Children develop different senses of self at a couple of different ages. Normally developing children pass the 'Sally-Anne' test at about 4 years of age and the 'Mirror test' at around 18 months. My question refers to these cognitive tests and the relation any loss of sense has on these developmental stages. I'm aware of the case studies of down-syndrome, and autism however i'm currently interested in the effect of blindness, loss of hearing, smell and if the effects of reduced sensory perception causes a delay in when these tests are passed.
This question is quite broad, firstly, because these tests measure different (though interrelated) cognitive faculties and at different developmental stages and secondly because there is a lot to say for each sensory impairment. However, it touches on quite interesting topics for which there have been many studies and I think a summary of the findings can be made without being too big. For this purpose, it will be more useful to talk about the capacities that are associated with the tests rather than just studies with these tests, in order to get the bigger picture. Also , I would like to point that my answer is almost entirely about visual and auditory impairment because that is what I could find. If anyone knows of anything else, feel free to edit my post.
- The Sally-Anne test is used by developmental psychologists to test the ability to attribute false belief which is a measure of one's theory of mind. Theory of mind is the "ability to attribute mental states — beliefs, intents, desires, pretending, knowledge, etc. — to oneself and others and to understand that others have beliefs, desires, and intentions that are different from one's own". As you described, this skill is almost fully developed at around 5 years of age.
- The Mirror test or Rouge test (specifically for human infants) is used by develompental psychologists to test self recognition/self awareness which can be defined as "the ability to become aware of one’s own mental and bodily states (e.g. perceptions, attitudes, opinions, intentions to act) as one’s own mental and bodily states" (Vogeley & Fink, 2003). As you described infants pass this test around 18 months of age, however it has been suggested that self-awareness should not be viewed as a unitary achievement but rather as a process that has successive stages being fully developed at around 5 years of age (Rochat, 2003).
Both these tests have to do with the sense of self as distinct from other beings which according to the proposed developmental pattern that it follows is also not to be treated in a unitary fashion (for a review see Baumeister, 2010 and Geangu, 2008). Theory of mind is more associated with the aspect of self which is called interpersonal self while self recognition as measured by the mirror test is associated with what has been called as bodily self or body image (Geangu, 2008).
So referring to your question about the effect of sensory impairment to these abilities:
- Regarding the theory of mind, there have been studies on blind and deaf children.Yagmurlu et al (2005) summarized such studies in their article.
Research with deaf children has emphasized the role of environment, particularly exposure to conversation, in theory of mind development (Peterson & Siegal, 2000). In their review, Peterson and Siegal (2000) have shown that children’s access to conversation is correlated with theory of mind development. They found that profoundly deaf children with hearing parents who generally have almost no access to any communication means until they start school are more severely impaired in theory of mind development than orally trained deaf children who use hearing aids or deaf children with deaf parents who use sign language from an early age (Peterson & Siegal, 1998, 1999; Woolfe, Want, & Siegal, 2002) Further, Peterson and Siegal (2000) argue that early conversations, especially those about imaginary or abstract ideas, or about beliefs appear to be necessary cognitive input in theory of mind development.
Research on children with visual impairment also shows that these children are delayed in theory of mind development (Green, Pring, & Swettenham, 2004; McAlpine & Moore, 1995; Minter, Hobson, & Bishop, 1998; Peterson, Peterson, & Webb, 2000). Visual impairment may limit communication with parents due to lack of shared visual experience (Minter et al, 1998), and may also impair understanding what is in others’ minds because access to visual cues is cut (Peterson et al., 2000). Despite this disadvantage, language skills of visually impaired children continue to improve, and their social experiences with peers and teachers become richer, which contribute to a gradual acquisition of theory of mind skills (Green et al., 2004)
Reviewing the findings of some of the above studies Malle (2002) suggested that anything that prevents the development of language and communication in general, is likely to cause a delay in the development of theory mind.
- Regarding the mirror test, as it is dependent on visual cues alone, I don't think blind people would be able to pass it, while there is no reason to expect that people with hearing or olfactory impairment wouldn't pass it. Of course an inability to pass this test does not lead to the conclusion that blind people and especially congenitally blind people lack a sense of self and specifically a body image. This is likely achieved through different sensory inputs. Geangu (2008) noted that while a perceptual sense of self requires the integration of sensory information such as visual, auditory, tactile and kinesthetic, it is the proprioception and visual processing of the body that have higher relevance for the construction of a personal representation of one’s body in space. Bermudez (1998) had a slightly different opinion.
The developing child may first acquire a sense of self when it becomes able selectively to attend , in however ill differentiated a fashion , to its individual body parts in the somatosensory modality . It would then become acquainted with the internal causal consistency of their positions and displacements relative to its own volitions . The assumption that the visual channel soon reveals to the infant which body parts are its own (Neisser 1978) may be mistaken . Logically , the visual channel should soon betray which (body) parts are always present and one ' s own and which (external ) objects are present only sometimes (Neisser 1978) . But the mechanisms for accomplishing this during development (Gibson 1969, Bower 1974) may follow rather than precede somatosensory attending . Poeck and Orgass (1964a, 1964b) found that blind children developed knowledge of their body at about the same age as sighted children
Also, maybe blind people can rely on auditory input from early age to form a sense of self and this view is supported by a recent imaging study (Ma & Han, 2011).
So, to conclude this section, while I didn't find enough empirical data on blindness or anything on deafness to support a typical development of self awareness in these people, I don't think there are enough reasons to think that such a developmental delay occurs when these sensory systems are impaired.