Tuesday, 31 March 2015

Can we Really Afford it? (Part 1 of 2)

This post is the first in a two part series, wherein I consider the notion of “affordances”, that first appeared in the work of the ecological psychologist J.J. Gibson (1966), and ask whether or not this concept can be applied to social perception, or more particularly, to the perception of faces. 

In the first post I will outline a positive account of this position as it is offered by those who champion it. However, in the second post - available here next week - I will present some of the difficulties with this position.

The ecological approach to the question of face perception is offered as an alternative to the more traditional cognitivist approaches. Such approaches tend to be quite limited in the questions they ask, mostly asking what are the mechanisms within our brains that organise the perception of someone’s face, and how do they operate. Moreover, the attributes of face perception traditional approaches are concerned with are also rather limited, prefering to focus only on the perception of identity, emotion and directional attention.

Ecological psychologists, on the other hand, suggest that an inclusive account of facial perception must not only account for the perception of emotion, identity and directional attention, but should also seek to explain the perception of social category, of psychological and physical traits, sexual orientation and so on.

Additionally, the ecological approach is concerned with questions of how face perception facilitates adaptive behaviour, it asks what information is available in the stimulus that might communicate various traits; and it takes into consideration the perceiver qualities that mediate facial perception. 

The assumptions of the EA hinge in large part on a particular piece of jargon, that of the ‘affordance’ (Gibson, 1979). Thus, prior to making any explication we will first clarify what is intended with this notion of affordance.

Affordances are posited as a way of answering the question of meaning in perceptual experience. In the cognitivist approach meaning is imposed upon sensory input through higher mental processes. For Gibson, however, meaning is functional significance and it is picked up by the perceptual system from the structured information embedded in ambient light (sound, smell, feel etc.) reflecting off the surfaces of objects (McGann, 2014). This can be translated into the realisation that familiar objects are perceived according to their functional significance for us (what we can do with them), and different perceivers are attuned to different information, and so the same object takes on different meanings for different people, or the same person at different times.

Although traditionally considered with respect to physical objects in the environment, taken to its logical extension it seems unsurprising that researchers have applied this concept of affordances to the social realm, and that it might be further extended to the perception of faces was almost inevitable. Gibson himself suggests as much when he quotes Koffka (1935, p. 7) “a fruit says 'eat me'; water says 'drink me'; thunder says 'fear me'; and woman says 'love me' " (J. Gibson, 1979, p. 138).

It is worth noting that perception is said to be direct in this model i.e. the perceptual mechanism is adequate to derive functional significance from the environment, and is not in need of any intervening from higher order cognition, their is no ‘mental gymnastics’ involved (Chemero, 2009).

And so, any satisfying ecological account of face perception should be shown to comply with the following assumptions:1.) that the perception of faces guides adaptive behaviour through the perception of affordances; 2.) that such perceptions often rely upon dynamic multimodal stimulus information, and; 3.) who perceives any particular affordance is for whom it is behaviourally relevant - who is attuned to it.

Affordances in this account are not simply for action, but also for interaction.

1.) FP guides adaptive behaviour through the perception of affordances. 

Some of the best evidence in support of this position is research concerning facial attractiveness. What the findings suggest is that people with attractive faces are perceived more positively and tend to be afforded preferential treatment: attractive faces are said to facilitate approaching behaviour, whereas unattractive faces promote avoidance behaviour in perceivers (Zebrowitz, 1997).

An explanation that suggests the adaptive value of these findings is found in the effect of anomalous face overgeneralisation (AFO). This concept suggests that the adaptive value of recognising an individual who is in a diseased state, or has ‘bad genes’, has instilled a certain disposition to respond avoidently to facial attributes - i.e. anomalous faces afford avoidance - indicative of low-fitness, and this readiness becomes overgeneralised to healthy but unattractive persons whose facial features resemble those of genuine low-fitness (Zebrowitz and Rhodes, 2004).

This tendency to overgeneralise is often explained within the purview of error management theory (EM). EM suggests that we are biased towards making judgments that have even a slight adaptive value. Thus, someone who looks to have low-fitness, is better to be responded to as having low-fitness, rather than taking the chance that they just look that way (Haselton & Buss, 2000).  

In consideration of such findings, ecological psychologists deduce that perception of faces affords concomitant behaviours that are in many cases adaptive, facilitating the adaptive aims of both the species, and the individual. 

 2.) Perception of affordances often relies upon information from numerous interdependent facial qualities and this information is often disclosed temporally.

In a study by Smith et al. (2005), considering the notion of the interdependence of face regions in the expression of various emotions, they found that perceivers use information gleaned from different but interdependent face regions to recognise varying emotions. Moreover, Minghault & Chaudhuri (2003) found that perception of facial orientation relative to the body leads to individuals being perceived as proud (dominant etc.) when the head is tilted back or ashamed (submissive etc.) when the head is tilted forward. 

Many studies of emotional perception have highlighted the importance of dynamic stimuli information also. Sato and Yoshikawa (2007) found that emotional arousal was stronger in perceivers when viewing dynamic facial expressions as opposed to more simple static displays. 

 3.) The person who perceives the functional significance of a particular facial attribute is often the person for whom it is functionally or biologically relevant.

One good demonstration of attunement is that women at the time of peak fertility tend to show a stronger preference for facial symmetry in men being considered as short term mates (Little et al., 2007). This suggests that perceivers are attuned to the ostensible adaptive value of the mate at times when such perceptions are most advantageous.  
Though not to be found in the face perception literature, a study by Wheeler et al. (2009) asked the question of whether individuals scoring “higher on psychopathic traits would be better able to judge vulnerability to victimisation after viewing short clips of targets walking” (p.635). What they found was that higher scores on the SRP - III (Self-report Psychopathy Scale: Version III) were associated with greater accuracy in assessing the vulnerability of targets to victimisation. What is apparent in this finding is the tight coupling between the willingness to victimise, and the easily victimizable. Psychological vulnerability - i.e. the affordance of victimizable - is communicated in the gate of the walk etc. but much more so to those of a psychopathic disposition than normal perceivers. 

For some, this is taken as compelling evidence for the construct of attunement in social perception.

And so, for certain ecological psychologists (Valenti et al, 1991McArthur & Baron, 1983) the ecological approach to face perception is thought to be valid; for in bearing out the foregoing assumptions the empirical findings hold true to the basic principles of ecological psychology and thus justify its application in the social domain.

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