Final answer:
Tool use in Homo habilis and Homo erectus is linked with increased intelligence because of the cognitive planning required to make tools and the development of imitation skills which may have spurred the onset of language. Advancements in tool technology and language likely evolved together, suggesting a reciprocal relationship that influenced brain development and social interactions.
Step-by-step explanation:
The relationship between tool use and increased intelligence in Homo habilis and Homo erectus has been a subject of considerable interest among scientists. One theory posits that the cognitive planning required to make tools, such as selecting proper materials and executing a sequence of precise actions, also supported complex speech development. This planning is believed to have improved cognitive abilities in these hominins, reflecting an increased intelligence. Tool making required understanding of the objective and method, which likely expanded their cognitive capacities.
Another theory highlights the importance of imitation in transmitting tool-making skills. The development of mirror neurons, which are associated with imitation, could have led to the emergence of gestural language and, eventually, protolanguage, further enhancing communication and collaborative efforts. Furthermore, an interactive tool (not the digging/chopping kind but a learning aid) from the Smithsonian Institution suggests that a colder and changing climate might have influenced encephalization and hence tool use and brain size.
As tool technology progressed, so did language abilities, suggesting a reciprocal relationship between the two. Innovations in tools and language likely co-evolved, with tool use potentially driving the development of language, and vice versa. Archaeological evidence shows a clear advancement from basic stone choppers to more complex blade tools, indicative of the sophistication in manufacturing and potentially necessitating more complex forms of communication.