A products form (shape, colour and label) communicates information to shoppers more quickly than the individual components of its packaging. It creates the initial impression and generates inferences regarding other product characteristics such as durability, dollar value, technical sophistication, ease of use, sex role appropriateness and prestige. (Block, 1995)

In this way visual elements of the form transfer non-verbal information. (Vitalija Butkeviciene, 2008)

A good example of form influencing product appropriateness is this test that found Dove’s Women’s deodorant packaging that was taller and thinner package suggested a more feminine product than its competitors. (Young S. , 2004)

Another good example of using form, this time to increase consumer penetration, can be found in the Nordic wine market. Tetra packs of wine were introduced (a bag in a box) and sales rose given the popularity of the away from home occasion. In this instance the packaging form was much friendlier than bottles. (Packaging News, 2011)

An interesting aside about packaging size is that shoppers are less responsive to package size changes than to package price. A Nielsen study in 2007 concluded that “the demand elasticity with respect to package size is approximately one-fourth of the magnitude of the demand elasticity with respect to price.” (Cakir & Balagtas)

When packaging shape is able to attract more attention than those around it, it is also perceived as containing greater volume than same sized packs that receive less attention! (FOLKES & MATTA, 2004)

References
Block, P. H. (1995, July). Seeking the ideal form: Product design and consumer response. Journal of Marketing.
Cakir, M., & Balagtas, J. V. (n.d.). Consumer Response to Package Downsizing:An Application to the Chicago Ice Cream Market. Retrieved MY 5, 2014, from http://ageconsearch.umn.edu/bitstream/123980/2/Cakir_Balagtas_ConsumerResponsetoPackageDownsizing.pdf
FOLKES, V., & MATTA, S. (2004). Judgments of Product Volume: Attention as a Mental Contaminant. JOURNAL OF CONSUMER RESEARCH Vol. 31.
Packaging News. (2011, July 8). Drinks: the search for a refreshing new look. Retrieved June 19, 2012, from Packaging News: http://www.packagingnews.co.uk/markets/drinks/the-search-for-a-refreshing-new-look/
Vitalija Butkeviciene, J. S. (2008). Impact of Consumer Package Communication on Consumer Decision Making. Retrieved June 20, 2012, from Kauno technologijos universitas: http://www.ktu.lt/lt/mokslas/zurnalai/inzeko/56/1392-2758-2008-1-56-57.pdf
Young, S. (2004, Winter). Breaking Down the Barriers to Packaging Innovation. Design Management Review.