For this exercise, please try to reproduce the results from Experiment 2 of the associated paper (de la Fuente, Santiago, Roman, Dumitrache, & Casasanto, 2014). The PDF of the paper is included in the same folder as this Rmd file.

Methods summary:

Researchers tested the question of whether temporal focus differs between Moroccan and Spanish cultures, hypothesizing that Moroccans are more past-focused, whereas Spaniards are more future-focused. Two groups of participants (\(N = 40\) Moroccan and \(N=40\) Spanish) completed a temporal-focus questionnaire that contained questions about past-focused (“PAST”) and future-focused (“FUTURE”) topics. In response to each question, participants provided a rating on a 5-point Likert scale on which lower scores indicated less agreement and higher scores indicated greater agreement. The authors then performed a mixed-design ANOVA with agreement score as the dependent variable, group (Moroccan or Spanish, between-subjects) as the fixed-effects factor, and temporal focus (past or future, within-subjects) as the random effects factor. In addition, the authors performed unpaired two-sample t-tests to determine whether there was a significant difference between the two groups in agreement scores for PAST questions, and whether there was a significant difference in scores for FUTURE questions.

Target outcomes:

Below is the specific result you will attempt to reproduce (quoted directly from the results section of Experiment 2):

According to a mixed analysis of variance (ANOVA) with group (Spanish vs. Moroccan) as a between-subjects factor and temporal focus (past vs. future) as a within-subjectS factor, temporal focus differed significantly between Spaniards and Moroccans, as indicated by a significant interaction of temporal focus and group, F(1, 78) = 19.12, p = .001, ηp2 = .20 (Fig. 2). Moroccans showed greater agreement with past-focused statements than Spaniards did, t(78) = 4.04, p = .001, and Spaniards showed greater agreement with future-focused statements than Moroccans did, t(78) = −3.32, p = .001. (de la Fuente et al., 2014, p. 1685).

Step 1: Load packages

library(tidyverse) # for data munging
library(knitr) # for kable table formating
library(haven) # import and export 'SPSS', 'Stata' and 'SAS' Files
library(readxl) # import excel files

# #optional packages/functions:
library(afex) # anova functions
# library(ez) # anova functions 2
# library(scales) # for plotting
# std.err <- function(x) sd(x)/sqrt(length(x)) # standard error

Step 2: Load data

# Just Experiment 2
data_path <- 'data/DeLaFuenteEtAl_2014_RawData.xls'
df_raw <- read_excel(data_path, sheet=3)

Step 3: Tidy data

df = df_raw %>% 
  rename(rating = `Agreement (0=complete disagreement; 5=complete agreement)`) %>% 
  select(!item) %>% 
  group_by(group, participant, subscale) %>% 
  summarise(avg_rating = mean(rating, na.rm = T)) %>% 
  ungroup() %>% 
  mutate(
    participant = if_else(group == "Moroccan", participant, participant +40),
    group = case_match(group,
                       "Moroccan" ~ "Moroccan",
                       "young Spaniard" ~ "Spaniard"))

Step 4: Run analysis

Pre-processing

Descriptive statistics

Try to recreate Figure 2 (fig2.png, also included in the same folder as this Rmd file):

df %>% 
  mutate(subscale = factor(subscale, levels = c("PAST", "FUTURE")),
         group = factor(group, levels = c("Spaniard", "Moroccan"))) %>% 
  ggplot(aes(x = group, y = avg_rating, fill = subscale)) + 
  stat_summary(fun = "mean", 
               geom = "col", 
               position = "dodge") +
  stat_summary(fun.data = mean_se, 
               geom = "errorbar", 
               position = position_dodge(width = 0.9), 
               width = 0.2) +
  coord_cartesian(ylim = c(2, 4))

Inferential statistics

According to a mixed analysis of variance (ANOVA) with group (Spanish vs. Moroccan) as a between-subjects factor and temporal focus (past vs. future) as a within-subjects factor, temporal focus differed significantly between Spaniards and Moroccans, as indicated by a significant interaction of temporal focus and group, F(1, 78) = 19.12, p = .001, ηp2 = .20 (Fig. 2).

anova_result <- aov_ez(
  id = "participant",
  dv = "avg_rating",
  between = "group",
  within = "subscale",
  data = df)

# View results
summary(anova_result)
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                 Sum Sq num Df Error SS den Df   F value    Pr(>F)    
## (Intercept)    1543.46      1   15.250     76 7692.0904 < 2.2e-16 ***
## group             0.44      1   15.250     76    2.1920   0.14287    
## subscale          3.97      1   37.777     76    7.9793   0.00604 ** 
## group:subscale    9.12      1   37.777     76   18.3456 5.328e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Moroccans showed greater agreement with past-focused statements than Spaniards did, t(78) = 4.04, p = .001,

# reproduce the above results here
df %>% 
  filter(subscale == "PAST") %>% 
  t.test(avg_rating ~ group, data = .)
## 
##  Welch Two Sample t-test
## 
## data:  avg_rating by group
## t = 3.8562, df = 74.91, p-value = 0.0002416
## alternative hypothesis: true difference in means between group Moroccan and group Spaniard is not equal to 0
## 95 percent confidence interval:
##  0.2850812 0.8944060
## sample estimates:
## mean in group Moroccan mean in group Spaniard 
##               3.280886               2.691142

and Spaniards showed greater agreement with future-focused statements than Moroccans did, t(78) = −3.32, p = .001.(de la Fuente et al., 2014, p. 1685)

# reproduce the above results here
df %>% 
  filter(subscale == "FUTURE") %>% 
  t.test(avg_rating ~ group, data = .)
## 
##  Welch Two Sample t-test
## 
## data:  avg_rating by group
## t = -3.2098, df = 70.047, p-value = 0.002005
## alternative hypothesis: true difference in means between group Moroccan and group Spaniard is not equal to 0
## 95 percent confidence interval:
##  -0.5762537 -0.1345797
## sample estimates:
## mean in group Moroccan mean in group Spaniard 
##               3.138333               3.493750

Step 5: Reflection

Were you able to reproduce the results you attempted to reproduce? If not, what part(s) were you unable to reproduce?

I was able to reproduce the results reported in the original paper insofar as the same things were significant and in the same direction in my analysis as they were in the paper and the F and t values were within one unit of the original values.

How difficult was it to reproduce your results?

More difficult than the Group A paper.

What aspects made it difficult? What aspects made it easy?

The data were not in the format needed to reproduce the target results. The paper didn’t specify how to reshape the data so I guessed at it.