Investigating Gender Differences in Spatial Working Memory Performance: The Role of Sex Hormone Levels.

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memory.

Method

Participants

The participants were Monash University undergraduate students enrolled in Developmental and Biological Psychology, 385 females and 112 males with a mean age of 23.4 years, obtained through convenience sampling. Participation in the study was voluntary and informed consent was provided when scores were submitted online.

Design

An independent-measures design was implemented to identify any gender differences in spatial working memory. The independent variable was the gender of the participants; male (small 2D:4D ratio) or female (larger 2D:4D ratio), and the accuracy and reaction time on the n-back test was the dependent variable. Participant’s data was split into two groups, female and male for further analysis.

Materials

The n-back test was accessed online through the university student portal Moodle and the 2D:4D ratio was measured manually by a clear ruler. Two-tailed independent samples t-tests was conducted to compare the accuracy, reaction times and 2D:4D ratio between genders, furthermore two-tailed Pearson’s correlations were preformed in order to discover any relationships between 2D:4D, accuracy and reaction times. An alpha value of .05 was used across all statistical analyses.

Procedure

The n-back test was accessed online through the university student portal Moodle; it measured accuracy and reaction time, the participants were asked to record the scores from the n-back test. Then participants were then asked to manually measure their 2D:4D ratios by measuring the length of their index (2D) and ring finger (4D), then dividing the length of the index finger by the length of the ring finger. Finally participants were asked to submit both the n-back score and 2D:4D ratio through a data submission link questionnaire, also accessed through Moodle. The submissions of data were then analyzed using SPSSStatistics.

Results

All data was analysed using SPSSStatistics, an independent samples t-test was used to compare differences between genders in accuracy and reactions times on the n-back test, as well as the 2D:4D ratio. Furthermore, a Pearson’s correlation was used to investigate relationships between 2D:4D ratios, accuracy and reaction times.

The accuracy on the n-back tests was analysed using an independent-values t-test in order to determine whether or not there was a difference between the genders. There was a statistically significant difference with males performing better (M = 81.85, SD = 16.40) than females (M = 77.45, SD = 16.40), t(495) = -2.310, p = .035, two tailed.

Despite scoring with higher accuracy on the n-back tests, males had a slower reaction time than females, with a mean difference of 1.291 seconds, however this was not statistically significant, t(495) = -.029, p = .977, two tailed.

A two-tailed independent-samples t-test found that male participants had statistically significant lower 2D:4D ratios (M = .96, SD = .06) than females (M = .98 SD = .04), t(495) = 3.292, p = .001, two tailed.

Table 1:

Correlations among Accuracy, Reaction Time and 2D:4D

Accuracy Reaction_Time Ratio_2D4D

Accuracy Pearson Correlation 1 .034 .034

Sig. (2-tailed) .455 .456

N 497 497 497

Reaction_Time Pearson Correlation .034 1 -.090*

Sig. (2-tailed) .455 .046

N 497 497 497

Ratio_2D4D Pearson Correlation .034 -.090* 1

Sig. (2-tailed) .456 .046

N 497 497 497

*. Correlation is significant at the 0.05 level (2-tailed).

As shown in Table 1, there is no statistically significant correlation between accuracy and reaction time as well as accuracy and 2D:4D ratios. There is a statistically significant correlation between 2D:4D ratios and reaction times, however it is a very weak negative correlation r(495) = -.090, p = .046.

Discussion

The purpose of this study was investigate whether there are any cognitive differences in genders and whether there is a relationship between the 2D:4D ratio and working memory. Analysis of the data obtained showed partial support for the first hypothesis as it was revealed it was statistically significant that males scored with higher accuracy than females on the n-back test, however the reaction times were not statistically significant. Likewise to the first hypothesis results showed only partial support for the second hypothesis, whereby it was anticipated that there would be a stronger relationship between the two working memory variables (accuracy and reaction time) and the 2D:4D ratio.

The observation that males (with smaller 2D:4D ratios) scored with greater accuracy on the n-back than females (with larger 2D:4D ratios) was consistent with the findings of Kalmady et al (2013) and Burton et al (2014). However the second component of the working memory variable “reaction time” showed no statistically significant difference in male and female performance thereby allowing only limited support for the first hypothesis, however this may be a result of sampling error as the sample only consisted of university students.

Despite Kalmady (2013) reporting a positive correlation with lower 2D:4D and left brain lateralization (enhanced cognitive performance), our findings did not align with this. 2D:4D ratios and reaction time’s did show a statistically significant very weak positive correlation, however 2D:4D and accuracy showed no significant correlations, again, suggesting limited support for the second hypothesis. Despite not replicating similar results as Kalmady, our results showed some similarity to Hill et al (2014), whereby they suggest differences in cognitive ability are due to different cortical activity, Goldstein et al (2005) also reported no differences in working memory attributing differences only in cortical activity. Female brain activity was recorded in the limbic system and the prefrontal cortex and in males was recorded at the cerebellum, parietal lobe and thalamus. Perhaps there was only partial support due to cortical activity difference being a more substantial factor in explaining differences