The research was conducted by C. Garcia-Co, A. Dewulf, F. Verbruggen, J. Morales and W. Müller, working across the University of Antwerp, Ghent University and the Spanish National Research Council. The team took advantage of a well-characterised lab-bred population of domestic canaries (Serinus canaria), a species in which maternal aggression toward nestlings varies noticeably between females. Because the birds were kept under controlled, semi-natural conditions, the researchers could observe maternal behaviour at the nest directly, define each mother’s aggression phenotype through careful observation, and then measure cognition in both mothers and offspring using standardised behavioural assays. This combination of ecological realism and experimental control is rare, and it is precisely what made the study capable of addressing the transmission question head-on.

Inhibitory control was assessed with a detour task, one of the most widely used benchmarks of self-regulation in comparative psychology. In this task, an animal can see a reward through a transparent barrier but cannot reach it directly; success requires suppressing the instinctive, straight-line approach and instead taking an indirect route around the obstacle. The task sounds simple, yet it reliably separates individuals: those with stronger response inhibition tend to solve the detour quickly, while those prone to impulsive approach repeatedly bump into the barrier. Detour performance has been linked to a range of ecological and social traits across species, which is exactly why the canary team expected that mothers differing in aggression might also differ in how well they executed the task. The transparent-cylinder style detour used here forced each bird to inhibit a prepotent response in favour of a learned, circuitous solution.

The first key prediction concerned the mothers themselves. If maternal aggression reflected a failure of behavioural inhibition, then aggressive females should have performed worse on the detour task than their more tolerant counterparts. The data did not support this. When the researchers compared detour performance between aggressive and non-aggressive mothers, they found no meaningful differences in inhibitory control between the two groups. Aggressive mothers were neither slower to learn the detour nor more likely to make impulsive approach errors. In other words, in this population, striking a nestling does not appear to be the behavioural signature of a female who cannot inhibit her impulses. The cognitive-deficit hypothesis, at least in its simplest form, failed to find support in adult canaries.

The second and arguably more ambitious prediction concerned the offspring. Early-life stressors, including hostile social environments, are known in many species to leave lasting marks on behaviour and cognition, and some theoretical frameworks propose intergenerational transmission of such effects. The canary study asked two distinct questions: does growing up with an aggressive mother impair a juvenile’s later inhibitory control, and do offspring resemble their biological mothers in detour performance regardless of who raises them? To disentangle these possibilities, the team employed a cross-fostering design, in which chicks were swapped between nests so that some were raised by females other than their biological mothers. This elegant manipulation separates post-hatching environmental influences, such as exposure to maternal aggression, from prenatal and genetic contributions carried by the biological mother.

Once again, the results were unambiguous in their null finding. Juvenile inhibitory control was not influenced by post-hatching exposure to maternal aggression, nor was it predicted by the aggression phenotype of the biological mother. Moreover, the researchers detected no mother–offspring covariation in inhibitory control: daughters and sons did not systematically resemble either the foster mothers who raised them or the biological mothers who produced them in this cognitive measure. Taken together, these findings suggest that maternal aggression in canaries is unlikely to be transmitted across generations through the pathway of inhibitory control, and that the cognitive trait measured by the detour task is not a heritable or environmentally transmitted correlate of aggressive parenting in this system.

Amid all the null results, the study did uncover something striking: powerful ontogenetic effects. Juvenile canaries took substantially longer to complete the detour than adults, but they improved more steeply across trials, a pattern consistent with a post-hatching maturation of inhibitory control. In other words, young birds start out impulsive and slow to suppress the direct approach, but with experience and development their self-regulation improves rapidly. This developmental trajectory is itself scientifically important. It demonstrates that inhibitory control, as measured by the detour task, is not a fixed trait but a capacity that changes markedly with age in canaries, echoing findings from a broad range of vertebrates in which response inhibition continues to mature well after fledging or weaning.

The authors argue that their findings carry a broader methodological lesson for the field of comparative cognition. Inhibitory control measures are notoriously task- and context-specific: an individual that performs poorly on one inhibition assay may excel on another, and performance can be swayed by motivation, neophobia, motor capacity and prior experience. The absence of a link between maternal aggression and detour performance in canaries does not necessarily mean that no cognitive difference exists between aggressive and tolerant mothers; it may mean that the detour task captures only one facet of a multidimensional construct. The study therefore serves as a caution against overinterpreting single-task measures and against building sweeping theories of behavioural syndromes on the basis of one assay in one context.

The research also speaks to a long-running debate in behavioural ecology about the origins and persistence of harmful parental behaviour. Maternal aggression toward offspring represents an early-life social stressor that has been linked to long-term behavioural differences in several species, making its underlying mechanisms a matter of genuine scientific and welfare interest. By showing that this aggression is unlikely to reflect deficits in inhibitory control, and equally unlikely to be transmitted to offspring via that cognitive route, the canary study narrows the space of plausible explanations. Future work may need to explore alternative mechanisms, including hormonal states, stress physiology, neural circuits of social behaviour, or entirely different cognitive dimensions. The study was approved by the ethics committees of the University of Antwerp and Ghent University, and the birds remain part of an ongoing transgenerational transmission experiment, meaning this carefully bred population may yet reveal what does and does not pass from mother to chick. For now, the message is a refreshing dose of rigour: a plausible and popular hypothesis, tested thoroughly, simply did not hold up, and science is stronger for knowing it.

Subject of Research: The relationship between maternal aggression and inhibitory control, and its potential intergenerational transmission, in domestic canaries.

Article Title: No evidence for a link between maternal aggression and inhibitory control across generations in domestic canaries

Article References: Garcia-Co, C., Dewulf, A., Verbruggen, F., Morales, J., & Müller, W. (2026). No evidence for a link between maternal aggression and inhibitory control across generations in domestic canaries. Animal Cognition. https://doi.org/10.1007/s10071-026-02110-z

Image Credits: AI Generated

DOI: 10.1007/s10071-026-02110-z

Keywords: inhibitory control, maternal aggression, detour task, domestic canaries, animal cognition, cross-fostering, transgenerational transmission, response inhibition, ontogeny, behavioral ecology, early-life stress, Serinus canaria