The Private Life of... turns its attention this week towards the mental lives of pigs. Presented by Jimmy Doherty the series sets out to reveal the hidden lives of farmyard animals using a variety of simple psychometric testing measures. Set on a farm in Dartmoor, Jimmy embarks on a quest to uncover the answers to questions such as, how sensitive is a pigs nose? Why can they find truffles underground? How do piglets find the right teat to feed from? (and by far the most interesting question of the episode), Can pigs recognise themselves in a mirror?
Traditionally the mirror test is a measure of self-awareness developed by Gordon Gallup Jr. (1970). Inspired by the written accounts of Charles Darwin (1809-1882) and his reports on holding a mirror up to an orangutan and recording the corresponding facial and bodily actions. Darwin suggested that these expressions were ambiguous and either signified that the primate was making expressions at what it perceived to the another animal, or it could be playing a sort of game with a new toy - the animal might not be recognising itself but instead be attributing that image to another or, alternatively it might be recognising that the object that it holds represents an image of itself and so demonstrate an understanding of self-awareness.
It was through these observations that Gallup devised a test that attempted to gauge self-awareness by trying to discover whether an animal could recognise its own reflection in a mirror mark test. Also referred to as the rouge test, the experiment is conducted covertly placing a mark of the participants body. Ideally the spot should be placed in an area that is clearly visible to the animal in the mirror and can be physically reached with an appendage (reaching in this manner might suggest the identification of the foreign agent). The control measure would therefore be a mark to an accessible part of the body but still remains out-of-sight. Researchers then observe behaviours that might show the recognition of the placed mark.
To date animals that have passed the mirror test include all of the great apes, bottle-nosed dolphins, orcas, elephants and European magpies, with human children failing this test until they reach 18 months old. Not surprisingly, pigs have previously been found to pass a variation of the mirror mark test, using the mirrors image to obtain information about a food source (Broom, Sena and Moynihan, 2009). Under the watchful eye of Broom, it was precisely this measure of mirror self recognition that the programme used during the procedure.
Whilst the total amount of piglets used during testing was relatively low (expectantly due to the time constraints of the programme), the piglets did show a marked preference towards the location of the food when the mirror was present, suggesting that each piglet used the information from the mirror and its surroundings, deduced the relationship between the two and acted accordingly in finding the food source. This therefore might suggest a form of assessment awareness in pigs. Whilst the results were by no means conclusive, with a friend commenting on the suitability of the mirror mark test on an animal that has no flexible appendages and whether or not the piglet recognised itself in relation to the food (or just simple recognised the food), it does highlight the need for further research into the areas of animal cognition and self recognition. I therefore suggest that what is needed are better designed measures of self-awareness and the acknowledgement of these mental lives in order to help in the welfare of all animal species.