4.546 45
dprhi 2.177 1.982 2.372 45
dprvh 2.707 2.517 2.896 45
dprloMhi 2.072 1.890 2.253 45
dprloMvh 1.542 1.343 1.741 45
dprhiMvh -0.530 -0.638 -0.422 45
meanRTmslo 381.114 369.712 392.517 45
meanRTmshi 500.728 487.701 513.755 45
meanRTmsvh 460.841 448.851 472.832 45
meanRTloMhi -119.614 -129.930 -109.298 45
meanRTloMvh -79.727 -87.900 -71.554 45
meanRThiMvh 39.887 31.211 48.563 45
pcu 0.772 0.728 0.816 40
vP3lo 6.912 5.225 8.599 42
vP3hi 2.108 1.097 3.118 42
vP3vh 3.862 2.563 5.161 42
vP3loMhi 4.804 3.524 6.084 42
vP3loMvh 3.050 2.089 4.010 42
vP3hiMvh -1.754 -2.475 -1.034 42

plot task performance

Ddpr$Condition = c("low", "high", "very high")
DRT$Condition = c("low", "high", "very high")
Ddpr$Condition = factor(Ddpr$Condition, levels=c("low", "high", "very high"))
DRT$Condition = factor(DRT$Condition, levels=c("low", "high", "very high"))
fig_dpr = ggplot(Ddpr, aes(x=Condition, y=Mean, fill=Condition)) + 
  geom_bar(stat="identity"
          ,color="black" # add black border to each bar
          ,position=position_dodge()) + # separare bars
  theme_bw() + # get rid of background
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank()) + #no grid lines
  geom_errorbar(position=position_dodge(.9), width=.25, 
                aes(ymin=LL, ymax=UL)) + 
  scale_fill_manual(
        values = c("#999999", "#CCCCCC", "#FFFFFF"),
        name = "Condition",
        labels = c("low","high","very high")) +
  labs(title = paste0("d´(N = ", nrow(D),")")) +
    theme(plot.title = element_text(hjust = 0.5)) +
  labs(x = "Condition") +
  labs(y = "Sensitivity (d´)") +
  labs(legend = "Condition")
fig_RT = ggplot(DRT, aes(x=Condition, y=Mean, fill=Condition)) + 
  geom_bar(stat="identity"
          ,color="black" # add black border to each bar
          ,position=position_dodge()) + # separare bars
  theme_bw() + # get rid of background
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank()) + #no grid lines
  geom_errorbar(position=position_dodge(.9), width=.25, 
                aes(ymin=LL, ymax=UL)) + 
  scale_fill_manual(
        values = c("#999999", "#CCCCCC", "#FFFFFF"),
        name = "Condition",
        labels = c("low","high","very high")) +
  labs(title = paste0("RT (N = ", nrow(D),")")) +
    theme(plot.title = element_text(hjust = 0.5)) +
  labs(x = "Condition") +
  labs(y = "Reaction time (ms)") +
  labs(legend = "Condition")
grid.arrange(fig_dpr, fig_RT, ncol = 2)

NASA-TLX ratings

mental

Mental Mean LL UL N
no 20.922 14.969 26.876 45
lo 34.606 28.841 40.370 45
hi 51.678 45.003 58.352 45
vh 46.367 40.165 52.568 45
noMlo -13.683 -18.609 -8.758 45
noMhi -30.756 -37.870 -23.641 45
noMvh -25.444 -31.714 -19.175 45
loMhi -17.072 -22.468 -11.677 45
loMvh -11.761 -16.116 -7.407 45
hiMvh 5.311 1.957 8.665 45

physical

Physical Mean LL UL N
no 17.017 11.599 22.435 45
lo 22.767 16.608 28.925 45
hi 28.444 20.947 35.942 45
vh 26.539 19.223 33.855 45
noMlo -5.750 -8.409 -3.091 45
noMhi -11.428 -16.198 -6.657 45
noMvh -9.522 -14.005 -5.040 45
loMhi -5.678 -9.191 -2.165 45
loMvh -3.772 -6.997 -0.547 45
hiMvh 1.906 -0.517 4.328 45

temporal

Temporal Mean LL UL N
no 22.417 16.423 28.411 45
lo 37.222 31.753 42.692 45
hi 52.206 45.036 59.375 45
vh 46.239 39.664 52.814 45
noMlo -14.806 -19.388 -10.223 45
noMhi -29.789 -36.854 -22.724 45
noMvh -23.822 -29.969 -17.676 45
loMhi -14.983 -19.364 -10.602 45
loMvh -9.017 -12.388 -5.645 45
hiMvh 5.967 3.247 8.686 45

performance

Performance Mean LL UL N
no 69.422 61.773 77.072 45
lo 61.094 54.059 68.130 45
hi 36.006 29.508 42.503 45
vh 44.772 37.847 51.698 45
noMlo 8.328 1.480 15.175 45
noMhi 33.417 25.166 41.667 45
noMvh 24.650 17.376 31.924 45
loMhi 25.089 20.512 29.666 45
loMvh 16.322 12.710 19.934 45
hiMvh -8.767 -11.935 -5.598 45

effort

Effort Mean LL UL N
no 21.028 15.808 26.248 45
lo 38.539 33.064 44.013 45
hi 51.133 44.820 57.447 45
vh 48.306 42.149 54.463 45
noMlo -17.511 -22.687 -12.335 45
noMhi -30.106 -37.123 -23.088 45
noMvh -27.278 -33.507 -21.049 45
loMhi -12.594 -17.061 -8.128 45
loMvh -9.767 -13.139 -6.394 45
hiMvh 2.828 -0.370 6.026 45

frustration

Frustration Mean LL UL N
no 17.300 12.054 22.546 45
lo 22.678 15.929 29.427 45
hi 34.767 26.629 42.904 45
vh 29.722 21.961 37.484 45
noMlo -5.378 -9.127 -1.629 45
noMhi -17.467 -23.720 -11.213 45
noMvh -12.422 -17.634 -7.210 45
loMhi -12.089 -16.329 -7.849 45
loMvh -7.044 -9.857 -4.232 45
hiMvh 5.044 2.116 7.973 45

visual P3

The sample lacks three subjects for visual P3 because of equipment failure: The visual onsets were not recorded.

Variable Mean LL UL N
vP3lo 6.912 5.225 8.599 42
vP3hi 2.108 1.097 3.118 42
vP3vh 3.862 2.563 5.161 42
vP3loMhi 4.804 3.524 6.084 42
vP3loMvh 3.050 2.089 4.010 42
vP3hiMvh -1.754 -2.475 -1.034 42

Bayes factors for load

Bayes factor (BF) analyses from Bayesian one-sample t tests of difference scores (e.g., no minus high load). Although the focus is on signal-minus-noise (SmN), the output includes SNR (signal-to-noise ratio) and S (signal).

The BFs were computed with Aladins R script.
https://doi.org/10.17045/sthlmuni.4981154.v3

The BF01 uses uniform H1 models with different lower limits (LL) and upper limits (UL).
BF01 is the evidence for the null hypothesis relative to the alternative hypothesis.
If BF01 > 3, this is evidence for the null.
If BF01 < 1/3, this is evidence against the null.

amplitude SmN

Descriptives
Variable Mean LL UL N
no 0.243 0.210 0.275 45
lo 0.244 0.212 0.275 45
hi 0.243 0.211 0.275 45
vh 0.242 0.210 0.274 45
noMlo -0.001 -0.012 0.010 45
noMhi 0.000 -0.013 0.012 45
noMvh 0.000 -0.013 0.013 45
loMhi 0.000 -0.012 0.013 45
loMvh 0.001 -0.012 0.014 45
hiMvh 0.001 -0.011 0.012 45
BF results
BF01
Variable Mean [-1, +1] [0, +1] [0, +0.2]
noMlo -0.001 144.1 152.2 33.5
noMhi 0.000 127.0 125.7 27.2
noMvh 0.000 123.6 113.6 24.4
loMhi 0.000 123.8 110.8 23.7
loMvh 0.001 123.5 103.3 22.0
hiMvh 0.001 142.6 122.7 26.4

amplitude SNR

Descriptives
Variable Mean LL UL N
no 6.609 5.643 7.575 45
lo 6.742 5.723 7.761 45
hi 6.746 5.766 7.727 45
vh 6.805 5.749 7.861 45
noMlo -0.133 -0.559 0.292 45
noMhi -0.138 -0.503 0.227 45
noMvh -0.196 -0.548 0.156 45
loMhi -0.004 -0.399 0.391 45
loMvh -0.062 -0.465 0.340 45
hiMvh -0.058 -0.376 0.259 45
BF results
BF01
Variable Mean [-1, +1] [0, +1] [0, +0.2]
noMlo -0.134 3.1 5.8 1.5
noMhi -0.138 3.3 7.2 1.7
noMvh -0.196 2.4 9.0 2.0
loMhi -0.004 4.0 4.1 1.2
loMvh -0.062 3.8 5.0 1.3
hiMvh -0.058 4.7 6.6 1.6

amplitude S

Descriptives
Variable Mean LL UL N
no 0.297 0.265 0.329 45
lo 0.295 0.263 0.326 45
hi 0.294 0.263 0.325 45
vh 0.293 0.261 0.324 45
noMlo 0.003 -0.007 0.012 45
noMhi 0.003 -0.007 0.014 45
noMvh 0.005 -0.006 0.015 45
loMhi 0.001 -0.012 0.013 45
loMvh 0.002 -0.010 0.014 45
hiMvh 0.002 -0.009 0.012 45
BF results
BF01
Variable Mean [-1, +1] [0, +1] [0, +0.2]
noMlo 0.003 143.1 95.7 20.3
noMhi 0.003 126.1 83.2 17.5
noMvh 0.005 100.8 60.0 12.4
loMhi 0.000 129.0 114.2 24.5
loMvh 0.002 128.7 96.2 20.4
hiMvh 0.002 145.9 112.0 24.0

ITC SmN

Descriptives
Variable Mean LL UL N
no 0.368 0.323 0.413 45
lo 0.373 0.327 0.419 45
hi 0.364 0.317 0.411 45
vh 0.361 0.315 0.408 45
noMlo -0.004 -0.021 0.012 45
noMhi 0.005 -0.015 0.024 45
noMvh 0.007 -0.008 0.022 45
loMhi 0.009 -0.009 0.027 45
loMvh 0.011 -0.006 0.028 45
hiMvh 0.002 -0.012 0.017 45
BF results
BF01
Variable Mean [-1, +1] [0, +1] [0, +0.2]
noMlo -0.004 84.5 135.0 29.4
noMhi 0.004 73.5 52.7 10.9
noMvh 0.007 68.4 40.8 8.3
loMhi 0.009 53.4 31.5 6.4
loMvh 0.011 37.5 20.4 4.1
hiMvh 0.002 104.5 79.2 16.6

ITC SNR

Descriptives
Variable Mean LL UL N
no 5.676 5.101 6.251 45
lo 5.632 5.055 6.209 45
hi 5.661 5.063 6.260 45
vh 5.605 5.003 6.208 45
noMlo 0.043 -0.175 0.262 45
noMhi 0.014 -0.246 0.274 45
noMvh 0.070 -0.151 0.292 45
loMhi -0.029 -0.294 0.236 45
loMvh 0.027 -0.199 0.253 45
hiMvh 0.056 -0.162 0.275 45
BF results
BF01
Variable Mean [-1, +1] [0, +1] [0, +0.2]
noMlo 0.043 6.8 5.1 1.2
noMhi 0.014 6.1 5.6 1.3
noMvh 0.070 5.9 4.0 1.0
loMhi -0.029 5.9 7.1 1.6
loMvh 0.027 6.9 5.8 1.3
hiMvh 0.056 6.4 4.6 1.1

ITC S

Descriptives
Variable Mean LL UL N
no 0.448 0.403 0.493 45
lo 0.454 0.408 0.500 45
hi 0.443 0.396 0.490 45
vh 0.441 0.395 0.488 45
noMlo -0.006 -0.022 0.011 45
noMhi 0.005 -0.015 0.025 45
noMvh 0.007 -0.008 0.022 45
loMhi 0.011 -0.007 0.029 45
loMvh 0.013 -0.004 0.030 45
hiMvh 0.002 -0.012 0.016 45
BF results
BF01
Variable Mean [-1, +1] [0, +1] [0, +0.2]
noMlo -0.006 75.8 141.2 30.9
noMhi 0.005 69.8 48.4 10.0
noMvh 0.007 67.0 39.7 8.1
loMhi 0.011 42.3 23.7 4.8
loMvh 0.013 30.5 16.3 3.3
hiMvh 0.002 108.2 86.0 18.1

correlations with behavior

Data exploration (fishing) suggests that across subjects, an RT increase from low to high load correlated with a decrease in visual P3 (r = -0.366). Suggests also that an increase in mental NASA rating from low to high load correlated with a d´ decrease (r = -0.335).

table

dprloMhi meanRTloMhi MentalloMhi vP3loMhi AmploMhi ItcloMhi
dprloMhi 1.000 -0.147 -0.335 0.235 0.029 -0.005
meanRTloMhi -0.147 1.000 0.117 -0.367 -0.256 -0.114
MentalloMhi -0.335 0.117 1.000 -0.159 -0.064 -0.037
vP3loMhi 0.235 -0.367 -0.159 1.000 0.107 0.180
AmploMhi 0.029 -0.256 -0.064 0.107 1.000 0.743
ItcloMhi -0.005 -0.114 -0.037 0.180 0.743 1.000

correlations with wm capacity

Working memory capacity was the wmc.pcu score.

Any difference scores refer to signal minus noise (SmN) measures.

The sample is smaller: The first three subjects were excluded because they performed the task at the end (rather than at the beginning), and two more subjects were excluded because of equipment failure.

LL and UL refer to the 95% confidence interval of the correlation (from one-tailed t tests).

The BFs were computed with the BayesFactor package in R.
https://richarddmorey.github.io/BayesFactor/

The BF01 used a flat prior (beta width = 1). Note that this prior is the default in JASP, which is a stand-alone program to conduct Bayesian analyses.
https://jasp-stats.org/

Cred_LL and Cred_UL refer to the 95% credible interval of the correlation (from BayesFactor).

table

Variable Correlation LL UL BF01 Cred_LL Cred_UL N
Amp_no 0.042 -0.273 0.349 4.915 -0.265 0.334 40
Amp_lo 0.088 -0.229 0.389 4.405 -0.223 0.379 40
Amp_hi 0.041 -0.274 0.348 4.927 -0.264 0.336 40
Amp_vh 0.025 -0.289 0.334 5.020 -0.281 0.327 40
Amp_noMlo -0.127 -0.422 0.192 3.780 -0.407 0.187 40
Amp_noMhi 0.006 -0.306 0.317 5.074 -0.297 0.303 40
Amp_noMvh 0.039 -0.276 0.347 4.938 -0.265 0.330 40
Amp_loMhi 0.116 -0.203 0.413 3.969 -0.191 0.397 40
Amp_loMvh 0.149 -0.170 0.440 3.377 -0.170 0.422 40
Amp_hiMvh 0.040 -0.275 0.347 4.933 -0.266 0.331 40
Itc_no 0.054 -0.262 0.360 4.815 -0.261 0.353 40
Itc_lo 0.077 -0.240 0.380 4.556 -0.228 0.368 40
Itc_hi 0.021 -0.293 0.330 5.039 -0.284 0.318 40
Itc_vh 0.045 -0.271 0.351 4.898 -0.263 0.333 40
Itc_noMlo -0.071 -0.374 0.246 4.630 -0.363 0.230 40
Itc_noMhi 0.079 -0.238 0.381 4.533 -0.238 0.360 40
Itc_noMvh 0.023 -0.290 0.332 5.029 -0.279 0.316 40
Itc_loMhi 0.145 -0.175 0.436 3.463 -0.175 0.418 40
Itc_loMvh 0.085 -0.232 0.387 4.449 -0.225 0.379 40
Itc_hiMvh -0.079 -0.381 0.238 4.528 -0.368 0.234 40

effect of block

Explore factorial analyses (load x block).

  • ASSRs: no vs high load
  • visual P3: low vs high load

by measure

amplitude SmN

## =====================================================================
##                         Amplitude_SmN
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.2514559 0.2155149 0.2873969
##    no     2 45 0.2431811 0.2045487 0.2818135
##    no     3 45 0.2559860 0.2217547 0.2902174
##    no     4 45 0.2201614 0.1874002 0.2529226
##  high     1 45 0.2468285 0.2117379 0.2819192
##  high     2 45 0.2560215 0.2243014 0.2877415
##  high     3 45 0.2460925 0.2099493 0.2822356
##  high     4 45 0.2235309 0.1904516 0.2566101
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 21.2414      1   3.8643     44 241.8630 < 2.2e-16 ***
## load         0.0000      1   0.1541     44   0.0046 0.9463522    
## block        0.0534      3   0.3387    132   6.9377 0.0002261 ***
## load:block   0.0066      3   0.3555    132   0.8209 0.4845334    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.67429 0.00483
## load:block        0.94568 0.79362
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])    
## block      0.79333  0.0007558 ***
## load:block 0.96256  0.4806937    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps   Pr(>F[HF])
## block      0.8417401 0.0005690922
## load:block 1.0373621 0.4845334175
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                      Value Df  test stat   approx F num Df den Df Pr(>F)
## load1 : block1 -0.00019868  1 1.2438e-05 0.00054726      1     44 0.9814
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 13.60731 ±2.05%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

amplitude SNR

## =====================================================================
##                         Amplitude_SNR
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N     Mean    CI_LL    CI_UL
##    no     1 45 7.026529 5.878655 8.174403
##    no     2 45 7.036133 5.860118 8.212148
##    no     3 45 6.556063 5.519877 7.592250
##    no     4 45 5.816517 4.902929 6.730104
##  high     1 45 7.101279 6.087925 8.114634
##  high     2 45 6.930762 5.881942 7.979582
##  high     3 45 6.868489 5.731600 8.005378
##  high     4 45 6.085284 4.950328 7.220240
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 16052.7      1   3563.7     44 198.1991 < 2.2e-16 ***
## load            1.7      1    129.9     44   0.5777    0.4513    
## block          69.5      3    361.6    132   8.4557 3.515e-05 ***
## load:block      2.5      3    486.5    132   0.2254    0.8786    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.90386 0.50466
## load:block        0.84125 0.19365
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])    
## block      0.93346  5.799e-05 ***
## load:block 0.89337      0.858    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps   Pr(>F[HF])
## block      1.0033800 3.514749e-05
## load:block 0.9568011 8.707257e-01
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                   Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 -0.15809  1 0.0052277  0.23123      1     44  0.633
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 25.68044 ±2.69%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

amplitude S

## =====================================================================
##                         Amplitude_S
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.3030946 0.2671156 0.3390736
##    no     2 45 0.2941862 0.2575843 0.3307881
##    no     3 45 0.3135706 0.2795390 0.3476022
##    no     4 45 0.2783396 0.2468592 0.3098199
##  high     1 45 0.2936031 0.2595675 0.3276387
##  high     2 45 0.3078343 0.2770129 0.3386558
##  high     3 45 0.2962455 0.2603443 0.3321467
##  high     4 45 0.2788185 0.2473201 0.3103168
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 31.4803      1   3.7578     44 368.6022 < 2.2e-16 ***
## load         0.0009      1   0.1078     44   0.3697  0.546280    
## block        0.0372      3   0.2926    132   5.5905  0.001219 ** 
## load:block   0.0121      3   0.3133    132   1.6952  0.171145    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.81724 0.12520
## load:block        0.98243 0.97967
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])   
## block      0.87475   0.002093 **
## load:block 0.98819   0.171805   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps  Pr(>F[HF])
## block      0.9352657 0.001610889
## load:block 1.0674201 0.171145153
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                     Value Df  test stat   approx F num Df den Df Pr(>F)
## load1 : block1 0.00016788  1 1.1574e-05 0.00050925      1     44 0.9821
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 3.652064 ±13.11%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

ITC SmN

## =====================================================================
##                         Intertrial_Coherence_SmN
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.3650258 0.3144738 0.4155778
##    no     2 45 0.3829952 0.3325454 0.4334449
##    no     3 45 0.3764730 0.3303361 0.4226099
##    no     4 45 0.3486003 0.3003355 0.3968651
##  high     1 45 0.3749499 0.3273693 0.4225306
##  high     2 45 0.3752265 0.3240165 0.4264366
##  high     3 45 0.3679060 0.3158521 0.4199600
##  high     4 45 0.3369472 0.2876637 0.3862307
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 48.228      1   7.8927     44 268.8630 < 2.2e-16 ***
## load         0.002      1   0.3698     44   0.2184  0.642576    
## block        0.069      3   0.6482    132   4.6769  0.003876 ** 
## load:block   0.006      3   0.6359    132   0.4459  0.720584    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.83195 0.16423
## load:block        0.84592 0.20993
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])   
## block      0.89046   0.005567 **
## load:block 0.90132   0.700478   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps  Pr(>F[HF])
## block      0.9534298 0.004519667
## load:block 0.9660190 0.713908294
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                   Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 0.010361  1  0.022342   1.0055      1     44 0.3215
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 22.53883 ±2.1%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

ITC SNR

## =====================================================================
##                         Intertrial_Coherence_SNR
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N     Mean    CI_LL    CI_UL
##    no     1 45 5.616130 4.936821 6.295440
##    no     2 45 5.860586 5.191262 6.529911
##    no     3 45 5.861011 5.260676 6.461346
##    no     4 45 5.365169 4.750441 5.979896
##  high     1 45 5.846516 5.241097 6.451935
##  high     2 45 5.715651 5.039596 6.391705
##  high     3 45 5.868372 5.150802 6.585941
##  high     4 45 5.215323 4.578267 5.852378
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df  F value  Pr(>F)    
## (Intercept) 11567.9      1  1278.26     44 398.1879 < 2e-16 ***
## load            0.0      1    65.84     44   0.0122 0.91245    
## block          18.0      3   140.56    132   5.6295 0.00116 ** 
## load:block      2.2      3   168.91    132   0.5614 0.64144    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.80305 0.09525
## load:block        0.95681 0.86467
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])   
## block      0.87759   0.001979 **
## load:block 0.97118   0.636426   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps  Pr(>F[HF])
## block      0.9385436 0.001516115
## load:block 1.0474625 0.641440300
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                  Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 0.15628  1  0.019326  0.86711      1     44 0.3568
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 17.92473 ±1.87%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

ITC S

## =====================================================================
##                         Intertrial_Coherence_S
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.4462053 0.3965190 0.4958917
##    no     2 45 0.4632179 0.4130473 0.5133884
##    no     3 45 0.4547615 0.4083251 0.5011980
##    no     4 45 0.4292198 0.3807013 0.4777384
##  high     1 45 0.4528388 0.4048025 0.5008751
##  high     2 45 0.4560185 0.4048860 0.5071510
##  high     3 45 0.4453270 0.3937112 0.4969428
##  high     4 45 0.4180863 0.3688029 0.4673696
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 71.516      1   7.8710     44 399.7894 < 2.2e-16 ***
## load         0.003      1   0.3816     44   0.2897  0.593146    
## block        0.064      3   0.6568    132   4.3006  0.006259 ** 
## load:block   0.004      3   0.6020    132   0.3242  0.807860    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.82732 0.15100
## load:block        0.84065 0.19162
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])   
## block      0.88718   0.008675 **
## load:block 0.89642   0.786000   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps Pr(>F[HF])
## block      0.9496345 0.00723897
## load:block 0.9603401 0.79985032
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                   Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 0.008781  1  0.017496  0.78355      1     44 0.3809
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 26.38811 ±3.47%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

visual P3

## =====================================================================
##                         Visual_P3
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N     Mean       CI_LL    CI_UL
##   low     1 42 7.526945  5.22281119 9.831078
##   low     2 42 6.905203  4.97479183 8.835615
##   low     3 42 6.929089  5.33363977 8.524537
##   low     4 42 6.285659  4.63110959 7.940208
##  high     1 42 1.218411 -0.07473078 2.511552
##  high     2 42 2.198978  0.95162162 3.446334
##  high     3 42 2.411057  1.23859668 3.583517
##  high     4 42 2.601892  1.47603053 3.727753
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df F value    Pr(>F)    
## (Intercept) 6833.2      1   5149.2     41 54.4084 4.876e-09 ***
## load        1938.7      1   1383.8     41 57.4430 2.539e-09 ***
## block          4.3      3   1116.6    123  0.1562   0.92553    
## load:block    75.8      3    874.3    123  3.5550   0.01641 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.68061 0.00924
## load:block        0.80846 0.13344
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])  
## block      0.79972     0.8899  
## load:block 0.89595     0.0204 *
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps Pr(>F[HF])
## block      0.8528708 0.90092668
## load:block 0.9647891 0.01766311
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                  Value Df test stat approx F num Df den Df   Pr(>F)   
## load1 : block1 -1.2748  1   0.22852   12.145      1     41 0.001187 **
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 2.459765 ±1.29%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

summary

Summary of interaction analyses:

  • Overall_interaction has 3 dfs.
  • Linear_interaction has 1 df and captures the interaction of load with the linear trend over blocks.
  • BF01_interaction is the BF for a model without the overall interaction versus a model with the overall interaction (prior: Cauchy r scale = 0.5).
  • BF01_error% estimates the error of the BF in percent. For example, if BF = 10 and the error is 10%, then the BF is estimated to vary between 9 and 11.
Variable Overall_Interaction_p Linear_Interaction_p BF01_Interaction BF01_error%
Amplitude_SmN 0.481 0.981 13.607 2.049
Amplitude_SNR 0.858 0.633 25.680 2.689
Amplitude_S 0.172 0.982 3.652 13.111
Intertrial_Coherence_SmN 0.700 0.321 22.539 2.100
Intertrial_Coherence_SNR 0.636 0.357 17.925 1.870
Intertrial_Coherence_S 0.786 0.381 26.388 3.465
Visual_P3 0.020 0.001 2.460 1.294

reliability

Reliability of EEG variables over blocks. Results show mean correlations between the four blocks.
Note that raw scores (i.e., no and high load) have decent reliability whereas the difference scores show low reliability. This is not necessarily a problem: If all subjects change similarly, any variability in the difference scores would reflect mainly measurement noise, and the difference scores would show a low correlations over blocks (i.e., low reliability). Because of their low reliability, the difference scores are a poor measure if the goal is to distinguish the order among individual subjects.

Variable no high noMhi
ampSNR 0.791 0.834 0.074
ampS 0.764 0.761 -0.041
ampSmN 0.812 0.839 0.008
itcSNR 0.817 0.840 0.163
itcS 0.748 0.769 0.037
itcSmN 0.822 0.840 0.192

effect of minute

Analysis of EEG data in 1-min blocks.
Compares no vs high load.

The data in each 3-min block were analyzed by minute (this was done during preprocessing in MNE-python). For each minute, mean amp (and itc) were computed and then averaged across the four blocks of load.
Note that the R output uses the term “block,” but this is meant to refer to “minute.”

by measure

amplitude SmN

## =====================================================================
##                         Amplitude_SmN
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.2673304 0.2276504 0.3070103
##    no     2 45 0.2598172 0.2211833 0.2984511
##    no     3 45 0.2497098 0.2107499 0.2886697
##  high     1 45 0.2541013 0.2142862 0.2939163
##  high     2 45 0.2624151 0.2273724 0.2974579
##  high     3 45 0.2491483 0.2101146 0.2881820
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df  F value Pr(>F)    
## (Intercept) 17.8453      1   3.8880     44 201.9542 <2e-16 ***
## load         0.0009      1   0.1009     44   0.4096 0.5255    
## block        0.0079      2   0.2244     88   1.5535 0.2172    
## load:block   0.0032      2   0.1359     88   1.0224 0.3640    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.82977  0.0181
## load:block        0.95715  0.3900
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])
## block      0.85453     0.2200
## load:block 0.95891     0.3615
## 
##               HF eps Pr(>F[HF])
## block      0.8856283  0.2195016
## load:block 1.0016340  0.3639655
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                     Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 -0.0063338  1  0.026833   1.2132      1     44 0.2767
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 7.586289 ±1.13%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

amplitude SNR

## =====================================================================
##                         Amplitude_SNR
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N     Mean    CI_LL    CI_UL
##    no     1 45 4.866360 4.164390 5.568330
##    no     2 45 4.721056 4.030760 5.411352
##    no     3 45 4.492041 3.798660 5.185421
##  high     1 45 4.751134 4.056132 5.446137
##  high     2 45 4.624352 3.997678 5.251026
##  high     3 45 4.337621 3.682142 4.993100
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 5793.2      1  1221.12     44 208.7440 < 2.2e-16 ***
## load           1.0      1    46.72     44   0.9480  0.335543    
## block          7.2      2    42.89     88   7.3915  0.001078 ** 
## load:block     0.0      2    32.50     88   0.0529  0.948501    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.86049 0.03954
## load:block        0.96500 0.46483
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])   
## block      0.87757   0.001823 **
## load:block 0.96618   0.944152   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps  Pr(>F[HF])
## block      0.9111302 0.001578235
## load:block 1.0097561 0.948500839
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                   Value Df  test stat approx F num Df den Df Pr(>F)
## load1 : block1 0.019597  1 0.00092632 0.040796      1     44 0.8409
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 13.45949 ±2.06%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

amplitude S

## =====================================================================
##                         Amplitude_S
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.3580625 0.3189450 0.3971799
##    no     2 45 0.3520963 0.3133708 0.3908217
##    no     3 45 0.3438373 0.3054124 0.3822621
##  high     1 45 0.3372365 0.2992148 0.3752582
##  high     2 45 0.3503366 0.3156798 0.3849934
##  high     3 45 0.3423072 0.3057068 0.3789076
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value Pr(>F)    
## (Intercept) 32.569      1   3.7216     44 385.0554 <2e-16 ***
## load         0.004      1   0.0794     44   2.4156 0.1273    
## block        0.003      2   0.2181     88   0.6052 0.5482    
## load:block   0.006      2   0.1208     88   2.0105 0.1400    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.87166 0.05218
## load:block        0.95819 0.39926
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])
## block      0.88626     0.5292
## load:block 0.95987     0.1421
## 
##               HF eps Pr(>F[HF])
## block      0.9207657  0.5352293
## load:block 1.0027088  0.1400295
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                     Value Df test stat approx F num Df den Df  Pr(>F)  
## load1 : block1 -0.0096479  1  0.065045   3.0611      1     44 0.08716 .
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 4.067075 ±2.01%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

ITC SmN

## =====================================================================
##                         Intertrial_Coherence_SmN
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.4067182 0.3510711 0.4623653
##    no     2 45 0.3853908 0.3349144 0.4358673
##    no     3 45 0.3672219 0.3122740 0.4221698
##  high     1 45 0.3946982 0.3373811 0.4520153
##  high     2 45 0.3846980 0.3348897 0.4345064
##  high     3 45 0.3593230 0.3056851 0.4129609
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 39.608      1   7.5927     44 229.5275 < 2.2e-16 ***
## load         0.003      1   0.2798     44   0.5010 0.4827765    
## block        0.064      2   0.3156     88   8.8697 0.0003096 ***
## load:block   0.001      2   0.2486     88   0.2618 0.7702622    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic  p-value
## block             0.89743 0.097623
## load:block        0.89406 0.090022
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])    
## block      0.90698  0.0005117 ***
## load:block 0.90421  0.7480920    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps   Pr(>F[HF])
## block      0.9437688 0.0004194039
## load:block 0.9406909 0.7568612430
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                     Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 -0.0020605  1 0.0014841 0.065398      1     44 0.7994
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 11.65029 ±2.13%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

ITC SNR

## =====================================================================
##                         Intertrial_Coherence_SNR
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N     Mean    CI_LL    CI_UL
##    no     1 45 4.049719 3.618167 4.481271
##    no     2 45 3.800942 3.421601 4.180284
##    no     3 45 3.695258 3.292194 4.098322
##  high     1 45 3.941257 3.506068 4.376446
##  high     2 45 3.813865 3.459928 4.167802
##  high     3 45 3.625299 3.226132 4.024466
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept) 3942.1      1   416.52     44 416.4325 < 2.2e-16 ***
## load           0.2      1    15.98     44   0.5658    0.4559    
## block          5.1      2    20.47     88  10.9243 5.785e-05 ***
## load:block     0.2      2    18.23     88   0.4179    0.6597    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic p-value
## block             0.90886 0.12813
## load:block        0.90170 0.10810
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])    
## block      0.91647  0.0001032 ***
## load:block 0.91050  0.6408600    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps   Pr(>F[HF])
## block      0.9543252 7.935582e-05
## load:block 0.9476846 6.489116e-01
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                    Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 -0.019251  1 0.0020468 0.090243      1     44 0.7653
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 9.601923 ±9.03%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

ITC S

## =====================================================================
##                         Intertrial_Coherence_S
## =====================================================================
## 
## 
## Descriptives
## ============
##  load block  N      Mean     CI_LL     CI_UL
##    no     1 45 0.5426056 0.4872752 0.5979359
##    no     2 45 0.5258366 0.4752990 0.5763743
##    no     3 45 0.5057792 0.4508772 0.5606812
##  high     1 45 0.5311734 0.4741227 0.5882242
##  high     2 45 0.5232539 0.4727252 0.5737826
##  high     3 45 0.4997347 0.4467401 0.5527294
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##             Sum Sq num Df Error SS den Df  F value  Pr(>F)    
## (Intercept) 73.401      1   7.5609     44 427.1518 < 2e-16 ***
## load         0.003      1   0.2858     44   0.4646 0.49906    
## block        0.054      2   0.3242     88   7.2961 0.00117 ** 
## load:block   0.001      2   0.2362     88   0.1667 0.84673    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##            Test statistic  p-value
## block             0.90138 0.107279
## load:block        0.89567 0.093588
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##             GG eps Pr(>F[GG])   
## block      0.91023   0.001708 **
## load:block 0.90553   0.825970   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##               HF eps  Pr(>F[HF])
## block      0.9473896 0.001460326
## load:block 0.9421621 0.834392724
## 
## 
## Linear interaction contrast
## ===========================
## Multivariate Test: Pillai test statistic
## P-value adjustment method: holm
##                     Value Df test stat approx F num Df den Df Pr(>F)
## load1 : block1 -0.0026938  1 0.0026347  0.11623      1     44 0.7348
## 
## 
## 
## BF without vs with interaction
## ==============================
## Bayes factor analysis
## --------------
## [1] load + block + fp : 12.44145 ±1.72%
## 
## Against denominator:
##   eeg_dv ~ load + block + load:block + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

summary

Summary of interaction analyses:

  • Overall_interaction has 3 dfs.
  • Linear_interaction has 1 df and captures the interaction of load with the linear trend over blocks.
  • BF01_interaction is the BF for a model without the overall interaction versus a model with the overall interaction (prior: Cauchy r scale = 0.5).
  • BF01_error% estimates the error of the BF in percent. For example, if BF = 10 and the error is 10%, then the BF is estimated to vary between 9 and 11.
Variable Overall_Interaction_p Linear_Interaction_p BF01_Interaction BF01_error%
Amplitude_SmN 0.362 0.277 7.586 1.126
Amplitude_SNR 0.944 0.841 13.459 2.061
Amplitude_S 0.142 0.087 4.067 2.014
Intertrial_Coherence_SmN 0.748 0.799 11.650 2.135
Intertrial_Coherence_SNR 0.641 0.765 9.602 9.027
Intertrial_Coherence_S 0.826 0.735 12.441 1.723

time-frequency analysis at 2 Hz

The goal of this exploratory time-frequency analysis was to examine if the 40-Hz signal changed periodically with the onset of the visual stimuli, which were shown every 500 ms (i.e., at 2 Hz). To detect this period change, epochs were rather long (10 s), and each epoch began every 20th visual stimulus (see MNE-python script).

  • These epochs should contain a 40-Hz signal (even though the phase shifts between epochs).
  • If the onsets of the visual stimuli affect the 40-Hz signal periodically, then the 40-Hz signal should change at 2 Hz within an epoch.
  • Thus, within the 40-Hz signal, there should be a signal at 2 Hz.
  • The noise can be defined by surrounding frequencies (10 on each side excluding the 2 nearest neighbors).
  • Results show amplitude SmN and S for the 2-Hz signal.

A potential concern is that the 40-Hz response may be confounded by indirect visual effects on the same electrodes as used for ASSRs. That is, the electrodes that were used to record ASSRs may pick up unrelated ERP activity from visual onsets. However, because the response is recorded at 40 Hz whereas visual events occur at 2 Hz, an analysis of only the 40-Hz response should already remove confounding effects of the visual events at 2 Hz (because the frequency is much lower). Accordingly, any 2-Hz activity within the 40-Hz response suggests that the 40-Hz response is actually affected by the visual onsets.

Although results suggest some activity at 2 Hz, there were no differences among the load conditions.

by measure

amplitude SmN

## =====================================================================
##                         AmpSmN
## =====================================================================
## 
## 
## Descriptives
## ============
##       load  N      Mean      CI_LL    CI_UL
##         no 42 0.8405075 -0.1889680 1.869983
##        low 42 1.3182676  0.1596759 2.476859
##       high 42 1.1394366  0.4187611 1.860112
##  very high 42 0.9122387  0.3366768 1.487801
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df F value  Pr(>F)  
## (Intercept) 186.143      1  1083.90     41  7.0411 0.01128 *
## load          5.998      3   289.46    123  0.8495 0.46939  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##      Test statistic    p-value
## load         0.5855 0.00072565
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##       GG eps Pr(>F[GG])
## load 0.75449     0.4431
## 
##        HF eps Pr(>F[HF])
## load 0.800841  0.4487255
## 
## 
## Polynomial contrasts
## ====================
## Analysis of Variance Table
## 
## Response: eeg_dv
##            Df  Sum Sq Mean Sq F value Pr(>F)    
## loadlin     1    0.00  0.0028  0.0012 0.9727    
## loadqua     1    5.22  5.2181  2.2174 0.1390    
## loadcub     1    0.78  0.7769  0.3301 0.5666    
## fp         41 1083.90 26.4367 11.2338 <2e-16 ***
## Residuals 123  289.46  2.3533                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## 
## BF of main effect
## =================
## Bayes factor analysis
## --------------
## [1] fp : 11.8772 ±0.46%
## 
## Against denominator:
##   eeg_dv ~ load + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

amplitude S

## =====================================================================
##                         AmpS
## =====================================================================
## 
## 
## Descriptives
## ============
##       load  N     Mean    CI_LL    CI_UL
##         no 42 3.012330 1.686699 4.337962
##        low 42 3.310861 1.882000 4.739721
##       high 42 3.010470 2.103617 3.917323
##  very high 42 2.835109 2.057216 3.613002
## 
## 
## Anova
## =====
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##              Sum Sq num Df Error SS den Df F value    Pr(>F)    
## (Intercept) 1554.83      1  1893.07     41 33.6744 8.248e-07 ***
## load           4.91      3   313.58    123  0.6423    0.5892    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##      Test statistic    p-value
## load        0.52581 0.00011053
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##      GG eps Pr(>F[GG])
## load 0.6968     0.5353
## 
##         HF eps Pr(>F[HF])
## load 0.7350124  0.5431675
## 
## 
## Polynomial contrasts
## ====================
## Analysis of Variance Table
## 
## Response: eeg_dv
##            Df  Sum Sq Mean Sq F value Pr(>F)    
## loadlin     1    1.45   1.454  0.5703 0.4516    
## loadqua     1    2.36   2.358  0.9249 0.3381    
## loadcub     1    1.10   1.101  0.4317 0.5124    
## fp         41 1893.07  46.172 18.1108 <2e-16 ***
## Residuals 123  313.58   2.549                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## 
## BF of main effect
## =================
## Bayes factor analysis
## --------------
## [1] fp : 15.1405 ±0.62%
## 
## Against denominator:
##   eeg_dv ~ load + fp 
## ---
## Bayes factor type: BFlinearModel, JZS

summary

Summary of 2-Hz tf analysis:

  • P_load is the p value (from the ANOVA) for the main effect of load with 3 dfs.
  • BF01_load is the BF for a model without the main effect versus a model with the main effect (prior: Cauchy r scale = 0.5).
  • BF01_error% estimates the error of the BF in percent. For example, if BF = 10 and the error is 10%, then the BF is estimated to vary between 9 and 11.
Variable P_load BF01_load BF01_error%
AmpSmN 0.449 11.877 0.456
AmpS 0.543 15.141 0.617