Biology Reference
In-Depth Information
suggests a more general relationship between the sensory and motor
systems of bees.
2.5.7.2 Associative Learning
h e relationship between sucrose re-
sponsiveness and learning is also continuous, not binary. Associative
learning is the response of an individual to the pairing of a stimulus
with a reward (Figure 2.10). Performance on associative-learning as-
says is conditional on the sucrose-response thresholds of the bees.
Honey bees can be conditioned to tactile stimuli or to odors. To study
tactile learning, bees are pretested for their responsiveness to sucrose
solutions and are given a gustatory response score (GRS; the total num-
ber of times they respond while being presented with the series of su-
crose solutions—see Figure 2.7). Each bee then receives an acquisition
score, which is the number of unconditioned stimulus (US)-conditioned
stimulus (CS) pairings that are necessary before the bee presents a con-
ditioned response. Bees that are more responsive to lower concentra-
tions of sucrose and water take fewer trials to acquire a response to the
CS—they have faster acquisition. h us the perceived value of the re-
ward, not the actual value, determines the strength of learning. h e dif-
ference between the concentration of sucrose of ered and the response
threshold of the bee represents the suprathreshold reward value of a su-
crose stimulus. A larger dif erential results in better and more rapid ac-
quisition and better memory retention—a continuous rather than bi-
nary function. h is is true for both tactile and olfactory learning.
h e word
motivation
is ot en used in behavioral studies, especially in
studies of associative learning. A bee that is replete with food is not
motivated to learn. A hungry bee is very motivated. Bees that are re-
plete are less responsive to sugar than those that are hungry, and their
performance on associative-learning tests rel ects this. h eir response
thresholds are modulated by their nutritional status, and the dif erence
between their responsiveness to sugar and the value of sugar reward
af ects their learning. Jochen Erber and I dei ned the dif erence be-
tween response threshold and the reward value as motivation, making
it a relative rather than an absolute concept.
