I am sure that you do not mean literally the sum since there is nothing to sum. For instance, 50% perceive the best apple is the yellow and 50% perceive the best is the red one, the social perception neither will be very yellow and very red nor green.

I think the best statistics supporting exploring and understanding the social perception based on individual's perception are the clustering (segmentation) and Principal Component Analyses (PCA).

The clustering helps to identify internally homogeneous groups what differ from other groups, and based on the individual perceptions in the group (means, frequencies, distribution, t-tests, etc.) and demographics the characteristic of the segment is explorable, describable and explainable.

PCA helps to identify the important factors and clean from the noise.

When you have the important factors and your segments, you have to consider the dynamics among the groups because this is how society works.

Article Public perception of bioenergy in North Carolina and Tennessee

Conference Paper Consumer Segments by Perception of Biofuels

You might also refer to the work of Garriy Shteynberg and collaborators: Article Shared Attention

Hello,

I think social perception of an event is different from a sum of individual perceptions; because of the attribution. Social perception of an event from an individual view, affected by self-perception and person-perception, which is affected by many qualities as; personality, physical appearance, behavioral tendencies, moral stature, athletic prowess, and the like, all affect the focal point of perception and attribution.

While individual perception represents other attribution; two sets of approaches to group perception predominate: those concerned with reference group choices and effects, and those addressing social categorization processes. (Farmer 1992) .

I hope you find my answer helpful for you, with all my best,

Samah.