23
Original Research
The effectiveness of  
teaching human evolution  
to 14- to 15-year-olds  
in Slovenia
Jelka Strgar 1*
Abstract
In Slovenia, human evolution is first taught in biology classes to 14–15-year-old 
students. For many, this will be the only contact with this topic at school. The 
objective was to determine how much knowledge students acquired about 
human evolution. Data were collected with a questionnaire using a 5-point Likert 
scale. The participants were 13–14-year-olds who had not yet learned about 
human evolution (the control group) and 15–16-year-olds who had learned about 
human evolution one year earlier in biology classes (the experimental group). 
The results show that students significantly improved their knowledge of human 
evolution with small to medium effect sizes. Students knew very well that modern 
humans are the only species of humans today and that they did not live at the 
same time as dinosaurs. The achievements were low on the following topics: 
modern humans lived at the same time as Neanderthals and mammoths, and 
modern humans did not evolve from Neanderthals. To the problematic topics, 
attention should be paid to teacher education and the biology curriculum. Few 
correlations were found between the knowledge of human evolution, acceptance 
of evolution, religiosity, and attitudes toward biology.
Keywords
knowledge of human evolution; acceptance of evolution; religiosity; attitudes 
toward biology; primary school
1 University of Ljubljana, Biotechnical Faculty
* Corresponding author:  
E-mail address: jelka.strgar@bf.uni-lj.si
Citation: Strgar, J., (2024). The effectiveness of 
teaching human evolution to 14- to 15-year-olds 
in Slovenia. Acta Biologica Slovenica 68 (1)
Received: 15.05.2024 / Accepted: 07.10.2024 /  
Published: 28.10.2024
https://doi.org/10.14720/abs.68.01.18729
This article is an open access article distributed 
under the terms and conditions of the Creative 
Commons Attribution (CC BY SA) license
24
Acta Biologica Slovenica, 2025, 68 (1)
Učinkovitost poučevanja evolucije človeka pri 14-do 15-letnikih v Sloveniji
Izvleček
V Sloveniji se pri biologiji evolucijo človeka prvič učijo 14- do 15-letniki. Za mnoge od njih bo to v šoli edini stik s to temo. 
Cilj raziskave je bil ugotoviti, koliko znanja evolucije človeka so učenci usvojili. Podatke smo zbrali z vprašalnikom s 
petstopenjsko Likertovo lestvico. Udeleženci so bili 13- do 14-letniki, ki se še niso učili evolucije človeka (kontrolna 
skupina) in 15- do 16-letniki, ki so se evolucijo človeka učili pri biologiji eno leto pred tem (poskusna skupina). Resultati 
kažejo, da so učenci signifikantno izboljšali svoje znanje evolucije človeka, in sicer z majhno do srednjo velikostjo 
učinka. Učenci so dobro vedeli, da je moderni človek danes edina vrsta človeka in da ni živel sočasno z dinozavri. 
Dosežki pa so bili nizki pri naslednjih temah: moderni človek je živel sočasno z neandertalcem in mamutom, moderni 
človek se ni razvil iz neandertalca. Problematičnim temam je treba posvetiti pozornost v izobraževanju učiteljev in 
osnovnošolskem učnem načrtu. Med znanjem evolucije človeka, sprejemanjem evolucije, vernostjo in odnososm do 
biologije je bilo malo korelacij.
Ključne besede 
znanje evolucije človeka; sprejemanje evolucije; vernost; odnos do biologije; osnovna šola
Introduction
Human evolution is a topic that students can quickly lose 
interest in, especially if the teacher distracts them with too 
much theory and data that make no sense to them (Flammer, 
2006). Motivation to learn about evolution is influenced by 
many factors, one of which is prior knowledge. Bloom and 
Weisberg (2007) claim that students' prior knowledge is the 
main reason for not accepting evolution, as misconceptions 
and beliefs can hinder the process of accepting new knowl-
edge (Wescott & Cunningham, 2005; Smith, 2010; Yates & 
Marek, 2014). If the prior knowledge is good, the student can 
add new knowledge to the already existing one. However, if 
the student has misconceptions, motivation decreases, as it 
is extremely difficult to change entrenched misconceptions 
with classical teaching methods.
Slovenia ranks above average in the PISA survey. In 
the latest survey, which was conducted in 2022, Slovenian 
15-year-olds ranked above average in scientific literacy. 
From these results, we can conclude that science literacy 
among primary and secondary school students in Slovenia 
is good, and it is also stable according to prior PISA surveys 
(Strgar, 2010; Štraus et al., 2016).
In a survey about the acceptance of the theory of 
evolution (Miller et al., 2006), Slovenia ranked in 16th place 
among 34 countries. University students in Slovenia think 
that understanding evolutionary concepts is a necessary 
part of solid general education, but there is also evidence 
that their actual understanding of evolution is not satisfac-
tory. Surprisingly, they also think that alternative nonscien-
tific theories of evolution should be presented in schools 
(Šorgo et al., 2014).
According to Pinxten et al. (2020), most of the popula-
tion in many countries has a very limited formal introduction 
to the understanding of evolutionary theory. However, in 
most countries, there are national regulations that demand 
scientific teaching of evolutionary theory (Borgerding et al., 
2016; Tavares & Bobrowski, 2018). In Slovenia, the theory of 
evolution was first introduced in school in 1945 (Vesel, 1977). 
According to the current national curriculum (Učni načrt. 
Program osnovna šola. Biologija, 2011), 14- to 15-year-old 
students learn about biological evolution in biology classes 
for the first time. However, some evolutionary concepts are 
already included in the curriculum for history that is taught 
to younger students (Učni načrt. Program osnovna šola. 
Zgodovina, 2011).
At the age of 14 to 15, students in Slovenia finish their 
compulsory primary education. Biological evolution is 
introduced to them in the final year (Učni načrt. Program 
osnovna šola. Biologija, 2011). There is one single national 
curriculum for all students up to this age. Afterwards, the 
students attend different secondary schools according to 
their career choices. These schools vary in the amount 
of biology courses that they offer. This means that some 
25
Acta Biologica Slovenica, 2025, 68 (1)
of the students continue their education at secondary 
schools, which have no evolution as part of their curricu-
lum. Into their adult life, these students take with them only 
the knowledge of evolution they had learned in primary 
school. Therefore, it is important to know what level of 
understanding of evolution the Slovenian school system 
provides during obligatory primary education.
In the Slovenian national curriculum for 14 to 15-year-
olds, there are 18 objectives concerning evolution and 
only one objective regarding human evolution, namely, 
“Students can explain the origin of humans and primates 
and the kinship of humans with other primates” (Učni načrt. 
Program osnovna šola. Biologija, 2011, p. 17).
Published research shows that understanding evolu-
tion is challenging for students at all levels of education 
for a variety of reasons. Surroundings and socio-economic 
factors also influence students and take part in structur-
ing students’ preconceptions about evolution and their 
attitudes toward evolution (da Silva Oliveira et al., 2022). 
The problem, therefore, is how much students can learn 
at that age, specifically, how well they can understand 
evolutionary concepts and what contextual factors shape 
students’ knowledge. Many studies (Miller et al., 2006; 
Hermann, 2013; Mantelas & Mavrikaki, 2020; da Silva 
et al., 2022; Salazar-Enriquez et al., 2023) confirmed a 
negative correlation between acceptance of evolution and 
religiosity. It differed depending on the country and cultural 
background of the people tested. For Slovenia, this prob-
lem was addressed in studies by Šorgo et al. (2014), Kralj et 
al. (2018), and Torkar and Šorgo (2020).
This research aimed to establish how much knowledge 
about human evolution students had before they learned 
about this topic in formal education and how much new 
knowledge about human evolution they acquired during 
formal education. Therefore, the aim was to determine 
how effective were the lessons on human evolution, which, 
according to the national curriculum for biology (Učni načrt. 
Program osnovna šola. Biologija, 2011), were attended by 
students aged 14 to 15 years. The point of interest was 
also whether contextual factors, such as attitudes toward 
biology, acceptance of evolution, and religiosity, were con-
nected with students’ knowledge of human evolution. The 
outcome could help make changes in the current national 
curriculum as well as be guidance for teacher educators 
and teachers themselves (Salazar-Enriquez et al., 2023). 
The following research questions were formulated:
RQ1: How effective are lessons about human evolution in 
Slovenia taught to 14–15-year-old students?
RQ2: Are the chosen contextual factors (students’ accep-
tance of evolution, attitudes toward biology, and religiosity) 
connected with students' achievements on the knowledge 
test about human evolution?
Materials and Methods
General Background
The data were gathered in the 2021/22 and 2022/23 
school years. The survey was anonymous; all the parents 
of the students signed an agreement to allow their children 
to participate. No benefits were offered to the participants. 
According to Slovenian legislation, such a survey does not 
need the approval of an ethics committee or similar body.
Sample
Our sample consisted of 593 students. The national curric-
ulum for biology in Slovenia (Učni načrt. Program osnovna 
šola. Biologija, 2011) mandates for evolution to be taught 
to 14- to 15-year-olds. Students of this age were not part 
of the sample. In the survey, there were one year younger 
students (13- to 14-year-olds; a control group; n = 364).) who 
had not yet learned about human evolution. The experi-
mental group (15- to 16-year-olds; n = 229) was represented 
by the students who had learned about human evolution in 
biology classes in the previous school year. In the sample, 
there was a slightly higher percentage (53.5%) of females 
compared to males.
Instrument and Procedures
Data were collected using a questionnaire. In the begin-
ning, there were two demographic questions (gender 
and grade). These were followed by 59 statements that 
assessed students’ knowledge of human evolution, their 
acceptance of evolution, attitudes toward biology, and 
religiosity. This part of the questionnaire used a 5-point 
Likert scale, ranging from strongly disagree (1) to strongly 
agree (5). Eleven items were originally worded in such a 
way that disagreement was required as a correct answer; 
these items were re-coded for statistical analysis. The 
questionnaire was compiled from statements used in sev-
eral prior studies. The religiosity of participants was tested 
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Acta Biologica Slovenica, 2025, 68 (1)
with ten statements using the PERF scale, which was 
created by Beniermann (2019) and translated into the Slo-
venian language and used by Torkar and Šorgo (2020) on 
the Slovenian population. Eight statements that explored 
students’ attitudes toward biology were adapted from The 
Relevance of Science Education study (Sjøberg & Sch-
reiner, 2019). Seventeen statements that tested students’ 
acceptance of evolution were taken from the MATE ques-
tionnaire (Rutledge & Sadler, 2007), and ten were adapted 
from the questionnaire used by Miller et al. (2006). The 
remaining 14 statements that tested students’ knowledge 
about human evolution were partly adapted from the study 
by Miller et al. (2006) and partly designed in line with the 
curriculum and the textbooks that the participants of this 
study used when learning about evolution. Face validity of 
these 14 statements was ensured by the author and the 
three biology teachers who judged and revised them.
The questionnaire was administered during students’ 
regular biology classes. Students completed it in approxi-
mately 15 minutes.
Data analysis
Data were tested for normal distribution with the Kolmog-
orov-Smirnov test; because the distribution of data was not 
normal (ps < 0.001), non-parametric testing was used. The 
statistical significance of differences in knowledge about 
human evolution between the control and the experimental 
groups was established by a Mann-Whitney U test. Effect 
size r was calculated using the equation r = Z/√N.
On 14 statements of the knowledge test about human 
evolution, descriptive statistics (mean, standard deviation) 
were used. On 45 statements assessing acceptance 
of evolution, attitudes toward biology, and religiosity, 
principal component analysis (PCA) was conducted using 
the orthogonal rotation (varimax) method with Kaiser nor-
malization (Table S1). The value of the Kaiser-Meyer-Olkin 
measure of sampling adequacy was .925, which means 
that the sample size was adequate for PCA. Bartlett’s test of 
sphericity was highly significant (χ2 = 11253.468, df = 990, 
p < .001), indicating that correlations between statements 
were sufficiently large for PCA. According to the scree plot, 
retaining five components was justified. Following this, 
three statements were removed from the analysis. Thirteen 
statements loaded onto component 1 (religiosity); 14 state-
ments loaded onto component 2 (acceptance of evolution 
– the theory); eight statements loaded onto component 
3 (attitudes toward biology); four statements loaded onto 
component 4 (acceptance of evolution – the theory is (not) 
scientific), and three statements loaded onto component 
5 (acceptance of evolution – organisms do (not) evolve). 
Cronbach’s alphas for three components were highly reli-
able (from .85 to .91), while for two components, they were 
relatively less reliable (.53 and .68). These five components 
explained 55.926% of the variance. Cronbach’s alpha for all 
42 statements was .83. Additional results are available as 
supplementary material accompanying the online article.
Correlations between the knowledge of human 
evolution, acceptance of evolution, religiosity, and atti-
tudes toward biology were analyzed using Spearman’s 
correlation coefficient (rs). Comparisons of these correla-
tions were then calculated to establish if the differences 
between correlations of the two students’ age groups were 
statistically significant. For this, the following equation was 
used: Zdifference = (zr1-zr2)/√{[1/(N1-3)]+[1/(N2+3)]} (Field, 
2009, p. 191).
Results
Students’ Achievements on the Knowledge 
Test about Human Evolution
Students’ knowledge of human evolution was tested with 
14 statements. Results show that all students showed the 
least knowledge (M = 2.41-2.57) in statements rE1 (Modern 
humans did not evolve from Neanderthals.), E2 (Modern 
humans lived in today's Slovenia at the same time as 
mammoths), and E36 (Modern humans and Neanderthals 
lived on Earth at the same time) (Tab. 1). In nine statements, 
they showed an average knowledge (M = 3.03-3.43). The 
highest knowledge (M = 3.63-4.13) was achieved on the 
following two statements: E3 (Today, all human species 
are extinct, except for our species, modern humans), rE38 
(Modern humans did not live in today's Slovenia at the 
same time as dinosaurs.).
Differences among Students’ Achievements 
on the Knowledge Test about Human 
Evolution by Age
On 12 out of 14 statements about the knowledge of 
human evolution, 13-14-year-olds answered significantly 
differently than 15-16-year-olds (Tab. 1). On one of those 12 
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Acta Biologica Slovenica, 2025, 68 (1)
statements (rE33 Modern humans did not evolve less than 
15,000 years ago.), 13–14-year-olds showed more knowl-
edge. On the remaining 11 statements, 15–16-year-olds 
had more knowledge. The effect sizes of differences in 
knowledge between 13–14-year-olds and 15–16-year-olds 
were mostly small (on 8 out of 14 statements) to medium 
(6 statements).
Correlations between Students’ 
Achievements on the Knowledge Test about 
Human Evolution and Contextual Factors
Correlations for the subsample of 13–14-year-olds and the 
subsample of 15–16-year-olds were established, respec-
tively. The variables were the average achievement on 
Age (years)
All students 
(N = 589)
13-14 
(n = 360)
15-16 
(n = 229) 
Mann-Whitney U test Effect 
Size
Statement M SD M SD M SD U Z p r
rE1 Modern humans did not  
evolve from Neanderthals.* 2.41 1.229 2.29 1.183 2.60 1.276 35473.500 -2.742 .006 -.11
E2 Modern humans lived in  
today's Slovenia at the same  
time as mammoths.
2.51 1.237 2.44 1.248 2.62 1.215 36871.000 1.780 .075 .07
E36 Modern humans and 
Neanderthals lived on Earth  
at the same time.
2.57 1.348 2.43 1.267 2.79 1.441 33830.000 -2.933 .003 -.12
rE33 Modern humans did not  
evolve less than 15,000 years ago.* 2.99 1.045 3.06 1.060 2.89 1.015 36477.000 -2.108 .035 -.09
E34 Modern humans evolved  
in Africa. 3.03 1.086 2.78 1.084 3.43 .964 27174.500 -7.220 <.001 -.30
rE35 Humans did not evolve  
from chimpanzees. 3.08 1.183 2.81 1.102 3.49 1.185 28028.000 -6.466 <.001 -.27
E4 Neanderthals and modern 
humans share 99.7% of their genes. 3.14 .967 3.03 .924 3.32 1.008 33892.500 -3.532 <.001 -.15
E19 Neanderthals lived in Europe, 
Asia, and the Middle East. 3.30 .921 3.22 .962 3.41 .843 35868.500 -2.478 .013 -.10
E37 Humans's three closest 
relatives in terms of evolutionary 
development are gorillas, 
orangutans, and chimpanzees.
3.38 1.073 3.36 1.092 3.42 1.043 38414.500 -.774 .439 -.03
rE26 Humans today do not have 
more or less the same shape as  
we have always had.*
3.40 1.052 3.21 1.016 3.70 1.040 30096.500 -5.518 <.001 -.23
E41 Humans and chimpanzees 
evolved from a common ancestor. 3.42 1.089 3.22 1.060 3.74 1.062 29122.000 -6.138 <.001 -.25
rE5 The common ancestor of 
humans and chimpanzees does  
not live in Africa anymore.*
3.43 1.107 3.34 1.093 3.57 1.116 35846.000 -2.333 .020 -.10
E3 Today, all human species are 
extinct, except for our species, 
modern humans.
3.63 1.198 3.41 1.179 3.99 1.141 28594.500 -6.177 <.001 -.26
rE38 Modern humans did not live  
in today's Slovenia at the same  
time as dinosaurs.*
4.13 1.174 3.86 1.282 4.54 .823 28347.500 -6.678 <.001 -.28
Table 1. Differences in the students’ knowledge of human evolution and effect sizes of differences.
Tabela 1. Razlike v znanju učencev o evoluciji človeka in velikost učinka razlik.
*reversed statement
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Acta Biologica Slovenica, 2025, 68 (1)
the knowledge test about human evolution and five com-
ponents extracted by PCA: religiosity (F1), attitudes toward 
biology (F3), acceptance of evolution – the theory (F2), 
acceptance of evolution – the theory is (not) scientific (F4), 
and acceptance of evolution - organisms do (not) evolve 
(F5). There were six significant correlations altogether (Tab. 
2, Tab. 3). Acceptance of evolution – the theory is (not) sci-
entific (F4) was significantly correlated with religiosity (F1) in 
both subsamples and also with acceptance of evolution – 
the theory (F2) in 15–16-year-olds. Acceptance of evolution 
- organisms do (not) evolve (F5) was significantly correlated 
with attitudes toward biology (F3) in 15–16-year-olds. 
Knowledge of human evolution was significantly correlated 
with acceptance of evolution – the theory (F2) and atti-
tudes toward biology (F3) in the group of 13–14-year-olds. 
All correlations were small (.13 < rs < .21).
Comparison of Correlations between the 
Control Group and the Experimental Group
A comparison of correlations between the control and 
the experimental group of students was calculated. The 
correlations between the knowledge of human evolution 
and the five components obtained by PCA in the group that 
had not yet learned about evolution (13–14-year-olds) were 
mostly significantly different (ps < .01) from the correlations 
in the group that had already learned about human evolu-
tion (15–16-year-olds). Only the correlation between accep-
tance of evolution (i.e., the theory is (not) scientific (F4) and 
acceptance of evolution - organisms do (not) evolve (F5)) 
was similar in both age groups (p = .223).
Discussion
The first research question dealt with whether teaching 
about human evolution to 14–15-year-old students in Slo-
venia is effective and whether it attains the standards set in 
the national curriculum for biology. 
Overall, the average achievements on the knowledge 
test of human evolution ranged from very poor (M = 2.41) to 
very good (M = 4.31). In summary, Slovenian students knew 
very well that modern humans did not live at the same 
time as dinosaurs (rE38) and that modern humans are the 
Name of the Wetlands, (Blocks). F1 F2 F3 F4 F5
F1 Religiosity 1.00
F2 Acceptance of evolution – the theory .06 1.00
F3 Attitudes toward biology .07 .00 1.00
F4 Acceptance of evolution - the theory is (not) scientific .16* -.07 -.00 1.00
F5 Acceptance of evolution - organisms do (not) evolve .12 -.05 -.13 -.05 1.00
Knowledge of human evolution -.08 .13* -.18** -.00 .03
Name of the Wetlands, (Blocks). F1 F2 F3 F4 F5
F1 Religiosity 1.00
F2 Acceptance of evolution – the theory .04 1.00
F3 Attitudes toward biology -.05 -.07 1.00
F4 Acceptance of evolution - the theory is (not) scientific -.15* .21** .07 1.00
F5 Acceptance of evolution - organisms do (not) evolve .04 -.04 .20** -.07 1.00
Knowledge of human evolution -.07 -.04 .09 -.02 .02
Table 2. Correlations between Students’ Achievements on the Knowledge Test about Human Evolution and Contextual Factors (13–14-year-olds).
Tabela 2. Korelacije med dosežki učencev na testu znanja o evoluciji človeka in ozadenjskimi dejavniki (13-do 14-letniki).
Table 3. Correlations between Students’ Achievements on the Knowledge Test about Human Evolution and Contextual Factors (15–16-year-olds).
Tabela 3. Korelacije med dosežki učencev na testu znanja o evoluciji človeka in ozadenjskimi dejavniki (15-do 16-letniki).
* p < .05, ** p < .01
* p < .05, ** p < .01
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Acta Biologica Slovenica, 2025, 68 (1)
only species of humans today (E3). They also knew above 
averagely well that humans had changed their shape over 
time (rE26), that humans and chimpanzees evolved from a 
common ancestor (E41) that no longer lives (rE5), and that 
gorillas, orangutans and chimpanzees are humans' closest 
relatives (E37).
Students knew averagely well that modern humans 
evolved in Africa (E34), that they evolved more than 
15,000 years ago (rE33), and that humans did not evolve 
from chimpanzees (rE35). In two of these statements, the 
knowledge improved significantly after the biology lessons 
in the ninth grade.
Students knew beyond average that modern humans 
and Neanderthals lived at the same time (E36), that modern 
humans lived at the same time as mammoths (E2), and that 
modern humans did not evolve from Neanderthals (rE1). 
For two of these statements, the biology lesson slightly 
improved knowledge.
In contrast, students were unsure what proportion of 
genes Neanderthals and modern humans share (E4) and 
where Neanderthals lived (E19), although knowledge 
improved significantly after the biology lessons in the ninth 
grade of primary school.
The fact that even the younger students had above-av-
erage achievements in seven out of 14 statements 
suggested that they might have gained some of this 
knowledge in history classes one year earlier (Učni načrt. 
Program osnovna šola. Zgodovina, 2011), through popular 
media (Modell & Wenderoth, 2005), digital and print media 
(Garibi et al., 2021), or their social surroundings (OECD, 
2016; OECD, 2017; Šterman Ivančič & Mlekuž, 2023), espe-
cially their parents (Salazar-Enriquez et al., 2023).
The comparison of the knowledge of both groups 
showed that there were significant differences between stu-
dents' answers in most of the statements. The experimental 
group (15–16-year-olds) showed mostly a better knowledge 
of human evolution than the control group (13–14-year-
olds). Interestingly, younger students showed significantly 
better knowledge of one statement (rE33, Modern humans 
did not evolve less than 15,000 years ago). No knowledge 
was gained on the following two statements (E37) Human 
three closest relatives in terms of evolutionary develop-
ment are gorillas, orangutans, and chimpanzees, and (E2) 
modern humans lived in today's Slovenia at the same time 
as mammoths. This suggested that these three topics were 
probably not addressed in biology classes. On the remain-
ing 11 statements, older students answered significantly 
better. Therefore, we can conclude that in Slovenia, the 
teaching of (at least human) evolution at the primary school 
level is reasonably good. This is in line with Mead et al. 
(2017), who found that after classes, students' knowledge 
of evolution was improved immediately after the lesson 
and was retained. Some studies in other European coun-
tries showed that teaching evolution was not satisfactory 
and that evolution was taught only after the other topics 
had been covered (Pinxten et al., 2020). Some teachers 
also do not have sufficient content knowledge (Borgerding 
et al., 2015; Hartelt et al., 2022) and pedagogical skills to 
teach such a demanding topic (Stasinakis & Athanasiou, 
2016). However, the fact that the effect sizes of all eleven 
improvements in knowledge of human evolution in the 
present study were mostly small or medium suggested that 
there is room for improvement in the way human evolution 
is taught. Changes in the curriculum should be made con-
cerning the topics with low achievements. Despite some 
research not showing any connection between students' 
knowledge and the quality of the national curriculum (Belin 
& Kisida, 2015), other studies showed that the structure of 
the curriculum influences knowledge and acceptance of 
evolution (Vaughn & Robbins, 2017).
Information gathered in the present study can be 
applied immediately to improve the curriculum (Sala-
zar-Enriquez et al., 2023), which is currently underway in 
Slovenia. The results will also be important for pre-service 
teachers' educational programs because by securing the 
understanding and acceptance of evolution in teachers, 
the transfer of these to new generations of students will be 
more favourable (Balgopal, 2014; Cofre et al., 2017; Torkar 
& Šorgo, 2020).
The second research question dealt with the chosen 
contextual factors (students' religiosity, attitudes toward 
biology, and acceptance of evolution) and their possible 
correlations with students' achievements on the knowl-
edge test about human evolution. Six significant but small 
correlations were found.
According to most studies, the knowledge and accep-
tance of evolution are positively correlated (Carter et al., 
2015; Tavares & Bobrowski, 2018; Torkar & Šorgo, 2020; 
Salazar-Enriquez et al., 2023). Surprisingly, there was no 
such correlation for 15–16-year-olds in the present study. 
However, for 13–14-year-olds, the results showed that the 
better knowledge they possessed, the more they accepted 
the general statements of the evolutionary theory (F2). This 
is in line with other studies indicating that the correlation 
30
Acta Biologica Slovenica, 2025, 68 (1)
between knowledge and acceptance of evolution is not 
strong (Mead et al., 2017).
Most of the research (e.g., Salazar-Enriquez et al., 
2023) found that knowledge and acceptance of evolution 
negatively correlate with religious beliefs. Interestingly, the 
present study showed no correlation between religiosity 
and knowledge. However, in both age groups, there was 
a small negative correlation between religiosity and con-
viction that evolutionary theory is scientific (F4). The more 
religious 15–16-year-olds were, the less convinced they 
were that the evolutionary theory is scientific. At the same 
time, more religious 13-14-year-old students were also 
more convinced that the evolutionary theory was scientific. 
This result is consistent with Mpeta et al. (2015) and Fiedler 
et al. (2024), who stated that the acceptance of evolution is 
also related to age, religiosity, and the time that has passed 
since the first learning about evolution.
A small negative correlation was found between atti-
tudes toward biology (F3) in 13- to 14-year-olds and knowl-
edge of human evolution. This is not surprising—despite 
a positive attitude toward biology, these students lacked 
knowledge of human evolution because they had not 
been formally taught this topic yet. Students 15 to 16 years 
old with more positive attitudes toward biology (F3) were 
more convinced that organisms evolved (F5). This could 
be explained by the findings of Prokop et al. (2007) and 
Kubiatko et al. (2017), who report that good teaching strate-
gies and a positive teacher personality positively influence 
students’ attitudes toward biology. It might be that students 
who were taught by such teachers were also more likely to 
accept the scientific facts presented by these teachers. The 
only correlation between two aspects of the acceptance of 
evolution was observed in 15- to 16-year-olds: the more the 
students accepted the theory of evolution (F2), the more 
they were convinced that it is scientific (F4).
Correlations calculated for the 13- to 14-year-olds were 
then compared with the correlations calculated for the 
15- to 16-year-olds for statistical significance. Fourteen out 
of 15 correlations calculated differed significantly between 
these two groups (ps < .01). The results show that teaching 
evolution not only significantly improved the students’ 
knowledge of human evolution but also caused changes 
in the acceptance of the evolutionary theory. This is in line 
with other studies that found positive correlations between 
knowledge and acceptance of evolution (Carter et al., 
2015; Tavares & Bobrowski, 2018; Torkar & Šorgo, 2020; 
Salazar-Enriquez et al., 2023). There was no difference (p 
= .223) only regarding one correlation: in both groups, stu-
dents who were more convinced that evolutionary theory 
is scientific (F4) were also more convinced that organisms 
evolve (F5). The fact that the 13- to 14-year-olds who had 
not learned evolution yet had the same convictions as the 
15- to 16-year-olds was surprising, and it could be the con-
sequence of contextual factors, such as the students’ social 
surroundings (OECD, 2016; OECD, 2017; Šterman Ivančič 
& Mlekuž, 2023) or parental education level (Salazar-En-
riquez et al., 2023).
A limitation of this study was its cross-sectional nature. 
A longitudinal study would have yielded more reliable 
results, but it would have been impossible to conduct due 
to logistical issues. 
Conclusions
We can conclude that students in the ninth grade of ele-
mentary school improved their knowledge of human evo-
lution. The progress was small to medium. The question 
is how to eliminate some important misconceptions our 
students have concerning Neanderthals, specifically that 
modern humans evolved from Neanderthals (rE1) and that 
modern humans and Neanderthals did not live on Earth 
at the same time (E36). The student's knowledge should 
also be improved on the following topics: modern humans 
evolved in Africa (E34) more than 15,000 years ago (rE33), 
they did not evolve from chimpanzees (rE35), and they 
lived at the same time as mammoths (E2). In these topics, 
attention should be given to teacher education programs 
in curricular renewal.
Author Contributions
Conceptualization, J.S.; methodology J.S.; formal analysis, 
J.S.; investigation, J.S.; data curation, J.S.; writing—original 
draft preparation, J.S.; writing—review, editing, and paper 
communication, J.S. All authors have read and agreed to 
the final version of the manuscript.
Conflicts of Interest
The author declares no conflict of interest.
31
Acta Biologica Slovenica, 2025, 68 (1)
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