There are several plausible explanations for the initial evolution of aposematism and warning signals but, since these all have support in the form of experimental evidence, it is unlikely that there is one single, simple evolutionary pathway. I investigated the influence of predator psychology on the design of aposematic signals and concentrated on the effects of (innate) colour preferences, learning and memory, using two species of avian predators: ('naYve') domestic chicks (Gallus domesticus) and wild (and therefore experienced) great tits (Paros major). I found that young chicks had innate preferences for some specific colours that were. more saturated and from the long-wavelength part of the spectrum. Furthermore, these preferences were not based on an effect of contrast with the viewing background. However, I did not observe any colour preferences in the great tits, perhaps because they are naturally a generalist species. Domestic chicks trained with two rewarded colours generalise between them to strongly prefer an intermediate colour. I used this phenomenon to further investigate the learning and memorability of colours in chicks. I found an interesting effect, where there is a delay between an encounter with novel prey and when this experience affects behaviour, which could potentially affect avoidance learning. I additionally investigated the relationship between attractiveness and memorability of coloured signals and found that these are potentially distinct features of warning patterns. Finally, observed how great tits learnt and remembered some typically-aposematic colours and compared this to my findings from the chicks. The great tits not only failed to show any colour preferences, but red, yellow and neutral grey stimuli were also equally well learnt in a discrimination task and remembered. The great tits did not show the same generalisation to an intermediate colour as the chicks, but generalised their learning to the novel colour more strongly when the trained colours were unpalatable than when they were palatable

The effect of neonatal testosterone propionate (TP) (100 ug/day for the first 5 days of life or 1.25 mg. on day 1 of birth) injections on the acquisition of both active and passive avoidance was studied. Testing was initiated during both the prepubescent and adult periods of life. Neonatal TP injections facilitated the acquisition of active avoidance responding prior to puberty and also in adulthood. Neonatal TP injections had no effect on passive avoidance responding. A number of physiological (body, gonadal and adrenal weights) and behavioural (activity, shock sensitivity) measures were also studied to investigate their possible role in influencing our results. The TP injections led to significantly lower gonadal weights in the TP-injected group. Prior to puberty the TP-injected animals also possessed heavier adrenal glands, and were more active than the control group. The TP-injected group also had lower shock thresholds than the control group. The results suggest that excess neonatal TP injections affect an organism's ability to acquire an active avoidance response. The exact mechanism by which TP injections have their effect is unknown at this time. Future research would help to clarify whether the effect of excess neonatal TP is directly on the associative process or indirectly through a number of other factors, investigated in this article. Paradoxically, increased activity would be expected to interfere with the acquisition of passive avoidance behaviour, but this did not prove to be the case as TP injected animals acquired this response just as well or slightly better than controls. The observed differences between groups on shock reactivity measures suggest another plausible explanation of the results. Neonatal TP injections could facilitate acquisition of an active avoidance response by increasing sensitivity to the motivational stimulus. This possibility becomes even more tenable when we consider that other investigators have found a positive correlation between shock sensitivity and learning an active avoidance response (Beatty et. al. 1970, Pare, 1969). Specifically, these investigators have found that females acquire an active avoidance response faster than males and also have lower reactivity thresholds to footshock than males. Our finding of lowered shock sensitivity following neonatal TP injections would appear to parallel these observations and suggests shock sensitivity may be making an important contribution to the active avoidance data. / Arts, Faculty of / Psychology, Department of / Graduate

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

Rats were trained on a four-way shuttle box with a compound light-tone conditioned stimulus (CS) until they emitted 7 avoidance responses in 10 trials (7/10) prior to bilateral ablation of the visual cortex or sham surgery. On Day 5 after surgery, rats were cued with either the compound light-tone CS, the light or tone portion of the CS only, or had no exposure to the CS. On Day 10 after surgery, all animals were tested for avoidance retention under the same conditions as preoperative training. The findings indicate that following a lesion, cueing with the light-tone compound CS facilitates performance as does light alone. Cueing to the tone alone has no effect. In sham animals, only cueing with the light-tone CS was effective in enhancing avoidance retention. Results are interpreted as early and modality-specific sensory cueing may facilitate the recovery process.

The topic of this master thesis was the effects of pattern, size and background contrast of prey on discrimination learning of avian predators. The aim of this study was to investigate the influence of selected components of warning coloration on aversive discrimination learning of avian predators of different age and sex. The choosen model organism was the Great tit (Parus major). The comparision was done between hand-reared naïve birds and wild-caught adults of different age and sex. The experiment was taking place in the experimental cage with one way mirror. The experiment used a design of simultaneous task with two pray which differed in one component of the coloration (pattern, size and background kontrast). The differencies in the ability of discrimination learning was found just between hand-rared naïve birds and wild-caught adults. Better results were shown by the wild-caught adults. The ability of discrimination learning of wild-caught adults was not influenced by the age and sex. Pattern was the only significant component of the warning coloration due to which the birds were able to memorise the discrimination task. Key words: avoidance learning, unpalatable prey, pattern, size, background, contrast

In aposematism a prey species use bright colours, often combined with a black contrasting pattern, to signal unprofitability as prey to potential predators. Although there are several different hypotheses about the presence of these internally contrasting patterns, there is little experimental evidence of any beneficial effects. In this thesis I have used bird predators and artificial prey signals to investigate if the contrasting internal patterns in warning displays may have evolved to increase signal efficacy, especially regarding the speed of avoidance learning. In paper I the relative importance of colour and pattern in avoidance learning was studied. The conclusion was that birds primarily attend to colour, not pattern, when learning the discrimination, which was further supported by the results in paper II-IV, all suggesting a secondary role of patterns. In paper II I show that predators may to some degree use patterns for discrimination, if they convey important information about prey quality. The predators showed a hierarchical way of learning warning colour components, where colour is learned to a higher degree than pattern. In paper III I investigate if internal contrasting patterns promote avoidance learning by increasing conspicuousness as prey-to-background contrast does. The study did not support this idea, as the presence of internal black patterns did not improve avoidance learning on a colour matching background. In paper IV, however, I show that the presence of many internal colour boundaries resulted in faster avoidance learning on a multi-coloured background, and predator generalization favoured more internal boundaries, while there was no effect of pattern regularity. From these studies I conclude that internal pattern contrasts may function to increase the efficacy of the warning colour, its salience, and as a means for aposematic prey to be discriminated from harmful mimics. However, the major finding is the importance of colour over pattern. / <strong><em></em></strong><em></em><em></em>At  the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript; Paper 4: Manuscript<strong><em> </em></strong>

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 6 uppsatser.

Following a cortical injury, neurons in areas near and connected to the site of injury begin to degenerate. The observed neuronal death may contribute to the severity of the observed behavioral impairments. The purpose of the present study was to examine if progesterone, a hormone known for its effectiveness at reducing cerebral edema, could protect against secondary neuronal death and facilitate the acquisition of an avoidance learning task in an ablation model of cortical injury. Rats served as sham controls or received bilateral ablation of the medial prefrontal cortex followed by a 10-day regimen of progesterone (4 mg/kg) or oil vehicle (1 ml/kg) beginning 1 h after cortical lesions. Progesterone-treated lesion rats showed a significant facilitation of avoidance learning compared to oil- treated lesion controls. In addition, progesterone-treated lesion animals did not differ from either progesterone- or oil-treated sham controls in avoidance learning. Anatomical analysis revealed that progesterone treatment decreased the amount of neuronal death seen in the striatum and the mediodorsal nucleus of the thalamus. The findings are consistent with the notion that progesterone is an effective neuroprotective agent and suggest that the hormone can reduce the behavioral impairments associated with frontal cortical ablation injury.

yes / This paper considers the importance of applying sound instructional systems design to the development of a learning intervention aimed at developing skills for the effective deployment of an enhanced methodology for engineering systems design analysis within a Product Development context. The leading features of the learning intervention are summarised including the content and design of a training course for senior engineering management which is central to the intervention. The importance of promoting behavioural change by fostering meaningful learning as a collaborative process is discussed. Comparison is made between the instructional design of the corporate learning intervention being developed and the systems engineering based product design process which is the subject of the intervention.

The ability to memorize and recognize edible prey from inedible prey is essential for an individuals survival. Many species use aposematic signals for their defense. These are most often represented by distinctive colors or contrast patterns. The aim of this study was to find out in which time the memory consolidation for aposematic pray is achieved and if color or pattern increase its memorability. The choosen model species was the Great tit (Parus major). The comparision was done between handreared naïve birds and wild-caught adults of different age and sex. During the discriminatory task of consolidation experiment, birds were simultaneously presented with palatable and unpalatable prey in the form of paper dummies of bugs, differing in color (red versus green). The birds were divided into three groups with a different interval (0, 1 or 3 hours) for consolidation. The results of consolidation test show that adult birds were more successfull in solving the task than juvenile birds. The only difference between the experimental groups was that the group with one-hour interval achieved better results than other groups. The effect of color of palatable and unpalatable prey on discrimination learning was also found only in adults. Memorability of warning signals was tested using paper bugs of...