WUD Flupa Part 1: Smartphone Street Observer

The latest WUD (World Usability Day) was held in Criteo’s sleek offices, with 3 interesting conferences on innovation. Read on for the first article in our 3 part series covering some of the conference’s highlights: Smatphone Street Observer, Human Factor and Designers in ergonomy, and Elegantt for Trello.

The idea of the Smartphone Street Observer

(Nabil Thalmann – Personae user lab)


The goal is to understand the different uses of mobile phones under the assumption that although “making declarations is good, it is often not enough.” Indeed, users’ memories and anecdotal usage tend to differ from reality, therefore it’s necessary to observe users in their “natural” usage.

This is exactly what Steven Hoober noticed while observing users’ mobile habits and behavior. However, because he did not interview the users after this period of observation, certain information is missing from his studies, such as: users’ ages, the size and age of their phones, what they were doing on their phones, etc.   

Therefore, the idea of the “Smartphone Street Observer” is to pair observation with user interviews to collect a richer quality and quantity of information. 

First observations

They began in “quick & dirty” style, in which they conducted a first wave of tests in the streets of Nantes, France. First, they had to check that it was feasible to observe people in the street, and then to approach them and ask them what they were doing on their phones during the interview phase.

Out of 1,024 people observed, 515 were directly questioned.


5 overall trends emerged on how people hold their smartphones


  • The usages varied from generation to generation. Youth (under 35) used their thumbs more often (figures A and B) whereas users older than 35 tended to use their index fingers (figure E).
  • Both hands are often used for activities that require precision or while writing messages
  • A majority of left-handed users held their phones in their right hands
  • 64% of smartphones have a screen size larger than 4” (as the screen size of smartphones increases, so will usage requiring two hands)
  • The privileged access area remains the center of the screen

Observing how people use their phones

These interviews were used to find out what users were doing on their phones at the time (they were observed in action while walking on the street).

The top activities were:


  • Searching for or looking up information
  • Writing messages

Strangely enough, few people were looking for directions. However, we wonder if this would have been different had the study been conducted in a larger city such as Paris.

Another study: in a Dublin bar 

The first thing that needs to be noted is the radical change in context from the first study. Out of 150 users observed:

  • 56% of people used only one hand (while their second hands were busy holding beer)
  • Users tended to employ landscape mode on their phones more often due to the social context of the bar (showing and sharing content with others, taking photos, etc.)

This shows that major trends tend to emerge depending on the context of the study. If you’re interested in reading the full study, you can find it in French here.

Stay tuned for the 2nd article in our WUD series: on the human factor and designers.