Foraging zebra finches (Taeniopygia guttata) are public information users rather than conformists

Abstract

Social learning enables adaptive information acquisition provided that it is not random but selective. To understand species typical decision-making and to trace the evolutionary origins of social learning, the heuristics social learners use need to be identified. Here, we experimentally tested the nature of majority influence in the zebra finch. Subjects simultaneously observed two demonstrator groups differing in relative and absolute numbers (ratios 1 : 2/2 : 4/3 : 3/1 : 5) foraging from two novel food sources (black and white feeders). We find that demonstrator groups influenced observers' feeder choices (social learning), but that zebra finches did not copy the majority of individuals. Instead, observers were influenced by the foraging activity (pecks) of the demonstrators and in an anti-conformist fashion. These results indicate that zebra finches are not conformist, but are public information users.

Keywords: conformity; frequency-dependent learning; social learning; zebra finches.

Figure 1.

Experimental set-up: observer and demonstrator cages contained sand and grit bedding and were equipped with two water dispensers (grey squares) and three perches (not shown). Black and white feeders were added at the indicated spots during the demonstration (for demonstrators) and testing (for observer) phases. The feeders in the observer cage (depicted with dashed lines) were absent during demonstrations and only added after the demonstration was over and the curtain (dashed line between the cages) had been shut again. The location placement of the black and white feeders was counterbalanced across trials. The cages stood 70 cm apart and could be visually separated by a dark textile curtain that was suspended from above and hung midway between the two cages.

Figure 2.

Regression of whether the observer bird's first peck was at the black feeder (y-axis) on to (a) the proportion of demonstrator birds at the black feeder (the red shaded area corresponds to conformist transmission), (b) the proportion of demonstrator visits to the black feeder and (c) the proportion of demonstrator pecks at the black feeder (all on x-axis). Points show the raw data (semi-transparent in (a) as many overlap), while lines show the median estimate (solid) and 95% central credible interval (dashed). Model estimates for coefficients are included in all panels. Note that strong evidence of an effect is only found for pecks, and the effect is anti-conformist (c). For versions of this figure that directly show the posterior samples or raw data averages, see the electronic supplementary material.