In tactile learning, sucrose is the unconditioned stimulus and reward, which is usually applied to the antenna to elicit proboscis extension and which the bee can drink when it is subsequently applied to the extended proboscis. The conditioned stimulus is a tactile object that the bee can scan with its antennae. In this paper we describe the quantitative relationships between gustatory antennal stimulation, gustatory proboscis stimulation, and tactile learning and memory. Bees are 10-fold more responsive to sucrose solutions when they are applied to the antenna compared to proboscis stimulation. During tactile conditioning, the sucrose solution applied to the proboscis determines the level of acquisition, whereas antennal input is of minor importance. Bees differing in their gustatory responsiveness measured at the antenna differ strongly in their tactile acquisition and memory. We demonstrate how these differences in tactile acquisition and memory can be greatly reduced by calculating equal subjective rewards, based on individual gustatory responsiveness.Learning in animals depends on many factors including the salience of the conditioned stimulus (CS) and the strength of the unconditioned stimulus (US) (Rescorla and Wagner 1972). Even under controlled laboratory conditions, individuals show variance in the rate of acquisition, the asymptote of acquisition, and in retention (Scheiner et al. 2001a(Scheiner et al. ,b, 2003Matzel et al. 2003;Hedden and Gabrieli 2004;Dellu-Hagedorn 2005). Multiple intrinsic factors can contribute to these behavioral differences. Some of these factors may be related to individual differences in evaluating CS and US (Scheiner et al. 1999;Chester et al. 2003). These differences could reflect genetic heterogeneity at the individual level.Studies in honeybees (Apis mellifera L.) can be very useful to identify important factors leading to inter-individual learning differences and their potential sources of control. Associative learning plays an important part in honeybee behavior. Bees learn very fast the location of a foraging site and the numerous characteristics of reward-yielding plants (for review, see Menzel

Flying an aircraft is an often targeted domain for the study of skilled human performance in general and for applied problems of spatial cognition in particular. The flight-deck crew's spatial awareness is mainly informed by the outside view and the primary flight instruments (PFI) with the latter becoming the sole source of spatial information in low-visibility weather conditions. The transparent and collimated head-up display (HUD) and the 3-D perspective pathway-in-the-sky representation format are two wellstudied innovative display concepts with proven evidence of promoting improved spatial awareness of pilots. However, there is also evidence that both display concepts are associated with a sub-optimal distribution of the pilot's visual attention resources between PFI and outside view. In case of the HUD, a delayed or even missing detection of unanticipated events in the outside view has been found. This deficiency has been attributed to attention fixation to the HUD triggered by the presence of differential motion between the static near domain PFI and the dynamic far domain outside world. A pathway-induced attention fixation to head-down views, likewise occurring at the expense of event detection in the outside, has been attributed to the very compelling character of the pathway attracting an undue amount of the pilot's attention resources.These findings raise the question whether a combined pathway-HUD amplifies attention fixation problems with the effect of potentially offsetting the independent and conclusively established benefits of both display concepts. The aim of the present study was to test the hypothesis that HUD symbology that is presented scene-linked, thus moves as virtual instrument gauges in the outside scene can promote a better distribution of attention between both visual domains. Such an advantage has been substantiated in simulated aircraft operation on the airport surface where a pathway of runway route markers was overlaid to the existing runway edges. We developed a part-task simulation to investigate an airborne application of this concept using the pathway-in-the-sky as an outside-world referent for the projection of virtual PFI in the world. Experienced pilots (N = 14) flew a series of low-altitude curved trajectories through mountainous terrain and had to detect display events (discrete changes in a command speed indicator to be matched with current speed) and outside scene events (hostile SAM stations on ground). The speed indicator was either superimposed with a fixed HUD-location or attached to the pathway, thus underwent the same visual transformation as the object elements of the pathway during the dynamics of the flight. Outside scene event detection was superior using PFI with a scene-linked HUD location as compared to a fixed-HUD location, however, flight-path tracking was markedly deteriorated. Reasons for and means to cope with this performance trade-off will be discussed.

Pathway-in-the-sky displays enable pilots to accurately fly difficult trajectories. However, these displays may drive pilots' attention to the aircraft guidance task at the expense of other tasks particularly when the pathway display is located head-down. A pathway HUD may be a viable solution to overcome this disadvantage. Moreover, the pathway may mitigate the perceptual segregation between the static near domain and the dynamic far domain and hence, may improve attention switching between both sources. In order to more comprehensively overcome the perceptual near-tofar domain disconnect alphanumeric symbols could be attached to the pathway leading to a HUD design concept called 'scene-linking'. Two studies are presented that investigated this concept. The first study used a simplified laboratory flight experiment. Pilots (N=14) flew a curved trajectory through mountainous terrain and had to detect display events (discrete changes in a command speed indicator to be matched with current speed) and outside scene events (hostile SAM station on ground). The speed indicators were presented in superposition to the scenery either in fixed position or scene-linked to the pathway. Outside scene event detection was found improved with scene linking, however, flightpath tracking was markedly deteriorated. In the second study a scene-linked pathway concept was implemented on a monocular retinal scanning HMD and tested in real flights on a Do228 involving 5 test pilots. The flight test mainly focused at usability issues of the display in combination with an optical head tracker. Visual and instrument departure and approach tasks were evaluated comparing HMD navigation with standard instrument or terrestrial navigation. The study revealed limitations of the HMD regarding its see-through capability, field of view, weight and wearing comfort that showed to have a strong influence on pilot acceptance rather than rebutting the approach of the display concept as such.