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General scales unlock AI evaluation with explanatory and predictive power

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Why This Matters

The development of a general taxonomy of AI capabilities, inspired by human psychological constructs, offers a unified framework to evaluate and compare artificial intelligence systems across diverse tasks. This approach enhances our understanding of AI behavior, fostering more transparent and adaptable AI development aligned with human cognition models.

Key Takeaways

General scales

For more than a century, psychology has introduced many constructs with explanatory and predictive power about human behaviour, from conscientiousness to metacognition. On the basis of experimental data and theories of human cognition, these constructs are usually organized into hierarchical taxonomies, such as the Cattell–Horn–Carroll structure of human cognitive abilities51 or the Big Five personality traits52. In principle, we could build a similar taxonomy for artificial cognition, based on theory and experiments about machine behaviour4. However, as the base population of machines is much more arbitrary and changing than those of humans, it makes more sense to devise a taxonomy that could encompass any kind of natural and artificial intelligence, by considering capabilities that are meaningful for more general theories of cognition53. Under this paradigm and by integrating and generalizing taxonomies from human psychology, comparative cognition and AI53, a general taxonomy of 14 capabilities was designed54 and later extended with corresponding 14 rubrics by Tolan et al.55 for the study of AI and human capabilities in the workplace. These rubrics assigned the presence or absence of the need for each capability in generic tasks extracted from worker surveys, occupational databases and AI benchmarks.

This taxonomy serves as a basis to construct a catalogue of capabilities following these four criteria: (1) the capabilities are general rather than specific, enabling the characterization of a wide range of tasks usually present in human activities; (2) the capabilities represent concepts that are understandable to humans (and LLMs), enabling their levels to be expressed through rubrics in plain natural language; (3) there is no a priori assumption of correlation or orthogonality in these capabilities as observed in humans or LLMs, to accommodate various present and future AI paradigms (rather than overfitting to a specific state of the art of AI); and (4) two capabilities are considered distinct as long as many tasks could conceivably require a high level of one but not the other. Following criteria (1) and (2), we use capabilities that are familiar in human and non-human cognition and AI practice (see Supplementary Information Section 1.1 for a coverage of taxonomies in humans and AI). Despite these inspirations, we follow (3) to ensure that the catalogue does not replicate human intelligence hierarchies or taxonomies derived from populational methods. But we do not look for a middle ground either: we do not assume that humans and AI systems share a common capability structure. Finally, ensuring (4), we consider two dimensions to be different (for example, metacognition and logical reasoning) if it is possible to conceive tasks that require one but not the other, independently of whether they are correlated in human or AI populations. Indeed, we include dimensions that may not be the most discriminative ones for the population of benchmarks or LLMs we use in this paper but can be useful to detect emergent properties in the future. This population independence is especially critical in the present era in which benchmarks and models get replaced every few months: for instance, for models without chain-of-thought, dominant until 2024, the set of reasoning capabilities we use may not have been very discriminative; however, with the advent of models with reinforcement learning and integrated chain-of-thought in 2025, reasoning capabilities become more informative. If our catalogue had not included them, we would have been unable to detect this shift, and the same applies for capabilities that may not be discriminative now but can be conceived of as different from others and may be informative in the future. As we may nevertheless miss some capabilities that will become relevant, the catalogue is expected to expand to include new dimensions in the future, provided they are understandable to humans.

As mentioned, our work builds on that of Tolan et al.55. First, we extend the taxonomy by including both knowledge and extraneous dimensions. Second, we develop new scales and rubrics in a quantitative range between 0 and 5+, with 0 representing absence of demand, values 1–4 representing increasing demand levels of the capability and 5+ representing 5 or above. For instance, the famous Sally–Anne false-belief task assesses understanding of an individual’s false belief about the properties of an object if those properties change while they are not looking (Sally will look for her marble in the basket where she left it, even though Anne moved it to the box when Sally was away). This may be level 4 for dimension MS (Mind Modelling and Social Cognition) but may be level 0 for dimension QLq (Quantitative Reasoning). Similarly, the question “if all A are B, some B are C, no C are D, and all D are E, what can be inferred about the relationship between A and E?” may be level 4 for QLl (Logical Reasoning) but level 0 for MS (Mind Modelling and Social Cognition).

Extended Data Table 5 shows the set of dimensions we have included in the first version of the DeLeAn rubric set (DeLeAn v1.0). We adapt seven broad capabilities from Tolan et al.55, applicable to LLMs (for example, ‘auditory processing’ was discarded), and refine a subset of them hierarchically with subdimensions, making them a group of 11 ‘proper’ cognitive capabilities that we call ‘elemental’; by ‘elemental’, we mean that these capabilities are not derived from others, as opposed to the knowledge dimensions, which are more acquisitive. These ‘elemental’ subdimensions were included after several rounds of discussions about whether some of the original seven broad subdimensions could be carved into finer, but still general, subdimensions that are conceptually distinct. Beyond the capabilities, we also include new dimensions accounting for domain ‘knowledge’, separated into five subdimensions (KNn, KNs, KNa, KNf, KNc) covering large branches of human knowledge, and three ‘extraneous’ ones, AT (Atypicality), VO (Volume) and UG (Unguessability), to account for elements that make the task more challenging independently of elemental capabilities or knowledge demands.

In particular, Atypicality deals with contamination56,57 and other familiarization effects leading to capability overestimation because similar data were seen during training. An AI system may simply succeed because it has memorized the instance. This dimension can be used to explain and predict performance, by identifying AT as a confounder with the other demands. The second extraneous dimension, Volume, represents the use of ‘collages’ to make instances more difficult. For instance, if we put ten simple additions in an exercise and we score whether all of them are correct, then we have increased the difficulty greatly, but the quantitative reasoning demand is the same. We call this phenomenon amalgamation and it is a recurrent trick to make instances more difficult, either in benchmarks of increasing hardness46,58,59 or in adversarial testing60. There is a correlation between the size of the questions (and the answers) and the difficulty you can achieve with it46 (Figs. 3 and 4). In the end, amalgamation produces an underestimation of the capabilities, because the subjects fail at tasks that are incorporating many simple things. The chances of error accumulate, even if the cognitive load is not necessarily increased61,62. Finally, Unguessability captures the very usual funnelling effect to make a question more amenable for scoring but, at the same time, reducing its difficulty. The obvious case is the use of multiple-choice questions, which have become predominant in most AI benchmarks, despite its issues63. Reducing or increasing the number of options has been a common practice to change the ‘difficulty’ of a task without modifying its cognitive demands35. In general, these three extraneous dimensions will account for an important proportion of the predictability in LLM success and including them helps clarify these confounding effects.

Although we have 19 dimensions in total, only the first 18 correspond to proper capability demands (11 elemental, five knowledge and two extraneous) that may be met by the subject or not, with Unguessability being a special extraneous dimension reflecting the funnelling in the item design (for example, multiple-choice questions). Because of that, it is the only dimension expressed between 0 (the correct answer is trivially determined by the question) and 100 (unguessable, that is, a good open-ended question). Each of the other 18 demand rubrics includes a general description of the construct to be annotated, followed by a description of each of the levels, from 0 to 5+, with three ‘anchor’ instances each. By following Supplementary Information Section 2, we can better understand the trade-offs in the construction of the rubrics.

It is important to highlight that the catalogue is not definitive and is meant to be extended in the future using the same criteria of dimensions being general and conceptually distinct. We use the term ‘catalogue’ instead of ‘taxonomy’ to better emphasize its non-definitive nature. This is also why we call the rubrics and battery DeLeAn v1.0 and ADeLe v1.0, respectively, with the vision of incorporating new capabilities and propensities in the future. This will also include considering safety, fairness and values64,65 and not only performance (correctness) as the variable to predict.

Ratio scales

We deliberately design the demand scales as ‘ratio’ scales66, with an absolute zero(no demand) and differences that are comparable across the scale. In the social sciences, a common interest lies in understanding differences, as no human has zero capabilities, and an ‘interval’ scale with negative capabilities makes sense (as in IRT) or as percentiles of a normal distribution (as IQ scores). We argue that for AI, we should aim for the top level in Stevens’s topology of measurement67: the ratio scales. Ratio scales have all of the properties of the previous scales: intervals and differences are meaningful but so too are ratios. Given the flexibility with which we can regulate compute and time use in AI, it makes more sense to set an absolute zero (no compute) on the demands and build the scales in such a way that ratios are meaningful. We wish to say that instance x i at level 6 doubles the demand of an instance x j at level 3. Taking into account that we fit logistic functions, this can be understood in terms of the log odds of being correct halving when moving 2x in the scale and doubling when moving x/2 in the scale68.

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