  We consider a population of mobile agents able to make noisy observation of
the environment and communicate their observation by production and
comprehension of signals. Individuals try to align their movement direction
with their neighbors. Besides, they try to collectively find and travel towards
an environmental direction. We show that, when the fraction of informed
individuals is small, by increasing the noise in communication, similarly to
the Viscek model, the model shows a discontinuous order-disorder transition
with strong finite size effects. In contrast, for large fraction of informed
individuals, it is possible to go from the ordered phase to the disordered
phase without passing any phase transition. The ordered phase is composed of
two phases separated by a discontinuous transition. Informed collective motion,
in which the population collectively infers the correct environmental
direction, occurs for high fraction of informed individuals. When the fraction
of informed individuals is low, misinformed collective motion, where the
population fails to find the environmental direction becomes stable as well.
Besides, we show that an amount of noise in the production of signals is more
detrimental for the inference capability of the population, and increases the
density fluctuations and the probability of group fragmentation, compared to
the same amount of noise in the comprehension.
