BACKGROUND:Since the 1940s, the concept of autism has undergone marked changes, and autism spectrum disorder (ASD) is a wildly heterogenous condition. At the same time, the prevalence of ASD has increased massively. METHODS:This essay considers possible reasons for the changes and their consequences. RESULTS:Among drivers for the increase in prevalence are cultural changes, such as the desire for inclusion, harm avoidance, reliance on self-report, and the acceptance of masking. These have all led to a lowering of the diagnostic threshold. Furthermore, the popularity of the concept of autism boosted numbers via self-diagnosis and a search for identity. CONCLUSIONS:Marked differences now exist between those first diagnosed in childhood and others first diagnosed in adolescence or adulthood. The time has come to examine reasons for these conceptual changes and the consequences for clinical practice and research.

Autism has influenced social-cognitive neuroscience in important ways. It has provided the impetus to look for the brain basis of mentalizing and encouraged the search for the brain bases of other social abilities. A fundamental aspect of social interaction is the ability to predict what other agents are going to do. We propose a hierarchy of three worlds—the world of objects, the world of agents, and the world of ideas—that respectively present their own challenges and solutions to such predictions. The world of ideas provides a direct interface between individual minds and other minds (i.e., culture). We highlight the power of culture to change subjective experiences and the power of subjective experiences to influence culture. The example of autism shows these mutual influences at work. These influences have led to dramatic changes in the concept of “autism” since its first use in child psychiatry.

Looking back on our life and work, we reflect on the changes in our thinking due to three scientific and technological revolutions. These are information processing, computers, and brain imaging, and together they ousted behaviorism from its dominant position in experimental psychology. We champion a model of the mind that is hierarchically organized with both a robust unconscious and a harder-to-pin-down conscious mode of operation. Our studies were inspired by disorders that made us realize that cognitive processes at all levels of the information processing hierarchy impact social interactions. We locate the influence of culture at the highest level of this processing hierarchy. Here we see the interface between different minds and the importance of norms when regulating the opposing trends in our complex and even contradictory social nature.

The terminology used in discussions on mental state attribution is extensive and lacks consistency. In the current paper, experts from various disciplines collaborate to introduce a shared set of concepts and make recommendations regarding future use.

Uta Frith and Chris Frith spoke at the Royal Institution around the launch of their 'graphic biography' Two Heads, written with their son Alex Frith and illustrated by Daniel Locke.

Nature and culture work together to shape who we are. We are embedded in culture and are profoundly influenced by what those around us say and do. The interface between minds occurs at the level of explicit metacognition, which is at the top of our brain's control hierarchy. But how do our brains do this?

Child psychiatrist who transformed understanding of autism. Child psychiatrist who transformed understanding of autism.

Laurent Mottron (2021) has done the community a great service by courageously calling out the problems we are facing in the diagnosis of autism. I agree with his stark assessment that the autism spectrum, as currently defined by DSM and operationalized by standardized tools, is hampering scientific research. I can recall the research environment of 50 years ago, when autism was considered a rare disorder. Research was not better in those days. It barely got off the ground. The main challenge was recruiting participants for experiments, and I remember my own desperate efforts to do this. I was eager to embrace a widening of the diagnostic criteria, and I welcomed and promoted the notion of the autism spectrum (Frith, 1991), but I had no idea just how elastic it would become. I had no idea that the boundaries of the spectrum would be so blurred that the terms “disorder” and “deficit” would become meaningless. However, this blurring of boundaries has not changed my belief in categories as being just as important as dimensions (Happé & Frith, 2020). After all, differences in autistic traits, inherent in normal variation, are one thing, and differences due to neurological glitches are another. We cannot put aside the fact that there is a long history of neurological signs in autism. The widened criteria were a boon for researchers like me to be able to recruit more participants, and it was a boon to use standardized diagnostic instruments. However, this came at a cost. Larger samples nowadays are likely to be extremely heterogenous, and this leads to a massive increase in statistical noise. For group comparisons, this means weak or null results. Unfortunately, they tend to be blamed on sloppy theories rather than on sloppy subject recruitment. This has battered the belief in the ability to find real group differences on any experimental psychological tests. But, while the group differences of old have vanished, autism has not. It is still an open question whether autism is a natural entity. There are now calls for abandoning autism as a category and merging it with other neurodevelopmental disorders. I believe this would be a great loss. We know that, despite the multitude of biological causes and the variety of behavioral signs of autism, there remains a recognizable phenotype. In addition, this phenotype is not just in the imagination of some autism experts. Young children can quickly detect the presence of an autistic child at a playground or school. Naïve adults can perceive the subtle signs of oddness or strangeness in able autistic individuals, present in the manner or content of their speech or their motor movements. Of course, such thin slice judgments can be wrong and are subject to various biases. They do not replace a thorough clinical assessment. I agree with Laurent Mottron that autism at present is a category at the wrong level in the hierarchy, and I am optimistic that we can arrive at an agreed prototype if we try. I believe we can do this best by going straight to the cognitive level, where we might find the proximate causes of the ostensible strangeness of autistic behavior (Frith, 2012). These cognitive causes should explain clusters of social and non-social features, allowing for the fact that the resulting behavior will look different at different ages and levels of ability. The clusters should point to specific problems in neuro-cognitive mechanisms, and it is these that we still have to nail in order to link them to their neural basis. I am hoping for a systematic attempt to identify meaningful subgroups in the whole of the autism spectrum, not just at the center. Although the search for subgroups has yielded very little so far, it may not have been conducted with a sufficiently strong theoretical basis and has been tied too much to the behavioral rather than the cognitive level. Finding subgroups at the biological level seems just out of reach at present. There are important questions to be asked about children who are diagnosed early and how they differ from those who are diagnosed late. What about those people who were never recognized as children, but strongly feel they are part of the autism spectrum? Are they possibly in search of a diagnostic category that does not yet exist, but should? Prototypes can only provisionally be based on behavior, whether through observation, interview, or self-report. This is because behavior is influenced by a multitude of variables that are forever outside our control. I believe that differences at the cognitive level can validate, not just clinical judgment, but also the naïve intuition of what is different and strange, and wonderful, about the nature of autism.

Recent studies on mentalizing have shown that autistic individuals who pass explicit mentalizing tasks may still have difficulties with implicit mentalizing tasks. This study explores implicit mentalizing by examining spontaneous speech that is likely to contain mentalistic expressions. The spontaneous production of meta-statements provides a clear measure for implicit mentalizing that is unlikely to be learned through experience. We examined the self- and other-descriptions of highly verbally able autistic and non-autistic adults in terms of their spontaneous use of mentalistic language and meta-representational utterances through quantitative and qualitative analysis. We devised a hierarchical coding system that allowed us to study the types of statements produced in comparable conditions for the self and for a familiar other. The descriptions of autistic participants revealed less mentalistic content relating to psychological traits and meta-statements. References to physical traits were similar between groups. Within each group, participants produced a similar pattern of types of mental utterance across 'self' and 'other' conditions. This suggests that autistic individuals show a unique pattern of mental-state-representation for both self and other. Meta-statements add a degree of complexity to self- and other-descriptions and to the understanding of mental states; their reduction in autism provides evidence for implicit mentalizing difficulties. Lay abstract Autistic people can have difficulties in understanding non-autistic people's mental states such as beliefs, emotions and intentions. Although autistic adults may learn to overcome difficulties in understanding of explicit (overt) mental states, they may nevertheless struggle with implicit (indirect) understanding of mental states. This study explores how spontaneous language is used in order to specifically point to this implicit (indirect) understanding of mental states. In particular, our study compares the spontaneous statements that were used in descriptions of oneself and a familiar other person. Here, we found that autistic and non-autistic adults were comparable in the number of statements about physical traits they made. In contrast, non-autistic adults made more statements about mentalistic traits (about the mental including psychological traits, relationship traits and statements reflecting about these) both for the self and the other. Non-autistic and autistic adults showed no difference in the number of statements about relationships but in the number of statements about psychological traits and especially in the statements reflecting on these. Each group showed a similar pattern of kinds of statements for the self and for the other person. This suggests that autistic individuals show the same unique pattern of description in mentalistic terms for the self and another person. This study also indicates that investigating spontaneous use of language, especially for statements reflecting about mental states, enables us to look into difficulties with implicit (indirect) understanding of mental states.

The concept of autism is a significant contribution from child psychiatry that has entered wider culture and public consciousness, and has evolved significantly over the last four decades. Taking a rather personal retrospective, reflecting on our own time in autism research, this review explores changes in the concept of autism and the implications of these for future research. We focus on seven major changes in how autism is thought of, operationalised, and recognised: (1) from a narrow definition to wide diagnostic criteria; (2) from a rare to a relatively common condition, although probably still under-recognised in women; (3) from something affecting children, to a lifelong condition; (4) from something discreet and distinct, to a dimensional view; (5) from one thing to many 'autisms', and a compound or 'fractionable' condition; (6) from a focus on 'pure' autism, to recognition that complexity and comorbidity is the norm; and finally, (7) from conceptualising autism purely as a 'developmental disorder', to recognising a neurodiversity perspective, operationalised in participatory research models. We conclude with some challenges for the field and suggestions for areas currently neglected in autism research.

El concepto de autismo es una contribucion significativa de la psiquiatria infantil que ha entrado en una cultura y conciencia publica mas amplias, y ha evolucionado significativamente en las ultimas cuatro decadas. Tomando una retrospectiva bastante personal, reflexionando sobre nuestro tiempo en la investigacion del autismo, esta revision explora los cambios en el concepto de autismo y las implicaciones de estos para futuras investigaciones. Nos centramos en siete cambios importantes en la forma en que se piensa, se opera y se reconoce el autismo: 1) desde una definicion estrecha hasta criterios de diagnostico amplios; 2) de una condicion rara a una condicion relativamente comun, aunque probablemente todavia subreconocida en las mujeres; 3) desde algo que afecte a los ninos, hasta una condicion de por vida; 4) de algo discreto y distinto, a una vista dimensional; 5) de una cosa a muchos “autismos”, y una condicion compuesta o “fraccionada”; 6) desde el enfoque en el autismo “puro”, hasta el reconocimiento de que la complejidad y la comorbilidad son la norma; y, por ultimo, 7) de conceptualizar el autismo puramente como un “trastorno del desarrollo”, a reconocer una perspectiva de neurodiversidad, operacionalizada en modelos de investigacion participativos. Concluimos con algunos desafios para el campo y sugerencias para areas actualmente descuidadas en la investigacion del autismo

The concept of autism is a significant contribution from child psychiatry that has entered wider culture and public consciousness, and has evolved significantly over the last four decades. Taking a rather personal retrospective, reflecting on our own time in autism research, this review explores changes in the concept of autism and the implications of these for future research. We focus on seven major changes in how autism is thought of, operationalised, and recognised: (1) from a narrow definition to wide diagnostic criteria; (2) from a rare to a relatively common condition, although probably still under-recognised in women; (3) from something affecting children, to a lifelong condition; (4) from something discreet and distinct, to a dimensional view; (5) from one thing to many ‘autisms’, and a compound or ‘fractionable’ condition; (6) from a focus on ‘pure’ autism, to recognition that complexity and comorbidity is the norm; and finally, (7) from conceptualising autism purely as a ‘developmental disorder’, to recognising a neurodiversity perspective, operationalised in participatory research models. We conclude with some challenges for the field and suggestions for areas currently neglected in autism research.