Figure 1.

Latent inhibition. A, Odor conditioning protocol for the LI experiments. The odor was first presented from 0 to 50 times (preconditioning) in different groups of honeybees before applying odor conditioning during the test phase. The protocol for the test phase produces robust and long-lasting associative conditioning (Menzel, 1990). The number of responses across six trials of the test phase, as a function of the number of preconditioning trials, is the measure of LI. B, 3D plot of the recall value versus the number of pre-exposures and the number of training presentations. Performance in honeybees that received 20–30 or more pre-exposures is poorer relative to groups that received fewer pre-exposures. C, Proboscis extension (black) versus no extension (light gray) after different numbers of pre-exposures to the odorant (top to bottom 50, 40, 30, 20, 10, 5, to 1 pre-exposures). Each of the rows represents one honeybee, and each figure shows mean levels of responding over a group of 15–20 honeybees. D, An example of behavior in a subset of honeybees at the transition from not responding to responding.