Can the reward associated with gaze leading train faster gaze shifts to a jointly attended target?

We investigated whether the reward that has previously been associated with initiated joint attention (the experience of having one’s gaze followed by someone else; Pfeiffer et al., 2014, Schilbach et al., 2010) can influence gaze behaviour and, similarly to monetary rewards (Blaukopf & DiGirolamo, 2005; Manohar et al., 2017; Milstein & Dorris, 2007), elicit learning effects. To this end, we adapted Milstein and Dorris (2007) gaze contingent paradigm, so it required participants to look at an anthropomorphic avatar and then conduct a saccade towards the left or right peripheral target. If participants were fast enough, they could experience social reward in terms of the avatar looking at the same target as they did and thus engaging with them in joint attention. One side had higher reward probability than the other (80 % vs 20 %; on the other fast trials the avatar would simply keep staring ahead). We expected that if participants learned about the reward contingency and if they found the experience of having their gaze followed rewarding, their latency and success rate would improve for saccades to the high rewarded targets. Although our current study did not demonstrate that such social reward has a long lasting effect on gaze behaviour, we found that latencies became shorter over time and that latencies were longer on congruent trials (target location was identical to the previous trial) than on noncongruent trials (target location different than on the previous trial), which could reflect inhibition of return.