More than one way to see it: Individual heuristics in avian visual computation

Comparative pattern learning experiments investigate how different species find regularities in sensory input, providing insights into cognitive processing in humans and other animals. Past research has focused either on one species’ ability to process pattern classes or different species’ performance in recognizing the same pattern, with little attention to individual and species-specific heuristics and decision strategies. We trained and tested two bird species, pigeons (Columba livia) and kea (Nestor notabilis, a parrot species), on visual patterns using touch-screen technology. Patterns were composed of several abstract elements and had varying degrees of structural complexity. We developed a model selection paradigm, based on regular expressions, that allowed us to reconstruct the specific decision strategies and cognitive heuristics adopted by a given individual in our task. Individual birds showed considerable differences in the number, type and heterogeneity of heuristic strategies adopted. Birds’ choices also exhibited consistent species-level differences. Kea adopted effective heuristic strategies, based on matching learned bigrams to stimulus edges. Individual pigeons, in contrast, adopted an idiosyncratic mix of strategies that included local transition probabilities and global string similarity. Although performance was above chance and quite high for kea, no individual of either species provided clear evidence of learning exactly the rule used to generate the training stimuli. Our results show that similar behavioral outcomes can be achieved using dramatically different strategies and highlight the dangers of combining multiple individuals in a group analysis. These findings, and our general approach, have implications for the design of future pattern learning experiments, and the interpretation of comparative cognition research more generally

Framing-effects approach: A theoretical and methodological critique

The article deals with research on framing effects. First, I will start with classifying different approaches on framing. Subsequently, I will provide a definition of the concepts of frame, schema and framing, expand on framing research conducted so far - both theoretically and operationally. Having this equipment at hand, I will initiate a discussion on studies of framing-effects in terms of theory, methods and empirical results. This discussion leads to the conclusion that studies on framing effects are insufficiently concerned with the more recent psychological constructs and theories. In merely focusing on the activation of schemata, most studies ignore the more elaborate types of framing-effects. Therefore, several empirical questions remain unanswered and some methodical chances seem to be wasted

Pillars of judgment : how memory abilities, task feedback, and cognitive load guide judgment strategies

Making judgments is an essential part of everyday life and how people form a judgment has instigated a plethora of research. Research in judgment and categorization has particularly contrasted two types of judgment strategies: rule-based and similarity-based strategies. Recent research suggests that people can make use of both rule- and similaritybased strategies and frequently shift between these strategies. To select between strategies, contingency approaches propose that people trade off the strategies’ accuracy against the effort needed to execute strategy so that the selected strategy matches the demands of the task environment and the capabilities of the decision maker. This dissertation presents three papers investigating how accuracy-effort trade-offs between rule-based and similarity-based judgment strategies change strategy selection in judgment and categorization tasks. The first paper studies how reducing working memory by imposing a cognitive load may foster shifts to a less demanding similarity-based strategy and, in turn, enhances judgment performance in tasks well solved by a similarity-based strategy, but not in tasks for which rules are better suited. The second paper compares judgment strategies to strategies people apply in categorization. It shows that the same task characteristics, namely the number of cues and the functional relationship between cues and criterion, foster shifts between rulebased and similarity-based strategies in judgment and categorization. The third manuscript explores which memory abilities underlie rule-based and similarity-based judgments. Specifically, it shows that working memory predicts to a stronger degree how well people solve rule-based judgment tasks, whereas episodic memory is more closely linked to judgment performance in similarity-based tasks. Furthermore, episodic memory also predicts selecting a similarity-based strategy, but not working memory