Comparison of different behavioural measures between the <i>Mechanical UMO</i> and <i>Mechanical Human</i> condition during a 30 sec period in each trial when dogs were allowed to move freely.

<p>a; mean duration of looking at the partner (UMO or Human) b; mean frequency of gaze alternations between the partner (UMO or Human) and the place of food c; ratio of dogs who touched the partner with its muzzle (UMO or Human) d; mean latency of touching the partner with muzzle (UMO or Human).</p

The three test partners: a; <i>Mechanical UMO</i> b; <i>Social UMO</i> c; <i>Mechanical Human</i> (for more details see text).

<p>The three test partners: a; <i>Mechanical UMO</i> b; <i>Social UMO</i> c; <i>Mechanical Human</i> (for more details see text).</p

Tolerance of eye-contact.

<p>Mean duration of eye-contact during a 30 sec period while the subject was gently held by the owner or the experimenter without restricting head-movements. (***: p<0.001, ns.: p>0.05; error bars represent SD).</p

Correct choices out of six trials in the two choice situations based on directional signals.

<p>In the sustained touching trials the subject was released while the experimenter was still touching the hiding place. In the momentary pointing trials the experimenter withdraw her hand following the pointing gesture before the subject was released to make a choice. Red line represents chance performance. (***: p<0.001, **: p<0.01, ns.: p>0.05; median, quartiles, whiskers and outliers).</p

Analysis of the dogs’ behavioural variables during the first and last trials in each condition.

<p>a; mean duration of looking at the partner (UMO or Human) b; mean frequency of gaze alternations between the partner (UMO or Human) and the place of food c; mean latency of looking at the partner (UMO or Human) d; mean latency of touching the partner with muzzle (UMO or Human) (* p<0.05, ** p<0.005).</p

Comparison of the ratio of looking dogs and the latency of looking at the partner in the <i>Mechanical UMO</i>, <i>Mechanical Human</i> and <i>Social UMO</i> conditions during a 30 sec period in each trial when dogs were allowed to move freely.

<p>a; ratio of dogs looked at the partner b; mean latency of looking at the partner.</p

Experimental room and paths of partners’ move.

<p>O = place of the owner, D = place of the dog, E = position of Experimenter 2, F = three plates as potential food sources, A = start point of the partner, B = place of the box. Green circles indicate the location of the cameras. The triangle presents distance between the dog the partner and the place of the inaccessible food (box). Black lines show the paths of the partner to the plate (location of the food), to the box and back to the start point. Orange lines show the different path of the <i>Social UMO</i> compared to the Mechanical partners (UMO or Human) to each plates, box and different start points during the 2^nd to 6^th trials (red X). Blue lines show the path which in the partner goes back to the box from the start point and bring the food to the dog.</p

An Investigation on Social Representations: Inanimate Agent Can Mislead Dogs (<i>Canis familiaris</i>) in a Food Choice Task

<div><p>The nature of mental representation of others plays a crucial role in social interactions. Dogs present an ideal model species for the investigation of such mental representations because they develop social ties with both conspecifics and heterospecifics. Former studies found that dogs’ preference for larger food quantity could be reversed by humans who indicate the smaller quantity. The question is whether this social bias is restricted to human partners. We suggest that after a short positive social experience, an unfamiliar moving inanimate agent (UMO) can also change dogs’ choice between two food quantities. We tested four groups of dogs with different partners: In the (1) <i>Helper UMO</i> and (2) <i>Helper UMO Control</i> groups the partner was an interactive remote control car that helped the dog to obtain an otherwise unreachable food. In the (3) <i>Non-helper UMO</i> and (4) Human partner groups dogs had restricted interaction with the remote control car and the unfamiliar human partners. In the <i>Human</i> partner, <i>Helper UMO</i> and <i>Helper UMO Control</i> groups the partners were able to revert dogs’ choice for the small amount by indicating the small one, but the <i>Non-helper UMO</i> was not. We suggest that dogs are able to generalize their wide range of experiences with humans to another type of agent as well, based on the recognition of similarities in simple behavioural patterns.</p></div

The experimental set up.

<p>(a) Phase 2 in the Helper UMO and Helper UMO Control groups, (b) Phase 3: the partner was either a human (E2) or the UMO. The experimental set up in Phase 1 was the same as in Phase 3, but without the presence of the partner. The drawing is not to scale.</p

Choice of the small food quantity in Phase 1 and 3.

<p>Data are only from dogs who chose the larger quantity more often (Phase 1) and the partner indicated the small food quantity in Phase 3; * shows the difference between phases, ¤ shows the difference between groups in Phase 3 (* p<0.05, ** p<0.001, ¤ p<0.01, ¤¤ p<0.001).</p