No abstract

ObjectivesHand coordination is a key feature in primate evolution at both behavioral and cognitive levels. Humans further improved their manual abilities, and their cognitive niche is deeply associated with hand‐tool relationships and technological capacity. A main cognitive change is thought to be related to the transition from Oldowan to Acheulean stone tool technology around 1.7 million years ago. In this survey, we test whether distinct Lower Paleolithic tools induce different electrophysiological reactions during haptic exploration.MethodsElectrodermal activity is a relatively quick way to measure emotional and attentional changes during specific tasks. We analyzed changes of the electrodermal response and electrodermal level during Oldowan and Acheulean stone tool handling in a sample of 46 right‐handed adult subjects with no previous archeological knowledge.ResultsElectrodermal proxies for attention and emotion display a skewed distribution. Females present more variable reactions than males and more emotional engagement. Acheulean tools require longer manipulation time and exert less emotional response than Oldowan tools. Attention is influenced by tool length and weight, emotion is sensitive to tool thickness and weight, and manipulation time depends on tool length and width.ConclusionsThis study suggests subtle but detectable perceptual differences when handling Oldowan and Acheulean stone tools. Such variations associated with hand‐tool interaction can provide information on haptic and prosthetic capacities associated with our specialized technological resources. Perceptual changes in the archeological record can reveal evolutionary changes in the corresponding body‐tool cognitive mechanisms.

No abstract

No abstract

Objectives: Tool use requires integration among sensorial, biomechanical, and cognitive factors. Taking into account the importance of tool use in human evolution, changes associated with the genus Homo are to be expected in all these three aspects. Haptics is based on both tactile and proprioceptive feedbacks, and it is associated with emotional reactions. Previous analyses have suggested a difference between males and females, and during haptic exploration of different typologies of stone tools. Here, we analyze the correlation between electrodermal reactions during stone tool handling and hand morphology to provide evidence of possible allometric factors shared by males and females.Methods: Electrodermal analysis was used to investigate some specific parameters involved in these reactions, such as changes in the level of attention and arousal. We analyzed the responses of 46 right-handed adults to 20 distinct stone tools while blindfolded. Results: Females have smaller hands and a wider range of electrodermal reactions. Within males and females, hand diameters and general hand size do not correlate with the degree of electrodermal level and response.Conclusions: Sex differences in electrodemal reaction during stone tool handling are apparently not due to the effect of hand size or proportions. Differences between males and females are better interpreted as real sex differences, either due to a biological or cultural influences. Hand size does not influence the degree of arousal or attention during tool exploration, suggesting that other factors trigger individual reactions. These results add to a general cognitive approach on hand-tool evolution and tool sensing.