Single Tool Use Research Articles

The ontogeny of termite gathering among chimpanzees in the Goualougo Triangle, Republic of Congo.

ObjectivesAcquiring tool‐assisted foraging skills can potentially improve dietary quality and increase fitness for wild chimpanzees (Pan troglodytes). In contrast to chimpanzees in East and West Africa, chimpanzees in the Congo Basin use tool sets and brush‐tipped fishing probes to gather termites. We investigated the ontogeny of these tool skills in chimpanzees of the Goualougo Triangle, Republic of Congo, and compared it to that for chimpanzees at Gombe, Tanzania. We assessed whether chimpanzees acquired simple tool behaviors and single tool use before more complex actions and sequential use of multiple tool types.Materials and MethodsUsing a longitudinal approach, we scored remote video footage to document the acquisition of termite‐gathering critical elements for 25 immature chimpanzees at Goualougo.ResultsAll chimpanzees termite fished by 2.9 years but did not manufacture brush‐tipped probes until an average of 4.3 years. Acquisition of sequential tool use extended into juvenility and adolescence. While we did not detect significant sex differences, most critical elements except tool manufacture were acquired slightly earlier by females.DiscussionThese findings contrast with Gombe, where chimpanzees learn to both use and make fishing probes between ages 1.5–3.5 and acquire the complete task by age 5.5. Differences between sites could reflect tool material selectivity and design complexity, the challenge of sequential tool behaviors, and strength requirements of puncturing subterranean termite nests at Goualougo. These results illustrate how task complexity may influence the timing and sequence of skill acquisition, improving models of the ontogeny of tool behavior among early hominins who likely used complex, perishable technologies.

The – weak – role of memory in tool use: Evidence from neurodegenerative diseases

ObjectiveAlthough tool use disorders are frequent in neurodegenerative diseases, the question of which cognitive mechanisms are at stake is still under debate. Memory-based hypotheses (i.e., the semantic knowledge hypothesis and the manipulation knowledge hypothesis) posit that tool use relies solely on stored information about either tools or gestures whereas a reasoning-based hypothesis (i.e., the technical-semantic hypothesis) suggests that loss of semantic knowledge can be partially compensated by technical reasoning about the physical properties of tools and objects. MethodThese three hypotheses were tested by comparing performance of 30 healthy controls, 30 patients with Alzheimer's disease and 13 patients with semantic dementia in gesture production tasks (i.e., pantomime of tool use, single tool use, real tool use) and tool or gesture recognition tasks (i.e., functional and contextual matching, recognition of tool manipulation). Individual, item-based patterns of performance were analyzed to answer the following question: Could participants demonstrate the use of tools about which they had lost knowledge? With this aim in mind, “validation” and “rebuttal” frequencies were calculated based on each prediction. ResultsPredictions from the technical-semantic hypothesis were more frequently observed than memory-based predictions. A number of patients were able to use and demonstrate the use of tools for which they had lost either semantic or manipulation knowledge (or both). ConclusionsThese data lead to question the role of different types of memory in tool use. The hypothesis of stored, tool-specific knowledge does not predict accurately clinical performances at the individual level. This may lead to explore the influence of either additional memory systems (e.g., personal/impersonal memory) or other modes of reasoning (e.g., theory of mind) on tool use skills.

Mechanical knowledge does matter to tool use even when assessed with a non-production task: Evidence from left brain-damaged patients.

In the literature on apraxia of tool use, it is now accepted that using familiar tools requires semantic and mechanical knowledge. However, mechanical knowledge is nearly always assessed with production tasks, so one may assume that mechanical knowledge and familiar tool use are associated only because of their common motor mechanisms. This notion may be challenged by demonstrating that familiar tool use depends on an alternative tool selection task assessing mechanical knowledge, where alternative uses of tools are assumed according to their physical properties but where actual use of tools is not needed. We tested 21 left brain-damaged patients and 21 matched controls with familiar tool use tasks (pantomime and single tool use), semantic tasks and an alternative tool selection task. The alternative tool selection task accounted for a large amount of variance in the single tool use task and was the best predictor among all the semantic tasks. Concerning the pantomime of tool use task, group and individual results suggested that the integrity of the semantic system and preserved mechanical knowledge are neither necessary nor sufficient to produce pantomimes. These results corroborate the idea that mechanical knowledge is essential when we use tools, even when tasks assessing mechanical knowledge do not require the production of any motor action. Our results also confirm the value of pantomime of tool use, which can be considered as a complex activity involving several cognitive abilities (e.g., communicative skills) rather than the activation of gesture engrams.

P104. Two methods for one network: Toward an understanding of the left lateralized pathways for tool use

Introduction This project investigates the neural networks involved in the daily use of tools, a fundamental human activity that may be impaired in patients who have suffered strokes, particularly in the middle cerebral artery, resulting in apraxia. Previous experiments with healthy young adults and brain damaged patients have employed various paradigms to address the neural representations of manipulation and employment of tools; but important factors, such as aging or side of brain injury, have not been addressed. Our goal is test the same task, the use of individual tools, using two fundamentally different methods of brain imaging to determine the consistency of findings and to discover the nature of the different components of tool use. Method The methodology comprised fMRI in healthy subjects and lesion analysis in brain damaged patients. Both approaches employed a similar version of the tool carousel, an apparatus built for the presentation of single tools and objects. Twelve tools in the lesion experiment and 10 in the fMRI were presented with the instruction, “Use the tool presented the way you know”. An event-related fMRI experiment was conducted on 17 young and 17 elderly controls. In the lesion study 31 left brain damaged patients and 19 patients with right brain injuries were tested. FMRI-data was analyzed with SPM8 in a factorial design (tool vs. non-tool and use vs. transport) during the planning- and execution-phase. In the lesion study Voxel Lesion Symptom Mapping was applied to the behavioral scoring of patients and VOIs damaged to analyze the following factors: score parameter, damaged side (left, right) and tools used; in addition a ROI analysis specified the findings. Results A left-lateralized network that includes the superior and inferior parietal lobes, the dorsal and ventral premotor cortex and the middle frontal gyrus, the temporal cortex and the lateral occipital complex is similarly involved in tool use in young and elderly controls and in left-brain damaged patients. A difference can be observed in the elderly subjects, who recruit a wider and less focused network during action planning but a smaller, weaker activation pattern during actual motion execution. Despite moderate performance errors in patients with right brain damage, these pathways were not detected, suggesting a more widely-spread distribution of responsible networks and different sources for failure in the correct use of the tools. Conclusions The correspondence of the areas revealed by fMRI in healthy subjects and left-side areas damaged in the patient group demonstrates the role of dorsal and ventral pathways in complex actions like tool use, with particular importance for the frontal and parietal areas. The carousel benefits to test single tool use in patients and healthy participants; this fact and, in addition, the employment of this two different populations validate the findings of the project.

Tool use disorders after left brain damage.

In this paper we review studies that investigated tool use disorders in left-brain damaged (LBD) patients over the last 30 years. Four tasks are classically used in the field of apraxia: Pantomime of tool use, single tool use, real tool use and mechanical problem solving. Our aim was to address two issues, namely, (1) the role of mechanical knowledge in real tool use and (2) the cognitive mechanisms underlying pantomime of tool use, a task widely employed by clinicians and researchers. To do so, we extracted data from 36 papers and computed the difference between healthy subjects and LBD patients. On the whole, pantomime of tool use is the most difficult task and real tool use is the easiest one. Moreover, associations seem to appear between pantomime of tool use, real tool use and mechanical problem solving. These results suggest that the loss of mechanical knowledge is critical in LBD patients, even if all of those tasks (and particularly pantomime of tool use) might put differential demands on semantic memory and working memory.

Apraxia and Alzheimer’s Disease: Review and Perspectives

Apraxia is one of the cognitive deficits that characterizes Alzheimer's disease. Despite its prevalence and relevance to diagnosing Alzheimer's disease, this topic has received little attention and is without comprehensive review. The review herein is aimed to fill this gap by first presenting an overview of the impairment caused in different clinical situations: pantomime of tool use, single tool use, real tool use, mechanical problem solving, function and manipulation knowledge tasks, and symbolic/meaningless gestures. On the basis of these results, we then propose alternative interpretations regarding the nature of the underlying mechanisms impaired by the disease. Also presented are principal methodological issues precluding firm conclusions from being drawn.

Apraxia of tool use: More evidence for the technical reasoning hypothesis

Various distinct cognitive processes such as semantic memory, executive planning or technical reasoning have been shown to support tool use. The aim of this study is to investigate the relationship between these processes. To do so, a large apraxia battery was submitted to 16 patients with left brain-damage (LBD) and aphasia and 19 healthy controls. The battery included: classical apraxia tests (Pantomime of Tool Use and Single Tool Use), familiar and novel tool use tests (Tool-Object Pairs and Sequential Mechanical Problem-Solving), semantic memory tests (Recognition of tool utilization gestures and Functional and Categorical Associations) as well as the Tower Of London. The Sequential Mechanical Problem-Solving task is a new task which permits the evaluation of pre-planning in unusual tool use situations. In this task as well as in the Tool-Object Pairs task, participants solved a tool use problem in a Choice and a No-Choice condition to examine the effect of tool selection. Globally, left brain damaged patients were impaired as compared to controls. We found high correlations in left brain damaged patients between performances on classical apraxia tests, familiar and novel tool use tests and Functional and Categorical Associations but no significant association between these performances and Tower Of London or Recognition of tool utilization gestures. Furthermore, the two conditions (Choice and No-Choice) of Tool-Object Pairs and Sequential Mechanical Problem-Solving were associated. In sum, all tasks involving tool use are strongly associated in LBD patients. Moreover, the ability to solve sequential mechanical problems does not depend on executive planning. Also, tool use appears to be associated with knowledge about object function but not with knowledge about tool manipulation. Taken together, these findings indicate that technical reasoning and, to a lesser extent, semantic memory may both play an important role in tool use.