Crows control working memory before and after stimulus encoding

Abstract

crows control working memory before and after stimulus encoding erica fongaro & Jonas Rose * the capacity of working memory is limited and this limit is comparable in crows and primates. to maximize this resource, humans use attention to select only relevant information for maintenance. Interestingly, attention-cues are effective not only before but also after the presentation of to-beremembered stimuli, highlighting control mechanisms beyond sensory selection. Here we explore if crows are also capable of these forms of control over working memory. two crows (Corvus corone) were trained to memorize two, four or six visual stimuli. comparable to our previous results, the crows showed a decrease in performance with increasing working memory load. Using attention cues, we indicated the critical stimulus on a given trial. these cues were either presented before (pre-cue) or after sample-presentation (retro-cue). on other trials no cue was given as to which stimulus was critical. We found that both pre-and retro-cues enhance the performance of the birds. these results show that crows, like humans, can utilize attention to select relevant stimuli for maintenance in working memory. importantly, crows can also utilize cues to make the most of their working memory capacity even after the stimuli are already held in working memory. This strongly implies that crows can engage in efficient control over working memory. Working memory (WM) refers to the ability to memorize information over short periods and, importantly, to process this information. This makes WM a core component of cognition that is critical for decision making, planning, goal directed behavior and many other cognitive abilities 1,2. It is well established that WM is not a passive storage but that it requires active maintenance of information 3. Consequentially, WM is not only vulnerable to distraction but also limited in duration and in capacity 4-6. It was estimated that healthy humans can maintain about three to five items in working memory 7-11. Capacity-limitation is a critical bottleneck of cognition and has recently been coined the 'bandwidth of cognition' 12,13. In light of these limitations, it is evident that WM must rely on effective top-down control 14. This control can occur in different ways. Attention can act as a 'gatekeeper' that prioritizes the encoding of relevant sensory stimuli and filters out irrelevant information 14-18. While this mechanism is highly effective, it requires prior knowledge about the relevance of upcoming sensory events. If this information is not available at the time of encoding, the system also needs to control the maintenance of information that is already held in WM. In humans, both mechanisms are well established-attention is used to gate stimuli for WM and executive control selects from information already maintained in WM. Pioneering work from Posner and Cohen 19 demonstrated that visual cues facilitate target detection if a location is cued prior to the presentation of the target. Likewise, such 'pre-cues' facil...

Working memory capacity of crows and monkeys arises from similar neuronal computations

“…As we did not use any form of attentional cueing in our study, we cannot explicitly test such an attention effect. However, we do know that the animals participating in this study can use attentional cues to enhance their WM ( Fongaro and Rose, 2020 ). The attention cues used by ( Fongaro and Rose, 2020 ) positively affected not only encoding but also the maintenance and retrieval of the information held in WM, comparable to results from monkeys and humans ( Brady and Hampton, 2018; Souza and Oberauer, 2016 ).…”

Working memory capacity of crows and monkeys arises from similar neuronal computations

“…It is important to clarify that, as we did not use any form of attentional cueing in our study, we cannot explicitly test for such an attention effect. However, we do know that the animals participating in this study can use attentional cues to enhance their WM ( Fongaro and Rose, 2020 ). The attention cues used by Fongaro and Rose, 2020 , positively affected not only encoding but also the maintenance and retrieval of the information held in WM, comparable to results from monkeys and humans ( Brady and Hampton, 2018 ; Souza and Oberauer, 2016 ).…”

“…However, we do know that the animals participating in this study can use attentional cues to enhance their WM ( Fongaro and Rose, 2020 ). The attention cues used by Fongaro and Rose, 2020 , positively affected not only encoding but also the maintenance and retrieval of the information held in WM, comparable to results from monkeys and humans ( Brady and Hampton, 2018 ; Souza and Oberauer, 2016 ). We, therefore, want to emphasize that our data is in line with the interpretation that the birds possibly attended a load 2 stimulus array differently than a load 1 stimulus array in order to enhance their performance in trials with higher loads.…”

Executive Functions in Birds

“…As the packing density of pallial neurons, regardless of pallial, brain or body size, might be the best predictor of cognitive performance [64; 83], these groups of birds cannot be overlooked in research on executive functions, and particularly in large-scale cross-species comparisons (e.g., [30]). Relevant research in the 20th century focused on more basal birds, predominantly pigeons, but more recently, a broader range of bird species, including corvids [97][98][99][100][101][102][103][104], have become involved in studies of EFs.…”