How we perceive our own hands: Effects of attention, aging, and sex

Abstract

This study investigates whether both the perception of somesthetic sensations arising spontaneously on the hand and their modulation by attention are subject to change with advancing age and sex. Participants aged between 50 and 68 (N = 24), and younger (19–27; N = 24), with an equal sex ratio in each group, described the spontaneous sensations they felt on one of their hands. Two 10-s tests were carried out with participants either seeing their tested hand (gaze towards the visible hand) or not (contralateral gaze, hidden hand). Within the age range covered by our participants, aging had an effect on the spatial distribution of sensations, insofar as the older participants reported feeling more sensations in their palm whereas the younger participants had more sensitive fingers. Age also influenced the number, nature, intensity, and duration of sensations in interaction with gaze and/or sex. The most frequent pattern was a benefit of ipsilateral relative to contralateral gazing in young women. Attentional modulation was seldom observed in men and was absent among older participants.

• Aging
• attention
• hands
• interoception
• sex
• Tactile spontaneous sensations

Acknowledgements

This work was supported by the LABEX CORTEX (ANR-11-LABX-0042) of the University of Lyon in the context of the “Investissements d’Avenir” (ANR-11-IDEX-0007) program run by the French National Research Agency (ANR). Our thanks go to Marie-Ange D’Hour-De-Gandt, Aurélie Hollant, Perine Schouteden, and Anthony Taesch for their help with data collection, and we are grateful to Romain Laisne, Anass Bouhlal, and François-Xavier Coudoux for their contribution to the scan-processing software. We would also like to thank all the volunteers who kindly agreed to take part in the experiment.

Declaration of interest

The authors report no conflicts of interest.

Notes

¹There was also a significant Gaze × Sex × Hand interaction for the sensation duration (F(1, 40) = 4.92, p < 0.05). For brevity and simplicity, we decided not to discuss it here since it was the sole significant effect of the Hand factor in this experiment, possibly because a between-subject design was used (see earlier publications of our group with a within-participant design for this factor).

²A preliminary study that applied the same procedure to participants between the ages of 70 and 92 supports the idea of a decline in sensory experience (number and intensity of sensations). In the “very old” age category, there were also more participants whose hands were totally “silent” (47%). However, the conclusive nature of these data is debatable owing to a lack of information about the older participants’ cognitive functional ability and the possibility of undiagnosed neuropathy, which is known to increase upwards of 80.