Extensive training is insufficient to produce the work-ethic effect in pigeons.

Marco and team ran two experiments with pigeons. Birds first learned to peck a key many times for one color and only a few times for another color.

After the birds could tell the two colors apart, the trainers kept going. They gave 60 extra sessions—way past mastery—to see if long practice would make the birds like the hard-work color more.

Even with all that extra training, the pigeons stayed neutral. They picked the high-effort color about half the time—no sign of the so-called “work-ethic” effect.

More sessions did not create a preference; the birds simply did not care which color had cost more work.

Vasconcelos et al. (2007) ran six similar tests and also saw flat choice. Together, the 2007 and 2009 papers form a clean replication chain: pigeons skip the work-ethic bias.

Sanabria et al. (2020) found another blank in pigeon choice—no “distance effect.” All three studies show pigeons ignoring cues that sway human or monkey decisions.

Varley et al. (1980) looks opposite at first glance. Their birds loved options that gave free choice. The twist: free choice added real control, while the work-ethic task only added extra pecks with no new payoff. Same lab, different lever—pigeons notice control, not sweat.

If you use effort requirements with learners, check the payoff. Extra work alone will not create lasting preference; the reward that follows must matter. Before you build “work before play” routines, test whether clients actually value the high-effort path, or if they just tolerate it.