The role of gestures in cognition extends beyond communication as people gesture not only when they speak but also think. This also holds for individuals who are blind from birth. However, studies showed that blind speakers produce fewer spontaneous gestures than sighted speakers when describing events. The present study aims to go beyond quantitative measures and gain insight into gesture kinematics. We compared the duration, size, and speed of path gestures (showing the trajectory of a movement) used by 20 blind, 21 blindfolded, and 21 sighted Turkish speakers when describing spatial events. Blind speakers took more time to produce larger gestures than sighted speakers, but the speed of gestures did not differ. The gestures of blindfolded speakers did not differ from those of blind and sighted speakers in any of the measures. These suggest a lifetime of blindness influences the kinematics of gesture production beyond a temporary lack of vision.

Linguistic strategies humans use for communication are designed to meet the informational needs of their addressees. Speakers not only adapt their speech but also increase the rate of iconic gestures to enhance the clarity of a message for children. Although sign languages allow signers to take advantage of iconicity far more than what is possible in speech, little is known about whether signers use iconicity as a strategy in child-directed communication. In the present study, we used automatic video pose estimation to analyze descriptions aimed at a child (12yo) vs. an adult produced by 7 deaf adult signers of Italian Sign Language. Overall, signers used iconic constructions more than lexical signs and with comparable frequency in descriptions for both age groups. However, iconic constructions were longer in duration for children. Thus, the present study presents the first evidence that, unlike speakers, signers do not modulate quantitative but only qualitative aspects of iconicity for children.