Mirrors provide a lot of useful information about the nature of an organism’s self-perception. The ability to recognise one’s mirror image as belonging to oneself indicates an awareness of the fact that one’s own consciousness resides within a body that resembles those with which one frequently interacts. This realisation is only a few steps away from the recognition that others, who possess bodies similar to that of oneself, also have thoughts and feelings just like oneself. This latter stage of understanding is known as “theory of mind”. Accordingly, a number of developmental theorists link children’s attainment of the self-awareness that is necessary for self-recognition in a mirror to the emergence of theory of mind.
However, children typically take about two years to recognise themselves in the mirror. Amsterdam (1972) describes the developmental changes observed in mirror-viewing infants as follows:
“the first prolonged and repeated reaction of an infant to his mirror image is that of a sociable “playmate” from about 6 through 12 months of age. In the second year of life wariness and withdrawal appeared; self‐admiring and embarrassed behaviour accompanied those avoidance behaviours starting at 14 months, and was shown by 75% of the subjects after 20 months of age. During the last part of the second year of life, from 20 to 24 months of age, 65% of the subjects demonstrated recognition of their mirror images.”
But research also indicates that past experience with mirrors is helpful in learning to recognise one’s image therein. I therefore thought it would be useful to record Dahlia’s behaviour in front of a mirror over her first years of life. Here are some videos that I have already recorded – I intend to continually add to this collection until Dahlia has ambiguously achieved self-recognition. Along the way, look out for interesting behaviours such as experimental/investigative movements (i.e. movements that appear to be designed to test the extent to which one’s own actions are imitated by the body observed in the mirror) and/or anything else that you think indicates some interesting cognitive goings-on.
Experimenters often focus on cues such as performing self-directed actions guided by visual input from the mirror (e.g. trying to rub away a dirty mark from one’s face that can only be seen in the mirror) or performing actions that appear intended to test the hypothesis that one’s own behaviour is immediately mimicked by the image in the mirror.
Personally, I am interested to see whether Dahlia’s repeated exposure to mirrors helps her to understand what she is seeing at an earlier-than-typical age. Given that this kind of self-understanding is important for other-understanding (Flavell, 1999), I hope that her repeated mirror exposure will facilitate the acquisition of skills related to theory of mind.
 Amsterdam, 1972; Anderson, 1984; Roma et al., 2007
 Gallup, 1998; Perner, 1991
 Amsterdam, 1984. Mirror self-recognition in infants and humans is usually assessed by observing the extent to which an individual utilises information attained from the mirror to act upon their own body. Specifically, a mark is placed on an area (usually the forehead) that can only be seen in the mirror. If, upon seeing their reflection, the individual touches the area of the forehead on which the mark has been placed, then self-recognition can be inferred. For more details and additional methodological considerations, see Chang et al., 2015.
 Chang et al., 2015
Amsterdam Mirror self-image reactions before age two Dev. Psychobiol., 5 (1972), pp. 297–305
Anderson, J. R. (1984). Monkeys with mirrors: Some questions for primate psychology. International Journal of Primatology, 5(1), 81-98.
Chang, L., Fang, Q., Zhang, S., Poo, M. M., & Gong, N. (2015). Mirror-induced self-directed behaviors in rhesus monkeys after visual-somatosensory training. Current Biology, 25(2), 212-217
Flavell, J. H. (1999). Cognitive development: Children’s knowledge about the mind. Annual review of psychology, 50(1), 21-45.
Gallup, G. G., Jr. (1998). Self-awareness and the evolution of social intelligence. Behavioural Processes, 42, 239–247.
Perner, J. (1991). Understanding the representational mind. Cambridge, MA: MIT Press.
Roma, P. G., Silberberg, A., Huntsberry, M. E., Christensen, C. J., Ruggiero, A. M., & Suomi, S. J. (2007). Mark Tests for mirror self‐recognition in capuchin monkeys (Cebus apella) trained to touch marks. American Journal of Primatology, 69(9), 989-1000.